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• How to get around LazyInitializationException in scheduled jobs?

  - by Shreerang

  I am working on a J2EE server application which is deployed on Tomcat. I use Spring source as MVC framework and Hibernate as ORM provider. My object model has lot of Lazy relationships (dependent objects are fetched on request). The high level design is like Service level methods call a few DAO methods to perform database operation. The service method is called either from the Flex UI or as a scheduled job. When it is called from Flex UI, the service method works fine i.e. it fetches some objects using DAO methods and even Lazy loading works. This is possible by the use of OpenSessionInViewFilter configured with the UI servlet. But when the same service method is called as scheduled Job, it gives LazyInitializationException. I can not configure OpenSessionInViewFilter because there is no servlet or UI request associated with that. I tried configuring Transaction around the scheduled job method so that service method starts a transaction and all the DAO methods participate in that same transaction, hoping that the transaction will remain active and hibernate session will be available. But it does not work. Please suggest if anyone has ever been able to get such a configuration working. If needed, I can post the Hibernate configuration and log messages. Thanks a lot for help! Shreerang

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• StreamReader returning another char

  - by Fernando

  I'm trying to read the content of a file with a StreamReader, that receives a FileStream. The file has some spaces inside (char 32) and the StreamReader is reading them as 0 (char 48). The screenshot shows the FileStream buffer and the StreamReader buffer. Both have the value 32, but when I call Read(), it returns 48. Am I missing something here? By the way, the code is running under .NET Compact Framework. The code that reads the data: public void Read() { using (StreamReader reader = new StreamReader(InputStream, Encoding.ASCII)) { foreach (var property in DataObject.EnumerateProperties()) { OffsetInfo offset = property.GetTextOffset(); reader.BaseStream.Position = offset.Start - 1; StringBuilder builder = new StringBuilder(offset.Size); int count = 0; while (reader.Peek() >= 0 && count < offset.Size) { char c = (char)reader.Read(); if ((int)c != 32 && c != '\r' && c != '\n') { builder.Append(c); count++; } else { reader.BaseStream.Position++; } } property.SetValue(DataObject, Convert.ChangeType(builder.ToString(), property.PropertyType, CultureInfo.CurrentCulture), null ); } } }

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• class modifier issues in C# with "private" classes

  - by devoured elysium

  I had a class that had lots of methods: public class MyClass { public bool checkConditions() { return checkCondition1() && checkCondition2() && checkCondition3(); } ...conditions methods public void DoProcess() { FirstPartOfProcess(); SecondPartOfProcess(); ThirdPartOfProcess(); } ...process methods } I identified two "vital" work areas, and decided to extract those methods to classes of its own: public class MyClass { private readonly MyClassConditions _conditions = new ...; private readonly MyClassProcessExecution = new ...; public bool checkConditions() { return _conditions.checkConditions(); } public void DoProcess() { _process.DoProcess(); } } In Java, I'd define MyClassConditions and MyClassProcessExecution as package protected, but I can't do that in C#. How would you go about doing this in C#? Setting both classes as inner classes of MyClass? I have 2 options: I either define them inside MyClass, having everything in the same file, which looks confusing and ugly, or I can define MyClass as a partial class, having one file for MyClass, other for MyClassConditions and other for MyClassProcessExecution. Defining them as internal? I don't really like that much of the internal modifier, as I don't find these classes add any value at all for the rest of my program/assembly, and I'd like to hide them if possible. It's not like they're gonna be useful/reusable in any other part of the program. Keep them as public? I can't see why, but I've let this option here. Any other? Name it! Thanks

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• Releasing Autopool crashes on iOS 4.0 (and only on 4.0)

  - by samsam

  Hi there. I'm wondering what could cause this. I have several methods in my code that i call using performSelectorInBackground. Within each of these methods i have an Autoreleasepool that is being alloced/initialized at the beginning and released at the end of the method. this perfectly works on iOS 3.1.3 / 3.2 / 4.2 / 4.2.1 but it fataly crashes on iOS 4.0 with a EXC_BAD_ACCESS Exception that happens after calling [myPool release]. After I noticed this strange behaviour I was thinking about rewriting portions of my code and to make my app "less parallel" in case that the client os is 4.0. After I did that, the next point where the app crashed was within the ReachabilityCallback-Method from Apples Reachability "Framework". well, now I'm not quite sure what to do. The things i do within my threaded methods is pretty simple xml parsing (no cocoa calls or stuff that would affect the UI). After each method finishes it posts a notification which the coordinating-thread listens to and once all the parallelized methods have finished, the coordinating thread calls viewcontrollers etc... I have absolutely no clue what could cause this weird behaviour. Especially because Apples Code fails as well. any help is greatly appreciated! thanks, sam

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• Performance issue finding weekdays over a given period

  - by Oysio

  I have some methods that return the number of weekdays between two given dates. Since calling these methods become very expensive to call when the two dates lie years apart, I'm wondering how these methods could be refactored in a more efficient way. The returned result is correct but I feel that the iphone processor is struggling to keep up and consequently freezes up the application when I would call these methods over a period of say 10years. Any suggestions ? //daysList contains all weekdays that need to be found between the two dates -(NSInteger) numberOfWeekdaysFromDaysList:(NSMutableArray*) daysList startingFromDate:(NSDate*)startDate toDate:(NSDate*)endDate { NSInteger retNumdays = 0; for (Day *dayObject in [daysList objectEnumerator]) { if ([dayObject isChecked]) { retNumdays += [self numberOfWeekday:[dayObject weekdayNr] startingFromDate:startDate toDate:endDate]; } } return retNumdays; } -(NSInteger) numberOfWeekday:(NSInteger)day startingFromDate:(NSDate*)startDate toDate:(NSDate*)endDate { NSInteger numWeekdays = 0; NSDate *nextDate = startDate; NSComparisonResult result = [endDate compare:nextDate]; //Do while nextDate is in the past while (result == NSOrderedDescending || result == NSOrderedSame) { if ([NSDate weekdayFromDate:nextDate] == day) { numWeekdays++; } nextDate = [nextDate dateByAddingDays:1]; result = [endDate compare:nextDate]; } return numWeekdays; }

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• How can I add two models in one form, where one model is a has_many :through?

  - by Angela

  How do I model having multiple Addresses for a Company and assign a single Address to a Contact? Contacts belong_to a Company. A Company has_many Contacts. A Company also has_many Addresses. And each Contact has_one Address. I want to be able, whenever I create a New Contact, to access all the addresses in all Contacts that belong to the Company. Here is are my Models: class Company < ActiveRecord::Base attr_accessible :name, :phone, :addresses has_many :contacts has_many :addresses, :through => :contacts end class Contact < ActiveRecord::Base attr_accessible :first_name, :last_name, :title, :phone, :fax, :email, :company, :date_entered, :campaign_id, :company_name, :address belongs_to :company has_one :address accepts_nested_attributes_for :address end class Address < ActiveRecord::Base attr_accessible :street1 has_many :contacts end How do I create the View in the _form for Contacts so that I can 1) Add an Address when creating a Contact; 2) Display the options of the Address. Here is how I am doing step 1, which is just to add a new address for a new contact: <% f.fields_for :addresses do |builder| %> <p> <%= builder.label :street1, "Street 1" %> </br> <%= builder.text_field :street1 %> <p> Right now, what I have doesn't work. The console says I cannot mass-assign addresses when I hit "submit" on this New contact form.

