void return - Page 95 - Developer IT

Why do I get a WCF timeout even though my service call and callback are successful?

- by KallDrexx

I'm playing around with hooking up an in-game console to a WCF interface, so an external application can send console commands and receive console output. To accomplish this I created the following service contracts: public interface IConsoleNetworkCallbacks { [OperationContract(IsOneWay = true)] void NewOutput(IEnumerable<string> text, string category); } [ServiceContract(SessionMode = SessionMode.Required, CallbackContract = typeof(IConsoleNetworkCallbacks))] public interface IConsoleInterface { [OperationContract] void ProcessInput(string input); [OperationContract] void ChangeCategory(string category); } On the server I implemented it with: public class ConsoleNetworkInterface : IConsoleInterface, IDisposable { public ConsoleNetworkInterface() { ConsoleManager.Instance.RegisterOutputUpdateHandler(OutputHandler); } public void Dispose() { ConsoleManager.Instance.UnregisterOutputHandler(OutputHandler); } public void ProcessInput(string input) { ConsoleManager.Instance.ProcessInput(input); } public void ChangeCategory(string category) { ConsoleManager.Instance.UnregisterOutputHandler(OutputHandler); ConsoleManager.Instance.RegisterOutputUpdateHandler(OutputHandler, category); } protected void OutputHandler(IEnumerable<string> text, string category) { var callbacks = OperationContext.Current.GetCallbackChannel<IConsoleNetworkCallbacks>(); callbacks.NewOutput(text, category); } } On the client I implemented the callback with: public class Callbacks : IConsoleNetworkCallbacks { public void NewOutput(IEnumerable<string> text, string category) { MessageBox.Show(string.Format("{0} lines received for '{1}' category", text.Count(), category)); } } Finally, I establish the service host with the following class: public class ConsoleServiceHost : IDisposable { protected ServiceHost _host; public ConsoleServiceHost() { _host = new ServiceHost(typeof(ConsoleNetworkInterface), new Uri[] { new Uri("net.pipe://localhost") }); _host.AddServiceEndpoint(typeof(IConsoleInterface), new NetNamedPipeBinding(), "FrbConsolePipe"); _host.Open(); } public void Dispose() { _host.Close(); } } and use the following code on my client to establish the connection: protected Callbacks _callbacks; protected IConsoleInterface _proxy; protected void ConnectToConsoleServer() { _callbacks = new Callbacks(); var factory = new DuplexChannelFactory<IConsoleInterface>(_callbacks, new NetNamedPipeBinding(), new EndpointAddress("net.pipe://localhost/FrbConsolePipe")); _proxy = factory.CreateChannel(); _proxy.ProcessInput("Connected"); } So what happens is that my ConnectToConsoleServer() is called and then it gets all the way to _proxy.ProcessInput("Connected");. In my game (on the server) I immediately see the output caused by the ProcessInput call, but the client is still stalled on the _proxy.ProcessInput() call. After a minute my client gets a JIT TimeoutException however at the same time my MessageBox message appears. So obviously not only is my command being sent immediately, my callback is being correctly called. So why am I getting a timeout exception? Note: Even removing the MessageBox call, I still have this issue, so it's not an issue of the GUI blocking the callback response.

Read the article

StreamWriter appends random data

- by void

Hi I'm seeing odd behaviour using the StreamWriter class writing extra data to a file using this code: public void WriteToCSV(string filename) { StreamWriter streamWriter = null; try { streamWriter = new StreamWriter(filename); Log.Info("Writing CSV report header information ... "); streamWriter.WriteLine("\"{0}\",\"{1}\",\"{2}\",\"{3}\"", ((int)CSVRecordType.Header).ToString("D2", CultureInfo.CurrentCulture), m_InputFilename, m_LoadStartDate, m_LoadEndDate); int recordCount = 0; if (SummarySection) { Log.Info("Writing CSV report summary section ... "); foreach (KeyValuePair<KeyValuePair<LoadStatus, string>, CategoryResult> categoryResult in m_DataLoadResult.DataLoadResults) { streamWriter.WriteLine("\"{0}\",\"{1}\",\"{2}\",\"{3}\"", ((int)CSVRecordType.Summary).ToString("D2", CultureInfo.CurrentCulture), categoryResult.Value.StatusString, categoryResult.Value.Count.ToString(CultureInfo.CurrentCulture), categoryResult.Value.Category); recordCount++; } } Log.Info("Writing CSV report cases section ... "); foreach (KeyValuePair<KeyValuePair<LoadStatus, string>, CategoryResult> categoryResult in m_DataLoadResult.DataLoadResults) { foreach (CaseLoadResult result in categoryResult.Value.CaseLoadResults) { if ((LoadStatus.Success == result.Status && SuccessCases) || (LoadStatus.Warnings == result.Status && WarningCases) || (LoadStatus.Failure == result.Status && FailureCases) || (LoadStatus.NotProcessed == result.Status && NotProcessedCases)) { streamWriter.Write("\"{0}\",\"{1}\",\"{2}\",\"{3}\",\"{4}\"", ((int)CSVRecordType.Result).ToString("D2", CultureInfo.CurrentCulture), result.Status, result.UniqueId, result.Category, result.ClassicReference); if (RawResponse) { streamWriter.Write(",\"{0}\"", result.ResponseXml); } streamWriter.WriteLine(); recordCount++; } } } streamWriter.WriteLine("\"{0}\",\"{1}\"", ((int)CSVRecordType.Count).ToString("D2", CultureInfo.CurrentCulture), recordCount); Log.Info("CSV report written to '{0}'", fileName); } catch (IOException execption) { string errorMessage = string.Format(CultureInfo.CurrentCulture, "Unable to write XML report to '{0}'", fileName); Log.Error(errorMessage); Log.Error(exception.Message); throw new MyException(errorMessage, exception); } finally { if (null != streamWriter) { streamWriter.Close(); } } } The file produced contains a set of records on each line 0 to N, for example: [Record Zero] [Record One] ... [Record N] However the file produced either contains nulls or incomplete records from further up the file appended to the end. For example: [Record Zero] [Record One] ... [Record N] [Lots of nulls] or [Record Zero] [Record One] ... [Record N] [Half complete records] This also happens in separate pieces of code that also use the StreamWriter class. Furthermore, the files produced all have sizes that are multiples of 1024. I've been unable to reproduce this behaviour on any other machine and have tried recreating the environment. Previous versions of the application didn't exhibite this behaviour despite having the same code for the methods in question. EDIT: Added extra code.

Read the article

Implement delegates for Core Data or not

- by Spanky

What advantage is there to implementing the four delegate methods: (void)controllerWillChangeContent:(NSFetchedResultsController *)controller (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id )sectionInfo atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type newIndexPath:(NSIndexPath *)newIndexPath (void)controllerDidChangeContent:(NSFetchedResultsController *)controller rather than implement: (void)controllerDidChangeContent:(NSFetchedResultsController *)controller Any help appreciated // :)

Read the article

Why can't I make my parameter like this?

- by mystify

- (void)setPropertyValue:(const *void)inValue forID:(UInt32)propertyID { } The compiler doesn't like the const *void, for some reason. When I have that, it says: error: expected ')' before 'void' When I make the parameter like (UInt32)foo there is no problem. Does const *void only work in functions? I need a parameter which can be a "pointer to anything" like UInt32, Float64, etc.

Read the article

Inserting data into a Database

- by Erebus

SO I'm making a "basic" login file where a person logs in and the data that person entered on that form gets transfered to another form aka my database/table. I think the problems is here but I'll post the rest of the code. CREATE FUNCTION dbo.Function4 ( parameter1 int = 5, parameter2 datatype ) RETURNS Table1 TABLE (UserName, Password, Password_Confirmation, Assets) AS BEGIN INSERT INTO Table1 (UserName, Password, Password_Confirmation, Assets) VALUES (a,b,c,d); /*SELECT ... FROM ...*/ RETURN END This is the Login Form using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; namespace Login_Basic { public partial class Form2 : Form { public Form2() { InitializeComponent(); } Form3 Delta = new Form3(); private void label3_Click(object sender, EventArgs e) { } private void Form2_Load(object sender, EventArgs e) { this.Hide(); } private void textBox6_TextChanged(object sender, EventArgs e) { } private void textBox6_KeyPress(object sender, KeyPressEventArgs e) { int i = Convert.ToInt32(e.KeyChar); if (!(Char.IsDigit(e.KeyChar) || Char.IsControl(e.KeyChar) || (e.KeyChar == '.' && this.Text.Contains(".") == false))) e.Handled = true; } private void button1_Click(object sender, EventArgs e) { Delta.Show(); //if (textBox3.Text.Equals("")) //{ // MessageBox.Show("Please enter your username"); //} //else //{ // this.Hide(); //} // if (textBox4.Text.Equals("")) //{ // MessageBox.Show("Please enter your password"); // } // else //{ // this.Hide(); // } // if (textBox5.Text.Equals("")) // { // MessageBox.Show("Please re-enter your password"); // } // else // { // this.Hide(); // } //if (textBox6.Text.Equals("")) //{ // MessageBox.Show("Please enter your amount"); // // } // else // { // this.Hide(); // } } private void button3_Click(object sender, EventArgs e) { this.Hide(); } private void textBox3_TextChanged(object sender, EventArgs e) { } private void textBox4_TextChanged(object sender, EventArgs e) { } private void textBox5_TextChanged(object sender, EventArgs e) { } private void panel2_Paint(object sender, PaintEventArgs e) { /*if (textBox3.Text.Equals("") && textBox4.Text.Equals("") && textBox5.Text.Equals("") && textBox6.Text.Equals("")) { button1.Enabled = false; } else { button1.Enabled = true; }*/ } } } Here's a "Pic" of my database http://s299.photobucket.com/albums/mm305/krsimms123/Code.jpg Thanks in advance (I'll try and check this every few hours so I can help explain anything)

Read the article

How can I call a method given only its name?

- by mfolnovich

I'm trying to have method void run( string method ) which would run method in that class. For example: class Foo { public: void run( string method ) { // this method calls method *method* from this class } void bar() { printf( "Function bar\n" ); } void foo2() { printf( "Function foo2\n" ); } } Foo foo; int main( void ) { foo.run( "bar" ); foo.run( "foo2" ); } this would print: Function bar Function foo2 Thanks! :)

Read the article

Writting a getter for a pointer to a function .

- by nomemory

I have the following problem: "list.c" struct nmlist_element_s { void *data; struct nmlist_element_s *next; }; struct nmlist_s { nmlist_element *head; nmlist_element *tail; unsigned int size; void (*destructor)(void *data); int (*match)(const void *e1, const void *e2); }; /*** Other code ***/ What will be the signature for a function that returns 'destructor' ?

Read the article

Writing Unit Tests for ASP.NET Web API Controller

- by shiju

In this blog post, I will write unit tests for a ASP.NET Web API controller in the EFMVC reference application. Let me introduce the EFMVC app, If you haven't heard about EFMVC. EFMVC is a simple app, developed as a reference implementation for demonstrating ASP.NET MVC, EF Code First, ASP.NET Web API, Domain-Driven Design (DDD), Test-Driven Development (DDD). The current version is built with ASP.NET MVC 4, EF Code First 5, ASP.NET Web API, Autofac, AutoMapper, Nunit and Moq. All unit tests were written with Nunit and Moq. You can download the latest version of the reference app from http://efmvc.codeplex.com/ Unit Test for HTTP Get Let’s write a unit test class for verifying the behaviour of a ASP.NET Web API controller named CategoryController. Let’s define mock implementation for Repository class, and a Command Bus that is used for executing write operations. [TestFixture] public class CategoryApiControllerTest { private Mock<ICategoryRepository> categoryRepository; private Mock<ICommandBus> commandBus; [SetUp] public void SetUp() { categoryRepository = new Mock<ICategoryRepository>(); commandBus = new Mock<ICommandBus>(); } The code block below provides the unit test for a HTTP Get operation. [Test] public void Get_All_Returns_AllCategory() { // Arrange IEnumerable<CategoryWithExpense> fakeCategories = GetCategories(); categoryRepository.Setup(x => x.GetCategoryWithExpenses()).Returns(fakeCategories); CategoryController controller = new CategoryController(commandBus.Object, categoryRepository.Object) { Request = new HttpRequestMessage() { Properties = { { HttpPropertyKeys.HttpConfigurationKey, new HttpConfiguration() } } } }; // Act var categories = controller.Get(); // Assert Assert.IsNotNull(categories, "Result is null"); Assert.IsInstanceOf(typeof(IEnumerable<CategoryWithExpense>),categories, "Wrong Model"); Assert.AreEqual(3, categories.Count(), "Got wrong number of Categories"); } The GetCategories method is provided below: private static IEnumerable<CategoryWithExpense> GetCategories() { IEnumerable<CategoryWithExpense> fakeCategories = new List<CategoryWithExpense> { new CategoryWithExpense {CategoryId=1, CategoryName = "Test1", Description="Test1Desc", TotalExpenses=1000}, new CategoryWithExpense {CategoryId=2, CategoryName = "Test2", Description="Test2Desc",TotalExpenses=2000}, new CategoryWithExpense { CategoryId=3, CategoryName = "Test3", Description="Test3Desc",TotalExpenses=3000} }.AsEnumerable(); return fakeCategories; } In the unit test method Get_All_Returns_AllCategory, we specify setup on the mocked type ICategoryrepository, for a call to GetCategoryWithExpenses method returns dummy data. We create an instance of the ApiController, where we have specified the Request property of the ApiController since the Request property is used to create a new HttpResponseMessage that will provide the appropriate HTTP status code along with response content data. Unit Tests are using for specifying the behaviour of components so that we have specified that Get operation will use the model type IEnumerable<CategoryWithExpense> for sending the Content data. The implementation of HTTP Get in the CategoryController is provided below: public IQueryable<CategoryWithExpense> Get() { var categories = categoryRepository.GetCategoryWithExpenses().AsQueryable(); return categories; } Unit Test for HTTP Post The following are the behaviours we are going to implement for the HTTP Post: A successful HTTP Post operation should return HTTP status code Created An empty Category should return HTTP status code BadRequest A successful HTTP Post operation should provide correct Location header information in the response for the newly created resource. Writing unit test for HTTP Post is required more information than we write for HTTP Get. In the HTTP Post implementation, we will call to Url.Link for specifying the header Location of Response as shown in below code block. var response = Request.CreateResponse(HttpStatusCode.Created, category); string uri = Url.Link("DefaultApi", new { id = category.CategoryId }); response.Headers.Location = new Uri(uri); return response; While we are executing Url.Link from unit tests, we have to specify HttpRouteData information from the unit test method. Otherwise, Url.Link will get a null value. The code block below shows the unit tests for specifying the behaviours for the HTTP Post operation. [Test] public void Post_Category_Returns_CreatedStatusCode() { // Arrange commandBus.Setup(c => c.Submit(It.IsAny<CreateOrUpdateCategoryCommand>())).Returns(new CommandResult(true)); Mapper.CreateMap<CategoryFormModel, CreateOrUpdateCategoryCommand>(); var httpConfiguration = new HttpConfiguration(); WebApiConfig.Register(httpConfiguration); var httpRouteData = new HttpRouteData(httpConfiguration.Routes["DefaultApi"], new HttpRouteValueDictionary { { "controller", "category" } }); var controller = new CategoryController(commandBus.Object, categoryRepository.Object) { Request = new HttpRequestMessage(HttpMethod.Post, "http://localhost/api/category/") { Properties = { { HttpPropertyKeys.HttpConfigurationKey, httpConfiguration }, { HttpPropertyKeys.HttpRouteDataKey, httpRouteData } } } }; // Act CategoryModel category = new CategoryModel(); category.CategoryId = 1; category.CategoryName = "Mock Category"; var response = controller.Post(category); // Assert Assert.AreEqual(HttpStatusCode.Created, response.StatusCode); var newCategory = JsonConvert.DeserializeObject<CategoryModel>(response.Content.ReadAsStringAsync().Result); Assert.AreEqual(string.Format("http://localhost/api/category/{0}", newCategory.CategoryId), response.Headers.Location.ToString()); } [Test] public void Post_EmptyCategory_Returns_BadRequestStatusCode() { // Arrange commandBus.Setup(c => c.Submit(It.IsAny<CreateOrUpdateCategoryCommand>())).Returns(new CommandResult(true)); Mapper.CreateMap<CategoryFormModel, CreateOrUpdateCategoryCommand>(); var httpConfiguration = new HttpConfiguration(); WebApiConfig.Register(httpConfiguration); var httpRouteData = new HttpRouteData(httpConfiguration.Routes["DefaultApi"], new HttpRouteValueDictionary { { "controller", "category" } }); var controller = new CategoryController(commandBus.Object, categoryRepository.Object) { Request = new HttpRequestMessage(HttpMethod.Post, "http://localhost/api/category/") { Properties = { { HttpPropertyKeys.HttpConfigurationKey, httpConfiguration }, { HttpPropertyKeys.HttpRouteDataKey, httpRouteData } } } }; // Act CategoryModel category = new CategoryModel(); category.CategoryId = 0; category.CategoryName = ""; // The ASP.NET pipeline doesn't run, so validation don't run. controller.ModelState.AddModelError("", "mock error message"); var response = controller.Post(category); // Assert Assert.AreEqual(HttpStatusCode.BadRequest, response.StatusCode); } In the above code block, we have written two unit methods, Post_Category_Returns_CreatedStatusCode and Post_EmptyCategory_Returns_BadRequestStatusCode. The unit test method Post_Category_Returns_CreatedStatusCode verifies the behaviour 1 and 3, that we have defined in the beginning of the section “Unit Test for HTTP Post”. The unit test method Post_EmptyCategory_Returns_BadRequestStatusCode verifies the behaviour 2. For extracting the data from response, we call Content.ReadAsStringAsync().Result of HttpResponseMessage object and deserializeit it with Json Convertor. The implementation of HTTP Post in the CategoryController is provided below: // POST /api/category public HttpResponseMessage Post(CategoryModel category) { if (ModelState.IsValid) { var command = new CreateOrUpdateCategoryCommand(category.CategoryId, category.CategoryName, category.Description); var result = commandBus.Submit(command); if (result.Success) { var response = Request.CreateResponse(HttpStatusCode.Created, category); string uri = Url.Link("DefaultApi", new { id = category.CategoryId }); response.Headers.Location = new Uri(uri); return response; } } else { return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState); } throw new HttpResponseException(HttpStatusCode.BadRequest); } The unit test implementation for HTTP Put and HTTP Delete are very similar to the unit test we have written for HTTP Get. The complete unit tests for the CategoryController is given below: [TestFixture] public class CategoryApiControllerTest { private Mock<ICategoryRepository> categoryRepository; private Mock<ICommandBus> commandBus; [SetUp] public void SetUp() { categoryRepository = new Mock<ICategoryRepository>(); commandBus = new Mock<ICommandBus>(); } [Test] public void Get_All_Returns_AllCategory() { // Arrange IEnumerable<CategoryWithExpense> fakeCategories = GetCategories(); categoryRepository.Setup(x => x.GetCategoryWithExpenses()).Returns(fakeCategories); CategoryController controller = new CategoryController(commandBus.Object, categoryRepository.Object) { Request = new HttpRequestMessage() { Properties = { { HttpPropertyKeys.HttpConfigurationKey, new HttpConfiguration() } } } }; // Act var categories = controller.Get(); // Assert Assert.IsNotNull(categories, "Result is null"); Assert.IsInstanceOf(typeof(IEnumerable<CategoryWithExpense>),categories, "Wrong Model"); Assert.AreEqual(3, categories.Count(), "Got wrong number of Categories"); } [Test] public void Get_CorrectCategoryId_Returns_Category() { // Arrange IEnumerable<CategoryWithExpense> fakeCategories = GetCategories(); categoryRepository.Setup(x => x.GetCategoryWithExpenses()).Returns(fakeCategories); CategoryController controller = new CategoryController(commandBus.Object, categoryRepository.Object) { Request = new HttpRequestMessage() { Properties = { { HttpPropertyKeys.HttpConfigurationKey, new HttpConfiguration() } } } }; // Act var response = controller.Get(1); // Assert Assert.AreEqual(HttpStatusCode.OK, response.StatusCode); var category = JsonConvert.DeserializeObject<CategoryWithExpense>(response.Content.ReadAsStringAsync().Result); Assert.AreEqual(1, category.CategoryId, "Got wrong number of Categories"); } [Test] public void Get_InValidCategoryId_Returns_NotFound() { // Arrange IEnumerable<CategoryWithExpense> fakeCategories = GetCategories(); categoryRepository.Setup(x => x.GetCategoryWithExpenses()).Returns(fakeCategories); CategoryController controller = new CategoryController(commandBus.Object, categoryRepository.Object) { Request = new HttpRequestMessage() { Properties = { { HttpPropertyKeys.HttpConfigurationKey, new HttpConfiguration() } } } }; // Act var response = controller.Get(5); // Assert Assert.AreEqual(HttpStatusCode.NotFound, response.StatusCode); } [Test] public void Post_Category_Returns_CreatedStatusCode() { // Arrange commandBus.Setup(c => c.Submit(It.IsAny<CreateOrUpdateCategoryCommand>())).Returns(new CommandResult(true)); Mapper.CreateMap<CategoryFormModel, CreateOrUpdateCategoryCommand>(); var httpConfiguration = new HttpConfiguration(); WebApiConfig.Register(httpConfiguration); var httpRouteData = new HttpRouteData(httpConfiguration.Routes["DefaultApi"], new HttpRouteValueDictionary { { "controller", "category" } }); var controller = new CategoryController(commandBus.Object, categoryRepository.Object) { Request = new HttpRequestMessage(HttpMethod.Post, "http://localhost/api/category/") { Properties = { { HttpPropertyKeys.HttpConfigurationKey, httpConfiguration }, { HttpPropertyKeys.HttpRouteDataKey, httpRouteData } } } }; // Act CategoryModel category = new CategoryModel(); category.CategoryId = 1; category.CategoryName = "Mock Category"; var response = controller.Post(category); // Assert Assert.AreEqual(HttpStatusCode.Created, response.StatusCode); var newCategory = JsonConvert.DeserializeObject<CategoryModel>(response.Content.ReadAsStringAsync().Result); Assert.AreEqual(string.Format("http://localhost/api/category/{0}", newCategory.CategoryId), response.Headers.Location.ToString()); } [Test] public void Post_EmptyCategory_Returns_BadRequestStatusCode() { // Arrange commandBus.Setup(c => c.Submit(It.IsAny<CreateOrUpdateCategoryCommand>())).Returns(new CommandResult(true)); Mapper.CreateMap<CategoryFormModel, CreateOrUpdateCategoryCommand>(); var httpConfiguration = new HttpConfiguration(); WebApiConfig.Register(httpConfiguration); var httpRouteData = new HttpRouteData(httpConfiguration.Routes["DefaultApi"], new HttpRouteValueDictionary { { "controller", "category" } }); var controller = new CategoryController(commandBus.Object, categoryRepository.Object) { Request = new HttpRequestMessage(HttpMethod.Post, "http://localhost/api/category/") { Properties = { { HttpPropertyKeys.HttpConfigurationKey, httpConfiguration }, { HttpPropertyKeys.HttpRouteDataKey, httpRouteData } } } }; // Act CategoryModel category = new CategoryModel(); category.CategoryId = 0; category.CategoryName = ""; // The ASP.NET pipeline doesn't run, so validation don't run. controller.ModelState.AddModelError("", "mock error message"); var response = controller.Post(category); // Assert Assert.AreEqual(HttpStatusCode.BadRequest, response.StatusCode); } [Test] public void Put_Category_Returns_OKStatusCode() { // Arrange commandBus.Setup(c => c.Submit(It.IsAny<CreateOrUpdateCategoryCommand>())).Returns(new CommandResult(true)); Mapper.CreateMap<CategoryFormModel, CreateOrUpdateCategoryCommand>(); CategoryController controller = new CategoryController(commandBus.Object, categoryRepository.Object) { Request = new HttpRequestMessage() { Properties = { { HttpPropertyKeys.HttpConfigurationKey, new HttpConfiguration() } } } }; // Act CategoryModel category = new CategoryModel(); category.CategoryId = 1; category.CategoryName = "Mock Category"; var response = controller.Put(category.CategoryId,category); // Assert Assert.AreEqual(HttpStatusCode.OK, response.StatusCode); } [Test] public void Delete_Category_Returns_NoContentStatusCode() { // Arrange commandBus.Setup(c => c.Submit(It.IsAny<DeleteCategoryCommand >())).Returns(new CommandResult(true)); CategoryController controller = new CategoryController(commandBus.Object, categoryRepository.Object) { Request = new HttpRequestMessage() { Properties = { { HttpPropertyKeys.HttpConfigurationKey, new HttpConfiguration() } } } }; // Act var response = controller.Delete(1); // Assert Assert.AreEqual(HttpStatusCode.NoContent, response.StatusCode); } private static IEnumerable<CategoryWithExpense> GetCategories() { IEnumerable<CategoryWithExpense> fakeCategories = new List<CategoryWithExpense> { new CategoryWithExpense {CategoryId=1, CategoryName = "Test1", Description="Test1Desc", TotalExpenses=1000}, new CategoryWithExpense {CategoryId=2, CategoryName = "Test2", Description="Test2Desc",TotalExpenses=2000}, new CategoryWithExpense { CategoryId=3, CategoryName = "Test3", Description="Test3Desc",TotalExpenses=3000} }.AsEnumerable(); return fakeCategories; } } The complete implementation for the Api Controller, CategoryController is given below: public class CategoryController : ApiController { private readonly ICommandBus commandBus; private readonly ICategoryRepository categoryRepository; public CategoryController(ICommandBus commandBus, ICategoryRepository categoryRepository) { this.commandBus = commandBus; this.categoryRepository = categoryRepository; } public IQueryable<CategoryWithExpense> Get() { var categories = categoryRepository.GetCategoryWithExpenses().AsQueryable(); return categories; } // GET /api/category/5 public HttpResponseMessage Get(int id) { var category = categoryRepository.GetCategoryWithExpenses().Where(c => c.CategoryId == id).SingleOrDefault(); if (category == null) { return Request.CreateResponse(HttpStatusCode.NotFound); } return Request.CreateResponse(HttpStatusCode.OK, category); } // POST /api/category public HttpResponseMessage Post(CategoryModel category) { if (ModelState.IsValid) { var command = new CreateOrUpdateCategoryCommand(category.CategoryId, category.CategoryName, category.Description); var result = commandBus.Submit(command); if (result.Success) { var response = Request.CreateResponse(HttpStatusCode.Created, category); string uri = Url.Link("DefaultApi", new { id = category.CategoryId }); response.Headers.Location = new Uri(uri); return response; } } else { return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState); } throw new HttpResponseException(HttpStatusCode.BadRequest); } // PUT /api/category/5 public HttpResponseMessage Put(int id, CategoryModel category) { if (ModelState.IsValid) { var command = new CreateOrUpdateCategoryCommand(category.CategoryId, category.CategoryName, category.Description); var result = commandBus.Submit(command); return Request.CreateResponse(HttpStatusCode.OK, category); } else { return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState); } throw new HttpResponseException(HttpStatusCode.BadRequest); } // DELETE /api/category/5 public HttpResponseMessage Delete(int id) { var command = new DeleteCategoryCommand { CategoryId = id }; var result = commandBus.Submit(command); if (result.Success) { return new HttpResponseMessage(HttpStatusCode.NoContent); } throw new HttpResponseException(HttpStatusCode.BadRequest); } } Source Code The EFMVC app can download from http://efmvc.codeplex.com/ . The unit test project can be found from the project EFMVC.Tests and Web API project can be found from EFMVC.Web.API.