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• android listview order changed when called notifyDataSetChanged

  - by 9nix00

  hi,all. when I use notifyDataSetChanged(), the listview display order will be change . like this 3 2 1 when current activy was created. but when I change the data. it will be 1 2 3 I don't want the order changed and i dont understand why its happening. This is a piece of code from my adapter class public static class ItemAdapter extends BaseAdapter { private String[] mData; private LayoutInflater mInflater; // I called this method to change data public void setEditText(int position, final String item) { mData[position] = item; notifyDataSetChanged(); } } I change data at some dialog like this builder = new AlertDialog.Builder(ct); builder.setTitle(R.string.pickStatus) .setView(edBuffer) .setPositiveButton(R.string.save, new DialogInterface.OnClickListener() { @Override public void onClick( DialogInterface dialog, int id) { // TODO Auto-generated method stub canPop = true; final String tmp = edBuffer.getText().toString(); KbonezLog.e(String.format( "set into key %d", key)); //use mData key to set value setEditText(key, tmp); dialog.dismiss(); }})

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• How to proxy calls to the instance of an object

  - by mr.b

  Edit: Changed question title from "Does C# allow method overloading, PHP style (__call)?" - figured out it doesn't have much to do with actual question. Also edited question text. What I want to accomplish is to proxy calls to a an instance of an object methods, so I could log calls to any of its methods. Right now, I have code similar to this: class ProxyClass { static logger; public AnotherClass inner { get; private set; } public ProxyClass() { inner = new AnotherClass(); } } class AnotherClass { public void A() {} public void B() {} public void C() {} // ... } // meanwhile, in happyCodeLandia... ProxyClass pc = new ProxyClass(); pc.inner.A(); // need to write log message like "method A called" pc.inner.B(); // need to write log message like "method B called" // ... So, how can I proxy calls to an object instance in extensible way? Method overloading would be most obvious solution (if it was supported in PHP way). By extensible, meaning that I don't have to modify ProxyClass whenever AnotherClass changes. In my case, AnotherClass can have any number of methods, so it wouldn't be appropriate to overload or wrap all methods to add logging. I am aware that this might not be the best approach for this kind of problem, so if anyone has idea what approach to use, shoot. Thanks!

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• cannot see values from list in c#

  - by PriceCheaperton

  I have the following code: But i cannot response write the values in the list for debugging purposes... public void LottoWinners(object sender, EventArgs e) { Dictionary<int, int> number = new Dictionary<int, int>(); Random generator = new Random(); while (number.Count < 6) { number[generator.Next(1, 49)] = 1; } int[] lotto = number.Keys.OrderBy(n => n).ToArray(); List<int> lst = lotto.OfType<int>().ToList(); StringBuilder builder = new StringBuilder(); for (int i = 0; i < lst.Count; i++) // Loop through List with for { builder.Append(lst).Append("|"); // Append string to StringBuilder } string result = builder.ToString(); // Get string from StringBuilder Response.Write(result); } But all i see is as my result. I should be seeing the values of my list! System.Collections.Generic.List`1

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• C++ traits question

  - by duli

  I have a templated class template <typename Data> class C { ..... } In most situations, I depend on the compiler to let me substitute types for Data. I call methods foo(), goo() on objects of type Data, so what I substitute needs to provide that. I now need to substitute int and string for my Data type. I do not want to specialize because the class is already too big and would require specializing each method (with only small code change). My options (please tell me if there are more) 1) I can provide wrapper classes around int and string which implement the methods foo(), goo() etc 2) provide a traits class traits that calls foo() or goo() on objects of classes that provide foo(),goo() (these are my present substitutable classes) and specialize these classes for int and string. Questions 1) what are the relative merits of 1 vs 2? 2) My traits classes will have static methods. Can a traits class have non-static methods as well? I see most traits classes define constants in the STL. 3) Do I make the traits classes global or should I pass them in as a template parameter for class C?

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• Using the JPA Criteria API, can you do a fetch join that results in only one join?

  - by Shaun

  Using JPA 2.0. It seems that by default (no explicit fetch), @OneToOne(fetch = FetchType.EAGER) fields are fetched in 1 + N queries, where N is the number of results containing an Entity that defines the relationship to a distinct related entity. Using the Criteria API, I might try to avoid that as follows: CriteriaBuilder builder = entityManager.getCriteriaBuilder(); CriteriaQuery<MyEntity> query = builder.createQuery(MyEntity.class); Root<MyEntity> root = query.from(MyEntity.class); Join<MyEntity, RelatedEntity> join = root.join("relatedEntity"); root.fetch("relatedEntity"); query.select(root).where(builder.equals(join.get("id"), 3)); The above should ideally be equivalent to the following: SELECT m FROM MyEntity m JOIN FETCH myEntity.relatedEntity r WHERE r.id = 3 However, the criteria query results in the root table needlessly being joined to the related entity table twice; once for the fetch, and once for the where predicate. The resulting SQL looks something like this: SELECT myentity.id, myentity.attribute, relatedentity2.id, relatedentity2.attribute FROM my_entity myentity INNER JOIN related_entity relatedentity1 ON myentity.related_id = relatedentity1.id INNER JOIN related_entity relatedentity2 ON myentity.related_id = relatedentity2.id WHERE relatedentity1.id = 3 Alas, if I only do the fetch, then I don't have an expression to use in the where clause. Am I missing something, or is this a limitation of the Criteria API? If it's the latter, is this being remedied in JPA 2.1 or are there any vendor-specific enhancements? Otherwise, it seems better to just give up compile-time type checking (I realize my example doesn't use the metamodel) and use dynamic JPQL TypedQueries.

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• C++, inject additional data in a method

  - by justik

  I am adding the new modul in some large library. All methods here are implemented as static. Let mi briefly describe the simplified model: typedef std::vector<double> TData; double test ( const TData &arg ) { return arg ( 0 ) * sin ( arg ( 1 ) + ...;} double ( * p_test ) ( const TData> &arg) = &test; class A { public: static T f1 (TData &input) { .... //some computations B::f2 (p_test); } }; Inside f1() some computations are perfomed and a static method B::f2 is called. The f2 method is implemented by another author and represents some simulation algorithm (example here is siplified). class B { public: static double f2 (double ( * p_test ) ( const TData &arg ) ) { //difficult algorithm working p_test many times double res = p_test(arg); } }; The f2 method has a pointer to some weight function (here p_test). But in my case some additional parameters computed in f1 for test() methods are required double test ( const TData &arg, const TData &arg2, char *arg3.... ) { } How to inject these parameters into test() (and so to f2) to avoid changing the source code of the f2 methods (that is not trivial), redesign of the library and without dirty hacks :-) ? The most simple step is to override f2 static double f2 (double ( * p_test ) ( const TData &arg ), const TData &arg2, char *arg3.... ) But what to do later? Consider, that methods are static, so there will be problems with objects. Thanks for your help.

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• customized form_for tag in rails

  - by poseid

  I want to make a table within a form by making a new form_tag. The following code in ApplicationHelper fails: module ApplicationHelper class TabularFormBuilder < ActionView::Helpers::FormBuilder # ... code to insert <tr> tags </tr> end def tabular_form_for(name, object = nil, options = nil, &proc) concat("<table>", proc.binding) form_for(name, object, (options||{}).merge(:builder => TabularFormBuilder), &proc) concat("</table>", proc.binding) end end The view I use is: <h1>New project</h1> <% tabular_form_for :project, :builder => ApplicationHelper::TabularFormBuilder do |f| %> <%= f.error_messages %> <%= f.text_field :name %> <%= f.text_area :description %> <%= f.text_field :location %> <%= f.submit 'Create' %> <% end %> The error I get is: NoMethodError in Projects#new Showing app/views/projects/new.html.erb where line #5 raised: undefined method `errors' for {:builder=ApplicationHelper::TabularFormBuilder}:Hash Any ideas how to make this custom tag work?

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• Initializing ExportFactory using MEF

  - by Riz

  Scenario Application has multiple parts. Each part is in separate dll and implements interface IFoo All such dlls are present in same directory (plugins) The application can instantiate multiple instances of each part Below is the code snippet for the interfaces, part(export) and the import. The problem I am running into is, the "factories" object is initialized with empty list. However, if I try container.Resolve(typeof(IEnumerable< IFoo )) I do get object with the part. But that doesn't serve my purpose (point 4). Can anyone point what I am doing wrong here? public interface IFoo { string Name { get; } } public interface IFooMeta { string CompType { get; } } Implementation of IFoo in separate Dll [ExportMetadata("CompType", "Foo1")] [Export(typeof(IFoo), RequiredCreationPolicy = CreationPolicy.NonShared))] public class Foo1 : IFoo { public string Name { get { return this.GetType().ToString(); } } } Main application that loads all the parts and instantiate them as needed class PartsManager { [ImportMany] private IEnumerable<ExportFactory<IFoo, IFooMeta>> factories; public PartsManager() { IContainer container = ConstructContainer(); factories = (IEnumerable<ExportFactory<IFoo, IFooMeta>>) container.Resolve(typeof(IEnumerable<ExportFactory<IFoo, IFooMeta>>)); } private static IContainer ConstructContainer() { var catalog = new DirectoryCatalog(@"C:\plugins\"); var builder = new ContainerBuilder(); builder.RegisterComposablePartCatalog(catalog); return builder.Build(); } public IFoo GetPart(string compType) { var matchingFactory = factories.FirstOrDefault( x => x.Metadata.CompType == compType); if (factories == null) { return null; } else { IFoo foo = matchingFactory.CreateExport().Value; return foo; } } }

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• One Common View In Every ViewController

  - by l3v

  I am having a hard time wording this when searching the internet so I am just going to ask the question. I have an options view in my app that slides into view when the user clicks a button. This options view will display app information like settings. I want this options view to be displayed on every view controller in my app. I do not want to copy and paste the code for the options view into every viewcontroller file. The options view has quite a few outlets and actions and also calls many delegates. How can I reuse this options view in all my view controllers without adding all the outlets, actions, and delegate methods each time? I was going to make a new file with public methods, but I would still have to copy the outlets. Would this public methods file have to include delegate methods as well then? Let me know if my question does not make sense. I am hoping there is a standard way of implementing something like this.

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• ASP.NET MVC 3 Hosting :: New Features in ASP.NET MVC 3

  - by mbridge

  Razor View Engine The Razor view engine is a new view engine option for ASP.NET MVC that supports the Razor templating syntax. The Razor syntax is a streamlined approach to HTML templating designed with the goal of being a code driven minimalist templating approach that builds on existing C#, VB.NET and HTML knowledge. The result of this approach is that Razor views are very lean and do not contain unnecessary constructs that get in the way of you and your code. ASP.NET MVC 3 Preview 1 only supports C# Razor views which use the .cshtml file extension. VB.NET support will be enabled in later releases of ASP.NET MVC 3. For more information and examples, see Introducing “Razor” – a new view engine for ASP.NET on Scott Guthrie’s blog. Dynamic View and ViewModel Properties A new dynamic View property is available in views, which provides access to the ViewData object using a simpler syntax. For example, imagine two items are added to the ViewData dictionary in the Index controller action using code like the following: public ActionResult Index() {          ViewData["Title"] = "The Title";          ViewData["Message"] = "Hello World!"; } Those properties can be accessed in the Index view using code like this: <h2>View.Title</h2> <p>View.Message</p> There is also a new dynamic ViewModel property in the Controller class that lets you add items to the ViewData dictionary using a simpler syntax. Using the previous controller example, the two values added to the ViewData dictionary can be rewritten using the following code: public ActionResult Index() {     ViewModel.Title = "The Title";     ViewModel.Message = "Hello World!"; } “Add View” Dialog Box Supports Multiple View Engines The Add View dialog box in Visual Studio includes extensibility hooks that allow it to support multiple view engines, as shown in the following figure: Service Location and Dependency Injection Support ASP.NET MVC 3 introduces improved support for applying Dependency Injection (DI) via Inversion of Control (IoC) containers. ASP.NET MVC 3 Preview 1 provides the following hooks for locating services and injecting dependencies: - Creating controller factories. - Creating controllers and setting dependencies. - Setting dependencies on view pages for both the Web Form view engine and the Razor view engine (for types that derive from ViewPage, ViewUserControl, ViewMasterPage, WebViewPage). - Setting dependencies on action filters. Using a Dependency Injection container is not required in order for ASP.NET MVC 3 to function properly. Global Filters ASP.NET MVC 3 allows you to register filters that apply globally to all controller action methods. Adding a filter to the global filters collection ensures that the filter runs for all controller requests. To register an action filter globally, you can make the following call in the Application_Start method in the Global.asax file: GlobalFilters.Filters.Add(new MyActionFilter()); The source of global action filters is abstracted by the new IFilterProvider interface, which can be registered manually or by using Dependency Injection. This allows you to provide your own source of action filters and choose at run time whether to apply a filter to an action in a particular request. New JsonValueProviderFactory Class The new JsonValueProviderFactory class allows action methods to receive JSON-encoded data and model-bind it to an action-method parameter. This is useful in scenarios such as client templating. Client templates enable you to format and display a single data item or set of data items by using a fragment of HTML. ASP.NET MVC 3 lets you connect client templates easily with an action method that both returns and receives JSON data. Support for .NET Framework 4 Validation Attributes and IvalidatableObject The ValidationAttribute class was improved in the .NET Framework 4 to enable richer support for validation. When you write a custom validation attribute, you can use a new IsValid overload that provides a ValidationContext instance. This instance provides information about the current validation context, such as what object is being validated. This change enables scenarios such as validating the current value based on another property of the model. The following example shows a sample custom attribute that ensures that the value of PropertyOne is always larger than the value of PropertyTwo: public class CompareValidationAttribute : ValidationAttribute {     protected override ValidationResult IsValid(object value,              ValidationContext validationContext) {         var model = validationContext.ObjectInstance as SomeModel;         if (model.PropertyOne > model.PropertyTwo) {            return ValidationResult.Success;         }         return new ValidationResult("PropertyOne must be larger than PropertyTwo");     } } Validation in ASP.NET MVC also supports the .NET Framework 4 IValidatableObject interface. This interface allows your model to perform model-level validation, as in the following example: public class SomeModel : IValidatableObject {     public int PropertyOne { get; set; }     public int PropertyTwo { get; set; }     public IEnumerable<ValidationResult> Validate(ValidationContext validationContext) {         if (PropertyOne <= PropertyTwo) {            yield return new ValidationResult(                "PropertyOne must be larger than PropertyTwo");         }     } } New IClientValidatable Interface The new IClientValidatable interface allows the validation framework to discover at run time whether a validator has support for client validation. This interface is designed to be independent of the underlying implementation; therefore, where you implement the interface depends on the validation framework in use. For example, for the default data annotations-based validator, the interface would be applied on the validation attribute. Support for .NET Framework 4 Metadata Attributes ASP.NET MVC 3 now supports .NET Framework 4 metadata attributes such as DisplayAttribute. New IMetadataAware Interface The new IMetadataAware interface allows you to write attributes that simplify how you can contribute to the ModelMetadata creation process. Before this interface was available, you needed to write a custom metadata provider in order to have an attribute provide extra metadata. This interface is consumed by the AssociatedMetadataProvider class, so support for the IMetadataAware interface is automatically inherited by all classes that derive from that class (notably, the DataAnnotationsModelMetadataProvider class). New Action Result Types In ASP.NET MVC 3, the Controller class includes two new action result types and corresponding helper methods. HttpNotFoundResult Action The new HttpNotFoundResult action result is used to indicate that a resource requested by the current URL was not found. The status code is 404. This class derives from HttpStatusCodeResult. The Controller class includes an HttpNotFound method that returns an instance of this action result type, as shown in the following example: public ActionResult List(int id) {     if (id < 0) {                 return HttpNotFound();     }     return View(); } HttpStatusCodeResult Action The new HttpStatusCodeResult action result is used to set the response status code and description. Permanent Redirect The HttpRedirectResult class has a new Boolean Permanent property that is used to indicate whether a permanent redirect should occur. A permanent redirect uses the HTTP 301 status code. Corresponding to this change, the Controller class now has several methods for performing permanent redirects: - RedirectPermanent - RedirectToRoutePermanent - RedirectToActionPermanent These methods return an instance of HttpRedirectResult with the Permanent property set to true. Breaking Changes The order of execution for exception filters has changed for exception filters that have the same Order value. In ASP.NET MVC 2 and earlier, exception filters on the controller with the same Order as those on an action method were executed before the exception filters on the action method. This would typically be the case when exception filters were applied without a specified order Order value. In MVC 3, this order has been reversed in order to allow the most specific exception handler to execute first. As in earlier versions, if the Order property is explicitly specified, the filters are run in the specified order. Known Issues When you are editing a Razor view (CSHTML file), the Go To Controller menu item in Visual Studio will not be available, and there are no code snippets.