Read the article

Design by Contract with Microsoft .Net Code Contract

- by Fredrik N

I have done some talks on different events and summits about Defensive Programming and Design by Contract, last time was at Cornerstone’s Developer Summit 2010. Next time will be at SweNug (Sweden .Net User Group). I decided to write a blog post about of some stuffs I was talking about. Users are a terrible thing! Protect your self from them ”Human users have a gift for doing the worst possible thing at the worst possible time.” – Michael T. Nygard, Release It! The kind of users Michael T. Nygard are talking about is the users of a system. We also have users that uses our code, the users I’m going to focus on is the users of our code. Me and you and another developers. “Any fool can write code that a computer can understand. Good programmers write code that humans can understand.” – Martin Fowler Good programmers also writes code that humans know how to use, good programmers also make sure software behave in a predictable manner despise inputs or user actions. Design by Contract Design by Contract (DbC) is a way for us to make a contract between us (the code writer) and the users of our code. It’s about “If you give me this, I promise to give you this”. It’s not about business validations, that is something completely different that should be part of the domain model. DbC is to make sure the users of our code uses it in a correct way, and that we can rely on the contract and write code in a way where we know that the users will follow the contract. It will make it much easier for us to write code with a contract specified. Something like the following code is something we may see often: public void DoSomething(Object value) { value.DoIKnowThatICanDoThis(); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Where “value” can be uses directly or passed to other methods and later be used. What some of us can easily forget here is that the “value” can be “null”. We will probably not passing a null value, but someone else that uses our code maybe will do it. I think most of you (including me) have passed “null” into a method because you don’t know if the argument need to be specified to a valid value etc. I bet most of you also have got the “Null reference exception”. Sometimes this “Null reference exception” can be hard and take time to fix, because we need to search among our code to see where the “null” value was passed in etc. Wouldn’t it be much better if we can as early as possible specify that the value can’t not be null, so the users of our code also know it when the users starts to use our code, and before run time execution of the code? This is where DbC comes into the picture. We can use DbC to specify what we need, and by doing so we can rely on the contract when we write our code. So the code above can actually use the DoIKnowThatICanDoThis() method on the value object without being worried that the “value” can be null. The contract between the users of the code and us writing the code, says that the “value” can’t be null. Pre- and Postconditions When working with DbC we are specifying pre- and postconditions. Precondition is a condition that should be met before a query or command is executed. An example of a precondition is: “The Value argument of the method can’t be null”, and we make sure the “value” isn’t null before the method is called. Postcondition is a condition that should be met when a command or query is completed, a postcondition will make sure the result is correct. An example of a postconditon is “The method will return a list with at least 1 item”. Commands an Quires When using DbC, we need to know what a Command and a Query is, because some principles that can be good to follow are based on commands and queries. A Command is something that will not return anything, like the SQL’s CREATE, UPDATE and DELETE. There are two kinds of Commands when using DbC, the Creation commands (for example a Constructor), and Others. Others can for example be a Command to add a value to a list, remove or update a value etc. //Creation commands public Stack(int size) //Other commands public void Push(object value); public void Remove(); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } A Query, is something that will return something, for example an Attribute, Property or a Function, like the SQL’s SELECT. There are two kinds of Queries, the Basic Queries (Quires that aren’t based on another queries), and the Derived Queries, queries that is based on another queries. Here is an example of queries of a Stack: //Basic Queries public int Count; public object this[int index] { get; } //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } To understand about some principles that are good to follow when using DbC, we need to know about the Commands and different Queries. The 6 Principles When working with DbC, it’s advisable to follow some principles to make it easier to define and use contracts. The following DbC principles are: Separate commands and queries. Separate basic queries from derived queries. For each derived query, write a postcondition that specifies what result will be returned, in terms of one or more basic queries. For each command, write a postcondition that specifies the value of every basic query. For every query and command, decide on a suitable precondition. Write invariants to define unchanging properties of objects. Before I will write about each of them I want you to now that I’m going to use .Net 4.0 Code Contract. I will in the rest of the post uses a simple Stack (Yes I know, .Net already have a Stack class) to give you the basic understanding about using DbC. A Stack is a data structure where the first item in, will be the first item out. Here is a basic implementation of a Stack where not contract is specified yet: public class Stack { private object[] _array; //Basic Queries public uint Count; public object this[uint index] { get { return _array[index]; } set { _array[index] = value; } } //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } //Is related to Count and this[] Query public object Top() { return this[Count]; } //Creation commands public Stack(uint size) { Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { this[++Count] = value; } public void Remove() { this[Count] = null; Count--; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Note: The Stack is implemented in a way to demonstrate the use of Code Contract in a simple way, the implementation may not look like how you would implement it, so don’t think this is the perfect Stack implementation, only used for demonstration. Before I will go deeper into the principles I will simply mention how we can use the .Net Code Contract. I mention before about pre- and postcondition, is about “Require” something and to “Ensure” something. When using Code Contract, we will use a static class called “Contract” and is located in he “System.Diagnostics.Contracts” namespace. The contract must be specified at the top or our member statement block. To specify a precondition with Code Contract we uses the Contract.Requires method, and to specify a postcondition, we uses the Contract.Ensure method. Here is an example where both a pre- and postcondition are used: public object Top() { Contract.Requires(Count > 0, "Stack is empty"); Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The contract above requires that the Count is greater than 0, if not we can’t get the item at the Top of a Stack. We also Ensures that the results (By using the Contract.Result method, we can specify a postcondition that will check if the value returned from a method is correct) of the Top query is equal to this[Count]. 1. Separate Commands and Queries When working with DbC, it’s important to separate Command and Quires. A method should either be a command that performs an Action, or returning information to the caller, not both. By asking a question the answer shouldn’t be changed. The following is an example of a Command and a Query of a Stack: public void Push(object value) public object Top() .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The Push is a command and will not return anything, just add a value to the Stack, the Top is a query to get the item at the top of the stack. 2. Separate basic queries from derived queries There are two different kinds of queries, the basic queries that doesn’t rely on another queries, and derived queries that uses a basic query. The “Separate basic queries from derived queries” principle is about about that derived queries can be specified in terms of basic queries. So this principles is more about recognizing that a query is a derived query or a basic query. It will then make is much easier to follow the other principles. The following code shows a basic query and a derived query: //Basic Queries public uint Count; //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } We can see that IsEmpty will use the Count query, and that makes the IsEmpty a Derived query. 3. For each derived query, write a postcondition that specifies what result will be returned, in terms of one or more basic queries. When the derived query is recognize we can follow the 3ed principle. For each derived query, we can create a postcondition that specifies what result our derived query will return in terms of one or more basic queries. Remember that DbC is about contracts between the users of the code and us writing the code. So we can’t use demand that the users will pass in a valid value, we must also ensure that we will give the users what the users wants, when the user is following our contract. The IsEmpty query of the Stack will use a Count query and that will make the IsEmpty a Derived query, so we should now write a postcondition that specified what results will be returned, in terms of using a basic query and in this case the Count query, //Basic Queries public uint Count; //Derived Queries public bool IsEmpty() { Contract.Ensures(Contract.Result<bool>() == (Count == 0)); return Count == 0; } The Contract.Ensures is used to create a postcondition. The above code will make sure that the results of the IsEmpty (by using the Contract.Result to get the result of the IsEmpty method) is correct, that will say that the IsEmpty will be either true or false based on Count is equal to 0 or not. The postcondition are using a basic query, so the IsEmpty is now following the 3ed principle. We also have another Derived Query, the Top query, it will also need a postcondition and it uses all basic queries. The Result of the Top method must be the same value as the this[] query returns. //Basic Queries public uint Count; public object this[uint index] { get { return _array[index]; } set { _array[index] = value; } } //Derived Queries //Is related to Count and this[] Query public object Top() { Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } 4. For each command, write a postcondition that specifies the value of every basic query. For each command we will create a postconditon that specifies the value of basic queries. If we look at the Stack implementation we will have three Commands, one Creation command, the Constructor, and two others commands, Push and Remove. Those commands need a postcondition and they should include basic query to follow the 4th principle. //Creation commands public Stack(uint size) { Contract.Ensures(Count == 0); Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { Contract.Ensures(Count == Contract.OldValue<uint>(Count) + 1); Contract.Ensures(this[Count] == value); this[++Count] = value; } public void Remove() { Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } As you can see the Create command will Ensures that Count will be 0 when the Stack is created, when a Stack is created there shouldn’t be any items in the stack. The Push command will take a value and put it into the Stack, when an item is pushed into the Stack, the Count need to be increased to know the number of items added to the Stack, and we must also make sure the item is really added to the Stack. The postconditon of the Push method will make sure the that old value of the Count (by using the Contract.OldValue we can get the value a Query has before the method is called) plus 1 will be equal to the Count query, this is the way we can ensure that the Push will increase the Count with one. We also make sure the this[] query will now contain the item we pushed into the Stack. The Remove method must make sure the Count is decreased by one when the top item is removed from the Stack. The Commands is now following the 4th principle, where each command now have a postcondition that used the value of basic queries. Note: The principle says every basic Query, the Remove only used one Query the Count, it’s because this command can’t use the this[] query because an item is removed, so the only way to make sure an item is removed is to just use the Count query, so the Remove will still follow the principle. 5. For every query and command, decide on a suitable precondition. We have now focused only on postcondition, now time for some preconditons. The 5th principle is about deciding a suitable preconditon for every query and command. If we starts to look at one of our basic queries (will not go through all Queries and commands here, just some of them) the this[] query, we can’t pass an index that is lower then 1 (.Net arrays and list are zero based, but not the stack in this blog post ;)) and the index can’t be lesser than the number of items in the stack. So here we will need a preconditon. public object this[uint index] { get { Contract.Requires(index >= 1); Contract.Requires(index <= Count); return _array[index]; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Think about the Contract as an documentation about how to use the code in a correct way, so if the contract could be specified elsewhere (not part of the method body), we could simply write “return _array[index]” and there is no need to check if index is greater or lesser than Count, because that is specified in a “contract”. The implementation of Code Contract, requires that the contract is specified in the code. As a developer I would rather have this contract elsewhere (Like Spec#) or implemented in a way Eiffel uses it as part of the language. Now when we have looked at one Query, we can also look at one command, the Remove command (You can see the whole implementation of the Stack at the end of this blog post, where precondition is added to more queries and commands then what I’m going to show in this section). We can only Remove an item if the Count is greater than 0. So we can write a precondition that will require that Count must be greater than 0. public void Remove() { Contract.Requires(Count > 0); Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } 6. Write invariants to define unchanging properties of objects. The last principle is about making sure the object are feeling great! This is done by using invariants. When using Code Contract we can specify invariants by adding a method with the attribute ContractInvariantMethod, the method must be private or public and can only contains calls to Contract.Invariant. To make sure the Stack feels great, the Stack must have 0 or more items, the Count can’t never be a negative value to make sure each command and queries can be used of the Stack. Here is our invariant for the Stack object: [ContractInvariantMethod] private void ObjectInvariant() { Contract.Invariant(Count >= 0); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Note: The ObjectInvariant method will be called every time after a Query or Commands is called. Here is the full example using Code Contract: public class Stack { private object[] _array; //Basic Queries public uint Count; public object this[uint index] { get { Contract.Requires(index >= 1); Contract.Requires(index <= Count); return _array[index]; } set { Contract.Requires(index >= 1); Contract.Requires(index <= Count); _array[index] = value; } } //Derived Queries //Is related to Count Query public bool IsEmpty() { Contract.Ensures(Contract.Result<bool>() == (Count == 0)); return Count == 0; } //Is related to Count and this[] Query public object Top() { Contract.Requires(Count > 0, "Stack is empty"); Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } //Creation commands public Stack(uint size) { Contract.Requires(size > 0); Contract.Ensures(Count == 0); Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { Contract.Requires(value != null); Contract.Ensures(Count == Contract.OldValue<uint>(Count) + 1); Contract.Ensures(this[Count] == value); this[++Count] = value; } public void Remove() { Contract.Requires(Count > 0); Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } [ContractInvariantMethod] private void ObjectInvariant() { Contract.Invariant(Count >= 0); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Summary By using Design By Contract we can make sure the users are using our code in a correct way, and we must also make sure the users will get the expected results when they uses our code. This can be done by specifying contracts. To make it easy to use Design By Contract, some principles may be good to follow like the separation of commands an queries. With .Net 4.0 we can use the Code Contract feature to specify contracts.

Read the article

Using an alternate search platform in Commerce Server 2009

- by Lewis Benge

Although Microsoft Commerce Server 2009's architecture is built upon Microsoft SQL Server, and has the full power of the SQL Full Text Indexing Search Platform, there are time however when you may require a richer or alternate search platform. One of these scenarios if when you want to implement a faceted (refinement) search into your site, which provides dynamic refinements based on the search results dataset. Faceted search is becoming popular in most online retail environments as a way of providing an enhanced user experience when browsing a larger catalogue. This is powerful for two reasons, firstly with a traditional search it is down to a user to think of a search term suitable for the product they are trying to find. This typically will not return similar products or help in any way to refine a larger dataset. Faceted searches on the other hand provide a comprehensive list of product properties, grouped together by similarity to help the user narrow down the results returned, as the user progressively restricts the search criteria by selecting additional criteria to search again, these facets needs to continually refresh. The whole experience allows users to explore alternate brands, price-ranges, or find products they hadn't initially thought of or where looking for in a bid to enhance cross sell in the retail environment. The second advantage of this type of search from a business perspective is also to harvest the search result to start to profile your user. Even though anonymous users may routinely visit your site, and will not necessarily register or complete a transaction to build up marketing data- profiling, you can still achieve the same result by recording search facets used within the search sequence. Below is a faceted search scenario generated from eBay using the search term "server". By creating a search profile of clicking through Computer & Networking -> Servers -> Dell - > New and recording this information against my user profile you can start to predict with a lot more certainty what types of products I am interested in. This will allow you to apply shopping-cart analysis against your search data and provide great cross-sale or advertising opportunity, or personalise the user experience based on your prediction of what the user may be interested in. This type of search is extremely beneficial in e-Commerce environments but achieving it out of the box with Commerce Server and SQL Full Text indexing can be challenging. In many deployments it is often easier to use an alternate search platform such as Microsoft's FAST, Apache SOLR, or Endecca, however you still want these products to integrate natively into Commerce Server to ensure that up-to-date inventory information is presented, profile information is generated, and you provide a consistant API. To do so we make the most of the Commerce Server extensibilty points called operation sequence components. In this example I will be talking about Apache Solr hosted on Apache Tomcat, in this specific example I have used the SolrNet C# library to interface to the Java platform. Also I am not going to talk about Solr configuration of indexing – but in a production envionrment this would typically happen by using Powershell to call the Commerce Server management webservice to export your catalog as XML, apply an XSLT transform to the file to make it conform to SOLR and use a simple HTTP Post to send it to the search enginge for indexing. Essentially a sequance component is a step in a serial workflow used to call a data repository (which in most cases is usually the Commerce Server pipelines or databases) and map to and from a Commerce Entity object whilst enforcing any business rules. So the first step in the process is to add a new class library to your existing Commerce Server site. You will need to use a new library as Sequence Components will need to be strongly named to be deployed. Once you are inside of your new project, add a new class file and add a reference to the Microsoft.Commerce.Providers, Microsoft.Commerce.Contracts and the Microsoft.Commerce.Broker assemblies. Now make your new class derive from the base object Microsoft.Commerce.Providers.Components.OperationSequanceComponent and overide the ExecuteQueryMethod. Your screen will then look something similar ot this: As all we are doing on this component is conducting a search we are only interested in the ExecuteQuery method. This method accepts three arguments, queryOperation, operationCache, and response. The queryOperation will be the object in which we receive our search parameters, the cache allows access to the Commerce Server cache allowing us to store regulary accessed information, and the response object is the object which we will return the result of our search upon. Inside this method is simply where we are going to inject our logic for our third party search platform. As I am not going to explain the inner-workings of actually making a SOLR call, I'll simply provide the sample code here. I would highly recommend however looking at the SolrNet wiki as they have some great explinations of how the API works. What you will find however is that there are some further extensions required when attempting to integrate a custom search provider. Firstly you out of the box the CommerceQueryOperation you will receive into the method when conducting a search against a catalog is specifically geared towards a SQL Full Text Search with properties such as a Where clause. To make the operation you receive more relevant you will need to create another class, this time derived from Microsoft.Commerce.Contract.Messages.CommerceSearchCriteria and within this you need to detail the properties you will require to allow you to submit as parameters to the SOLR search API. My exmaple looks like this: [DataContract(Namespace = "http://schemas.microsoft.com/microsoft-multi-channel-commerce-foundation/types/2008/03")] public class CommerceCatalogSolrSearch : CommerceSearchCriteria { private Dictionary<string, string> _facetQueries; public CommerceCatalogSolrSearch() { _facetQueries = new Dictionary<String, String>(); } public Dictionary<String, String> FacetQueries { get { return _facetQueries; } set { _facetQueries = value; } } public String SearchPhrase{ get; set; } public int PageIndex { get; set; } public int PageSize { get; set; } public IEnumerable<String> Facets { get; set; } public string Sort { get; set; } public new int FirstItemIndex { get { return (PageIndex-1)*PageSize; } } public int LastItemIndex { get { return FirstItemIndex + PageSize; } } } To allow you to construct a CommerceQueryOperation call within the API you will also need to construct another class to derived from Microsoft.Commerce.Common.MessageBuilders.CommerceSearchCriteriaBuilder and is simply used to construct an instance of the CommerceQueryOperation you have just created and expose the properties you want set. My Message builder looks like this: public class CommerceCatalogSolrSearchBuilder : CommerceSearchCriteriaBuilder { private CommerceCatalogSolrSearch _solrSearch; public CommerceCatalogSolrSearchBuilder() { _solrSearch = new CommerceCatalogSolrSearch(); } public String SearchPhrase { get { return _solrSearch.SearchPhrase; } set { _solrSearch.SearchPhrase = value; } } public int PageIndex { get { return _solrSearch.PageIndex; } set { _solrSearch.PageIndex = value; } } public int PageSize { get { return _solrSearch.PageSize; } set { _solrSearch.PageSize = value; } } public Dictionary<String,String> FacetQueries { get { return _solrSearch.FacetQueries; } set { _solrSearch.FacetQueries = value; } } public String[] Facets { get { return _solrSearch.Facets.ToArray(); } set { _solrSearch.Facets = value; } } public override CommerceSearchCriteria ToSearchCriteria() { return _solrSearch; } } Once you have these two classes in place you can now safely cast the CommerceOperation you receive as an argument of the overidden ExecuteQuery method in the SequenceComponent to the CommerceCatalogSolrSearch operation you have just created, e.g. public CommerceCatalogSolrSearch TryGetSearchCriteria(CommerceOperation operation) { var searchCriteria = operation as CommerceQueryOperation; if (searchCriteria == null) throw new Exception("No search criteria present"); var local = (CommerceCatalogSolrSearch) searchCriteria.SearchCriteria; if (local == null) throw new Exception("Unexpected Search Criteria in Operation"); return local; } Now you have all of your search parameters present, you can go off an call the external search platform API. You will of-course get proprietry objects returned, so the next step in the process is to convert the results being returned back into CommerceEntities. You do this via another extensibility point within the Commerce Server API called translatators. Translators are another separate class, this time derived inheriting the interface Microsoft.Commerce.Providers.Translators.IToCommerceEntityTranslator . As you can imaginge this interface is specific for the conversion of the object TO a CommerceEntity, you will need to implement a separate interface if you also need to go in the opposite direction. If you implement the required method for the interace you will get a single translate method which has a source onkect, destination CommerceEntity, and a collection of properties as arguments. For simplicity sake in this example I have hard-coded the mappings, however best practice would dictate you map the objects using your metadatadefintions.xml file . Once complete your translator would look something like the following: public class SolrEntityTranslator : IToCommerceEntityTranslator { #region IToCommerceEntityTranslator Members public void Translate(object source, CommerceEntity destinationCommerceEntity, CommercePropertyCollection propertiesToReturn) { if (source.GetType().Equals(typeof (SearchProduct))) { var searchResult = (SearchProduct) source; destinationCommerceEntity.Id = searchResult.ProductId; destinationCommerceEntity.SetPropertyValue("DisplayName", searchResult.Title); destinationCommerceEntity.ModelName = "Product"; } } Once you have a translator in place you can then safely map the results of your search platform into Commerce Entities and attach them on to the CommerceResponse object in a fashion similar to this: foreach (SearchProduct result in matchingProducts) { var destinationEntity = new CommerceEntity(_returnModelName); Translator.ToCommerceEntity(result, destinationEntity, _queryOperation.Model.Properties); response.CommerceEntities.Add(destinationEntity); } In SOLR I actually have two objects being returned – a product, and a collection of facets so I have an additional translator for facet (which maps to a custom facet CommerceEntity) and my facet response from SOLR is passed into the Translator helper class seperatley. When all of this is pieced together you have sucessfully completed the extensiblity point coding. You would have created a new OperationSequanceComponent, a custom SearchCritiera object and message builder class, and translators to convert the objects into Commerce Entities. Now you simply need to configure them, and can start calling them in your code. Make sure you sign you assembly, compile it and identiy its signature. Next you need to put this a reference of your new assembly into the Channel.Config configuration file replacing that of the existing SQL Full Text component: You will also need to add your translators to the Translators node of your Channel.Config too: Lastly add any custom CommerceEntities you have developed to your MetaDataDefintions.xml file. Your configuration is now complete, and you should now be able to happily make a call to the Commerce Foundation API, which will act as a proxy to your third party search platform and return back CommerceEntities of your search results. If you require data to be enriched, or logged, or any other logic applied then simply add further sequence components into the OperationSequence (obviously keeping the search response first) to the node of your Channel.Config file. Now to call your code you simply request it as per any other CommerceQuery operation, but taking into account you may be receiving multiple types of CommerceEntity returned: public KeyValuePair<FacetCollection ,List<Product>> DoFacetedProductQuerySearch(string searchPhrase, string orderKey, string sortOrder, int recordIndex, int recordsPerPage, Dictionary<string, string> facetQueries, out int totalItemCount) { var products = new List<Product>(); var query = new CommerceQuery<CatalogEntity, CommerceCatalogSolrSearchBuilder>(); query.SearchCriteria.PageIndex = recordIndex; query.SearchCriteria.PageSize = recordsPerPage; query.SearchCriteria.SearchPhrase = searchPhrase; query.SearchCriteria.FacetQueries = facetQueries; totalItemCount = 0; CommerceResponse response = SiteContext.ProcessRequest(query.ToRequest()); var queryResponse = response.OperationResponses[0] as CommerceQueryOperationResponse; // No results. Return the empty list if (queryResponse != null && queryResponse.CommerceEntities.Count == 0) return new KeyValuePair<FacetCollection, List<Product>>(); totalItemCount = (int)queryResponse.TotalItemCount; // Prepare a multi-operation to retrieve the product variants var multiOperation = new CommerceMultiOperation(); //Add products to results foreach (Product product in queryResponse.CommerceEntities.Where(x => x.ModelName == "Product")) { var productQuery = new CommerceQuery<Product>(Product.ModelNameDefinition); productQuery.SearchCriteria.Model.Id = product.Id; productQuery.SearchCriteria.Model.CatalogId = product.CatalogId; var variantQuery = new CommerceQueryRelatedItem<Variant>(Product.RelationshipName.Variants); productQuery.RelatedOperations.Add(variantQuery); multiOperation.Add(productQuery); } CommerceResponse variantsResponse = SiteContext.ProcessRequest(multiOperation.ToRequest()); foreach (CommerceQueryOperationResponse queryOpResponse in variantsResponse.OperationResponses) { if (queryOpResponse.CommerceEntities.Count() > 0) products.Add(queryOpResponse.CommerceEntities[0]); } //Get facet collection FacetCollection facetCollection = queryResponse.CommerceEntities.Where(x => x.ModelName == "FacetCollection").FirstOrDefault(); return new KeyValuePair<FacetCollection, List<Product>>(facetCollection, products); } ..And that is it – simply a few classes and some configuration will allow you to extend the Commerce Server query operations to call a third party search platform, whilst still maintaing a unifed API in the remainder of your code. This logic stands for any extensibility within CommerceServer, which requires excution in a serial fashioon such as call to LOB systems or web service to validate or enrich data. Feel free to use this example on other applications, and if you have any questions please feel free to e-mail and I'll help out where I can!