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• NoSQL with RavenDB and ASP.NET MVC - Part 2

  - by shiju

  In my previous post, we have discussed on how to work with RavenDB document database in an ASP.NET MVC application. We have setup RavenDB for our ASP.NET MVC application and did basic CRUD operations against a simple domain entity. In this post, let’s discuss on domain entity with deep object graph and how to query against RavenDB documents using Indexes.Let's create two domain entities for our demo ASP.NET MVC appplication  public class Category {       public string Id { 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 List<Expense> Expenses { get; set; }       public Category()     {         Expenses = new List<Expense>();     } }    public class Expense {       public string Id { get; set; }     public Category Category { get; set; }     public string  Transaction { get; set; }     public DateTime Date { get; set; }     public double Amount { get; set; }   }  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.Let's create  ASP.NET MVC view model  for Expense transaction public class ExpenseViewModel {     public string Id { get; set; }       public string CategoryId { get; set; }       [Required(ErrorMessage = "Transaction Required")]            public string Transaction { get; set; }       [Required(ErrorMessage = "Date Required")]            public DateTime Date { get; set; }       [Required(ErrorMessage = "Amount Required")]     public double Amount { get; set; }       public IEnumerable<SelectListItem> Category { get; set; } } Let's create a contract type for Expense Repository  public interface IExpenseRepository {     Expense Load(string id);     IEnumerable<Expense> GetExpenseTransactions(DateTime startDate,DateTime endDate);     void Save(Expense expense,string categoryId);     void Delete(string id);  } Let's create a concrete type for Expense Repository for handling CRUD operations. public class ExpenseRepository : IExpenseRepository {   private IDocumentSession session; public ExpenseRepository() {         session = MvcApplication.CurrentSession; } public Expense Load(string id) {     return session.Load<Expense>(id); } public IEnumerable<Expense> GetExpenseTransactions(DateTime startDate, DateTime endDate) {             //Querying using the Index name "ExpenseTransactions"     //filtering with dates     var expenses = session.LuceneQuery<Expense>("ExpenseTransactions")         .WaitForNonStaleResults()         .Where(exp => exp.Date >= startDate && exp.Date <= endDate)         .ToArray();     return expenses; } public void Save(Expense expense,string categoryId) {     var category = session.Load<Category>(categoryId);     if (string.IsNullOrEmpty(expense.Id))     {         //new expense transaction         expense.Category = category;         session.Store(expense);     }     else     {         //modifying an existing expense transaction         var expenseToEdit = Load(expense.Id);         //Copy values to  expenseToEdit         ModelCopier.CopyModel(expense, expenseToEdit);         //set category object         expenseToEdit.Category = category;       }     //save changes     session.SaveChanges(); } public void Delete(string id) {     var expense = Load(id);     session.Delete<Expense>(expense);     session.SaveChanges(); }   }  Insert/Update Expense Transaction The Save method is used for both insert a new expense record and modifying an existing expense transaction. For a new expense transaction, we store the expense object with associated category into document session object and load the existing expense object and assign values to it for editing a existing record.  public void Save(Expense expense,string categoryId) {     var category = session.Load<Category>(categoryId);     if (string.IsNullOrEmpty(expense.Id))     {         //new expense transaction         expense.Category = category;         session.Store(expense);     }     else     {         //modifying an existing expense transaction         var expenseToEdit = Load(expense.Id);         //Copy values to  expenseToEdit         ModelCopier.CopyModel(expense, expenseToEdit);         //set category object         expenseToEdit.Category = category;       }     //save changes     session.SaveChanges(); } Querying Expense transactions   public IEnumerable<Expense> GetExpenseTransactions(DateTime startDate, DateTime endDate) {             //Querying using the Index name "ExpenseTransactions"     //filtering with dates     var expenses = session.LuceneQuery<Expense>("ExpenseTransactions")         .WaitForNonStaleResults()         .Where(exp => exp.Date >= startDate && exp.Date <= endDate)         .ToArray();     return expenses; }  The GetExpenseTransactions method returns expense transactions using a LINQ query expression with a Date comparison filter. The Lucene Query is using a index named "ExpenseTransactions" for getting the result set. In RavenDB, Indexes are LINQ queries stored in the RavenDB server and would be  executed on the background and will perform query against the JSON documents. Indexes will be working with a lucene query expression or a set operation. Indexes are composed using a Map and Reduce function. Check out Ayende's blog post on Map/Reduce We can create index using RavenDB web admin tool as well as programmitically using its Client API. The below shows the screen shot of creating index using web admin tool. We can also create Indexes using Raven Cleint API as shown in the following code documentStore.DatabaseCommands.PutIndex("ExpenseTransactions",     new IndexDefinition<Expense,Expense>() {     Map = Expenses => from exp in Expenses                     select new { exp.Date } });  In the Map function, we used a Linq expression as shown in the following from exp in docs.Expensesselect new { exp.Date };We have not used a Reduce function for the above index. A Reduce function is useful while performing aggregate functions based on the results from the Map function. Indexes can be use with set operations of RavenDB.SET OperationsUnlike other document databases, RavenDB supports set based operations that lets you to perform updates, deletes and inserts to the bulk_docs endpoint of RavenDB. For doing this, you just pass a query to a Index as shown in the following commandDELETE http://localhost:8080/bulk_docs/ExpenseTransactions?query=Date:20100531The above command using the Index named "ExpenseTransactions" for querying the documents with Date filter and  will delete all the documents that match the query criteria. The above command is equivalent of the following queryDELETE FROM ExpensesWHERE Date='2010-05-31' Controller & ActionsWe have created Expense Repository class for performing CRUD operations for the Expense transactions. Let's create a controller class for handling expense transactions.   public class ExpenseController : Controller { private ICategoryRepository categoyRepository; private IExpenseRepository expenseRepository; public ExpenseController(ICategoryRepository categoyRepository, IExpenseRepository expenseRepository) {     this.categoyRepository = categoyRepository;     this.expenseRepository = expenseRepository; } //Get Expense transactions based on dates public ActionResult Index(DateTime? StartDate, DateTime? EndDate) {     //If date is not passed, take current month's first and last dte     DateTime dtNow;     dtNow = DateTime.Today;     if (!StartDate.HasValue)     {         StartDate = new DateTime(dtNow.Year, dtNow.Month, 1);         EndDate = StartDate.Value.AddMonths(1).AddDays(-1);     }     //take last date of startdate's month, if endate is not passed     if (StartDate.HasValue && !EndDate.HasValue)     {         EndDate = (new DateTime(StartDate.Value.Year, StartDate.Value.Month, 1)).AddMonths(1).AddDays(-1);     }       var expenses = expenseRepository.GetExpenseTransactions(StartDate.Value, EndDate.Value);     if (Request.IsAjaxRequest())     {           return PartialView("ExpenseList", expenses);     }     ViewData.Add("StartDate", StartDate.Value.ToShortDateString());     ViewData.Add("EndDate", EndDate.Value.ToShortDateString());             return View(expenses);            }   // GET: /Expense/Edit public ActionResult Edit(string id) {       var expenseModel = new ExpenseViewModel();     var expense = expenseRepository.Load(id);     ModelCopier.CopyModel(expense, expenseModel);     var categories = categoyRepository.GetCategories();     expenseModel.Category = categories.ToSelectListItems(expense.Category.Id.ToString());                    return View("Save", expenseModel);          }   // // GET: /Expense/Create   public ActionResult Create() {     var expenseModel = new ExpenseViewModel();               var categories = categoyRepository.GetCategories();     expenseModel.Category = categories.ToSelectListItems("-1");     expenseModel.Date = DateTime.Today;     return View("Save", expenseModel); }   // // POST: /Expense/Save // Insert/Update Expense Tansaction [HttpPost] public ActionResult Save(ExpenseViewModel expenseViewModel) {     try     {         if (!ModelState.IsValid)         {               var categories = categoyRepository.GetCategories();                 expenseViewModel.Category = categories.ToSelectListItems(expenseViewModel.CategoryId);                               return View("Save", expenseViewModel);         }           var expense=new Expense();         ModelCopier.CopyModel(expenseViewModel, expense);          expenseRepository.Save(expense, expenseViewModel.CategoryId);                       return RedirectToAction("Index");     }     catch     {         return View();     } } //Delete a Expense Transaction public ActionResult Delete(string id) {     expenseRepository.Delete(id);     return RedirectToAction("Index");     }     }     Download the Source - You can download the source code from http://ravenmvc.codeplex.com

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• Ubuntu Software Center starts, then crashes before fully loaded [closed]

  - by Nathan Weisser

  Possible Duplicate: Software center not opening I am brand new to Linux and Ubuntu, and I couldn't install GIMP without the software center. I looked up earlier how to fix it, and it said to fix my sources list, and I did, but now i get a new error in the terminal. 2012-08-14 15:29:08,941 - softwarecenter.ui.gtk3.app - INFO - setting up proxy 'None' 2012-08-14 15:29:08,954 - softwarecenter.db.database - INFO - open() database: path=None use_axi=True use_agent=True 2012-08-14 15:29:09,407 - softwarecenter.ui.gtk3.app - INFO - building local database 2012-08-14 15:29:09,408 - softwarecenter.db.pkginfo_impl.aptcache - INFO - aptcache.open() 2012-08-14 15:29:17,308 - softwarecenter.db.update - WARNING - Problem creating rebuild path '/var/cache/software-center/xapian_rb'. 2012-08-14 15:29:17,309 - softwarecenter.db.update - WARNING - Please check you have the relevant permissions. 2012-08-14 15:29:17,309 - softwarecenter.db.database - INFO - open() database: path=None use_axi=True use_agent=True 2012-08-14 15:29:18,039 - softwarecenter.backend.reviews - WARNING - Could not get usefulness from server, no username in config file 2012-08-14 15:29:18,431 - softwarecenter.ui.gtk3.app - INFO - show_available_packages: search_text is '', app is None. 2012-08-14 15:29:19,153 - softwarecenter.db.pkginfo_impl.aptcache - INFO - aptcache.open() Traceback (most recent call last): File "/usr/bin/software-center", line 176, in <module> app.run(args) File "/usr/share/software-center/softwarecenter/ui/gtk3/app.py", line 1422, in run self.show_available_packages(args) File "/usr/share/software-center/softwarecenter/ui/gtk3/app.py", line 1352, in show_available_packages self.view_manager.set_active_view(ViewPages.AVAILABLE) File "/usr/share/software-center/softwarecenter/ui/gtk3/session/viewmanager.py", line 154, in set_active_view view_widget.init_view() File "/usr/share/software-center/softwarecenter/ui/gtk3/panes/availablepane.py", line 136, in init_view SoftwarePane.init_view(self) File "/usr/share/software-center/softwarecenter/ui/gtk3/panes/softwarepane.py", line 215, in init_view self.icons, self.show_ratings) File "/usr/share/software-center/softwarecenter/ui/gtk3/views/appview.py", line 69, in __init__ self.helper = AppPropertiesHelper(db, cache, icons) File "/usr/share/software-center/softwarecenter/ui/gtk3/models/appstore2.py", line 109, in __init__ softwarecenter.paths.APP_INSTALL_PATH) File "/usr/share/software-center/softwarecenter/db/categories.py", line 255, in parse_applications_menu category = self._parse_menu_tag(child) File "/usr/share/software-center/softwarecenter/db/categories.py", line 444, in _parse_menu_tag query = self._parse_include_tag(element) File "/usr/share/software-center/softwarecenter/db/categories.py", line 402, in _parse_include_tag xapian.Query.OP_AND) File "/usr/share/software-center/softwarecenter/db/categories.py", line 341, in _parse_and_or_not_tag operator_elem, xapian.Query(), xapian.Query.OP_OR) File "/usr/share/software-center/softwarecenter/db/categories.py", line 385, in _parse_and_or_not_tag q = self.db.xapian_parser.parse_query(s, File "/usr/share/software-center/softwarecenter/db/database.py", line 174, in xapian_parser xapian_parser = self._get_new_xapian_parser() File "/usr/share/software-center/softwarecenter/db/database.py", line 200, in _get_new_xapian_parser xapian_parser.set_database(self.xapiandb) File "/usr/share/software-center/softwarecenter/db/database.py", line 166, in xapiandb self._db_per_thread[thread_name] = self._get_new_xapiandb() File "/usr/share/software-center/softwarecenter/db/database.py", line 179, in _get_new_xapiandb xapiandb = xapian.Database(self._db_pathname) File "/usr/lib/python2.7/dist-packages/xapian/__init__.py", line 3666, in __init__ _xapian.Database_swiginit(self,_xapian.new_Database(*args)) xapian.DatabaseOpeningError: Couldn't detect type of database I'm not sure how to fix the errors, and I couldn't find a topic on them anywhere. Be nice, because I am a two-day old Linux user :/ Tell me if you need my Sources list

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• SQL Monitor’s data repository