Read the article

How to add event receiver to SharePoint2010 content type programmatically

- by ybbest

Today , I’d like to show how to add event receiver to How to add event receiver to SharePoint2010 content type programmatically. 1. Create empty SharePoint Project and add a class called ItemContentTypeEventReceiver and make it inherit from SPItemEventReceiver and implement your logic as below public class ItemContentTypeEventReceiver : SPItemEventReceiver { private bool eventFiringEnabledStatus; public override void ItemAdded(SPItemEventProperties properties) { base.ItemAdded(properties); UpdateTitle(properties); } private void UpdateTitle(SPItemEventProperties properties) { SPListItem addedItem = properties.ListItem; string enteredTitle = addedItem["Title"] as string; addedItem["Title"] = enteredTitle + " Updated"; DisableItemEventsScope(); addedItem.Update(); EnableItemEventsScope(); } public override void ItemUpdated(SPItemEventProperties properties) { base.ItemUpdated(properties); UpdateTitle(properties); } private void DisableItemEventsScope() { eventFiringEnabledStatus = EventFiringEnabled; EventFiringEnabled = false; } private void EnableItemEventsScope() { eventFiringEnabledStatus = EventFiringEnabled; EventFiringEnabled = true; } } 2.Create a Site or Web(depending or your requirements) scoped feature and implement your feature event handler as below: public override void FeatureActivated(SPFeatureReceiverProperties properties) { SPWeb web = GetFeatureWeb(properties); //http://karinebosch.wordpress.com/walkthroughs/event-receivers-theory/ string assemblyName = System.Reflection.Assembly.GetExecutingAssembly().FullName; const string className = "YBBEST.AddEventReceiverToContentType.ItemContentTypeEventReceiver"; SPContentType contentType= web.ContentTypes["Item"]; AddEventReceiverToContentType(className, contentType, assemblyName, SPEventReceiverType.ItemAdded, SPEventReceiverSynchronization.Asynchronous); AddEventReceiverToContentType(className, contentType, assemblyName, SPEventReceiverType.ItemUpdated, SPEventReceiverSynchronization.Asynchronous); contentType.Update(); } protected static void AddEventReceiverToContentType(string className, SPContentType contentType, string assemblyName, SPEventReceiverType eventReceiverType, SPEventReceiverSynchronization eventReceiverSynchronization) { if (className == null) throw new ArgumentNullException("className"); if (contentType == null) throw new ArgumentNullException("contentType"); if (assemblyName == null) throw new ArgumentNullException("assemblyName"); SPEventReceiverDefinition eventReceiver = contentType.EventReceivers.Add(); eventReceiver.Synchronization = eventReceiverSynchronization; eventReceiver.Type = eventReceiverType; eventReceiver.Assembly = assemblyName; eventReceiver.Class = className; eventReceiver.Update(); } 3.Deploy your solution and now you have a event receiver that attached to the Item contentType. You can download the complete source code here.You can also check how to add event receiver to a list using SharePoint event receiver item in Visual Studio2010 in my previous blog.

Read the article

ASP.NET MVC 3 Hosting :: How to Deploy Web Apps Using ASP.NET MVC 3, Razor and EF Code First - Part I

- by mbridge

First, you can download the source code from http://efmvc.codeplex.com. The following frameworks will be used for this step by step tutorial. public class Category { public int CategoryId { get; set; } [Required(ErrorMessage = "Name Required")] [StringLength(25, ErrorMessage = "Must be less than 25 characters")] public string Name { get; set;} public string Description { get; set; } public virtual ICollection<Expense> Expenses { get; set; } } Expense Class public class Expense { public int ExpenseId { get; set; } public string Transaction { get; set; } public DateTime Date { get; set; } public double Amount { get; set; } public int CategoryId { get; set; } public virtual Category Category { get; set; } } Define Domain Model Let’s create domain model for our simple web application Category Class We have two domain entities - Category and Expense. A single category contains a list of expense transactions and every expense transaction should have a Category. In this post, we will be focusing on CRUD operations for the entity Category and will be working on the Expense entity with a View Model object in the later post. And the source code for this application will be refactored over time. The above entities are very simple POCO (Plain Old CLR Object) classes and the entity Category is decorated with validation attributes in the System.ComponentModel.DataAnnotations namespace. Now we want to use these entities for defining model objects for the Entity Framework 4. Using the Code First approach of Entity Framework, we can first define the entities by simply writing POCO classes without any coupling with any API or database library. This approach lets you focus on domain model which will enable Domain-Driven Development for applications. EF code first support is currently enabled with a separate API that is runs on top of the Entity Framework 4. EF Code First is reached CTP 5 when I am writing this article. Creating Context Class for Entity Framework We have created our domain model and let’s create a class in order to working with Entity Framework Code First. For this, you have to download EF Code First CTP 5 and add reference to the assembly EntitFramework.dll. You can also use NuGet to download add reference to EEF Code First. public class MyFinanceContext : DbContext { public MyFinanceContext() : base("MyFinance") { } public DbSet<Category> Categories { get; set; } public DbSet<Expense> Expenses { get; set; } } The above class MyFinanceContext is derived from DbContext that can connect your model classes to a database. The MyFinanceContext class is mapping our Category and Expense class into database tables Categories and Expenses using DbSet<TEntity> where TEntity is any POCO class. When we are running the application at first time, it will automatically create the database. EF code-first look for a connection string in web.config or app.config that has the same name as the dbcontext class. If it is not find any connection string with the convention, it will automatically create database in local SQL Express database by default and the name of the database will be same name as the dbcontext class. You can also define the name of database in constructor of the the dbcontext class. Unlike NHibernate, we don’t have to use any XML based mapping files or Fluent interface for mapping between our model and database. The model classes of Code First are working on the basis of conventions and we can also use a fluent API to refine our model. The convention for primary key is ‘Id’ or ‘<class name>Id’. If primary key properties are detected with type ‘int’, ‘long’ or ‘short’, they will automatically registered as identity columns in the database by default. Primary key detection is not case sensitive. We can define our model classes with validation attributes in the System.ComponentModel.DataAnnotations namespace and it automatically enforces validation rules when a model object is updated or saved. Generic Repository for EF Code First We have created model classes and dbcontext class. Now we have to create generic repository pattern for data persistence with EF code first. If you don’t know about the repository pattern, checkout Martin Fowler’s article on Repository Let’s create a generic repository to working with DbContext and DbSet generics. public interface IRepository<T> where T : class { void Add(T entity); void Delete(T entity); T GetById(long Id); IEnumerable<T> All(); } RepositoryBasse – Generic Repository class protected MyFinanceContext Database { get { return database ?? (database = DatabaseFactory.Get()); } } public virtual void Add(T entity) { dbset.Add(entity); } public virtual void Delete(T entity) { dbset.Remove(entity); } public virtual T GetById(long id) { return dbset.Find(id); } public virtual IEnumerable<T> All() { return dbset.ToList(); } } DatabaseFactory class public class DatabaseFactory : Disposable, IDatabaseFactory { private MyFinanceContext database; public MyFinanceContext Get() { return database ?? (database = new MyFinanceContext()); } protected override void DisposeCore() { if (database != null) database.Dispose(); } } Unit of Work If you are new to Unit of Work pattern, checkout Fowler’s article on Unit of Work . According to Martin Fowler, the Unit of Work pattern "maintains a list of objects affected by a business transaction and coordinates the writing out of changes and the resolution of concurrency problems." Let’s create a class for handling Unit of Work public interface IUnitOfWork { void Commit(); } UniOfWork class public class UnitOfWork : IUnitOfWork { private readonly IDatabaseFactory databaseFactory; private MyFinanceContext dataContext; public UnitOfWork(IDatabaseFactory databaseFactory) { this.databaseFactory = databaseFactory; } protected MyFinanceContext DataContext { get { return dataContext ?? (dataContext = databaseFactory.Get()); } } public void Commit() { DataContext.Commit(); } } The Commit method of the UnitOfWork will call the commit method of MyFinanceContext class and it will execute the SaveChanges method of DbContext class. Repository class for Category In this post, we will be focusing on the persistence against Category entity and will working on other entities in later post. Let’s create a repository for handling CRUD operations for Category using derive from a generic Repository RepositoryBase<T>. public class CategoryRepository: RepositoryBase<Category>, ICategoryRepository { public CategoryRepository(IDatabaseFactory databaseFactory) : base(databaseFactory) { } } public interface ICategoryRepository : IRepository<Category> { } If we need additional methods than generic repository for the Category, we can define in the CategoryRepository. Dependency Injection using Unity 2.0 If you are new to Inversion of Control/ Dependency Injection or Unity, please have a look on my articles at http://weblogs.asp.net/shijuvarghese/archive/tags/IoC/default.aspx. I want to create a custom lifetime manager for Unity to store container in the current HttpContext. public class HttpContextLifetimeManager<T> : LifetimeManager, IDisposable { public override object GetValue() { return HttpContext.Current.Items[typeof(T).AssemblyQualifiedName]; } public override void RemoveValue() { HttpContext.Current.Items.Remove(typeof(T).AssemblyQualifiedName); } public override void SetValue(object newValue) { HttpContext.Current.Items[typeof(T).AssemblyQualifiedName] = newValue; } public void Dispose() { RemoveValue(); } } Let’s create controller factory for Unity in the ASP.NET MVC 3 application. 404, String.Format( "The controller for path '{0}' could not be found" + "or it does not implement IController.", reqContext.HttpContext.Request.Path)); if (!typeof(IController).IsAssignableFrom(controllerType)) throw new ArgumentException( string.Format( "Type requested is not a controller: {0}", controllerType.Name), "controllerType"); try { controller= container.Resolve(controllerType) as IController; } catch (Exception ex) { throw new InvalidOperationException(String.Format( "Error resolving controller {0}", controllerType.Name), ex); } return controller; } } Configure contract and concrete types in Unity Let’s configure our contract and concrete types in Unity for resolving our dependencies. private void ConfigureUnity() { //Create UnityContainer IUnityContainer container = new UnityContainer() .RegisterType<IDatabaseFactory, DatabaseFactory>(new HttpContextLifetimeManager<IDatabaseFactory>()) .RegisterType<IUnitOfWork, UnitOfWork>(new HttpContextLifetimeManager<IUnitOfWork>()) .RegisterType<ICategoryRepository, CategoryRepository>(new HttpContextLifetimeManager<ICategoryRepository>()); //Set container for Controller Factory ControllerBuilder.Current.SetControllerFactory( new UnityControllerFactory(container)); } In the above ConfigureUnity method, we are registering our types onto Unity container with custom lifetime manager HttpContextLifetimeManager. Let’s call ConfigureUnity method in the Global.asax.cs for set controller factory for Unity and configuring the types with Unity. protected void Application_Start() { AreaRegistration.RegisterAllAreas(); RegisterGlobalFilters(GlobalFilters.Filters); RegisterRoutes(RouteTable.Routes); ConfigureUnity(); } Developing web application using ASP.NET MVC 3 We have created our domain model for our web application and also have created repositories and configured dependencies with Unity container. Now we have to create controller classes and views for doing CRUD operations against the Category entity. Let’s create controller class for Category Category Controller public class CategoryController : Controller { private readonly ICategoryRepository categoryRepository; private readonly IUnitOfWork unitOfWork; public CategoryController(ICategoryRepository categoryRepository, IUnitOfWork unitOfWork) { this.categoryRepository = categoryRepository; this.unitOfWork = unitOfWork; } public ActionResult Index() { var categories = categoryRepository.All(); return View(categories); } [HttpGet] public ActionResult Edit(int id) { var category = categoryRepository.GetById(id); return View(category); } [HttpPost] public ActionResult Edit(int id, FormCollection collection) { var category = categoryRepository.GetById(id); if (TryUpdateModel(category)) { unitOfWork.Commit(); return RedirectToAction("Index"); } else return View(category); } [HttpGet] public ActionResult Create() { var category = new Category(); return View(category); } [HttpPost] public ActionResult Create(Category category) { if (!ModelState.IsValid) { return View("Create", category); } categoryRepository.Add(category); unitOfWork.Commit(); return RedirectToAction("Index"); } [HttpPost] public ActionResult Delete(int id) { var category = categoryRepository.GetById(id); categoryRepository.Delete(category); unitOfWork.Commit(); var categories = categoryRepository.All(); return PartialView("CategoryList", categories); } } Creating Views in Razor Now we are going to create views in Razor for our ASP.NET MVC 3 application. Let’s create a partial view CategoryList.cshtml for listing category information and providing link for Edit and Delete operations. CategoryList.cshtml @using MyFinance.Helpers; @using MyFinance.Domain; @model IEnumerable<Category> <table> <tr> <th>Actions</th> <th>Name</th> <th>Description</th> </tr> @foreach (var item in Model) { <tr> <td> @Html.ActionLink("Edit", "Edit",new { id = item.CategoryId }) @Ajax.ActionLink("Delete", "Delete", new { id = item.CategoryId }, new AjaxOptions { Confirm = "Delete Expense?", HttpMethod = "Post", UpdateTargetId = "divCategoryList" }) </td> <td> @item.Name </td> <td> @item.Description </td> </tr> } </table> <p> @Html.ActionLink("Create New", "Create") </p> The delete link is providing Ajax functionality using the Ajax.ActionLink. This will call an Ajax request for Delete action method in the CategoryCotroller class. In the Delete action method, it will return Partial View CategoryList after deleting the record. We are using CategoryList view for the Ajax functionality and also for Index view using for displaying list of category information. Let’s create Index view using partial view CategoryList Index.chtml @model IEnumerable<MyFinance.Domain.Category> @{ ViewBag.Title = "Index"; } <h2>Category List</h2> <script src="@Url.Content("~/Scripts/jquery.unobtrusive-ajax.min.js")" type="text/javascript"></script> <div id="divCategoryList"> @Html.Partial("CategoryList", Model) </div> We can call the partial views using Html.Partial helper method. Now we are going to create View pages for insert and update functionality for the Category. Both view pages are sharing common user interface for entering the category information. So I want to create an EditorTemplate for the Category information. We have to create the EditorTemplate with the same name of entity object so that we can refer it on view pages using @Html.EditorFor(model => model) . So let’s create template with name Category. Category.cshtml @model MyFinance.Domain.Category <div class="editor-label"> @Html.LabelFor(model => model.Name) </div> <div class="editor-field"> @Html.EditorFor(model => model.Name) @Html.ValidationMessageFor(model => model.Name) </div> <div class="editor-label"> @Html.LabelFor(model => model.Description) </div> <div class="editor-field"> @Html.EditorFor(model => model.Description) @Html.ValidationMessageFor(model => model.Description) </div> Let’s create view page for insert Category information @model MyFinance.Domain.Category @{ ViewBag.Title = "Save"; } <h2>Create</h2> <script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script> @using (Html.BeginForm()) { @Html.ValidationSummary(true) <fieldset> <legend>Category</legend> @Html.EditorFor(model => model) <p> <input type="submit" value="Create" /> </p> </fieldset> } <div> @Html.ActionLink("Back to List", "Index") </div> ViewStart file In Razor views, we can add a file named _viewstart.cshtml in the views directory and this will be shared among the all views with in the Views directory. The below code in the _viewstart.cshtml, sets the Layout page for every Views in the Views folder. @{ Layout = "~/Views/Shared/_Layout.cshtml"; } Tomorrow, we will cotinue the second part of this article. :)

Read the article

How to handle "circular dependency" in dependency injection

- by Roel

The title says "Circular Dependency", but it is not the correct wording, because to me the design seems solid. However, consider the following scenario, where the blue parts are given from external partner, and orange is my own implementation. Also assume there is more then one ConcreteMain, but I want to use a specific one. (In reality, each class has some more dependencies, but I tried to simplify it here) I would like to instanciate all of this with Depency Injection (Unity), but I obviously get a StackOverflowException on the following code, because Runner tries to instantiate ConcreteMain, and ConcreteMain needs a Runner. IUnityContainer ioc = new UnityContainer(); ioc.RegisterType<IMain, ConcreteMain>() .RegisterType<IMainCallback, Runner>(); var runner = ioc.Resolve<Runner>(); How can I avouid this? Is there any way to structure this so that I can use it with DI? The scenario I'm doing now is setting everything up manually, but that puts a hard dependency on ConcreteMain in the class which instantiates it. This is what i'm trying to avoid (with Unity registrations in configuration). All source code below (very simplified example!); public class Program { public static void Main(string[] args) { IUnityContainer ioc = new UnityContainer(); ioc.RegisterType<IMain, ConcreteMain>() .RegisterType<IMainCallback, Runner>(); var runner = ioc.Resolve<Runner>(); Console.WriteLine("invoking runner..."); runner.DoSomethingAwesome(); Console.ReadLine(); } } public class Runner : IMainCallback { private readonly IMain mainServer; public Runner(IMain mainServer) { this.mainServer = mainServer; } public void DoSomethingAwesome() { Console.WriteLine("trying to do something awesome"); mainServer.DoSomething(); } public void SomethingIsDone(object something) { Console.WriteLine("hey look, something is finally done."); } } public interface IMain { void DoSomething(); } public interface IMainCallback { void SomethingIsDone(object something); } public abstract class AbstractMain : IMain { protected readonly IMainCallback callback; protected AbstractMain(IMainCallback callback) { this.callback = callback; } public abstract void DoSomething(); } public class ConcreteMain : AbstractMain { public ConcreteMain(IMainCallback callback) : base(callback){} public override void DoSomething() { Console.WriteLine("starting to do something..."); var task = Task.Factory.StartNew(() =>{ Thread.Sleep(5000);/*very long running task*/ }); task.ContinueWith(t => callback.SomethingIsDone(true)); } }