  - by Chris Lambrou

  As one of the developers of SQL Monitor, I often get requests passed on by our support people from customers who are looking to dip into SQL Monitor’s own data repository, in order to pull out bits of information that they’re interested in. Since there’s clearly interest out there in playing around directly with the data repository, I thought I’d write some blog posts to start to describe how it all works. The hardest part for me is knowing where to begin, since the schema of the data repository is pretty big. Hmmm… I guess it’s tricky for anyone to write anything but the most trivial of queries against the data repository without understanding the hierarchy of monitored objects, so perhaps my first post should start there. I always imagine that whenever a customer fires up SSMS and starts to explore their SQL Monitor data repository database, they become immediately bewildered by the schema – that was certainly my experience when I did so for the first time. The following query shows the number of different object types in the data repository schema: SELECT type_desc, COUNT(*) AS [count] FROM sys.objects GROUP BY type_desc ORDER BY type_desc;  type_desccount 1DEFAULT_CONSTRAINT63 2FOREIGN_KEY_CONSTRAINT181 3INTERNAL_TABLE3 4PRIMARY_KEY_CONSTRAINT190 5SERVICE_QUEUE3 6SQL_INLINE_TABLE_VALUED_FUNCTION381 7SQL_SCALAR_FUNCTION2 8SQL_STORED_PROCEDURE100 9SYSTEM_TABLE41 10UNIQUE_CONSTRAINT54 11USER_TABLE193 12VIEW124 With 193 tables, 124 views, 100 stored procedures and 381 table valued functions, that’s quite a hefty schema, and when you browse through it using SSMS, it can be a bit daunting at first. So, where to begin? Well, let’s narrow things down a bit and only look at the tables belonging to the data schema. That’s where all of the collected monitoring data is stored by SQL Monitor. The following query gives us the names of those tables: SELECT sch.name + '.' + obj.name AS [name] FROM sys.objects obj JOIN sys.schemas sch ON sch.schema_id = obj.schema_id WHERE obj.type_desc = 'USER_TABLE' AND sch.name = 'data' ORDER BY sch.name, obj.name; This query still returns 110 tables. I won’t show them all here, but let’s have a look at the first few of them:  name 1data.Cluster_Keys 2data.Cluster_Machine_ClockSkew_UnstableSamples 3data.Cluster_Machine_Cluster_StableSamples 4data.Cluster_Machine_Keys 5data.Cluster_Machine_LogicalDisk_Capacity_StableSamples 6data.Cluster_Machine_LogicalDisk_Keys 7data.Cluster_Machine_LogicalDisk_Sightings 8data.Cluster_Machine_LogicalDisk_UnstableSamples 9data.Cluster_Machine_LogicalDisk_Volume_StableSamples 10data.Cluster_Machine_Memory_Capacity_StableSamples 11data.Cluster_Machine_Memory_UnstableSamples 12data.Cluster_Machine_Network_Capacity_StableSamples 13data.Cluster_Machine_Network_Keys 14data.Cluster_Machine_Network_Sightings 15data.Cluster_Machine_Network_UnstableSamples 16data.Cluster_Machine_OperatingSystem_StableSamples 17data.Cluster_Machine_Ping_UnstableSamples 18data.Cluster_Machine_Process_Instances 19data.Cluster_Machine_Process_Keys 20data.Cluster_Machine_Process_Owner_Instances 21data.Cluster_Machine_Process_Sightings 22data.Cluster_Machine_Process_UnstableSamples 23… There are two things I want to draw your attention to: The table names describe a hierarchy of the different types of object that are monitored by SQL Monitor (e.g. clusters, machines and disks). For each object type in the hierarchy, there are multiple tables, ending in the suffixes _Keys, _Sightings, _StableSamples and _UnstableSamples. Not every object type has a table for every suffix, but the _Keys suffix is especially important and a _Keys table does indeed exist for every object type. In fact, if we limit the query to return only those tables ending in _Keys, we reveal the full object hierarchy: SELECT sch.name + '.' + obj.name AS [name] FROM sys.objects obj JOIN sys.schemas sch ON sch.schema_id = obj.schema_id WHERE obj.type_desc = 'USER_TABLE' AND sch.name = 'data' AND obj.name LIKE '%_Keys' ORDER BY sch.name, obj.name;  name 1data.Cluster_Keys 2data.Cluster_Machine_Keys 3data.Cluster_Machine_LogicalDisk_Keys 4data.Cluster_Machine_Network_Keys 5data.Cluster_Machine_Process_Keys 6data.Cluster_Machine_Services_Keys 7data.Cluster_ResourceGroup_Keys 8data.Cluster_ResourceGroup_Resource_Keys 9data.Cluster_SqlServer_Agent_Job_History_Keys 10data.Cluster_SqlServer_Agent_Job_Keys 11data.Cluster_SqlServer_Database_BackupType_Backup_Keys 12data.Cluster_SqlServer_Database_BackupType_Keys 13data.Cluster_SqlServer_Database_CustomMetric_Keys 14data.Cluster_SqlServer_Database_File_Keys 15data.Cluster_SqlServer_Database_Keys 16data.Cluster_SqlServer_Database_Table_Index_Keys 17data.Cluster_SqlServer_Database_Table_Keys 18data.Cluster_SqlServer_Error_Keys 19data.Cluster_SqlServer_Keys 20data.Cluster_SqlServer_Services_Keys 21data.Cluster_SqlServer_SqlProcess_Keys 22data.Cluster_SqlServer_TopQueries_Keys 23data.Cluster_SqlServer_Trace_Keys 24data.Group_Keys The full object type hierarchy looks like this: Cluster Machine LogicalDisk Network Process Services ResourceGroup Resource SqlServer Agent Job History Database BackupType Backup CustomMetric File Table Index Error Services SqlProcess TopQueries Trace Group Okay, but what about the individual objects themselves represented at each level in this hierarchy? Well that’s what the _Keys tables are for. This is probably best illustrated by way of a simple example – how can I query my own data repository to find the databases on my own PC for which monitoring data has been collected? Like this: SELECT clstr._Name AS cluster_name, srvr._Name AS instance_name, db._Name AS database_name FROM data.Cluster_SqlServer_Database_Keys db JOIN data.Cluster_SqlServer_Keys srvr ON db.ParentId = srvr.Id -- Note here how the parent of a Database is a Server JOIN data.Cluster_Keys clstr ON srvr.ParentId = clstr.Id -- Note here how the parent of a Server is a Cluster WHERE clstr._Name = 'dev-chrisl2' -- This is the hostname of my own PC ORDER BY clstr._Name, srvr._Name, db._Name;  cluster_nameinstance_namedatabase_name 1dev-chrisl2SqlMonitorData 2dev-chrisl2master 3dev-chrisl2model 4dev-chrisl2msdb 5dev-chrisl2mssqlsystemresource 6dev-chrisl2tempdb 7dev-chrisl2sql2005SqlMonitorData 8dev-chrisl2sql2005TestDatabase 9dev-chrisl2sql2005master 10dev-chrisl2sql2005model 11dev-chrisl2sql2005msdb 12dev-chrisl2sql2005mssqlsystemresource 13dev-chrisl2sql2005tempdb 14dev-chrisl2sql2008SqlMonitorData 15dev-chrisl2sql2008master 16dev-chrisl2sql2008model 17dev-chrisl2sql2008msdb 18dev-chrisl2sql2008mssqlsystemresource 19dev-chrisl2sql2008tempdb These results show that I have three SQL Server instances on my machine (a default instance, one named sql2005 and one named sql2008), and each instance has the usual set of system databases, along with a database named SqlMonitorData. Basically, this is where I test SQL Monitor on different versions of SQL Server, when I’m developing. There are a few important things we can learn from this query: Each _Keys table has a column named Id. This is the primary key. Each _Keys table has a column named ParentId. A foreign key relationship is defined between each _Keys table and its parent _Keys table in the hierarchy. There are two exceptions to this, Cluster_Keys and Group_Keys, because clusters and groups live at the root level of the object hierarchy. Each _Keys table has a column named _Name. This is used to uniquely identify objects in the table within the scope of the same shared parent object. Actually, that last item isn’t always true. In some cases, the _Name column is actually called something else. For example, the data.Cluster_Machine_Services_Keys table has a column named _ServiceName instead of _Name (sorry for the inconsistency). In other cases, a name isn’t sufficient to uniquely identify an object. For example, right now my PC has multiple processes running, all sharing the same name, Chrome (one for each tab open in my web-browser). In such cases, multiple columns are used to uniquely identify an object within the scope of the same shared parent object. Well, that’s it for now. I’ve given you enough information for you to explore the _Keys tables to see how objects are stored in your own data repositories. In a future post, I’ll try to explain how monitoring data is stored for each object, using the _StableSamples and _UnstableSamples tables. If you have any questions about this post, or suggestions for future posts, just submit them in the comments section below.