Read the article

Understanding C# async / await (1) Compilation

- by Dixin

Now the async / await keywords are in C#. Just like the async and ! in F#, this new C# feature provides great convenience. There are many nice documents talking about how to use async / await in specific scenarios, like using async methods in ASP.NET 4.5 and in ASP.NET MVC 4, etc. In this article we will look at the real code working behind the syntax sugar. According to MSDN: The async modifier indicates that the method, lambda expression, or anonymous method that it modifies is asynchronous. Since lambda expression / anonymous method will be compiled to normal method, we will focus on normal async method. Preparation First of all, Some helper methods need to make up. internal class HelperMethods { internal static int Method(int arg0, int arg1) { // Do some IO. WebClient client = new WebClient(); Enumerable.Repeat("http://weblogs.asp.net/dixin", 10) .Select(client.DownloadString).ToArray(); int result = arg0 + arg1; return result; } internal static Task<int> MethodTask(int arg0, int arg1) { Task<int> task = new Task<int>(() => Method(arg0, arg1)); task.Start(); // Hot task (started task) should always be returned. return task; } internal static void Before() { } internal static void Continuation1(int arg) { } internal static void Continuation2(int arg) { } } Here Method() is a long running method doing some IO. Then MethodTask() wraps it into a Task and return that Task. Nothing special here. Await something in async method Since MethodTask() returns Task, let’s try to await it: internal class AsyncMethods { internal static async Task<int> MethodAsync(int arg0, int arg1) { int result = await HelperMethods.MethodTask(arg0, arg1); return result; } } Because we used await in the method, async must be put on the method. Now we get the first async method. According to the naming convenience, it is called MethodAsync. Of course a async method can be awaited. So we have a CallMethodAsync() to call MethodAsync(): internal class AsyncMethods { internal static async Task<int> CallMethodAsync(int arg0, int arg1) { int result = await MethodAsync(arg0, arg1); return result; } } After compilation, MethodAsync() and CallMethodAsync() becomes the same logic. This is the code of MethodAsyc(): internal class CompiledAsyncMethods { [DebuggerStepThrough] [AsyncStateMachine(typeof(MethodAsyncStateMachine))] // async internal static /*async*/ Task<int> MethodAsync(int arg0, int arg1) { MethodAsyncStateMachine methodAsyncStateMachine = new MethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Builder = AsyncTaskMethodBuilder<int>.Create(), State = -1 }; methodAsyncStateMachine.Builder.Start(ref methodAsyncStateMachine); return methodAsyncStateMachine.Builder.Task; } } It just creates and starts a state machine MethodAsyncStateMachine: [CompilerGenerated] [StructLayout(LayoutKind.Auto)] internal struct MethodAsyncStateMachine : IAsyncStateMachine { public int State; public AsyncTaskMethodBuilder<int> Builder; public int Arg0; public int Arg1; public int Result; private TaskAwaiter<int> awaitor; void IAsyncStateMachine.MoveNext() { try { if (this.State != 0) { this.awaitor = HelperMethods.MethodTask(this.Arg0, this.Arg1).GetAwaiter(); if (!this.awaitor.IsCompleted) { this.State = 0; this.Builder.AwaitUnsafeOnCompleted(ref this.awaitor, ref this); return; } } else { this.State = -1; } this.Result = this.awaitor.GetResult(); } catch (Exception exception) { this.State = -2; this.Builder.SetException(exception); return; } this.State = -2; this.Builder.SetResult(this.Result); } [DebuggerHidden] void IAsyncStateMachine.SetStateMachine(IAsyncStateMachine param0) { this.Builder.SetStateMachine(param0); } } The generated code has been cleaned up so it is readable and can be compiled. Several things can be observed here: The async modifier is gone, which shows, unlike other modifiers (e.g. static), there is no such IL/CLR level “async” stuff. It becomes a AsyncStateMachineAttribute. This is similar to the compilation of extension method. The generated state machine is very similar to the state machine of C# yield syntax sugar. The local variables (arg0, arg1, result) are compiled to fields of the state machine. The real code (await HelperMethods.MethodTask(arg0, arg1)) is compiled into MoveNext(): HelperMethods.MethodTask(this.Arg0, this.Arg1).GetAwaiter(). CallMethodAsync() will create and start its own state machine CallMethodAsyncStateMachine: internal class CompiledAsyncMethods { [DebuggerStepThrough] [AsyncStateMachine(typeof(CallMethodAsyncStateMachine))] // async internal static /*async*/ Task<int> CallMethodAsync(int arg0, int arg1) { CallMethodAsyncStateMachine callMethodAsyncStateMachine = new CallMethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Builder = AsyncTaskMethodBuilder<int>.Create(), State = -1 }; callMethodAsyncStateMachine.Builder.Start(ref callMethodAsyncStateMachine); return callMethodAsyncStateMachine.Builder.Task; } } CallMethodAsyncStateMachine has the same logic as MethodAsyncStateMachine above. The detail of the state machine will be discussed soon. Now it is clear that: async /await is a C# level syntax sugar. There is no difference to await a async method or a normal method. A method returning Task will be awaitable. State machine and continuation To demonstrate more details in the state machine, a more complex method is created: internal class AsyncMethods { internal static async Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { HelperMethods.Before(); int resultOfAwait1 = await MethodAsync(arg0, arg1); HelperMethods.Continuation1(resultOfAwait1); int resultOfAwait2 = await MethodAsync(arg2, arg3); HelperMethods.Continuation2(resultOfAwait2); int resultToReturn = resultOfAwait1 + resultOfAwait2; return resultToReturn; } } In this method: There are multiple awaits. There are code before the awaits, and continuation code after each await After compilation, this multi-await method becomes the same as above single-await methods: internal class CompiledAsyncMethods { [DebuggerStepThrough] [AsyncStateMachine(typeof(MultiCallMethodAsyncStateMachine))] // async internal static /*async*/ Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { MultiCallMethodAsyncStateMachine multiCallMethodAsyncStateMachine = new MultiCallMethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Arg2 = arg2, Arg3 = arg3, Builder = AsyncTaskMethodBuilder<int>.Create(), State = -1 }; multiCallMethodAsyncStateMachine.Builder.Start(ref multiCallMethodAsyncStateMachine); return multiCallMethodAsyncStateMachine.Builder.Task; } } It creates and starts one single state machine, MultiCallMethodAsyncStateMachine: [CompilerGenerated] [StructLayout(LayoutKind.Auto)] internal struct MultiCallMethodAsyncStateMachine : IAsyncStateMachine { public int State; public AsyncTaskMethodBuilder<int> Builder; public int Arg0; public int Arg1; public int Arg2; public int Arg3; public int ResultOfAwait1; public int ResultOfAwait2; public int ResultToReturn; private TaskAwaiter<int> awaiter; void IAsyncStateMachine.MoveNext() { try { switch (this.State) { case -1: HelperMethods.Before(); this.awaiter = AsyncMethods.MethodAsync(this.Arg0, this.Arg1).GetAwaiter(); if (!this.awaiter.IsCompleted) { this.State = 0; this.Builder.AwaitUnsafeOnCompleted(ref this.awaiter, ref this); } break; case 0: this.ResultOfAwait1 = this.awaiter.GetResult(); HelperMethods.Continuation1(this.ResultOfAwait1); this.awaiter = AsyncMethods.MethodAsync(this.Arg2, this.Arg3).GetAwaiter(); if (!this.awaiter.IsCompleted) { this.State = 1; this.Builder.AwaitUnsafeOnCompleted(ref this.awaiter, ref this); } break; case 1: this.ResultOfAwait2 = this.awaiter.GetResult(); HelperMethods.Continuation2(this.ResultOfAwait2); this.ResultToReturn = this.ResultOfAwait1 + this.ResultOfAwait2; this.State = -2; this.Builder.SetResult(this.ResultToReturn); break; } } catch (Exception exception) { this.State = -2; this.Builder.SetException(exception); } } [DebuggerHidden] void IAsyncStateMachine.SetStateMachine(IAsyncStateMachine stateMachine) { this.Builder.SetStateMachine(stateMachine); } } The above code is already cleaned up, but there are still a lot of things. More clean up can be done, and the state machine can be very simple: [CompilerGenerated] [StructLayout(LayoutKind.Auto)] internal struct MultiCallMethodAsyncStateMachine : IAsyncStateMachine { // State: // -1: Begin // 0: 1st await is done // 1: 2nd await is done // ... // -2: End public int State; public TaskCompletionSource<int> ResultToReturn; // int resultToReturn ... public int Arg0; // int Arg0 public int Arg1; // int arg1 public int Arg2; // int arg2 public int Arg3; // int arg3 public int ResultOfAwait1; // int resultOfAwait1 ... public int ResultOfAwait2; // int resultOfAwait2 ... private Task<int> currentTaskToAwait; /// <summary> /// Moves the state machine to its next state. /// </summary> void IAsyncStateMachine.MoveNext() { try { switch (this.State) { // Orginal code is splitted by "case"s: // case -1: // HelperMethods.Before(); // MethodAsync(Arg0, arg1); // case 0: // int resultOfAwait1 = await ... // HelperMethods.Continuation1(resultOfAwait1); // MethodAsync(arg2, arg3); // case 1: // int resultOfAwait2 = await ... // HelperMethods.Continuation2(resultOfAwait2); // int resultToReturn = resultOfAwait1 + resultOfAwait2; // return resultToReturn; case -1: // -1 is begin. HelperMethods.Before(); // Code before 1st await. this.currentTaskToAwait = AsyncMethods.MethodAsync(this.Arg0, this.Arg1); // 1st task to await // When this.currentTaskToAwait is done, run this.MoveNext() and go to case 0. this.State = 0; IAsyncStateMachine this1 = this; // Cannot use "this" in lambda so create a local variable. this.currentTaskToAwait.ContinueWith(_ => this1.MoveNext()); // Callback break; case 0: // Now 1st await is done. this.ResultOfAwait1 = this.currentTaskToAwait.Result; // Get 1st await's result. HelperMethods.Continuation1(this.ResultOfAwait1); // Code after 1st await and before 2nd await. this.currentTaskToAwait = AsyncMethods.MethodAsync(this.Arg2, this.Arg3); // 2nd task to await // When this.currentTaskToAwait is done, run this.MoveNext() and go to case 1. this.State = 1; IAsyncStateMachine this2 = this; // Cannot use "this" in lambda so create a local variable. this.currentTaskToAwait.ContinueWith(_ => this2.MoveNext()); // Callback break; case 1: // Now 2nd await is done. this.ResultOfAwait2 = this.currentTaskToAwait.Result; // Get 2nd await's result. HelperMethods.Continuation2(this.ResultOfAwait2); // Code after 2nd await. int resultToReturn = this.ResultOfAwait1 + this.ResultOfAwait2; // Code after 2nd await. // End with resultToReturn. this.State = -2; // -2 is end. this.ResultToReturn.SetResult(resultToReturn); break; } } catch (Exception exception) { // End with exception. this.State = -2; // -2 is end. this.ResultToReturn.SetException(exception); } } /// <summary> /// Configures the state machine with a heap-allocated replica. /// </summary> /// <param name="stateMachine">The heap-allocated replica.</param> [DebuggerHidden] void IAsyncStateMachine.SetStateMachine(IAsyncStateMachine stateMachine) { // No core logic. } } Only Task and TaskCompletionSource are involved in this version. And MultiCallMethodAsync() can be simplified to: [DebuggerStepThrough] [AsyncStateMachine(typeof(MultiCallMethodAsyncStateMachine))] // async internal static /*async*/ Task<int> MultiCallMethodAsync_(int arg0, int arg1, int arg2, int arg3) { MultiCallMethodAsyncStateMachine multiCallMethodAsyncStateMachine = new MultiCallMethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Arg2 = arg2, Arg3 = arg3, ResultToReturn = new TaskCompletionSource<int>(), // -1: Begin // 0: 1st await is done // 1: 2nd await is done // ... // -2: End State = -1 }; (multiCallMethodAsyncStateMachine as IAsyncStateMachine).MoveNext(); // Original code are in this method. return multiCallMethodAsyncStateMachine.ResultToReturn.Task; } Now the whole state machine becomes very clear - it is about callback: Original code are split into pieces by “await”s, and each piece is put into each “case” in the state machine. Here the 2 awaits split the code into 3 pieces, so there are 3 “case”s. The “piece”s are chained by callback, that is done by Builder.AwaitUnsafeOnCompleted(callback), or currentTaskToAwait.ContinueWith(callback) in the simplified code. A previous “piece” will end with a Task (which is to be awaited), when the task is done, it will callback the next “piece”. The state machine’s state works with the “case”s to ensure the code “piece”s executes one after another. Callback Since it is about callback, the simplification can go even further – the entire state machine can be completely purged. Now MultiCallMethodAsync() becomes: internal static Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { TaskCompletionSource<int> taskCompletionSource = new TaskCompletionSource<int>(); try { // Oringinal code begins. HelperMethods.Before(); MethodAsync(arg0, arg1).ContinueWith(await1 => { int resultOfAwait1 = await1.Result; HelperMethods.Continuation1(resultOfAwait1); MethodAsync(arg2, arg3).ContinueWith(await2 => { int resultOfAwait2 = await2.Result; HelperMethods.Continuation2(resultOfAwait2); int resultToReturn = resultOfAwait1 + resultOfAwait2; // Oringinal code ends. taskCompletionSource.SetResult(resultToReturn); }); }); } catch (Exception exception) { taskCompletionSource.SetException(exception); } return taskCompletionSource.Task; } Please compare with the original async / await code: HelperMethods.Before(); int resultOfAwait1 = await MethodAsync(arg0, arg1); HelperMethods.Continuation1(resultOfAwait1); int resultOfAwait2 = await MethodAsync(arg2, arg3); HelperMethods.Continuation2(resultOfAwait2); int resultToReturn = resultOfAwait1 + resultOfAwait2; return resultToReturn; Yeah that is the magic of C# async / await: Await is literally pretending to wait. In a await expression, a Task object will be return immediately so that caller is not blocked. The continuation code is compiled as that Task’s callback code. When that task is done, continuation code will execute. Please notice that many details inside the state machine are omitted for simplicity, like context caring, etc. If you want to have a detailed picture, please do check out the source code of AsyncTaskMethodBuilder and TaskAwaiter.

Read the article

Understanding C# async / await (1) Compilation

- by Dixin

Now the async / await keywords are in C#. Just like the async and ! in F#, this new C# feature provides great convenience. There are many nice documents talking about how to use async / await in specific scenarios, like using async methods in ASP.NET 4.5 and in ASP.NET MVC 4, etc. In this article we will look at the real code working behind the syntax sugar. According to MSDN: The async modifier indicates that the method, lambda expression, or anonymous method that it modifies is asynchronous. Since lambda expression / anonymous method will be compiled to normal method, we will focus on normal async method. Preparation First of all, Some helper methods need to make up. internal class HelperMethods { internal static int Method(int arg0, int arg1) { // Do some IO. WebClient client = new WebClient(); Enumerable.Repeat("http://weblogs.asp.net/dixin", 10) .Select(client.DownloadString).ToArray(); int result = arg0 + arg1; return result; } internal static Task<int> MethodTask(int arg0, int arg1) { Task<int> task = new Task<int>(() => Method(arg0, arg1)); task.Start(); // Hot task (started task) should always be returned. return task; } internal static void Before() { } internal static void Continuation1(int arg) { } internal static void Continuation2(int arg) { } } Here Method() is a long running method doing some IO. Then MethodTask() wraps it into a Task and return that Task. Nothing special here. Await something in async method Since MethodTask() returns Task, let’s try to await it: internal class AsyncMethods { internal static async Task<int> MethodAsync(int arg0, int arg1) { int result = await HelperMethods.MethodTask(arg0, arg1); return result; } } Because we used await in the method, async must be put on the method. Now we get the first async method. According to the naming convenience, it is named MethodAsync. Of course a async method can be awaited. So we have a CallMethodAsync() to call MethodAsync(): internal class AsyncMethods { internal static async Task<int> CallMethodAsync(int arg0, int arg1) { int result = await MethodAsync(arg0, arg1); return result; } } After compilation, MethodAsync() and CallMethodAsync() becomes the same logic. This is the code of MethodAsyc(): internal class CompiledAsyncMethods { [DebuggerStepThrough] [AsyncStateMachine(typeof(MethodAsyncStateMachine))] // async internal static /*async*/ Task<int> MethodAsync(int arg0, int arg1) { MethodAsyncStateMachine methodAsyncStateMachine = new MethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Builder = AsyncTaskMethodBuilder<int>.Create(), State = -1 }; methodAsyncStateMachine.Builder.Start(ref methodAsyncStateMachine); return methodAsyncStateMachine.Builder.Task; } } It just creates and starts a state machine, MethodAsyncStateMachine: [CompilerGenerated] [StructLayout(LayoutKind.Auto)] internal struct MethodAsyncStateMachine : IAsyncStateMachine { public int State; public AsyncTaskMethodBuilder<int> Builder; public int Arg0; public int Arg1; public int Result; private TaskAwaiter<int> awaitor; void IAsyncStateMachine.MoveNext() { try { if (this.State != 0) { this.awaitor = HelperMethods.MethodTask(this.Arg0, this.Arg1).GetAwaiter(); if (!this.awaitor.IsCompleted) { this.State = 0; this.Builder.AwaitUnsafeOnCompleted(ref this.awaitor, ref this); return; } } else { this.State = -1; } this.Result = this.awaitor.GetResult(); } catch (Exception exception) { this.State = -2; this.Builder.SetException(exception); return; } this.State = -2; this.Builder.SetResult(this.Result); } [DebuggerHidden] void IAsyncStateMachine.SetStateMachine(IAsyncStateMachine param0) { this.Builder.SetStateMachine(param0); } } The generated code has been refactored, so it is readable and can be compiled. Several things can be observed here: The async modifier is gone, which shows, unlike other modifiers (e.g. static), there is no such IL/CLR level “async” stuff. It becomes a AsyncStateMachineAttribute. This is similar to the compilation of extension method. The generated state machine is very similar to the state machine of C# yield syntax sugar. The local variables (arg0, arg1, result) are compiled to fields of the state machine. The real code (await HelperMethods.MethodTask(arg0, arg1)) is compiled into MoveNext(): HelperMethods.MethodTask(this.Arg0, this.Arg1).GetAwaiter(). CallMethodAsync() will create and start its own state machine CallMethodAsyncStateMachine: internal class CompiledAsyncMethods { [DebuggerStepThrough] [AsyncStateMachine(typeof(CallMethodAsyncStateMachine))] // async internal static /*async*/ Task<int> CallMethodAsync(int arg0, int arg1) { CallMethodAsyncStateMachine callMethodAsyncStateMachine = new CallMethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Builder = AsyncTaskMethodBuilder<int>.Create(), State = -1 }; callMethodAsyncStateMachine.Builder.Start(ref callMethodAsyncStateMachine); return callMethodAsyncStateMachine.Builder.Task; } } CallMethodAsyncStateMachine has the same logic as MethodAsyncStateMachine above. The detail of the state machine will be discussed soon. Now it is clear that: async /await is a C# language level syntax sugar. There is no difference to await a async method or a normal method. As long as a method returns Task, it is awaitable. State machine and continuation To demonstrate more details in the state machine, a more complex method is created: internal class AsyncMethods { internal static async Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { HelperMethods.Before(); int resultOfAwait1 = await MethodAsync(arg0, arg1); HelperMethods.Continuation1(resultOfAwait1); int resultOfAwait2 = await MethodAsync(arg2, arg3); HelperMethods.Continuation2(resultOfAwait2); int resultToReturn = resultOfAwait1 + resultOfAwait2; return resultToReturn; } } In this method: There are multiple awaits. There are code before the awaits, and continuation code after each await After compilation, this multi-await method becomes the same as above single-await methods: internal class CompiledAsyncMethods { [DebuggerStepThrough] [AsyncStateMachine(typeof(MultiCallMethodAsyncStateMachine))] // async internal static /*async*/ Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { MultiCallMethodAsyncStateMachine multiCallMethodAsyncStateMachine = new MultiCallMethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Arg2 = arg2, Arg3 = arg3, Builder = AsyncTaskMethodBuilder<int>.Create(), State = -1 }; multiCallMethodAsyncStateMachine.Builder.Start(ref multiCallMethodAsyncStateMachine); return multiCallMethodAsyncStateMachine.Builder.Task; } } It creates and starts one single state machine, MultiCallMethodAsyncStateMachine: [CompilerGenerated] [StructLayout(LayoutKind.Auto)] internal struct MultiCallMethodAsyncStateMachine : IAsyncStateMachine { public int State; public AsyncTaskMethodBuilder<int> Builder; public int Arg0; public int Arg1; public int Arg2; public int Arg3; public int ResultOfAwait1; public int ResultOfAwait2; public int ResultToReturn; private TaskAwaiter<int> awaiter; void IAsyncStateMachine.MoveNext() { try { switch (this.State) { case -1: HelperMethods.Before(); this.awaiter = AsyncMethods.MethodAsync(this.Arg0, this.Arg1).GetAwaiter(); if (!this.awaiter.IsCompleted) { this.State = 0; this.Builder.AwaitUnsafeOnCompleted(ref this.awaiter, ref this); } break; case 0: this.ResultOfAwait1 = this.awaiter.GetResult(); HelperMethods.Continuation1(this.ResultOfAwait1); this.awaiter = AsyncMethods.MethodAsync(this.Arg2, this.Arg3).GetAwaiter(); if (!this.awaiter.IsCompleted) { this.State = 1; this.Builder.AwaitUnsafeOnCompleted(ref this.awaiter, ref this); } break; case 1: this.ResultOfAwait2 = this.awaiter.GetResult(); HelperMethods.Continuation2(this.ResultOfAwait2); this.ResultToReturn = this.ResultOfAwait1 + this.ResultOfAwait2; this.State = -2; this.Builder.SetResult(this.ResultToReturn); break; } } catch (Exception exception) { this.State = -2; this.Builder.SetException(exception); } } [DebuggerHidden] void IAsyncStateMachine.SetStateMachine(IAsyncStateMachine stateMachine) { this.Builder.SetStateMachine(stateMachine); } } Once again, the above state machine code is already refactored, but it still has a lot of things. More clean up can be done if we only keep the core logic, and the state machine can become very simple: [CompilerGenerated] [StructLayout(LayoutKind.Auto)] internal struct MultiCallMethodAsyncStateMachine : IAsyncStateMachine { // State: // -1: Begin // 0: 1st await is done // 1: 2nd await is done // ... // -2: End public int State; public TaskCompletionSource<int> ResultToReturn; // int resultToReturn ... public int Arg0; // int Arg0 public int Arg1; // int arg1 public int Arg2; // int arg2 public int Arg3; // int arg3 public int ResultOfAwait1; // int resultOfAwait1 ... public int ResultOfAwait2; // int resultOfAwait2 ... private Task<int> currentTaskToAwait; /// <summary> /// Moves the state machine to its next state. /// </summary> public void MoveNext() // IAsyncStateMachine member. { try { switch (this.State) { // Original code is split by "await"s into "case"s: // case -1: // HelperMethods.Before(); // MethodAsync(Arg0, arg1); // case 0: // int resultOfAwait1 = await ... // HelperMethods.Continuation1(resultOfAwait1); // MethodAsync(arg2, arg3); // case 1: // int resultOfAwait2 = await ... // HelperMethods.Continuation2(resultOfAwait2); // int resultToReturn = resultOfAwait1 + resultOfAwait2; // return resultToReturn; case -1: // -1 is begin. HelperMethods.Before(); // Code before 1st await. this.currentTaskToAwait = AsyncMethods.MethodAsync(this.Arg0, this.Arg1); // 1st task to await // When this.currentTaskToAwait is done, run this.MoveNext() and go to case 0. this.State = 0; MultiCallMethodAsyncStateMachine that1 = this; // Cannot use "this" in lambda so create a local variable. this.currentTaskToAwait.ContinueWith(_ => that1.MoveNext()); break; case 0: // Now 1st await is done. this.ResultOfAwait1 = this.currentTaskToAwait.Result; // Get 1st await's result. HelperMethods.Continuation1(this.ResultOfAwait1); // Code after 1st await and before 2nd await. this.currentTaskToAwait = AsyncMethods.MethodAsync(this.Arg2, this.Arg3); // 2nd task to await // When this.currentTaskToAwait is done, run this.MoveNext() and go to case 1. this.State = 1; MultiCallMethodAsyncStateMachine that2 = this; this.currentTaskToAwait.ContinueWith(_ => that2.MoveNext()); break; case 1: // Now 2nd await is done. this.ResultOfAwait2 = this.currentTaskToAwait.Result; // Get 2nd await's result. HelperMethods.Continuation2(this.ResultOfAwait2); // Code after 2nd await. int resultToReturn = this.ResultOfAwait1 + this.ResultOfAwait2; // Code after 2nd await. // End with resultToReturn. this.State = -2; // -2 is end. this.ResultToReturn.SetResult(resultToReturn); break; } } catch (Exception exception) { // End with exception. this.State = -2; // -2 is end. this.ResultToReturn.SetException(exception); } } /// <summary> /// Configures the state machine with a heap-allocated replica. /// </summary> /// <param name="stateMachine">The heap-allocated replica.</param> [DebuggerHidden] public void SetStateMachine(IAsyncStateMachine stateMachine) // IAsyncStateMachine member. { // No core logic. } } Only Task and TaskCompletionSource are involved in this version. And MultiCallMethodAsync() can be simplified to: [DebuggerStepThrough] [AsyncStateMachine(typeof(MultiCallMethodAsyncStateMachine))] // async internal static /*async*/ Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { MultiCallMethodAsyncStateMachine multiCallMethodAsyncStateMachine = new MultiCallMethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Arg2 = arg2, Arg3 = arg3, ResultToReturn = new TaskCompletionSource<int>(), // -1: Begin // 0: 1st await is done // 1: 2nd await is done // ... // -2: End State = -1 }; multiCallMethodAsyncStateMachine.MoveNext(); // Original code are moved into this method. return multiCallMethodAsyncStateMachine.ResultToReturn.Task; } Now the whole state machine becomes very clean - it is about callback: Original code are split into pieces by “await”s, and each piece is put into each “case” in the state machine. Here the 2 awaits split the code into 3 pieces, so there are 3 “case”s. The “piece”s are chained by callback, that is done by Builder.AwaitUnsafeOnCompleted(callback), or currentTaskToAwait.ContinueWith(callback) in the simplified code. A previous “piece” will end with a Task (which is to be awaited), when the task is done, it will callback the next “piece”. The state machine’s state works with the “case”s to ensure the code “piece”s executes one after another. Callback If we focus on the point of callback, the simplification can go even further – the entire state machine can be completely purged, and we can just keep the code inside MoveNext(). Now MultiCallMethodAsync() becomes: internal static Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { TaskCompletionSource<int> taskCompletionSource = new TaskCompletionSource<int>(); try { // Oringinal code begins. HelperMethods.Before(); MethodAsync(arg0, arg1).ContinueWith(await1 => { int resultOfAwait1 = await1.Result; HelperMethods.Continuation1(resultOfAwait1); MethodAsync(arg2, arg3).ContinueWith(await2 => { int resultOfAwait2 = await2.Result; HelperMethods.Continuation2(resultOfAwait2); int resultToReturn = resultOfAwait1 + resultOfAwait2; // Oringinal code ends. taskCompletionSource.SetResult(resultToReturn); }); }); } catch (Exception exception) { taskCompletionSource.SetException(exception); } return taskCompletionSource.Task; } Please compare with the original async / await code: HelperMethods.Before(); int resultOfAwait1 = await MethodAsync(arg0, arg1); HelperMethods.Continuation1(resultOfAwait1); int resultOfAwait2 = await MethodAsync(arg2, arg3); HelperMethods.Continuation2(resultOfAwait2); int resultToReturn = resultOfAwait1 + resultOfAwait2; return resultToReturn; Yeah that is the magic of C# async / await: Await is not to wait. In a await expression, a Task object will be return immediately so that execution is not blocked. The continuation code is compiled as that Task’s callback code. When that task is done, continuation code will execute. Please notice that many details inside the state machine are omitted for simplicity, like context caring, etc. If you want to have a detailed picture, please do check out the source code of AsyncTaskMethodBuilder and TaskAwaiter.

Read the article

Subterranean IL: Fault exception handlers

- by Simon Cooper

Fault event handlers are one of the two handler types that aren't available in C#. It behaves exactly like a finally, except it is only run if control flow exits the block due to an exception being thrown. As an example, take the following method: .method public static void FaultExample(bool throwException) { .try { ldstr "Entering try block" call void [mscorlib]System.Console::WriteLine(string) ldarg.0 brfalse.s NormalReturn ThrowException: ldstr "Throwing exception" call void [mscorlib]System.Console::WriteLine(string) newobj void [mscorlib]System.Exception::.ctor() throw NormalReturn: ldstr "Leaving try block" call void [mscorlib]System.Console::WriteLine(string) leave.s Return } fault { ldstr "Fault handler" call void [mscorlib]System.Console::WriteLine(string) endfault } Return: ldstr "Returning from method" call void [mscorlib]System.Console::WriteLine(string) ret } If we pass true to this method the following gets printed: Entering try block Throwing exception Fault handler and the exception gets passed up the call stack. So, the exception gets thrown, the fault handler gets run, and the exception propagates up the stack afterwards in the normal way. If we pass false, we get the following: Entering try block Leaving try block Returning from method Because we are leaving the .try using a leave.s instruction, and not throwing an exception, the fault handler does not get called. Fault handlers and C# So why were these not included in C#? It seems a pretty simple feature; one extra keyword that compiles in exactly the same way, and with the same semantics, as a finally handler. If you think about it, the same behaviour can be replicated using a normal catch block: try { throw new Exception(); } catch { // fault code goes here throw; } The catch block only gets run if an exception is thrown, and the exception gets rethrown and propagates up the call stack afterwards; exactly like a fault block. The only complications that occur is when you want to add a fault handler to a try block with existing catch handlers. Then, you either have to wrap the try in another try: try { try { // ... } catch (DirectoryNotFoundException) { // ... // leave.s as normal... } catch (IOException) { // ... throw; } } catch { // fault logic throw; } or separate out the fault logic into another method and call that from the appropriate handlers: try { // ... } catch (DirectoryNotFoundException ) { // ... } catch (IOException ioe) { // ... HandleFaultLogic(); throw; } catch (Exception e) { HandleFaultLogic(); throw; } To be fair, the number of times that I would have found a fault handler useful is minimal. Still, it's quite annoying knowing such functionality exists, but you're not able to access it from C#. Fortunately, there are some easy workarounds one can use instead. Next time: filter handlers.

Read the article

Adding SQL Cache Dependencies to the Loosely coupled .NET Cache Provider

- by Rhames

This post adds SQL Cache Dependency support to the loosely coupled .NET Cache Provider that I described in the previous post (http://geekswithblogs.net/Rhames/archive/2012/09/11/loosely-coupled-.net-cache-provider-using-dependency-injection.aspx). The sample code is available on github at https://github.com/RobinHames/CacheProvider.git. Each time we want to apply a cache dependency to a call to fetch or cache a data item we need to supply an instance of the relevant dependency implementation. This suggests an Abstract Factory will be useful to create cache dependencies as needed. We can then use Dependency Injection to inject the factory into the relevant consumer. Castle Windsor provides a typed factory facility that will be utilised to implement the cache dependency abstract factory (see http://docs.castleproject.org/Windsor.Typed-Factory-Facility-interface-based-factories.ashx). Cache Dependency Interfaces First I created a set of cache dependency interfaces in the domain layer, which can be used to pass a cache dependency into the cache provider. ICacheDependency The ICacheDependency interface is simply an empty interface that is used as a parent for the specific cache dependency interfaces. This will allow us to place a generic constraint on the Cache Dependency Factory, and will give us a type that can be passed into the relevant Cache Provider methods. namespace CacheDiSample.Domain.CacheInterfaces { public interface ICacheDependency { } } ISqlCacheDependency.cs The ISqlCacheDependency interface provides specific SQL caching details, such as a Sql Command or a database connection and table. It is the concrete implementation of this interface that will be created by the factory in passed into the Cache Provider. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace CacheDiSample.Domain.CacheInterfaces { public interface ISqlCacheDependency : ICacheDependency { ISqlCacheDependency Initialise(string databaseConnectionName, string tableName); ISqlCacheDependency Initialise(System.Data.SqlClient.SqlCommand sqlCommand); } } If we want other types of cache dependencies, such as by key or file, interfaces may be created to support these (the sample code includes an IKeyCacheDependency interface). Modifying ICacheProvider to accept Cache Dependencies Next I modified the exisitng ICacheProvider<T> interface so that cache dependencies may be passed into a Fetch method call. I did this by adding two overloads to the existing Fetch methods, which take an IEnumerable<ICacheDependency> parameter (the IEnumerable allows more than one cache dependency to be included). I also added a method to create cache dependencies. This means that the implementation of the Cache Provider will require a dependency on the Cache Dependency Factory. It is pretty much down to personal choice as to whether this approach is taken, or whether the Cache Dependency Factory is injected directly into the repository or other consumer of Cache Provider. I think, because the cache dependency cannot be used without the Cache Provider, placing the dependency on the factory into the Cache Provider implementation is cleaner. ICacheProvider.cs using System; using System.Collections.Generic; namespace CacheDiSample.Domain.CacheInterfaces { public interface ICacheProvider<T> { T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry); T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry, IEnumerable<ICacheDependency> cacheDependencies); IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry); IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry, IEnumerable<ICacheDependency> cacheDependencies); U CreateCacheDependency<U>() where U : ICacheDependency; } } Cache Dependency Factory Next I created the interface for the Cache Dependency Factory in the domain layer. ICacheDependencyFactory.cs namespace CacheDiSample.Domain.CacheInterfaces { public interface ICacheDependencyFactory { T Create<T>() where T : ICacheDependency; void Release<T>(T cacheDependency) where T : ICacheDependency; } } I used the ICacheDependency parent interface as a generic constraint on the create and release methods in the factory interface. Now the interfaces are in place, I moved on to the concrete implementations. ISqlCacheDependency Concrete Implementation The concrete implementation of ISqlCacheDependency will need to provide an instance of System.Web.Caching.SqlCacheDependency to the Cache Provider implementation. Unfortunately this class is sealed, so I cannot simply inherit from this. Instead, I created an interface called IAspNetCacheDependency that will provide a Create method to create an instance of the relevant System.Web.Caching Cache Dependency type. This interface is specific to the ASP.NET implementation of the Cache Provider, so it should be defined in the same layer as the concrete implementation of the Cache Provider (the MVC UI layer in the sample code). IAspNetCacheDependency.cs using System.Web.Caching; namespace CacheDiSample.CacheProviders { public interface IAspNetCacheDependency { CacheDependency CreateAspNetCacheDependency(); } } Next, I created the concrete implementation of the ISqlCacheDependency interface. This class also implements the IAspNetCacheDependency interface. This concrete implementation also is defined in the same layer as the Cache Provider implementation. AspNetSqlCacheDependency.cs using System.Web.Caching; using CacheDiSample.Domain.CacheInterfaces; namespace CacheDiSample.CacheProviders { public class AspNetSqlCacheDependency : ISqlCacheDependency, IAspNetCacheDependency { private string databaseConnectionName; private string tableName; private System.Data.SqlClient.SqlCommand sqlCommand; #region ISqlCacheDependency Members public ISqlCacheDependency Initialise(string databaseConnectionName, string tableName) { this.databaseConnectionName = databaseConnectionName; this.tableName = tableName; return this; } public ISqlCacheDependency Initialise(System.Data.SqlClient.SqlCommand sqlCommand) { this.sqlCommand = sqlCommand; return this; } #endregion #region IAspNetCacheDependency Members public System.Web.Caching.CacheDependency CreateAspNetCacheDependency() { if (sqlCommand != null) return new SqlCacheDependency(sqlCommand); else return new SqlCacheDependency(databaseConnectionName, tableName); } #endregion } } ICacheProvider Concrete Implementation The ICacheProvider interface is implemented by the CacheProvider class. This implementation is modified to include the changes to the ICacheProvider interface. First I needed to inject the Cache Dependency Factory into the Cache Provider: private ICacheDependencyFactory cacheDependencyFactory; public CacheProvider(ICacheDependencyFactory cacheDependencyFactory) { if (cacheDependencyFactory == null) throw new ArgumentNullException("cacheDependencyFactory"); this.cacheDependencyFactory = cacheDependencyFactory; } Next I implemented the CreateCacheDependency method, which simply passes on the create request to the factory: public U CreateCacheDependency<U>() where U : ICacheDependency { return this.cacheDependencyFactory.Create<U>(); } The signature of the FetchAndCache helper method was modified to take an additional IEnumerable<ICacheDependency> parameter: private U FetchAndCache<U>(string key, Func<U> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry, IEnumerable<ICacheDependency> cacheDependencies) and the following code added to create the relevant System.Web.Caching.CacheDependency object for any dependencies and pass them to the HttpContext Cache: CacheDependency aspNetCacheDependencies = null; if (cacheDependencies != null) { if (cacheDependencies.Count() == 1) // We know that the implementations of ICacheDependency will also implement IAspNetCacheDependency // so we can use a cast here and call the CreateAspNetCacheDependency() method aspNetCacheDependencies = ((IAspNetCacheDependency)cacheDependencies.ElementAt(0)).CreateAspNetCacheDependency(); else if (cacheDependencies.Count() > 1) { AggregateCacheDependency aggregateCacheDependency = new AggregateCacheDependency(); foreach (ICacheDependency cacheDependency in cacheDependencies) { // We know that the implementations of ICacheDependency will also implement IAspNetCacheDependency // so we can use a cast here and call the CreateAspNetCacheDependency() method aggregateCacheDependency.Add(((IAspNetCacheDependency)cacheDependency).CreateAspNetCacheDependency()); } aspNetCacheDependencies = aggregateCacheDependency; } } HttpContext.Current.Cache.Insert(key, value, aspNetCacheDependencies, absoluteExpiry.Value, relativeExpiry.Value); The full code listing for the modified CacheProvider class is shown below: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Caching; using CacheDiSample.Domain.CacheInterfaces; namespace CacheDiSample.CacheProviders { public class CacheProvider<T> : ICacheProvider<T> { private ICacheDependencyFactory cacheDependencyFactory; public CacheProvider(ICacheDependencyFactory cacheDependencyFactory) { if (cacheDependencyFactory == null) throw new ArgumentNullException("cacheDependencyFactory"); this.cacheDependencyFactory = cacheDependencyFactory; } public T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) { return FetchAndCache<T>(key, retrieveData, absoluteExpiry, relativeExpiry, null); } public T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry, IEnumerable<ICacheDependency> cacheDependencies) { return FetchAndCache<T>(key, retrieveData, absoluteExpiry, relativeExpiry, cacheDependencies); } public IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) { return FetchAndCache<IEnumerable<T>>(key, retrieveData, absoluteExpiry, relativeExpiry, null); } public IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry, IEnumerable<ICacheDependency> cacheDependencies) { return FetchAndCache<IEnumerable<T>>(key, retrieveData, absoluteExpiry, relativeExpiry, cacheDependencies); } public U CreateCacheDependency<U>() where U : ICacheDependency { return this.cacheDependencyFactory.Create<U>(); } #region Helper Methods private U FetchAndCache<U>(string key, Func<U> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry, IEnumerable<ICacheDependency> cacheDependencies) { U value; if (!TryGetValue<U>(key, out value)) { value = retrieveData(); if (!absoluteExpiry.HasValue) absoluteExpiry = Cache.NoAbsoluteExpiration; if (!relativeExpiry.HasValue) relativeExpiry = Cache.NoSlidingExpiration; CacheDependency aspNetCacheDependencies = null; if (cacheDependencies != null) { if (cacheDependencies.Count() == 1) // We know that the implementations of ICacheDependency will also implement IAspNetCacheDependency // so we can use a cast here and call the CreateAspNetCacheDependency() method aspNetCacheDependencies = ((IAspNetCacheDependency)cacheDependencies.ElementAt(0)).CreateAspNetCacheDependency(); else if (cacheDependencies.Count() > 1) { AggregateCacheDependency aggregateCacheDependency = new AggregateCacheDependency(); foreach (ICacheDependency cacheDependency in cacheDependencies) { // We know that the implementations of ICacheDependency will also implement IAspNetCacheDependency // so we can use a cast here and call the CreateAspNetCacheDependency() method aggregateCacheDependency.Add( ((IAspNetCacheDependency)cacheDependency).CreateAspNetCacheDependency()); } aspNetCacheDependencies = aggregateCacheDependency; } } HttpContext.Current.Cache.Insert(key, value, aspNetCacheDependencies, absoluteExpiry.Value, relativeExpiry.Value); } return value; } private bool TryGetValue<U>(string key, out U value) { object cachedValue = HttpContext.Current.Cache.Get(key); if (cachedValue == null) { value = default(U); return false; } else { try { value = (U)cachedValue; return true; } catch { value = default(U); return false; } } } #endregion } } Wiring up the DI Container Now the implementations for the Cache Dependency are in place, I wired them up in the existing Windsor CacheInstaller. First I needed to register the implementation of the ISqlCacheDependency interface: container.Register( Component.For<ISqlCacheDependency>() .ImplementedBy<AspNetSqlCacheDependency>() .LifestyleTransient()); Next I registered the Cache Dependency Factory. Notice that I have not implemented the ICacheDependencyFactory interface. Castle Windsor will do this for me by using the Type Factory Facility. I do need to bring the Castle.Facilities.TypedFacility namespace into scope: using Castle.Facilities.TypedFactory; Then I registered the factory: container.AddFacility<TypedFactoryFacility>(); container.Register( Component.For<ICacheDependencyFactory>() .AsFactory()); The full code for the CacheInstaller class is: using Castle.MicroKernel.Registration; using Castle.MicroKernel.SubSystems.Configuration; using Castle.Windsor; using Castle.Facilities.TypedFactory; using CacheDiSample.Domain.CacheInterfaces; using CacheDiSample.CacheProviders; namespace CacheDiSample.WindsorInstallers { public class CacheInstaller : IWindsorInstaller { public void Install(IWindsorContainer container, IConfigurationStore store) { container.Register( Component.For(typeof(ICacheProvider<>)) .ImplementedBy(typeof(CacheProvider<>)) .LifestyleTransient()); container.Register( Component.For<ISqlCacheDependency>() .ImplementedBy<AspNetSqlCacheDependency>() .LifestyleTransient()); container.AddFacility<TypedFactoryFacility>(); container.Register( Component.For<ICacheDependencyFactory>() .AsFactory()); } } } Configuring the ASP.NET SQL Cache Dependency There are a couple of configuration steps required to enable SQL Cache Dependency for the application and database. From the Visual Studio Command Prompt, the following commands should be used to enable the Cache Polling of the relevant database tables: aspnet_regsql -S <servername> -E -d <databasename> –ed aspnet_regsql -S <servername> -E -d CacheSample –et –t <tablename> (The –t option should be repeated for each table that is to be made available for cache dependencies). Finally the SQL Cache Polling needs to be enabled by adding the following configuration to the <system.web> section of web.config: <caching> <sqlCacheDependency pollTime="10000" enabled="true"> <databases> <add name="BloggingContext" connectionStringName="BloggingContext"/> </databases> </sqlCacheDependency> </caching> (obviously the name and connection string name should be altered as required). Using a SQL Cache Dependency Now all the coding is complete. To specify a SQL Cache Dependency, I can modify my BlogRepositoryWithCaching decorator class (see the earlier post) as follows: public IList<Blog> GetAll() { var sqlCacheDependency = cacheProvider.CreateCacheDependency<ISqlCacheDependency>() .Initialise("BloggingContext", "Blogs"); ICacheDependency[] cacheDependencies = new ICacheDependency[] { sqlCacheDependency }; string key = string.Format("CacheDiSample.DataAccess.GetAll"); return cacheProvider.Fetch(key, () => { return parentBlogRepository.GetAll(); }, null, null, cacheDependencies) .ToList(); } This will add a dependency of the “Blogs” table in the database. The data will remain in the cache until the contents of this table change, then the cache item will be invalidated, and the next call to the GetAll() repository method will be routed to the parent repository to refresh the data from the database.

Read the article

Registering InputListener in libGDX

- by JPRO

I'm just getting started with libGDX and have run into a snag registering an InputListener for a button. I've gone through many examples and this code appears correct to me but the associated callback never triggers ("touched" is not printed to console). I'm just posting the code with the abstract game screen and the implementing screen. The application starts successfully with a label of "Exit" in the bottom left hand corner, but clicking the button/label does nothing. I'm guessing the fix is something simple. What am I overlooking? public abstract class GameScreen<T> implements Screen { protected final T game; protected final SpriteBatch batch; protected final Stage stage; public GameScreen(T game) { this.game = game; this.batch = new SpriteBatch(); this.stage = new Stage(0, 0, true); } @Override public final void render(float delta) { update(delta); // Clear the screen with the given RGB color (black) Gdx.gl.glClearColor(0f, 0f, 0f, 1f); Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT); stage.act(delta); stage.draw(); } public abstract void update(float delta); @Override public void resize(int width, int height) { stage.setViewport(width, height, true); } @Override public void show() { Gdx.input.setInputProcessor(stage); } // hide, pause, resume, dipose } public class ExampleScreen extends GameScreen<MyGame> { private TextButton exitButton; public ExampleScreen(MyGame game) { super(game); } @Override public void show() { super.show(); TextButton.TextButtonStyle buttonStyle = new TextButton.TextButtonStyle(); buttonStyle.font = Font.getFont("Origicide", 32); buttonStyle.fontColor = Color.WHITE; exitButton = new TextButton("Exit", buttonStyle); exitButton.addListener(new InputListener() { @Override public void touchUp (InputEvent event, float x, float y, int pointer, int button) { System.out.println("touched"); } }); stage.addActor(exitButton); } @Override public void update(float delta) { } }

Read the article

Spritebatch drawing sprite with jagged borders

- by Mutoh

Alright, I've been on the making of a sprite class and a sprite sheet manager, but have come across this problem. Pretty much, the project is acting like so; for example: Let's take this .png image, with a transparent background. Note how it has alpha-transparent pixels around it in the lineart. Now, in the latter link's image, in the left (with CornflowerBlue background) it is shown the image drawn in another project (let's call it "Project1") with a simpler sprite class - there, it works. The right (with Purple background for differentiating) shows it drawn with a different class in "Project2" - where the problem manifests itself. This is the Sprite class of Project1: using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.Graphics; namespace WindowsGame2 { class Sprite { Vector2 pos = new Vector2(0, 0); Texture2D image; Rectangle size; float scale = 1.0f; // --- public float X { get { return pos.X; } set { pos.X = value; } } public float Y { get { return pos.Y; } set { pos.Y = value; } } public float Width { get { return size.Width; } } public float Height { get { return size.Height; } } public float Scale { get { return scale; } set { if (value < 0) value = 0; scale = value; if (image != null) { size.Width = (int)(image.Width * scale); size.Height = (int)(image.Height * scale); } } } // --- public void Load(ContentManager Man, string filename) { image = Man.Load<Texture2D>(filename); size = new Rectangle( 0, 0, (int)(image.Width * scale), (int)(image.Height * scale) ); } public void Become(Texture2D frame) { image = frame; size = new Rectangle( 0, 0, (int)(image.Width * scale), (int)(image.Height * scale) ); } public void Draw(SpriteBatch Desenhista) { // Desenhista.Draw(image, pos, Color.White); Desenhista.Draw( image, pos, new Rectangle( 0, 0, image.Width, image.Height ), Color.White, 0.0f, Vector2.Zero, scale, SpriteEffects.None, 0 ); } } } And this is the code in Project2, a rewritten, pretty much, version of the previous class. In this one I added sprite sheet managing and, in particular, removed Load and Become, to allow for static resources and only actual Sprites to be instantiated. using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.Graphics; namespace Mobby_s_Adventure { // Actually, I might desconsider this, and instead use static AnimationLocation[] and instanciated ID and Frame; // For determining the starting frame of an animation in a sheet and being able to iterate through // the Rectangles vector of the Sheet; class AnimationLocation { public int Location; public int FrameCount; // --- public AnimationLocation(int StartingRow, int StartingColumn, int SheetWidth, int NumberOfFrames) { Location = (StartingRow * SheetWidth) + StartingColumn; FrameCount = NumberOfFrames; } public AnimationLocation(int PositionInSheet, int NumberOfFrames) { Location = PositionInSheet; FrameCount = NumberOfFrames; } public static int CalculatePosition(int StartingRow, int StartingColumn, SheetManager Sheet) { return ((StartingRow * Sheet.Width) + StartingColumn); } } class Sprite { // The general stuff; protected SheetManager Sheet; protected Vector2 Position; public Vector2 Axis; protected Color _Tint; public float Angle; public float Scale; protected SpriteEffects _Effect; // --- // protected AnimationManager Animation; // For managing the animations; protected AnimationLocation[] Animation; public int AnimationID; protected int Frame; // --- // Properties for easy accessing of the position of the sprite; public float X { get { return Position.X; } set { Position.X = Axis.X + value; } } public float Y { get { return Position.Y; } set { Position.Y = Axis.Y + value; } } // --- // Properties for knowing the size of the sprite's frames public float Width { get { return Sheet.FrameWidth * Scale; } } public float Height { get { return Sheet.FrameHeight * Scale; } } // --- // Properties for more stuff; public Color Tint { set { _Tint = value; } } public SpriteEffects Effect { set { _Effect = value; } } public int FrameID { get { return Frame; } set { if (value >= (Animation[AnimationID].FrameCount)) value = 0; Frame = value; } } // --- // The only things that will be constantly modified will be AnimationID and FrameID, anything else only // occasionally; public Sprite(SheetManager SpriteSheet, AnimationLocation[] Animations, Vector2 Location, Nullable<Vector2> Origin = null) { // Assign the sprite's sprite sheet; // (Passed by reference! To allow STATIC sheets!) Sheet = SpriteSheet; // Define the animations that the sprite has available; // (Passed by reference! To allow STATIC animation boundaries!) Animation = Animations; // Defaulting some numerical values; Angle = 0.0f; Scale = 1.0f; _Tint = Color.White; _Effect = SpriteEffects.None; // If the user wants a default Axis, it is set in the middle of the frame; if (Origin != null) Axis = Origin.Value; else Axis = new Vector2( Sheet.FrameWidth / 2, Sheet.FrameHeight / 2 ); // Now that we have the axis, we can set the position with no worries; X = Location.X; Y = Location.Y; } // Simply put, draw the sprite with all its characteristics; public void Draw(SpriteBatch Drafter) { Drafter.Draw( Sheet.Texture, Position, Sheet.Rectangles[Animation[AnimationID].Location + FrameID], // Find the rectangle which frames the wanted image; _Tint, Angle, Axis, Scale, _Effect, 0.0f ); } } } And, in any case, this is the SheetManager class found in the previous code: using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.Graphics; namespace Mobby_s_Adventure { class SheetManager { protected Texture2D SpriteSheet; // For storing the sprite sheet; // Number of rows and frames in each row in the SpriteSheet; protected int NumberOfRows; protected int NumberOfColumns; // Size of a single frame; protected int _FrameWidth; protected int _FrameHeight; public Rectangle[] Rectangles; // For storing each frame; // --- public int Width { get { return NumberOfColumns; } } public int Height { get { return NumberOfRows; } } // --- public int FrameWidth { get { return _FrameWidth; } } public int FrameHeight { get { return _FrameHeight; } } // --- public Texture2D Texture { get { return SpriteSheet; } } // --- public SheetManager (Texture2D Texture, int Rows, int FramesInEachRow) { // Normal assigning SpriteSheet = Texture; NumberOfRows = Rows; NumberOfColumns = FramesInEachRow; _FrameHeight = Texture.Height / NumberOfRows; _FrameWidth = Texture.Width / NumberOfColumns; // Framing everything Rectangles = new Rectangle[NumberOfRows * NumberOfColumns]; int ID = 0; for (int i = 0; i < NumberOfRows; i++) { for (int j = 0; j < NumberOfColumns; j++) { Rectangles[ID] = new Rectangle ( _FrameWidth * j, _FrameHeight * i, _FrameWidth, _FrameHeight ); ID++; } } } public SheetManager (Texture2D Texture, int NumberOfFrames): this(Texture, 1, NumberOfFrames) { } } } For even more comprehending, if needed, here is how the main code looks like (it's just messing with the class' capacities, nothing actually; the result is a disembodied feet walking in place animation on the top-left of the screen and a static axe nearby): using System; using System.Collections.Generic; using System.Linq; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Audio; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.GamerServices; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using Microsoft.Xna.Framework.Media; using System.Threading; namespace Mobby_s_Adventure { /// <summary> /// This is the main type for your game /// </summary> public class Game1 : Microsoft.Xna.Framework.Game { GraphicsDeviceManager graphics; SpriteBatch spriteBatch; static List<Sprite> ToDraw; static Texture2D AxeSheet; static Texture2D FeetSheet; static SheetManager Axe; static Sprite Jojora; static AnimationLocation[] Hack = new AnimationLocation[1]; static SheetManager Feet; static Sprite Mutoh; static AnimationLocation[] FeetAnimations = new AnimationLocation[2]; public Game1() { graphics = new GraphicsDeviceManager(this); Content.RootDirectory = "Content"; this.TargetElapsedTime = TimeSpan.FromMilliseconds(100); this.IsFixedTimeStep = true; } /// <summary> /// Allows the game to perform any initialization it needs to before starting to run. /// This is where it can query for any required services and load any non-graphic /// related content. Calling base.Initialize will enumerate through any components /// and initialize them as well. /// </summary> protected override void Initialize() { // TODO: Add your initialization logic here base.Initialize(); } /// <summary> /// LoadContent will be called once per game and is the place to load /// all of your content. /// </summary> protected override void LoadContent() { // Create a new SpriteBatch, which can be used to draw textures. spriteBatch = new SpriteBatch(GraphicsDevice); // Loading logic ToDraw = new List<Sprite>(); AxeSheet = Content.Load<Texture2D>("Sheet"); FeetSheet = Content.Load<Texture2D>("Feet Sheet"); Axe = new SheetManager(AxeSheet, 1); Hack[0] = new AnimationLocation(0, 1); Jojora = new Sprite(Axe, Hack, new Vector2(100, 100), new Vector2(5, 55)); Jojora.AnimationID = 0; Jojora.FrameID = 0; Feet = new SheetManager(FeetSheet, 8); FeetAnimations[0] = new AnimationLocation(1, 7); FeetAnimations[1] = new AnimationLocation(0, 1); Mutoh = new Sprite(Feet, FeetAnimations, new Vector2(0, 0)); Mutoh.AnimationID = 0; Mutoh.FrameID = 0; } /// <summary> /// UnloadContent will be called once per game and is the place to unload /// all content. /// </summary> protected override void UnloadContent() { // TODO: Unload any non ContentManager content here } /// <summary> /// Allows the game to run logic such as updating the world, /// checking for collisions, gathering input, and playing audio. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Update(GameTime gameTime) { // Allows the game to exit if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed) this.Exit(); // Update logic Mutoh.FrameID++; ToDraw.Add(Mutoh); ToDraw.Add(Jojora); base.Update(gameTime); } /// <summary> /// This is called when the game should draw itself. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.Purple); // Drawing logic spriteBatch.Begin(); foreach (Sprite Element in ToDraw) { Element.Draw(spriteBatch); } spriteBatch.Draw(Content.Load<Texture2D>("Sheet"), new Rectangle(50, 50, 55, 60), Color.White); spriteBatch.End(); base.Draw(gameTime); } } } Please help me find out what I'm overlooking! One thing that I have noticed and could aid is that, if inserted the equivalent of this code spriteBatch.Draw( Content.Load<Texture2D>("Image Location"), new Rectangle(X, Y, images width, height), Color.White ); in Project2's Draw(GameTime) of the main loop, it works. EDIT Ok, even if the matter remains unsolved, I have made some more progress! As you see, I managed to get the two kinds of rendering in the same project (the aforementioned Project2, with the more complex Sprite class). This was achieved by adding the following code to Draw(GameTime): protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.Purple); // Drawing logic spriteBatch.Begin(); foreach (Sprite Element in ToDraw) { Element.Draw(spriteBatch); } // Starting here spriteBatch.Draw( Axe.Texture, new Vector2(65, 100), new Rectangle ( 0, 0, Axe.FrameWidth, Axe.FrameHeight ), Color.White, 0.0f, new Vector2(0, 0), 1.0f, SpriteEffects.None, 0.0f ); // Ending here spriteBatch.End(); base.Draw(gameTime); } (Supposing that Axe is the SheetManager containing the texture, sorry if the "jargons" of my code confuse you :s) Thus, I have noticed that the problem is within the Sprite class. But I only get more clueless, because even after modifying its Draw function to this: public void Draw(SpriteBatch Drafter) { /*Drafter.Draw( Sheet.Texture, Position, Sheet.Rectangles[Animation[AnimationID].Location + FrameID], // Find the rectangle which frames the wanted image; _Tint, Angle, Axis, Scale, _Effect, 0.0f );*/ Drafter.Draw( Sheet.Texture, Position, new Rectangle( 0, 0, Sheet.FrameWidth, Sheet.FrameHeight ), Color.White, 0.0f, Vector2.Zero, Scale, SpriteEffects.None, 0 ); } to make it as simple as the patch of code that works, it still draws the sprite jaggedly!