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• Code excavations, wishful invocations, perimeters and domain specific unit test frameworks

  - by RoyOsherove

  One of the talks I did at QCON London was about a subject that I’ve come across fairly recently , when I was building SilverUnit – a “pure” unit test framework for silverlight objects that depend on the silverlight runtime to run. It is the concept of “cogs in the machine” – when your piece of code needs to run inside a host framework or runtime that you have little or no control over for testability related matters. Examples of such cogs and machines can be: your custom control running inside silverlight runtime in the browser your plug-in running inside an IDE your activity running inside a windows workflow your code running inside a java EE bean your code inheriting from a COM+ (enterprise services) component etc.. Not all of these are necessarily testability problems. The main testability problem usually comes when your code actually inherits form something inside the system. For example. one of the biggest problems with testing objects like silverlight controls is the way they depend on the silverlight runtime – they don’t implement some silverlight interface, they don’t just call external static methods against the framework runtime that surrounds them – they actually inherit parts of the framework: they all inherit (in this case) from the silverlight DependencyObject Wrapping it up? An inheritance dependency is uniquely challenging to bring under test, because “classic” methods such as wrapping the object under test with a framework wrapper will not work, and the only way to do manually is to create parallel testable objects that get delegated with all the possible actions from the dependencies.    In silverlight’s case, that would mean creating your own custom logic class that would be called directly from controls that inherit from silverlight, and would be tested independently of these controls. The pro side is that you get the benefit of understanding the “contract” and the “roles” your system plays against your logic, but unfortunately, more often than not, it can be very tedious to create, and may sometimes feel unnecessary or like code duplication. About perimeters A perimeter is that invisible line that your draw around your pieces of logic during a test, that separate the code under test from any dependencies that it uses. Most of the time, a test perimeter around an object will be the list of seams (dependencies that can be replaced such as interfaces, virtual methods etc.) that are actually replaced for that test or for all the tests. Role based perimeters In the case of creating a wrapper around an object – one really creates a “role based” perimeter around the logic that is being tested – that wrapper takes on roles that are required by the code under test, and also communicates with the host system to implement those roles and provide any inputs to the logic under test. in the image below – we have the code we want to test represented as a star. No perimeter is drawn yet (we haven’t wrapped it up in anything yet). in the image below is what happens when you wrap your logic with a role based wrapper – you get a role based perimeter anywhere your code interacts with the system: There’s another way to bring that code under test – using isolation frameworks like typemock, rhino mocks and MOQ (but if your code inherits from the system, Typemock might be the only way to isolate the code from the system interaction.   Ad-Hoc Isolation perimeters the image below shows what I call ad-hoc perimeter that might be vastly different between different tests: This perimeter’s surface is much smaller, because for that specific test, that is all the “change” that is required to the host system behavior.   The third way of isolating the code from the host system is the main “meat” of this post: Subterranean perimeters Subterranean perimeters are Deep rooted perimeters  - “always on” seams that that can lie very deep in the heart of the host system where they are fully invisible even to the test itself, not just to the code under test. Because they lie deep inside a system you can’t control, the only way I’ve found to control them is with runtime (not compile time) interception of method calls on the system. One way to get such abilities is by using Aspect oriented frameworks – for example, in SilverUnit, I’ve used the CThru AOP framework based on Typemock hooks and CLR profilers to intercept such system level method calls and effectively turn them into seams that lie deep down at the heart of the silverlight runtime. the image below depicts an example of what such a perimeter could look like: As you can see, the actual seams can be very far away form the actual code under test, and as you’ll discover, that’s actually a very good thing. Here is only a partial list of examples of such deep rooted seams : disabling the constructor of a base class five levels below the code under test (this.base.base.base.base) faking static methods of a type that’s being called several levels down the stack: method x() calls y() calls z() calls SomeType.StaticMethod()  Replacing an async mechanism with a synchronous one (replacing all timers with your own timer behavior that always Ticks immediately upon calls to “start()” on the same caller thread for example) Replacing event mechanisms with your own event mechanism (to allow “firing” system events) Changing the way the system saves information with your own saving behavior (in silverunit, I replaced all Dependency Property set and get with calls to an in memory value store instead of using the one built into silverlight which threw exceptions without a browser) several questions could jump in: How do you know what to fake? (how do you discover the perimeter?) How do you fake it? Wouldn’t this be problematic  - to fake something you don’t own? it might change in the future How do you discover the perimeter to fake? To discover a perimeter all you have to do is start with a wishful invocation. a wishful invocation is the act of trying to invoke a method (or even just create an instance ) of an object using “regular” test code. You invoke the thing that you’d like to do in a real unit test, to see what happens: Can I even create an instance of this object without getting an exception? Can I invoke this method on that instance without getting an exception? Can I verify that some call into the system happened? You make the invocation, get an exception (because there is a dependency) and look at the stack trace. choose a location in the stack trace and disable it. Then try the invocation again. if you don’t get an exception the perimeter is good for that invocation, so you can move to trying out other methods on that object. in a future post I will show the process using CThru, and how you end up with something close to a domain specific test framework after you’re done creating the perimeter you need.

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• Mocking the Unmockable: Using Microsoft Moles with Gallio