Read the article

A first look at ConfORM - Part 1

- by thangchung

All source codes for this post can be found at here.Have you ever heard of ConfORM is not? I have read it three months ago when I wrote an post about NHibernate and Autofac. At that time, this project really has just started and still in beta version, so I still do not really care much. But recently when reading a book by Jason Dentler NHibernate 3.0 Cookbook, I started to pay attention to it. Author have mentioned quite a lot of OSS in his book. And now again I have reviewed ConfORM once again. I have been involved in ConfORM development group on google and read some articles about it. Fabio Maulo spent a lot of work for the OSS, and I hope it will adapt a great way for NHibernate (because he contributed to NHibernate that). So what is ConfORM? It is stand for Configuration ORM, and it was trying to use a lot of heuristic model for identifying entities from C# code. Today, it's mostly Model First Driven development, so the first thing is to build the entity model. This is really important and we can see it is the heart of business software. Then we have to tell DB about the entity of this model. We often will use Inversion Engineering here, Database Schema is will create based on recently Entity Model. From now we will absolutely not interested in the DB again, only focus on the Entity Model.Fluent NHibenate really good, I liked this OSS. Sharp Architecture and has done so well in Fluent NHibernate integration with applications. A Multiple Database technical in Sharp Architecture is truly awesome. It can receive configuration, a connection string and a dll containing entity model, which would then create a SessionFactory, finally caching inside the computer memory. As the number of SessionFactory can be very large and will full of the memory, it has also devised a way of caching SessionFactory in the file. This post I hope this will not completely explain about and building a model of multiple databases. I just tried to mount a number of posts from the community and apply some of my knowledge to build a management model Session for ConfORM.As well as Fluent NHibernate, ConfORM also supported on the interface mapping, see this to understand it. So the first thing we will build the Entity Model for it, and here is what I will use the model for this article. A simple model for managing news and polls, it will be too easy for a number of people, but I hope not to bring complexity to this post.I will then have some code to build super type for the Entity Model. public interface IEntity<TId> { TId Id { get; set; } } public abstract class EntityBase<TId> : IEntity<TId> { public virtual TId Id { get; set; } public override bool Equals(object obj) { return Equals(obj as EntityBase<TId>); } private static bool IsTransient(EntityBase<TId> obj) { return obj != null && Equals(obj.Id, default(TId)); } private Type GetUnproxiedType() { return GetType(); } public virtual bool Equals(EntityBase<TId> other) { if (other == null) return false; if (ReferenceEquals(this, other)) return true; if (!IsTransient(this) && !IsTransient(other) && Equals(Id, other.Id)) { var otherType = other.GetUnproxiedType(); var thisType = GetUnproxiedType(); return thisType.IsAssignableFrom(otherType) || otherType.IsAssignableFrom(thisType); } return false; } public override int GetHashCode() { if (Equals(Id, default(TId))) return base.GetHashCode(); return Id.GetHashCode(); } } Database schema will be created as:The next step is to build the ConORM builder to create a NHibernate Configuration. Patrick have a excellent article about it at here. Contract of it below: public interface IConfigBuilder { Configuration BuildConfiguration(string connectionString, string sessionFactoryName); } The idea here is that I will pass in a connection string and a set of the DLL containing the Entity Model and it makes me a NHibernate Configuration (shame that I stole this ideas of Sharp Architecture). And here is its code: public abstract class ConfORMConfigBuilder : RootObject, IConfigBuilder { private static IConfigurator _configurator; protected IEnumerable<Type> DomainTypes; private readonly IEnumerable<string> _assemblies; protected ConfORMConfigBuilder(IEnumerable<string> assemblies) : this(new Configurator(), assemblies) { _assemblies = assemblies; } protected ConfORMConfigBuilder(IConfigurator configurator, IEnumerable<string> assemblies) { _configurator = configurator; _assemblies = assemblies; } public abstract void GetDatabaseIntegration(IDbIntegrationConfigurationProperties dBIntegration, string connectionString); protected abstract HbmMapping GetMapping(); public Configuration BuildConfiguration(string connectionString, string sessionFactoryName) { Contract.Requires(!string.IsNullOrEmpty(connectionString), "ConnectionString is null or empty"); Contract.Requires(!string.IsNullOrEmpty(sessionFactoryName), "SessionFactory name is null or empty"); Contract.Requires(_configurator != null, "Configurator is null"); return CatchExceptionHelper.TryCatchFunction( () => { DomainTypes = GetTypeOfEntities(_assemblies); if (DomainTypes == null) throw new Exception("Type of domains is null"); var configure = new Configuration(); configure.SessionFactoryName(sessionFactoryName); configure.Proxy(p => p.ProxyFactoryFactory<ProxyFactoryFactory>()); configure.DataBaseIntegration(db => GetDatabaseIntegration(db, connectionString)); if (_configurator.GetAppSettingString("IsCreateNewDatabase").ConvertToBoolean()) { configure.SetProperty("hbm2ddl.auto", "create-drop"); } configure.Properties.Add("default_schema", _configurator.GetAppSettingString("DefaultSchema")); configure.AddDeserializedMapping(GetMapping(), _configurator.GetAppSettingString("DocumentFileName")); SchemaMetadataUpdater.QuoteTableAndColumns(configure); return configure; }, Logger); } protected IEnumerable<Type> GetTypeOfEntities(IEnumerable<string> assemblies) { var type = typeof(EntityBase<Guid>); var domainTypes = new List<Type>(); foreach (var assembly in assemblies) { var realAssembly = Assembly.LoadFrom(assembly); if (realAssembly == null) throw new NullReferenceException(); domainTypes.AddRange(realAssembly.GetTypes().Where( t => { if (t.BaseType != null) return string.Compare(t.BaseType.FullName, type.FullName) == 0; return false; })); } return domainTypes; } } I do not want to dependency on any RDBMS, so I made a builder as an abstract class, and so I will create a concrete instance for SQL Server 2008 as follows: public class SqlServerConfORMConfigBuilder : ConfORMConfigBuilder { public SqlServerConfORMConfigBuilder(IEnumerable<string> assemblies) : base(assemblies) { } public override void GetDatabaseIntegration(IDbIntegrationConfigurationProperties dBIntegration, string connectionString) { dBIntegration.Dialect<MsSql2008Dialect>(); dBIntegration.Driver<SqlClientDriver>(); dBIntegration.KeywordsAutoImport = Hbm2DDLKeyWords.AutoQuote; dBIntegration.IsolationLevel = IsolationLevel.ReadCommitted; dBIntegration.ConnectionString = connectionString; dBIntegration.LogSqlInConsole = true; dBIntegration.Timeout = 10; dBIntegration.LogFormatedSql = true; dBIntegration.HqlToSqlSubstitutions = "true 1, false 0, yes 'Y', no 'N'"; } protected override HbmMapping GetMapping() { var orm = new ObjectRelationalMapper(); orm.Patterns.PoidStrategies.Add(new GuidPoidPattern()); var patternsAppliers = new CoolPatternsAppliersHolder(orm); //patternsAppliers.Merge(new DatePropertyByNameApplier()).Merge(new MsSQL2008DateTimeApplier()); patternsAppliers.Merge(new ManyToOneColumnNamingApplier()); patternsAppliers.Merge(new OneToManyKeyColumnNamingApplier(orm)); var mapper = new Mapper(orm, patternsAppliers); var entities = new List<Type>(); DomainDefinition(orm); Customize(mapper); entities.AddRange(DomainTypes); return mapper.CompileMappingFor(entities); } private void DomainDefinition(IObjectRelationalMapper orm) { orm.TablePerClassHierarchy(new[] { typeof(EntityBase<Guid>) }); orm.TablePerClass(DomainTypes); orm.OneToOne<News, Poll>(); orm.ManyToOne<Category, News>(); orm.Cascade<Category, News>(Cascade.All); orm.Cascade<News, Poll>(Cascade.All); orm.Cascade<User, Poll>(Cascade.All); } private static void Customize(Mapper mapper) { CustomizeRelations(mapper); CustomizeTables(mapper); CustomizeColumns(mapper); } private static void CustomizeRelations(Mapper mapper) { } private static void CustomizeTables(Mapper mapper) { } private static void CustomizeColumns(Mapper mapper) { mapper.Class<Category>( cm => { cm.Property(x => x.Name, m => m.NotNullable(true)); cm.Property(x => x.CreatedDate, m => m.NotNullable(true)); }); mapper.Class<News>( cm => { cm.Property(x => x.Title, m => m.NotNullable(true)); cm.Property(x => x.ShortDescription, m => m.NotNullable(true)); cm.Property(x => x.Content, m => m.NotNullable(true)); }); mapper.Class<Poll>( cm => { cm.Property(x => x.Value, m => m.NotNullable(true)); cm.Property(x => x.VoteDate, m => m.NotNullable(true)); cm.Property(x => x.WhoVote, m => m.NotNullable(true)); }); mapper.Class<User>( cm => { cm.Property(x => x.UserName, m => m.NotNullable(true)); cm.Property(x => x.Password, m => m.NotNullable(true)); }); } } As you can see that we can do so many things in this class, such as custom entity relationships, custom binding on the columns, custom table name, ... Here I only made two so-Appliers for OneToMany and ManyToOne relationships, you can refer to it here public class ManyToOneColumnNamingApplier : IPatternApplier<PropertyPath, IManyToOneMapper> { #region IPatternApplier<PropertyPath,IManyToOneMapper> Members public void Apply(PropertyPath subject, IManyToOneMapper applyTo) { applyTo.Column(subject.ToColumnName() + "Id"); } #endregion #region IPattern<PropertyPath> Members public bool Match(PropertyPath subject) { return subject != null; } #endregion } public class OneToManyKeyColumnNamingApplier : OneToManyPattern, IPatternApplier<PropertyPath, ICollectionPropertiesMapper> { public OneToManyKeyColumnNamingApplier(IDomainInspector domainInspector) : base(domainInspector) { } #region Implementation of IPattern<PropertyPath> public bool Match(PropertyPath subject) { return Match(subject.LocalMember); } #endregion Implementation of IPattern<PropertyPath> #region Implementation of IPatternApplier<PropertyPath,ICollectionPropertiesMapper> public void Apply(PropertyPath subject, ICollectionPropertiesMapper applyTo) { applyTo.Key(km => km.Column(GetKeyColumnName(subject))); } #endregion Implementation of IPatternApplier<PropertyPath,ICollectionPropertiesMapper> protected virtual string GetKeyColumnName(PropertyPath subject) { Type propertyType = subject.LocalMember.GetPropertyOrFieldType(); Type childType = propertyType.DetermineCollectionElementType(); var entity = subject.GetContainerEntity(DomainInspector); var parentPropertyInChild = childType.GetFirstPropertyOfType(entity); var baseName = parentPropertyInChild == null ? subject.PreviousPath == null ? entity.Name : entity.Name + subject.PreviousPath : parentPropertyInChild.Name; return GetKeyColumnName(baseName); } protected virtual string GetKeyColumnName(string baseName) { return string.Format("{0}Id", baseName); } } Everyone also can download the ConfORM source at google code and see example inside it. Next part I will write about multiple database factory. Hope you enjoy about it. happy coding and see you next part.

Read the article

Using R to Analyze G1GC Log Files

- by user12620111

Using R to Analyze G1GC Log Files body, td { font-family: sans-serif; background-color: white; font-size: 12px; margin: 8px; } tt, code, pre { font-family: 'DejaVu Sans Mono', 'Droid Sans Mono', 'Lucida Console', Consolas, Monaco, monospace; } h1 { font-size:2.2em; } h2 { font-size:1.8em; } h3 { font-size:1.4em; } h4 { font-size:1.0em; } h5 { font-size:0.9em; } h6 { font-size:0.8em; } a:visited { color: rgb(50%, 0%, 50%); } pre { margin-top: 0; max-width: 95%; border: 1px solid #ccc; white-space: pre-wrap; } pre code { display: block; padding: 0.5em; } code.r, code.cpp { background-color: #F8F8F8; } table, td, th { border: none; } blockquote { color:#666666; margin:0; padding-left: 1em; border-left: 0.5em #EEE solid; } hr { height: 0px; border-bottom: none; border-top-width: thin; border-top-style: dotted; border-top-color: #999999; } @media print { * { background: transparent !important; color: black !important; filter:none !important; -ms-filter: none !important; } body { font-size:12pt; max-width:100%; } a, a:visited { text-decoration: underline; } hr { visibility: hidden; page-break-before: always; } pre, blockquote { padding-right: 1em; page-break-inside: avoid; } tr, img { page-break-inside: avoid; } img { max-width: 100% !important; } @page :left { margin: 15mm 20mm 15mm 10mm; } @page :right { margin: 15mm 10mm 15mm 20mm; } p, h2, h3 { orphans: 3; widows: 3; } h2, h3 { page-break-after: avoid; } } pre .operator, pre .paren { color: rgb(104, 118, 135) } pre .literal { color: rgb(88, 72, 246) } pre .number { color: rgb(0, 0, 205); } pre .comment { color: rgb(76, 136, 107); } pre .keyword { color: rgb(0, 0, 255); } pre .identifier { color: rgb(0, 0, 0); } pre .string { color: rgb(3, 106, 7); } var hljs=new function(){function m(p){return p.replace(/&/gm,"&").replace(/"}while(y.length||w.length){var v=u().splice(0,1)[0];z+=m(x.substr(q,v.offset-q));q=v.offset;if(v.event=="start"){z+=t(v.node);s.push(v.node)}else{if(v.event=="stop"){var p,r=s.length;do{r--;p=s[r];z+=("")}while(p!=v.node);s.splice(r,1);while(r'+M[0]+""}else{r+=M[0]}O=P.lR.lastIndex;M=P.lR.exec(L)}return r+L.substr(O,L.length-O)}function J(L,M){if(M.sL&&e[M.sL]){var r=d(M.sL,L);x+=r.keyword_count;return r.value}else{return F(L,M)}}function I(M,r){var L=M.cN?'':"";if(M.rB){y+=L;M.buffer=""}else{if(M.eB){y+=m(r)+L;M.buffer=""}else{y+=L;M.buffer=r}}D.push(M);A+=M.r}function G(N,M,Q){var R=D[D.length-1];if(Q){y+=J(R.buffer+N,R);return false}var P=q(M,R);if(P){y+=J(R.buffer+N,R);I(P,M);return P.rB}var L=v(D.length-1,M);if(L){var O=R.cN?"":"";if(R.rE){y+=J(R.buffer+N,R)+O}else{if(R.eE){y+=J(R.buffer+N,R)+O+m(M)}else{y+=J(R.buffer+N+M,R)+O}}while(L1){O=D[D.length-2].cN?"":"";y+=O;L--;D.length--}var r=D[D.length-1];D.length--;D[D.length-1].buffer="";if(r.starts){I(r.starts,"")}return R.rE}if(w(M,R)){throw"Illegal"}}var E=e[B];var D=[E.dM];var A=0;var x=0;var y="";try{var s,u=0;E.dM.buffer="";do{s=p(C,u);var t=G(s[0],s[1],s[2]);u+=s[0].length;if(!t){u+=s[1].length}}while(!s[2]);if(D.length1){throw"Illegal"}return{r:A,keyword_count:x,value:y}}catch(H){if(H=="Illegal"){return{r:0,keyword_count:0,value:m(C)}}else{throw H}}}function g(t){var p={keyword_count:0,r:0,value:m(t)};var r=p;for(var q in e){if(!e.hasOwnProperty(q)){continue}var s=d(q,t);s.language=q;if(s.keyword_count+s.rr.keyword_count+r.r){r=s}if(s.keyword_count+s.rp.keyword_count+p.r){r=p;p=s}}if(r.language){p.second_best=r}return p}function i(r,q,p){if(q){r=r.replace(/^((]+|\t)+)/gm,function(t,w,v,u){return w.replace(/\t/g,q)})}if(p){r=r.replace(/\n/g,"")}return r}function n(t,w,r){var x=h(t,r);var v=a(t);var y,s;if(v){y=d(v,x)}else{return}var q=c(t);if(q.length){s=document.createElement("pre");s.innerHTML=y.value;y.value=k(q,c(s),x)}y.value=i(y.value,w,r);var u=t.className;if(!u.match("(\\s|^)(language-)?"+v+"(\\s|$)")){u=u?(u+" "+v):v}if(/MSIE [678]/.test(navigator.userAgent)&&t.tagName=="CODE"&&t.parentNode.tagName=="PRE"){s=t.parentNode;var p=document.createElement("div");p.innerHTML=""+y.value+"";t=p.firstChild.firstChild;p.firstChild.cN=s.cN;s.parentNode.replaceChild(p.firstChild,s)}else{t.innerHTML=y.value}t.className=u;t.result={language:v,kw:y.keyword_count,re:y.r};if(y.second_best){t.second_best={language:y.second_best.language,kw:y.second_best.keyword_count,re:y.second_best.r}}}function o(){if(o.called){return}o.called=true;var r=document.getElementsByTagName("pre");for(var p=0;p|=||=||=|\\?|\\[|\\{|\\(|\\^|\\^=|\\||\\|=|\\|\\||~";this.ER="(?![\\s\\S])";this.BE={b:"\\\\.",r:0};this.ASM={cN:"string",b:"'",e:"'",i:"\\n",c:[this.BE],r:0};this.QSM={cN:"string",b:'"',e:'"',i:"\\n",c:[this.BE],r:0};this.CLCM={cN:"comment",b:"//",e:"$"};this.CBLCLM={cN:"comment",b:"/\\*",e:"\\*/"};this.HCM={cN:"comment",b:"#",e:"$"};this.NM={cN:"number",b:this.NR,r:0};this.CNM={cN:"number",b:this.CNR,r:0};this.BNM={cN:"number",b:this.BNR,r:0};this.inherit=function(r,s){var p={};for(var q in r){p[q]=r[q]}if(s){for(var q in s){p[q]=s[q]}}return p}}();hljs.LANGUAGES.cpp=function(){var a={keyword:{"false":1,"int":1,"float":1,"while":1,"private":1,"char":1,"catch":1,"export":1,virtual:1,operator:2,sizeof:2,dynamic_cast:2,typedef:2,const_cast:2,"const":1,struct:1,"for":1,static_cast:2,union:1,namespace:1,unsigned:1,"long":1,"throw":1,"volatile":2,"static":1,"protected":1,bool:1,template:1,mutable:1,"if":1,"public":1,friend:2,"do":1,"return":1,"goto":1,auto:1,"void":2,"enum":1,"else":1,"break":1,"new":1,extern:1,using:1,"true":1,"class":1,asm:1,"case":1,typeid:1,"short":1,reinterpret_cast:2,"default":1,"double":1,register:1,explicit:1,signed:1,typename:1,"try":1,"this":1,"switch":1,"continue":1,wchar_t:1,inline:1,"delete":1,alignof:1,char16_t:1,char32_t:1,constexpr:1,decltype:1,noexcept:1,nullptr:1,static_assert:1,thread_local:1,restrict:1,_Bool:1,complex:1},built_in:{std:1,string:1,cin:1,cout:1,cerr:1,clog:1,stringstream:1,istringstream:1,ostringstream:1,auto_ptr:1,deque:1,list:1,queue:1,stack:1,vector:1,map:1,set:1,bitset:1,multiset:1,multimap:1,unordered_set:1,unordered_map:1,unordered_multiset:1,unordered_multimap:1,array:1,shared_ptr:1}};return{dM:{k:a,i:"",k:a,r:10,c:["self"]}]}}}();hljs.LANGUAGES.r={dM:{c:[hljs.HCM,{cN:"number",b:"\\b0[xX][0-9a-fA-F]+[Li]?\\b",e:hljs.IMMEDIATE_RE,r:0},{cN:"number",b:"\\b\\d+(?:[eE][+\\-]?\\d*)?L\\b",e:hljs.IMMEDIATE_RE,r:0},{cN:"number",b:"\\b\\d+\\.(?!\\d)(?:i\\b)?",e:hljs.IMMEDIATE_RE,r:1},{cN:"number",b:"\\b\\d+(?:\\.\\d*)?(?:[eE][+\\-]?\\d*)?i?\\b",e:hljs.IMMEDIATE_RE,r:0},{cN:"number",b:"\\.\\d+(?:[eE][+\\-]?\\d*)?i?\\b",e:hljs.IMMEDIATE_RE,r:1},{cN:"keyword",b:"(?:tryCatch|library|setGeneric|setGroupGeneric)\\b",e:hljs.IMMEDIATE_RE,r:10},{cN:"keyword",b:"\\.\\.\\.",e:hljs.IMMEDIATE_RE,r:10},{cN:"keyword",b:"\\.\\.\\d+(?![\\w.])",e:hljs.IMMEDIATE_RE,r:10},{cN:"keyword",b:"\\b(?:function)",e:hljs.IMMEDIATE_RE,r:2},{cN:"keyword",b:"(?:if|in|break|next|repeat|else|for|return|switch|while|try|stop|warning|require|attach|detach|source|setMethod|setClass)\\b",e:hljs.IMMEDIATE_RE,r:1},{cN:"literal",b:"(?:NA|NA_integer_|NA_real_|NA_character_|NA_complex_)\\b",e:hljs.IMMEDIATE_RE,r:10},{cN:"literal",b:"(?:NULL|TRUE|FALSE|T|F|Inf|NaN)\\b",e:hljs.IMMEDIATE_RE,r:1},{cN:"identifier",b:"[a-zA-Z.][a-zA-Z0-9._]*\\b",e:hljs.IMMEDIATE_RE,r:0},{cN:"operator",b:"|=|| Using R to Analyze G1GC Log Files Using R to Analyze G1GC Log Files Introduction Working in Oracle Platform Integration gives an engineer opportunities to work on a wide array of technologies. My team’s goal is to make Oracle applications run best on the Solaris/SPARC platform. When looking for bottlenecks in a modern applications, one needs to be aware of not only how the CPUs and operating system are executing, but also network, storage, and in some cases, the Java Virtual Machine. I was recently presented with about 1.5 GB of Java Garbage First Garbage Collector log file data. If you’re not familiar with the subject, you might want to review Garbage First Garbage Collector Tuning by Monica Beckwith. The customer had been running Java HotSpot 1.6.0_31 to host a web application server. I was told that the Solaris/SPARC server was running a Java process launched using a commmand line that included the following flags: -d64 -Xms9g -Xmx9g -XX:+UseG1GC -XX:MaxGCPauseMillis=200 -XX:InitiatingHeapOccupancyPercent=80 -XX:PermSize=256m -XX:MaxPermSize=256m -XX:+PrintGC -XX:+PrintGCTimeStamps -XX:+PrintHeapAtGC -XX:+PrintGCDateStamps -XX:+PrintFlagsFinal -XX:+DisableExplicitGC -XX:+UnlockExperimentalVMOptions -XX:ParallelGCThreads=8 Several sources on the internet indicate that if I were to print out the 1.5 GB of log files, it would require enough paper to fill the bed of a pick up truck. Of course, it would be fruitless to try to scan the log files by hand. Tools will be required to summarize the contents of the log files. Others have encountered large Java garbage collection log files. There are existing tools to analyze the log files: IBM’s GC toolkit The chewiebug GCViewer gchisto HPjmeter Instead of using one of the other tools listed, I decide to parse the log files with standard Unix tools, and analyze the data with R. Data Cleansing The log files arrived in two different formats. I guess that the difference is that one set of log files was generated using a more verbose option, maybe -XX:+PrintHeapAtGC, and the other set of log files was generated without that option. Format 1 In some of the log files, the log files with the less verbose format, a single trace, i.e. the report of a singe garbage collection event, looks like this: {Heap before GC invocations=12280 (full 61): garbage-first heap total 9437184K, used 7499918K [0xfffffffd00000000, 0xffffffff40000000, 0xffffffff40000000) region size 4096K, 1 young (4096K), 0 survivors (0K) compacting perm gen total 262144K, used 144077K [0xffffffff40000000, 0xffffffff50000000, 0xffffffff50000000) the space 262144K, 54% used [0xffffffff40000000, 0xffffffff48cb3758, 0xffffffff48cb3800, 0xffffffff50000000) No shared spaces configured. 2014-05-14T07:24:00.988-0700: 60586.353: [GC pause (young) 7324M->7320M(9216M), 0.1567265 secs] Heap after GC invocations=12281 (full 61): garbage-first heap total 9437184K, used 7496533K [0xfffffffd00000000, 0xffffffff40000000, 0xffffffff40000000) region size 4096K, 0 young (0K), 0 survivors (0K) compacting perm gen total 262144K, used 144077K [0xffffffff40000000, 0xffffffff50000000, 0xffffffff50000000) the space 262144K, 54% used [0xffffffff40000000, 0xffffffff48cb3758, 0xffffffff48cb3800, 0xffffffff50000000) No shared spaces configured. } A simple grep can be used to extract a summary: $ grep "\[ GC pause (young" g1gc.log 2014-05-13T13:24:35.091-0700: 3.109: [GC pause (young) 20M->5029K(9216M), 0.0146328 secs] 2014-05-13T13:24:35.440-0700: 3.459: [GC pause (young) 9125K->6077K(9216M), 0.0086723 secs] 2014-05-13T13:24:37.581-0700: 5.599: [GC pause (young) 25M->8470K(9216M), 0.0203820 secs] 2014-05-13T13:24:42.686-0700: 10.704: [GC pause (young) 44M->15M(9216M), 0.0288848 secs] 2014-05-13T13:24:48.941-0700: 16.958: [GC pause (young) 51M->20M(9216M), 0.0491244 secs] 2014-05-13T13:24:56.049-0700: 24.066: [GC pause (young) 92M->26M(9216M), 0.0525368 secs] 2014-05-13T13:25:34.368-0700: 62.383: [GC pause (young) 602M->68M(9216M), 0.1721173 secs] But that format wasn't easily read into R, so I needed to be a bit more tricky. I used the following Unix command to create a summary file that was easy for R to read. $ echo "SecondsSinceLaunch BeforeSize AfterSize TotalSize RealTime" $ grep "\[GC pause (young" g1gc.log | grep -v mark | sed -e 's/[A-SU-z,]/ /g' -e 's/->/ /' -e 's/: / /g' | more SecondsSinceLaunch BeforeSize AfterSize TotalSize RealTime 2014-05-13T13:24:35.091-0700 3.109 20 5029 9216 0.0146328 2014-05-13T13:24:35.440-0700 3.459 9125 6077 9216 0.0086723 2014-05-13T13:24:37.581-0700 5.599 25 8470 9216 0.0203820 2014-05-13T13:24:42.686-0700 10.704 44 15 9216 0.0288848 2014-05-13T13:24:48.941-0700 16.958 51 20 9216 0.0491244 2014-05-13T13:24:56.049-0700 24.066 92 26 9216 0.0525368 2014-05-13T13:25:34.368-0700 62.383 602 68 9216 0.1721173 Format 2 In some of the log files, the log files with the more verbose format, a single trace, i.e. the report of a singe garbage collection event, was more complicated than Format 1. Here is a text file with an example of a single G1GC trace in the second format. As you can see, it is quite complicated. It is nice that there is so much information available, but the level of detail can be overwhelming. I wrote this awk script (download) to summarize each trace on a single line. #!/usr/bin/env awk -f BEGIN { printf("SecondsSinceLaunch IncrementalCount FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize\n") } ###################### # Save count data from lines that are at the start of each G1GC trace. # Each trace starts out like this: # {Heap before GC invocations=14 (full 0): # garbage-first heap total 9437184K, used 325496K [0xfffffffd00000000, 0xffffffff40000000, 0xffffffff40000000) ###################### /{Heap.*full/{ gsub ( "\\)" , "" ); nf=split($0,a,"="); split(a[2],b," "); getline; if ( match($0, "first") ) { G1GC=1; IncrementalCount=b[1]; FullCount=substr( b[3], 1, length(b[3])-1 ); } else { G1GC=0; } } ###################### # Pull out time stamps that are in lines with this format: # 2014-05-12T14:02:06.025-0700: 94.312: [GC pause (young), 0.08870154 secs] ###################### /GC pause/ { DateTime=$1; SecondsSinceLaunch=substr($2, 1, length($2)-1); } ###################### # Heap sizes are in lines that look like this: # [ 4842M->4838M(9216M)] ###################### /\[ .*]$/ { gsub ( "\\[" , "" ); gsub ( "\ \]" , "" ); gsub ( "->" , " " ); gsub ( "\$ " , " " ); gsub ( "\ $" , " " ); split($0,a," "); if ( split(a[1],b,"M") > 1 ) {BeforeSize=b[1]*1024;} if ( split(a[1],b,"K") > 1 ) {BeforeSize=b[1];} if ( split(a[2],b,"M") > 1 ) {AfterSize=b[1]*1024;} if ( split(a[2],b,"K") > 1 ) {AfterSize=b[1];} if ( split(a[3],b,"M") > 1 ) {TotalSize=b[1]*1024;} if ( split(a[3],b,"K") > 1 ) {TotalSize=b[1];} } ###################### # Emit an output line when you find input that looks like this: # [Times: user=1.41 sys=0.08, real=0.24 secs] ###################### /\[Times/ { if (G1GC==1) { gsub ( "," , "" ); split($2,a,"="); UserTime=a[2]; split($3,a,"="); SysTime=a[2]; split($4,a,"="); RealTime=a[2]; print DateTime,SecondsSinceLaunch,IncrementalCount,FullCount,UserTime,SysTime,RealTime,BeforeSize,AfterSize,TotalSize; G1GC=0; } } The resulting summary is about 25X smaller that the original file, but still difficult for a human to digest. SecondsSinceLaunch IncrementalCount FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize ... 2014-05-12T18:36:34.669-0700: 3985.744 561 0 0.57 0.06 0.16 1724416 1720320 9437184 2014-05-12T18:36:34.839-0700: 3985.914 562 0 0.51 0.06 0.19 1724416 1720320 9437184 2014-05-12T18:36:35.069-0700: 3986.144 563 0 0.60 0.04 0.27 1724416 1721344 9437184 2014-05-12T18:36:35.354-0700: 3986.429 564 0 0.33 0.04 0.09 1725440 1722368 9437184 2014-05-12T18:36:35.545-0700: 3986.620 565 0 0.58 0.04 0.17 1726464 1722368 9437184 2014-05-12T18:36:35.726-0700: 3986.801 566 0 0.43 0.05 0.12 1726464 1722368 9437184 2014-05-12T18:36:35.856-0700: 3986.930 567 0 0.30 0.04 0.07 1726464 1723392 9437184 2014-05-12T18:36:35.947-0700: 3987.023 568 0 0.61 0.04 0.26 1727488 1723392 9437184 2014-05-12T18:36:36.228-0700: 3987.302 569 0 0.46 0.04 0.16 1731584 1724416 9437184 Reading the Data into R Once the GC log data had been cleansed, either by processing the first format with the shell script, or by processing the second format with the awk script, it was easy to read the data into R. g1gc.df = read.csv("summary.txt", row.names = NULL, stringsAsFactors=FALSE,sep="") str(g1gc.df) ## 'data.frame': 8307 obs. of 10 variables: ## $ row.names : chr "2014-05-12T14:00:32.868-0700:" "2014-05-12T14:00:33.179-0700:" "2014-05-12T14:00:33.677-0700:" "2014-05-12T14:00:35.538-0700:" ... ## $ SecondsSinceLaunch: num 1.16 1.47 1.97 3.83 6.1 ... ## $ IncrementalCount : int 0 1 2 3 4 5 6 7 8 9 ... ## $ FullCount : int 0 0 0 0 0 0 0 0 0 0 ... ## $ UserTime : num 0.11 0.05 0.04 0.21 0.08 0.26 0.31 0.33 0.34 0.56 ... ## $ SysTime : num 0.04 0.01 0.01 0.05 0.01 0.06 0.07 0.06 0.07 0.09 ... ## $ RealTime : num 0.02 0.02 0.01 0.04 0.02 0.04 0.05 0.04 0.04 0.06 ... ## $ BeforeSize : int 8192 5496 5768 22528 24576 43008 34816 53248 55296 93184 ... ## $ AfterSize : int 1400 1672 2557 4907 7072 14336 16384 18432 19456 21504 ... ## $ TotalSize : int 9437184 9437184 9437184 9437184 9437184 9437184 9437184 9437184 9437184 9437184 ... head(g1gc.df) ## row.names SecondsSinceLaunch IncrementalCount ## 1 2014-05-12T14:00:32.868-0700: 1.161 0 ## 2 2014-05-12T14:00:33.179-0700: 1.472 1 ## 3 2014-05-12T14:00:33.677-0700: 1.969 2 ## 4 2014-05-12T14:00:35.538-0700: 3.830 3 ## 5 2014-05-12T14:00:37.811-0700: 6.103 4 ## 6 2014-05-12T14:00:41.428-0700: 9.720 5 ## FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize ## 1 0 0.11 0.04 0.02 8192 1400 9437184 ## 2 0 0.05 0.01 0.02 5496 1672 9437184 ## 3 0 0.04 0.01 0.01 5768 2557 9437184 ## 4 0 0.21 0.05 0.04 22528 4907 9437184 ## 5 0 0.08 0.01 0.02 24576 7072 9437184 ## 6 0 0.26 0.06 0.04 43008 14336 9437184 Basic Statistics Once the data has been read into R, simple statistics are very easy to generate. All of the numbers from high school statistics are available via simple commands. For example, generate a summary of every column: summary(g1gc.df) ## row.names SecondsSinceLaunch IncrementalCount FullCount ## Length:8307 Min. : 1 Min. : 0 Min. : 0.0 ## Class :character 1st Qu.: 9977 1st Qu.:2048 1st Qu.: 0.0 ## Mode :character Median :12855 Median :4136 Median : 12.0 ## Mean :12527 Mean :4156 Mean : 31.6 ## 3rd Qu.:15758 3rd Qu.:6262 3rd Qu.: 61.0 ## Max. :55484 Max. :8391 Max. :113.0 ## UserTime SysTime RealTime BeforeSize ## Min. :0.040 Min. :0.0000 Min. : 0.0 Min. : 5476 ## 1st Qu.:0.470 1st Qu.:0.0300 1st Qu.: 0.1 1st Qu.:5137920 ## Median :0.620 Median :0.0300 Median : 0.1 Median :6574080 ## Mean :0.751 Mean :0.0355 Mean : 0.3 Mean :5841855 ## 3rd Qu.:0.920 3rd Qu.:0.0400 3rd Qu.: 0.2 3rd Qu.:7084032 ## Max. :3.370 Max. :1.5600 Max. :488.1 Max. :8696832 ## AfterSize TotalSize ## Min. : 1380 Min. :9437184 ## 1st Qu.:5002752 1st Qu.:9437184 ## Median :6559744 Median :9437184 ## Mean :5785454 Mean :9437184 ## 3rd Qu.:7054336 3rd Qu.:9437184 ## Max. :8482816 Max. :9437184 Q: What is the total amount of User CPU time spent in garbage collection? sum(g1gc.df$UserTime) ## [1] 6236 As you can see, less than two hours of CPU time was spent in garbage collection. Is that too much? To find the percentage of time spent in garbage collection, divide the number above by total_elapsed_time*CPU_count. In this case, there are a lot of CPU’s and it turns out the the overall amount of CPU time spent in garbage collection isn’t a problem when viewed in isolation. When calculating rates, i.e. events per unit time, you need to ask yourself if the rate is homogenous across the time period in the log file. Does the log file include spikes of high activity that should be separately analyzed? Averaging in data from nights and weekends with data from business hours may alias problems. If you have a reason to suspect that the garbage collection rates include peaks and valleys that need independent analysis, see the “Time Series” section, below. Q: How much garbage is collected on each pass? The amount of heap space that is recovered per GC pass is surprisingly low: At least one collection didn’t recover any data. (“Min.=0”) 25% of the passes recovered 3MB or less. (“1st Qu.=3072”) Half of the GC passes recovered 4MB or less. (“Median=4096”) The average amount recovered was 56MB. (“Mean=56390”) 75% of the passes recovered 36MB or less. (“3rd Qu.=36860”) At least one pass recovered 2GB. (“Max.=2121000”) g1gc.df$Delta = g1gc.df$BeforeSize - g1gc.df$AfterSize summary(g1gc.df$Delta) ## Min. 1st Qu. Median Mean 3rd Qu. Max. ## 0 3070 4100 56400 36900 2120000 Q: What is the maximum User CPU time for a single collection? The worst garbage collection (“Max.”) is many standard deviations away from the mean. The data appears to be right skewed. summary(g1gc.df$UserTime) ## Min. 1st Qu. Median Mean 3rd Qu. Max. ## 0.040 0.470 0.620 0.751 0.920 3.370 sd(g1gc.df$UserTime) ## [1] 0.3966 Basic Graphics Once the data is in R, it is trivial to plot the data with formats including dot plots, line charts, bar charts (simple, stacked, grouped), pie charts, boxplots, scatter plots histograms, and kernel density plots. Histogram of User CPU Time per Collection I don't think that this graph requires any explanation. hist(g1gc.df$UserTime, main="User CPU Time per Collection", xlab="Seconds", ylab="Frequency") Box plot to identify outliers When the initial data is viewed with a box plot, you can see the one crazy outlier in the real time per GC. Save this data point for future analysis and drop the outlier so that it’s not throwing off our statistics. Now the box plot shows many outliers, which will be examined later, using times series analysis. Notice that the scale of the x-axis changes drastically once the crazy outlier is removed. par(mfrow=c(2,1)) boxplot(g1gc.df$UserTime,g1gc.df$SysTime,g1gc.df$RealTime, main="Box Plot of Time per GC\n(dominated by a crazy outlier)", names=c("usr","sys","elapsed"), xlab="Seconds per GC", ylab="Time (Seconds)", horizontal = TRUE, outcol="red") crazy.outlier.df=g1gc.df[g1gc.df$RealTime > 400,] g1gc.df=g1gc.df[g1gc.df$RealTime < 400,] boxplot(g1gc.df$UserTime,g1gc.df$SysTime,g1gc.df$RealTime, main="Box Plot of Time per GC\n(crazy outlier excluded)", names=c("usr","sys","elapsed"), xlab="Seconds per GC", ylab="Time (Seconds)", horizontal = TRUE, outcol="red") box(which = "outer", lty = "solid") Here is the crazy outlier for future analysis: crazy.outlier.df ## row.names SecondsSinceLaunch IncrementalCount ## 8233 2014-05-12T23:15:43.903-0700: 20741 8316 ## FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize ## 8233 112 0.55 0.42 488.1 8381440 8235008 9437184 ## Delta ## 8233 146432 R Time Series Data To analyze the garbage collection as a time series, I’ll use Z’s Ordered Observations (zoo). “zoo is the creator for an S3 class of indexed totally ordered observations which includes irregular time series.” require(zoo) ## Loading required package: zoo ## ## Attaching package: 'zoo' ## ## The following objects are masked from 'package:base': ## ## as.Date, as.Date.numeric head(g1gc.df[,1]) ## [1] "2014-05-12T14:00:32.868-0700:" "2014-05-12T14:00:33.179-0700:" ## [3] "2014-05-12T14:00:33.677-0700:" "2014-05-12T14:00:35.538-0700:" ## [5] "2014-05-12T14:00:37.811-0700:" "2014-05-12T14:00:41.428-0700:" options("digits.secs"=3) times=as.POSIXct( g1gc.df[,1], format="%Y-%m-%dT%H:%M:%OS%z:") g1gc.z = zoo(g1gc.df[,-c(1)], order.by=times) head(g1gc.z) ## SecondsSinceLaunch IncrementalCount FullCount ## 2014-05-12 17:00:32.868 1.161 0 0 ## 2014-05-12 17:00:33.178 1.472 1 0 ## 2014-05-12 17:00:33.677 1.969 2 0 ## 2014-05-12 17:00:35.538 3.830 3 0 ## 2014-05-12 17:00:37.811 6.103 4 0 ## 2014-05-12 17:00:41.427 9.720 5 0 ## UserTime SysTime RealTime BeforeSize AfterSize ## 2014-05-12 17:00:32.868 0.11 0.04 0.02 8192 1400 ## 2014-05-12 17:00:33.178 0.05 0.01 0.02 5496 1672 ## 2014-05-12 17:00:33.677 0.04 0.01 0.01 5768 2557 ## 2014-05-12 17:00:35.538 0.21 0.05 0.04 22528 4907 ## 2014-05-12 17:00:37.811 0.08 0.01 0.02 24576 7072 ## 2014-05-12 17:00:41.427 0.26 0.06 0.04 43008 14336 ## TotalSize Delta ## 2014-05-12 17:00:32.868 9437184 6792 ## 2014-05-12 17:00:33.178 9437184 3824 ## 2014-05-12 17:00:33.677 9437184 3211 ## 2014-05-12 17:00:35.538 9437184 17621 ## 2014-05-12 17:00:37.811 9437184 17504 ## 2014-05-12 17:00:41.427 9437184 28672 Example of Two Benchmark Runs in One Log File The data in the following graph is from a different log file, not the one of primary interest to this article. I’m including this image because it is an example of idle periods followed by busy periods. It would be uninteresting to average the rate of garbage collection over the entire log file period. More interesting would be the rate of garbage collect in the two busy periods. Are they the same or different? Your production data may be similar, for example, bursts when employees return from lunch and idle times on weekend evenings, etc. Once the data is in an R Time Series, you can analyze isolated time windows. Clipping the Time Series data Flashing back to our test case… Viewing the data as a time series is interesting. You can see that the work intensive time period is between 9:00 PM and 3:00 AM. Lets clip the data to the interesting period: par(mfrow=c(2,1)) plot(g1gc.z$UserTime, type="h", main="User Time per GC\nTime: Complete Log File", xlab="Time of Day", ylab="CPU Seconds per GC", col="#1b9e77") clipped.g1gc.z=window(g1gc.z, start=as.POSIXct("2014-05-12 21:00:00"), end=as.POSIXct("2014-05-13 03:00:00")) plot(clipped.g1gc.z$UserTime, type="h", main="User Time per GC\nTime: Limited to Benchmark Execution", xlab="Time of Day", ylab="CPU Seconds per GC", col="#1b9e77") box(which = "outer", lty = "solid") Cumulative Incremental and Full GC count Here is the cumulative incremental and full GC count. When the line is very steep, it indicates that the GCs are repeating very quickly. Notice that the scale on the Y axis is different for full vs. incremental. plot(clipped.g1gc.z[,c(2:3)], main="Cumulative Incremental and Full GC count", xlab="Time of Day", col="#1b9e77") GC Analysis of Benchmark Execution using Time Series data In the following series of 3 graphs: The “After Size” show the amount of heap space in use after each garbage collection. Many Java objects are still referenced, i.e. alive, during each garbage collection. This may indicate that the application has a memory leak, or may indicate that the application has a very large memory footprint. Typically, an application's memory footprint plateau's in the early stage of execution. One would expect this graph to have a flat top. The steep decline in the heap space may indicate that the application crashed after 2:00. The second graph shows that the outliers in real execution time, discussed above, occur near 2:00. when the Java heap seems to be quite full. The third graph shows that Full GCs are infrequent during the first few hours of execution. The rate of Full GC's, (the slope of the cummulative Full GC line), changes near midnight. plot(clipped.g1gc.z[,c("AfterSize","RealTime","FullCount")], xlab="Time of Day", col=c("#1b9e77","red","#1b9e77")) GC Analysis of heap recovered Each GC trace includes the amount of heap space in use before and after the individual GC event. During garbage coolection, unreferenced objects are identified, the space holding the unreferenced objects is freed, and thus, the difference in before and after usage indicates how much space has been freed. The following box plot and bar chart both demonstrate the same point - the amount of heap space freed per garbage colloection is surprisingly low. par(mfrow=c(2,1)) boxplot(as.vector(clipped.g1gc.z$Delta), main="Amount of Heap Recovered per GC Pass", xlab="Size in KB", horizontal = TRUE, col="red") hist(as.vector(clipped.g1gc.z$Delta), main="Amount of Heap Recovered per GC Pass", xlab="Size in KB", breaks=100, col="red") box(which = "outer", lty = "solid") This graph is the most interesting. The dark blue area shows how much heap is occupied by referenced Java objects. This represents memory that holds live data. The red fringe at the top shows how much data was recovered after each garbage collection. barplot(clipped.g1gc.z[,c("AfterSize","Delta")], col=c("#7570b3","#e7298a"), xlab="Time of Day", border=NA) legend("topleft", c("Live Objects","Heap Recovered on GC"), fill=c("#7570b3","#e7298a")) box(which = "outer", lty = "solid") When I discuss the data in the log files with the customer, I will ask for an explaination for the large amount of referenced data resident in the Java heap. There are two are posibilities: There is a memory leak and the amount of space required to hold referenced objects will continue to grow, limited only by the maximum heap size. After the maximum heap size is reached, the JVM will throw an “Out of Memory” exception every time that the application tries to allocate a new object. If this is the case, the aplication needs to be debugged to identify why old objects are referenced when they are no longer needed. The application has a legitimate requirement to keep a large amount of data in memory. The customer may want to further increase the maximum heap size. Another possible solution would be to partition the application across multiple cluster nodes, where each node has responsibility for managing a unique subset of the data. Conclusion In conclusion, R is a very powerful tool for the analysis of Java garbage collection log files. The primary difficulty is data cleansing so that information can be read into an R data frame. Once the data has been read into R, a rich set of tools may be used for thorough evaluation.

Read the article

Design for an interface implementation that provides additional functionality

- by Limbo Exile

There is a design problem that I came upon while implementing an interface: Let's say there is a Device interface that promises to provide functionalities PerformA() and GetB(). This interface will be implemented for multiple models of a device. What happens if one model has an additional functionality CheckC() which doesn't have equivalents in other implementations? I came up with different solutions, none of which seems to comply with interface design guidelines: To add CheckC() method to the interface and leave one of its implementations empty: interface ISomeDevice { void PerformA(); int GetB(); bool CheckC(); } class DeviceModel1 : ISomeDevice { public void PerformA() { // do stuff } public int GetB() { return 1; } public bool CheckC() { bool res; // assign res a value based on some validation return res; } } class DeviceModel2 : ISomeDevice { public void PerformA() { // do stuff } public int GetB() { return 1; } public bool CheckC() { return true; // without checking anything } } This solution seems incorrect as a class implements an interface without truly implementing all the demanded methods. To leave out CheckC() method from the interface and to use explicit cast in order to call it: interface ISomeDevice { void PerformA(); int GetB(); } class DeviceModel1 : ISomeDevice { public void PerformA() { // do stuff } public int GetB() { return 1; } public bool CheckC() { bool res; // assign res a value based on some validation return res; } } class DeviceModel2 : ISomeDevice { public void PerformA() { // do stuff } public int GetB() { return 1; } } class DeviceManager { private ISomeDevice myDevice; public void ManageDevice(bool newDeviceModel) { myDevice = (newDeviceModel) ? new DeviceModel1() : new DeviceModel2(); myDevice.PerformA(); int b = myDevice.GetB(); if (newDeviceModel) { DeviceModel1 newDevice = myDevice as DeviceModel1; bool c = newDevice.CheckC(); } } } This solution seems to make the interface inconsistent. For the device that supports CheckC(): to add the logic of CheckC() into the logic of another method that is present in the interface. This solution is not always possible. So, what is the correct design to be used in such cases? Maybe creating an interface should be abandoned altogether in favor of another design?

Read the article

Why would fopen fail to open a file that exists?

- by void

I'm on Windows XP using Visual Studio 6 (yes I know it's old) building/maintaining a C++ DLL. I'm encountered a problem with fopen failing to open an existing file, it always returns NULL. I've tried: Checking errno and _doserrno by setting both to zero and then checking them again, both remain zero, and thus GetLastError() reports no errors. I know fopen isn't required to set errno when it encounters an error according to a C standard. Hardcoding the file path, which are not relative. Tried on another developers machine which the same result. The really strange thing is CreateFile works and the file can be read with ReadFile. We believe this works in a release build, however we are also seeing some very odd behaviour in other areas of the application and we're not sure if this is related. The code is below, I don't see anything odd it looks quite standard to me. The source file hasn't changed for just under half a year. HRESULT CDataHandler::LoadFile( CStdString szFilePath ) { //Code FILE* pFile; if ( NULL == ( pFile = fopen( szFilePath.c_str(), "rb") ) ) { return S_FALSE; } //More code }

Read the article

Building applications with WCF - Intro

- by skjagini

I am going to write series of articles using Windows Communication Framework (WCF) to develop client and server applications and this is the first part of that series. What is WCF As Juwal puts in his Programming WCF book, WCF provides an SDK for developing and deploying services on Windows, provides runtime environment to expose CLR types as services and consume services as CLR types. Building services with WCF is incredibly easy and it’s implementation provides a set of industry standards and off the shelf plumbing including service hosting, instance management, reliability, transaction management, security etc such that it greatly increases productivity Scenario: Lets consider a typical bank customer trying to create an account, deposit amount and transfer funds between accounts, i.e. checking and savings. To make it interesting, we are going to divide the functionality into multiple services and each of them working with database directly. We will run test cases with and without transactional support across services. In this post we will build contracts, services, data access layer, unit tests to verify end to end communication etc, nothing big stuff here and we dig into other features of the WCF in subsequent posts with incremental changes. In any distributed architecture we have two pieces i.e. services and clients. Services as the name implies provide functionality to execute various pieces of business logic on the server, and clients providing interaction to the end user. Services can be built with Web Services or with WCF. Service built on WCF have the advantage of binding independent, i.e. can run against TCP and HTTP protocol without any significant changes to the code. Solution Services Profile: For creating a new bank customer, getting details about existing customer ProfileContract ProfileService Checking Account: To get checking account balance, deposit or withdraw amount CheckingAccountContract CheckingAccountService Savings Account: To get savings account balance, deposit or withdraw amount SavingsAccountContract SavingsAccountService ServiceHost: To host services, i.e. running the services at particular address, binding and contract where client can connect to Client: Helps end user to use services like creating account and amount transfer between the accounts BankDAL: Data access layer to work with database BankDAL It’s no brainer not to use an ORM as many matured products are available currently in market including Linq2Sql, Entity Framework (EF), LLblGenPro etc. For this exercise I am going to use Entity Framework 4.0, CTP 5 with code first approach. There are two approaches when working with data, data driven and code driven. In data driven we start by designing tables and their constrains in database and generate entities in code while in code driven (code first) approach entities are defined in code and the metadata generated from the entities is used by the EF to create tables and table constrains. In previous versions the entity classes had to derive from EF specific base classes. In EF 4 it is not required to derive from any EF classes, the entities are not only persistence ignorant but also enable full test driven development using mock frameworks. Application consists of 3 entities, Customer entity which contains Customer details; CheckingAccount and SavingsAccount to hold the respective account balance. We could have introduced an Account base class for CheckingAccount and SavingsAccount which is certainly possible with EF mappings but to keep it simple we are just going to follow 1 –1 mapping between entity and table mappings. Lets start out by defining a class called Customer which will be mapped to Customer table, observe that the class is simply a plain old clr object (POCO) and has no reference to EF at all. using System; namespace BankDAL.Model { public class Customer { public int Id { get; set; } public string FullName { get; set; } public string Address { get; set; } public DateTime DateOfBirth { get; set; } } } In order to inform EF about the Customer entity we have to define a database context with properties of type DbSet<> for every POCO which needs to be mapped to a table in database. EF uses convention over configuration to generate the metadata resulting in much less configuration. using System.Data.Entity; namespace BankDAL.Model { public class BankDbContext: DbContext { public DbSet<Customer> Customers { get; set; } } } Entity constrains can be defined through attributes on Customer class or using fluent syntax (no need to muscle with xml files), CustomerConfiguration class. By defining constrains in a separate class we can maintain clean POCOs without corrupting entity classes with database specific information. using System; using System.Data.Entity.ModelConfiguration; namespace BankDAL.Model { public class CustomerConfiguration: EntityTypeConfiguration<Customer> { public CustomerConfiguration() { Initialize(); } private void Initialize() { //Setting the Primary Key this.HasKey(e => e.Id); //Setting required fields this.HasRequired(e => e.FullName); this.HasRequired(e => e.Address); //Todo: Can't create required constraint as DateOfBirth is not reference type, research it //this.HasRequired(e => e.DateOfBirth); } } } Any queries executed against Customers property in BankDbContext are executed against Cusomers table. By convention EF looks for connection string with key of BankDbContext when working with the context. We are going to define a helper class to work with Customer entity with methods for querying, adding new entity etc and these are known as repository classes, i.e., CustomerRepository using System; using System.Data.Entity; using System.Linq; using BankDAL.Model; namespace BankDAL.Repositories { public class CustomerRepository { private readonly IDbSet<Customer> _customers; public CustomerRepository(BankDbContext bankDbContext) { if (bankDbContext == null) throw new ArgumentNullException(); _customers = bankDbContext.Customers; } public IQueryable<Customer> Query() { return _customers; } public void Add(Customer customer) { _customers.Add(customer); } } } From the above code it is observable that the Query methods returns customers as IQueryable i.e. customers are retrieved only when actually used i.e. iterated. Returning as IQueryable also allows to execute filtering and joining statements from business logic using lamba expressions without cluttering the data access layer with tens of methods. Our CheckingAccountRepository and SavingsAccountRepository look very similar to each other using System; using System.Data.Entity; using System.Linq; using BankDAL.Model; namespace BankDAL.Repositories { public class CheckingAccountRepository { private readonly IDbSet<CheckingAccount> _checkingAccounts; public CheckingAccountRepository(BankDbContext bankDbContext) { if (bankDbContext == null) throw new ArgumentNullException(); _checkingAccounts = bankDbContext.CheckingAccounts; } public IQueryable<CheckingAccount> Query() { return _checkingAccounts; } public void Add(CheckingAccount account) { _checkingAccounts.Add(account); } public IQueryable<CheckingAccount> GetAccount(int customerId) { return (from act in _checkingAccounts where act.CustomerId == customerId select act); } } } The repository classes look very similar to each other for Query and Add methods, with the help of C# generics and implementing repository pattern (Martin Fowler) we can reduce the repeated code. Jarod from ElegantCode has posted an article on how to use repository pattern with EF which we will implement in the subsequent articles along with WCF Unity life time managers by Drew Contracts It is very easy to follow contract first approach with WCF, define the interface and append ServiceContract, OperationContract attributes. IProfile contract exposes functionality for creating customer and getting customer details. using System; using System.ServiceModel; using BankDAL.Model; namespace ProfileContract { [ServiceContract] public interface IProfile { [OperationContract] Customer CreateCustomer(string customerName, string address, DateTime dateOfBirth); [OperationContract] Customer GetCustomer(int id); } } ICheckingAccount contract exposes functionality for working with checking account, i.e., getting balance, deposit and withdraw of amount. ISavingsAccount contract looks the same as checking account. using System.ServiceModel; namespace CheckingAccountContract { [ServiceContract] public interface ICheckingAccount { [OperationContract] decimal? GetCheckingAccountBalance(int customerId); [OperationContract] void DepositAmount(int customerId,decimal amount); [OperationContract] void WithdrawAmount(int customerId, decimal amount); } } Services Having covered the data access layer and contracts so far and here comes the core of the business logic, i.e. services. .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } ProfileService implements the IProfile contract for creating customer and getting customer detail using CustomerRepository. using System; using System.Linq; using System.ServiceModel; using BankDAL; using BankDAL.Model; using BankDAL.Repositories; using ProfileContract; namespace ProfileService { [ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class Profile: IProfile { public Customer CreateAccount( string customerName, string address, DateTime dateOfBirth) { Customer cust = new Customer { FullName = customerName, Address = address, DateOfBirth = dateOfBirth }; using (var bankDbContext = new BankDbContext()) { new CustomerRepository(bankDbContext).Add(cust); bankDbContext.SaveChanges(); } return cust; } public Customer CreateCustomer(string customerName, string address, DateTime dateOfBirth) { return CreateAccount(customerName, address, dateOfBirth); } public Customer GetCustomer(int id) { return new CustomerRepository(new BankDbContext()).Query() .Where(i => i.Id == id).FirstOrDefault(); } } } From the above code you shall observe that we are calling bankDBContext’s SaveChanges method and there is no save method specific to customer entity because EF manages all the changes centralized at the context level and all the pending changes so far are submitted in a batch and it is represented as Unit of Work. Similarly Checking service implements ICheckingAccount contract using CheckingAccountRepository, notice that we are throwing overdraft exception if the balance falls by zero. WCF has it’s own way of raising exceptions using fault contracts which will be explained in the subsequent articles. SavingsAccountService is similar to CheckingAccountService. using System; using System.Linq; using System.ServiceModel; using BankDAL.Model; using BankDAL.Repositories; using CheckingAccountContract; namespace CheckingAccountService { [ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class Checking:ICheckingAccount { public decimal? GetCheckingAccountBalance(int customerId) { using (var bankDbContext = new BankDbContext()) { CheckingAccount account = (new CheckingAccountRepository(bankDbContext) .GetAccount(customerId)).FirstOrDefault(); if (account != null) return account.Balance; return null; } } public void DepositAmount(int customerId, decimal amount) { using(var bankDbContext = new BankDbContext()) { var checkingAccountRepository = new CheckingAccountRepository(bankDbContext); CheckingAccount account = (checkingAccountRepository.GetAccount(customerId)) .FirstOrDefault(); if (account == null) { account = new CheckingAccount() { CustomerId = customerId }; checkingAccountRepository.Add(account); } account.Balance = account.Balance + amount; if (account.Balance < 0) throw new ApplicationException("Overdraft not accepted"); bankDbContext.SaveChanges(); } } public void WithdrawAmount(int customerId, decimal amount) { DepositAmount(customerId, -1*amount); } } } BankServiceHost The host acts as a glue binding contracts with it’s services, exposing the endpoints. The services can be exposed either through the code or configuration file, configuration file is preferred as it allows run time changes to service behavior even after deployment. We have 3 services and for each of the service you need to define name (the class that implements the service with fully qualified namespace) and endpoint known as ABC, i.e. address, binding and contract. We are using netTcpBinding and have defined the base address with for each of the contracts .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } <system.serviceModel> <services> <service name="ProfileService.Profile"> <endpoint binding="netTcpBinding" contract="ProfileContract.IProfile"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Profile"/> </baseAddresses> </host> </service> <service name="CheckingAccountService.Checking"> <endpoint binding="netTcpBinding" contract="CheckingAccountContract.ICheckingAccount"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Checking"/> </baseAddresses> </host> </service> <service name="SavingsAccountService.Savings"> <endpoint binding="netTcpBinding" contract="SavingsAccountContract.ISavingsAccount"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Savings"/> </baseAddresses> </host> </service> </services> </system.serviceModel> Have to open the services by creating service host which will handle the incoming requests from clients. using System; namespace ServiceHost { class Program { static void Main(string[] args) { CreateHosts(); Console.ReadLine(); } private static void CreateHosts() { CreateHost(typeof(ProfileService.Profile),"Profile Service"); CreateHost(typeof(SavingsAccountService.Savings), "Savings Account Service"); CreateHost(typeof(CheckingAccountService.Checking), "Checking Account Service"); } private static void CreateHost(Type type, string hostDescription) { System.ServiceModel.ServiceHost host = new System.ServiceModel.ServiceHost(type); host.Open(); if (host.ChannelDispatchers != null && host.ChannelDispatchers.Count != 0 && host.ChannelDispatchers[0].Listener != null) Console.WriteLine("Started: " + host.ChannelDispatchers[0].Listener.Uri); else Console.WriteLine("Failed to start:" + hostDescription); } } } BankClient The client has no knowledge about service business logic other than the functionality it exposes through the contract, end points and a proxy to work against. The endpoint data and server proxy can be generated by right clicking on the project reference and choosing ‘Add Service Reference’ and entering the service end point address. Or if you have access to source, you can manually reference contract dlls and update clients configuration file to point to the service end point if the server and client happens to be being built using .Net framework. One of the pros with the manual approach is you don’t have to work against messy code generated files. <system.serviceModel> <client> <endpoint name="tcpProfile" address="net.tcp://localhost:1000/Profile" binding="netTcpBinding" contract="ProfileContract.IProfile"/> <endpoint name="tcpCheckingAccount" address="net.tcp://localhost:1000/Checking" binding="netTcpBinding" contract="CheckingAccountContract.ICheckingAccount"/> <endpoint name="tcpSavingsAccount" address="net.tcp://localhost:1000/Savings" binding="netTcpBinding" contract="SavingsAccountContract.ISavingsAccount"/> </client> </system.serviceModel> The client uses a façade to connect to the services using System.ServiceModel; using CheckingAccountContract; using ProfileContract; using SavingsAccountContract; namespace Client { public class ProxyFacade { public static IProfile ProfileProxy() { return (new ChannelFactory<IProfile>("tcpProfile")).CreateChannel(); } public static ICheckingAccount CheckingAccountProxy() { return (new ChannelFactory<ICheckingAccount>("tcpCheckingAccount")) .CreateChannel(); } public static ISavingsAccount SavingsAccountProxy() { return (new ChannelFactory<ISavingsAccount>("tcpSavingsAccount")) .CreateChannel(); } } } With that in place, lets get our unit tests going using System; using System.Diagnostics; using BankDAL.Model; using NUnit.Framework; using ProfileContract; namespace Client { [TestFixture] public class Tests { private void TransferFundsFromSavingsToCheckingAccount(int customerId, decimal amount) { ProxyFacade.CheckingAccountProxy().DepositAmount(customerId, amount); ProxyFacade.SavingsAccountProxy().WithdrawAmount(customerId, amount); } private void TransferFundsFromCheckingToSavingsAccount(int customerId, decimal amount) { ProxyFacade.SavingsAccountProxy().DepositAmount(customerId, amount); ProxyFacade.CheckingAccountProxy().WithdrawAmount(customerId, amount); } [Test] public void CreateAndGetProfileTest() { IProfile profile = ProxyFacade.ProfileProxy(); const string customerName = "Tom"; int customerId = profile.CreateCustomer(customerName, "NJ", new DateTime(1982, 1, 1)).Id; Customer customer = profile.GetCustomer(customerId); Assert.AreEqual(customerName,customer.FullName); } [Test] public void DepositWithDrawAndTransferAmountTest() { IProfile profile = ProxyFacade.ProfileProxy(); string customerName = "Smith" + DateTime.Now.ToString("HH:mm:ss"); var customer = profile.CreateCustomer(customerName, "NJ", new DateTime(1982, 1, 1)); // Deposit to Savings ProxyFacade.SavingsAccountProxy().DepositAmount(customer.Id, 100); ProxyFacade.SavingsAccountProxy().DepositAmount(customer.Id, 25); Assert.AreEqual(125, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); // Withdraw ProxyFacade.SavingsAccountProxy().WithdrawAmount(customer.Id, 30); Assert.AreEqual(95, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); // Deposit to Checking ProxyFacade.CheckingAccountProxy().DepositAmount(customer.Id, 60); ProxyFacade.CheckingAccountProxy().DepositAmount(customer.Id, 40); Assert.AreEqual(100, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Withdraw ProxyFacade.CheckingAccountProxy().WithdrawAmount(customer.Id, 30); Assert.AreEqual(70, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Transfer from Savings to Checking TransferFundsFromSavingsToCheckingAccount(customer.Id,10); Assert.AreEqual(85, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); Assert.AreEqual(80, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Transfer from Checking to Savings TransferFundsFromCheckingToSavingsAccount(customer.Id, 50); Assert.AreEqual(135, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); Assert.AreEqual(30, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); } [Test] public void FundTransfersWithOverDraftTest() { IProfile profile = ProxyFacade.ProfileProxy(); string customerName = "Angelina" + DateTime.Now.ToString("HH:mm:ss"); var customerId = profile.CreateCustomer(customerName, "NJ", new DateTime(1972, 1, 1)).Id; ProxyFacade.SavingsAccountProxy().DepositAmount(customerId, 100); TransferFundsFromSavingsToCheckingAccount(customerId,80); Assert.AreEqual(20, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customerId)); Assert.AreEqual(80, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customerId)); try { TransferFundsFromSavingsToCheckingAccount(customerId,30); } catch (Exception e) { Debug.WriteLine(e.Message); } Assert.AreEqual(110, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customerId)); Assert.AreEqual(20, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customerId)); } } } We are creating a new instance of the channel for every operation, we will look into instance management and how creating a new instance of channel affects it in subsequent articles. The first two test cases deals with creation of Customer, deposit and withdraw of month between accounts. The last case, FundTransferWithOverDraftTest() is interesting. Customer starts with depositing $100 in SavingsAccount followed by transfer of $80 in to checking account resulting in $20 in savings account. Customer then initiates $30 transfer from Savings to Checking resulting in overdraft exception on Savings with $30 being deposited to Checking. As we are not running both the requests in transactions the customer ends up with more amount than what he started with $100. In subsequent posts we will look into transactions handling. Make sure the ServiceHost project is set as start up project and start the solution. Run the test cases either from NUnit client or TestDriven.Net/Resharper which ever is your favorite tool. Make sure you have updated the data base connection string in the ServiceHost config file to point to your local database

Read the article

A star algorithm implementation problems

- by bryan226

I’m having some trouble implementing the A* algorithm in a 2D tile based game. The problem is basically that the algorithm gets stuck when something gets in its direct way (e.g. walls) Note that it only allows Horizontal and Vertical movement. Here's a picture as it works fine across the map without something in its direct way: (Green tile = destination, Blue = In closed list, Green = in open list) This is what happens if I try to walk 'around' a wall: I calculate costs with the F = G + H formula: G = 1 Cost per Step H = 10 Cost per Step //Count how many tiles are between current-tile & destination-tile The functions: short c_astar::GuessH(short Startx,short Starty,short Destinationx,short Destinationy) { hgeVector Start, Destination; Start.x = Startx; Start.y = Starty; Destination.x = Destinationx; Destination.y = Destinationy; short a = 0; short b = 0; if(Start.x > Destination.x) a = Start.x - Destination.x; else a = Destination.x - Start.x; if(Start.y > Destination.y) b = Start.y - Destination.y; else b = Destination.y - Start.y; return (a+b)*10; } short c_astar::GuessG(short Startx,short Starty,short Currentx,short Currenty) { hgeVector Start, Destination; Start.x = Startx; Start.y = Starty; Destination.x = Currentx; Destination.y = Currenty; short a = 0; short b = 0; if(Start.x > Destination.x) a = Start.x - Destination.x; else a = Destination.x - Start.x; if(Start.y > Destination.y) b = Start.y - Destination.y; else b = Destination.y - Start.y; return (a+b); } At the end of the loop I check which tile is the cheapest to go according to its F value: Then some quick checks are done for each tile (UP,DOWN,LEFT,RIGHT): //...CX are holding the F value of the TILE specified // Info: C0 = Center (Current) // C1 = UP // C2 = DOWN // C3 = LEFT // C4 = RIGHT //Quick checks if(((C1 < C2) && (C1 < C3) && (C1 < C4))) { Current.y -= 1; bSimilar = false; if(DEBUG) hge->System_Log("C1 < ALL"); } //.. same for C2,C3 & C4 If there are multiple tiles with the same F value: It’s actually a switch for DOWNLEFT,UPRIGHT.. etc. Here’s one of it: case UPRIGHT: { //UP Temporary = Current; Temporary.y -= 1; bTileStatus[0] = IsTileWalkable(Temporary.x,Temporary.y); if(bTileStatus[0]) { //Proceed normal we are OK & walkable Tilex.Tile = map.at(Temporary.y).at(Temporary.x); //Search in lists if(SearchInClosedList(Tilex.Tile.ID,C0)) bFoundInClosedList[0] = true; if(SearchInOpenList(Tilex.Tile.ID,C0)) bFoundInOpenList[0] = true; //RIGHT Temporary = Current; Temporary.x += 1; bTileStatus[1] = IsTileWalkable(Temporary.x,Temporary.y); if(bTileStatus[1]) { //Proceed normal we are OK & walkable Tilex.Tile = map.at(Temporary.y).at(Temporary.x); //Search in lists if(SearchInClosedList(Tilex.Tile.ID,C0)) bFoundInClosedList[1] = true; if(SearchInOpenList(Tilex.Tile.ID,C0)) bFoundInOpenList[1] = true; //************************************************* // Purpose: ClosedList behavior //************************************************* if(bFoundInClosedList[0] && !bFoundInClosedList[1]) { //UP found in ClosedList. Go RIGHT return RIGHT; } if(!bFoundInClosedList[0] && bFoundInClosedList[1]) { //RIGHT found in ClosedList. Go UP return UP; } if(bFoundInClosedList[0] && bFoundInClosedList[1]) { //Both found in ClosedList. Random value switch(hge->Random_Int(8,9)) { case 8: return UP; break; case 9: return RIGHT; break; } } //************************************************* // Purpose: OpenList behavior //************************************************* if(bFoundInOpenList[0] && !bFoundInOpenList[1]) { //UP found in OpenList. Go RIGHT return RIGHT; } if(!bFoundInOpenList[0] && bFoundInOpenList[1]) { //RIGHT found in OpenList. Go UP return UP; } if(bFoundInOpenList[0] && bFoundInOpenList[1]) { //Both found in OpenList. Random value switch(hge->Random_Int(8,9)) { case 8: return UP; break; case 9: return RIGHT; break; } } } else if(!bTileStatus[1]) { //RIGHT is not walkable OR out of range //Choose UP return UP; } } else if(!bTileStatus[0]) { //UP is not walkable OR out of range //Fast check RIGHT Temporary = Current; Temporary.x += 1; bTileStatus[1] = IsTileWalkable(Temporary.x,Temporary.y); if(bTileStatus[1]) { return RIGHT; } else return FAILED; //Failed, no valid path found! } } break; A log for the second picture: (Cut down to ten passes, because it’s just repeating itself) ----------------------------------------------------- PASS: 1 | C1: 211 | C2: 191 | C3: 211 | C4: 191 DOWN + RIGHT SIMILAR Going DOWN ----------------------------------------------------- PASS: 2 | C1: 200 | C2: 182 | C3: 202 | C4: 182 DOWN + RIGHT SIMILAR Going DOWN ----------------------------------------------------- PASS: 3 | C1: 191 | C2: 193 | C3: 193 | C4: 173 C4 < ALL Tile(12.000000,6.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 4 | C1: 182 | C2: 184 | C3: 182 | C4: 999 UP + LEFT SIMILAR Going UP Tile(12.000000,5.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 5 | C1: 191 | C2: 173 | C3: 191 | C4: 999 C2 < ALL Tile(12.000000,6.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 6 | C1: 182 | C2: 184 | C3: 182 | C4: 999 UP + LEFT SIMILAR Going UP Tile(12.000000,5.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 7 | C1: 191 | C2: 173 | C3: 191 | C4: 999 C2 < ALL Tile(12.000000,6.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 8 | C1: 182 | C2: 184 | C3: 182 | C4: 999 UP + LEFT SIMILAR Going LEFT ----------------------------------------------------- PASS: 9 | C1: 191 | C2: 193 | C3: 193 | C4: 173 C4 < ALL Tile(12.000000,6.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 10 | C1: 182 | C2: 184 | C3: 182 | C4: 999 UP + LEFT SIMILAR Going LEFT ----------------------------------------------------- Its always going after the cheapest F value, which seems to be wrong. If someone could point me to the right direction I'd be thankful. Regards, bryan226

Search Results

Search found 48020 results on 1921 pages for 'void return'.

Page 95/1921 | < Previous Page | 91 92 93 94 95 96 97 98 99 100 101 102 | Next Page >

- by KallDrexx

- by void

- by Spanky

- by mystify

- by Erebus

- by mfolnovich

- by nomemory

- by shiju

- by Fredrik N

- by Lewis Benge

- by ybbest

- by mbridge

- by Roel

- by Dixin

- by Dixin

- by Simon Cooper

- by Rhames

- by JPRO

- by Mutoh

- by thangchung

- by user12620111

- by Limbo Exile

- by void

- by skjagini

- by bryan226

< Previous Page | 91 92 93 94 95 96 97 98 99 100 101 102 | Next Page >