  - by Thomas Weller

  Usual opensource mocking frameworks (like e.g. Moq or Rhino.Mocks) can mock only interfaces and virtual methods. In contrary to that, Microsoft’s Moles framework can ‘mock’ virtually anything, in that it uses runtime instrumentation to inject callbacks in the method MSIL bodies of the moled methods. Therefore, it is possible to detour any .NET method, including non-virtual/static methods in sealed types. This can be extremely helpful when dealing e.g. with code that calls into the .NET framework, some third-party or legacy stuff etc… Some useful collected resources (links to website, documentation material and some videos) can be found in my toolbox on Delicious under this link: http://delicious.com/thomasweller/toolbox+moles A Gallio extension for Moles Originally, Moles is a part of Microsoft’s Pex framework and thus integrates best with Visual Studio Unit Tests (MSTest). However, the Moles sample download contains some additional assemblies to also support other unit test frameworks. They provide a Moled attribute to ease the usage of mole types with the respective framework (there are extensions for NUnit, xUnit.net and MbUnit v2 included with the samples). As there is no such extension for the Gallio platform, I did the few required lines myself – the resulting Gallio.Moles.dll is included with the sample download. With this little assembly in place, it is possible to use Moles with Gallio like that: [Test, Moled] public void SomeTest() {     ... What you can do with it Moles can be very helpful, if you need to ‘mock’ something other than a virtual or interface-implementing method. This might be the case when dealing with some third-party component, legacy code, or if you want to ‘mock’ the .NET framework itself. Generally, you need to announce each moled type that you want to use in a test with the MoledType attribute on assembly level. For example: [assembly: MoledType(typeof(System.IO.File))] Below are some typical use cases for Moles. For a more detailed overview (incl. naming conventions and an instruction on how to create the required moles assemblies), please refer to the reference material above.  Detouring the .NET framework Imagine that you want to test a method similar to the one below, which internally calls some framework method:   public void ReadFileContent(string fileName) {     this.FileContent = System.IO.File.ReadAllText(fileName); } Using a mole, you would replace the call to the File.ReadAllText(string) method with a runtime delegate like so: [Test, Moled] [Description("This 'mocks' the System.IO.File class with a custom delegate.")] public void ReadFileContentWithMoles() {     // arrange ('mock' the FileSystem with a delegate)     System.IO.Moles.MFile.ReadAllTextString = (fname => fname == FileName ? FileContent : "WrongFileName");       // act     var testTarget = new TestTarget.TestTarget();     testTarget.ReadFileContent(FileName);       // assert     Assert.AreEqual(FileContent, testTarget.FileContent); } Detouring static methods and/or classes A static method like the below… public static string StaticMethod(int x, int y) {     return string.Format("{0}{1}", x, y); } … can be ‘mocked’ with the following: [Test, Moled] public void StaticMethodWithMoles() {     MStaticClass.StaticMethodInt32Int32 = ((x, y) => "uups");       var result = StaticClass.StaticMethod(1, 2);       Assert.AreEqual("uups", result); } Detouring constructors You can do this delegate thing even with a class’ constructor. The syntax for this is not all  too intuitive, because you have to setup the internal state of the mole, but generally it works like a charm. For example, to replace this c’tor… public class ClassWithCtor {     public int Value { get; private set; }       public ClassWithCtor(int someValue)     {         this.Value = someValue;     } } … you would do the following: [Test, Moled] public void ConstructorTestWithMoles() {     MClassWithCtor.ConstructorInt32 =            ((@class, @value) => new MClassWithCtor(@class) {ValueGet = () => 99});       var classWithCtor = new ClassWithCtor(3);       Assert.AreEqual(99, classWithCtor.Value); } Detouring abstract base classes You can also use this approach to ‘mock’ abstract base classes of a class that you call in your test. Assumed that you have something like that: public abstract class AbstractBaseClass {     public virtual string SaySomething()     {         return "Hello from base.";     } }      public class ChildClass : AbstractBaseClass {     public override string SaySomething()     {         return string.Format(             "Hello from child. Base says: '{0}'",             base.SaySomething());     } } Then you would set up the child’s underlying base class like this: [Test, Moled] public void AbstractBaseClassTestWithMoles() {     ChildClass child = new ChildClass();     new MAbstractBaseClass(child)         {                 SaySomething = () => "Leave me alone!"         }         .InstanceBehavior = MoleBehaviors.Fallthrough;       var hello = child.SaySomething();       Assert.AreEqual("Hello from child. Base says: 'Leave me alone!'", hello); } Setting the moles behavior to a value of  MoleBehaviors.Fallthrough causes the ‘original’ method to be called if a respective delegate is not provided explicitly – here it causes the ChildClass’ override of the SaySomething() method to be called. There are some more possible scenarios, where the Moles framework could be of much help (e.g. it’s also possible to detour interface implementations like IEnumerable<T> and such…). One other possibility that comes to my mind (because I’m currently dealing with that), is to replace calls from repository classes to the ADO.NET Entity Framework O/R mapper with delegates to isolate the repository classes from the underlying database, which otherwise would not be possible… Usage Since Moles relies on runtime instrumentation, mole types must be run under the Pex profiler. This only works from inside Visual Studio if you write your tests with MSTest (Visual Studio Unit Test). While other unit test frameworks generally can be used with Moles, they require the respective tests to be run via command line, executed through the moles.runner.exe tool. A typical test execution would be similar to this: moles.runner.exe <mytests.dll> /runner:<myframework.console.exe> /args:/<myargs> So, the moled test can be run through tools like NCover or a scripting tool like MSBuild (which makes them easy to run in a Continuous Integration environment), but they are somewhat unhandy to run in the usual TDD workflow (which I described in some detail here). To make this a bit more fluent, I wrote a ReSharper live template to generate the respective command line for the test (it is also included in the sample download – moled_cmd.xml). - This is just a quick-and-dirty ‘solution’. Maybe it makes sense to write an extra Gallio adapter plugin (similar to the many others that are already provided) and include it with the Gallio download package, if  there’s sufficient demand for it. As of now, the only way to run tests with the Moles framework from within Visual Studio is by using them with MSTest. From the command line, anything with a managed console runner can be used (provided that the appropriate extension is in place)… A typical Gallio/Moles command line (as generated by the mentioned R#-template) looks like that: "%ProgramFiles%\Microsoft Moles\bin\moles.runner.exe" /runner:"%ProgramFiles%\Gallio\bin\Gallio.Echo.exe" "Gallio.Moles.Demo.dll" /args:/r:IsolatedAppDomain /args:/filter:"ExactType:TestFixture and Member:ReadFileContentWithMoles" -- Note: When using the command line with Echo (Gallio’s console runner), be sure to always include the IsolatedAppDomain option, otherwise the tests won’t use the instrumentation callbacks! -- License issues As I already said, the free mocking frameworks can mock only interfaces and virtual methods. if you want to mock other things, you need the Typemock Isolator tool for that, which comes with license costs (Although these ‘costs’ are ridiculously low compared to the value that such a tool can bring to a software project, spending money often is a considerable gateway hurdle in real life...).  The Moles framework also is not totally free, but comes with the same license conditions as the (closely related) Pex framework: It is free for academic/non-commercial use only, to use it in a ‘real’ software project requires an MSDN Subscription (from VS2010pro on). The demo solution The sample solution (VS 2008) can be downloaded from here. It contains the Gallio.Moles.dll which provides the here described Moled attribute, the above mentioned R#-template (moled_cmd.xml) and a test fixture containing the above described use case scenarios. To run it, you need the Gallio framework (download) and Microsoft Moles (download) being installed in the default locations. Happy testing…

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• New DMV… not yet

  - by Michael Zilberstein

  Downloaded and installed new toy: And while reading BOL, stumbled upon new extremely useful DMV: sys.dm_exec_query_profiles . This DMV enables DBA to monitor query progress while it is being executed. Counters in the DMV are per operation per thread. So we’ll be able to monitor in real time which thread (even for parallel processing) processes which node in the plan. Or find heavy operations “post mortem”. We all know the uncomfortable feeling when some heavy query runs and the boss starts asking...(read more)

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• Google I/O 2011: Querying Freebase: Get More From MQL

  Google I/O 2011: Querying Freebase: Get More From MQL Jamie Taylor Freebase's query language, MQL, lets you access data about more than 20 million curated entities and the connections between them. Level up your Freebase query skills with advanced syntax, optimisation tricks, schema introsopection, metaschema, and more. From: GoogleDevelopers Views: 2007 15 ratings Time: 46:49 More in Science & Technology

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• Using OpenQuery

  - by Derek Dieter

  The OPENQUERY command is used to initiate an ad-hoc distributed query using a linked-server. It is initiated by specifying OPENQUERY as the table name in the from clause. Essentially, it opens a linked server, then executes a query as if executing from that server. While executing queries directly and receiving data directly in this [...]

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• Parallel LINQ - PLINQ

  - by nmarun

  Turns out now with .net 4.0 we can run a query like a multi-threaded application. Say you want to query a collection of objects and return only those that meet certain conditions. Until now, we basically had one ‘control’ that iterated over all the objects in the collection, checked the condition on each object and returned if it passed. We obviously agree that if we can ‘break’ this task into smaller ones, assign each task to a different ‘control’ and ask all the controls to do their job - in-parallel, the time taken the finish the entire task will be much lower. Welcome to PLINQ. Let’s take some examples. I have the following method that uses our good ol’ LINQ. 1: private static void Linq(int lowerLimit, int upperLimit) 2: { 3: // populate an array with int values from lowerLimit to the upperLimit 4: var source = Enumerable.Range(lowerLimit, upperLimit); 5:  6: // Start a timer 7: Stopwatch stopwatch = new Stopwatch(); 8: stopwatch.Start(); 9:  10: // set the expectation => build the expression tree 11: var evenNumbers =   from num in source 12: where IsDivisibleBy(num, 2) 13: select num; 14: 15: // iterate over and print the returned items 16: foreach (var number in evenNumbers) 17: { 18: Console.WriteLine(string.Format("** {0}", number)); 19: } 20:  21: stopwatch.Stop(); 22:  23: // check the metrics 24: Console.WriteLine(String.Format("Elapsed {0}ms", stopwatch.ElapsedMilliseconds)); 25: } I’ve added comments for the major steps, but the only thing I want to talk about here is the IsDivisibleBy() method. I know I could have just included the logic directly in the where clause. I called a method to add ‘delay’ to the execution of the query - to simulate a loooooooooong operation (will be easier to compare the results). 1: private static bool IsDivisibleBy(int number, int divisor) 2: { 3: // iterate over some database query 4: // to add time to the execution of this method; 5: // the TableB has around 10 records 6: for (int i = 0; i < 10; i++) 7: { 8: DataClasses1DataContext dataContext = new DataClasses1DataContext(); 9: var query = from b in dataContext.TableBs select b; 10: 11: foreach (var row in query) 12: { 13: // Do NOTHING (wish my job was like this) 14: } 15: } 16:  17: return number % divisor == 0; 18: } Now, let’s look at how to modify this to PLINQ. 1: private static void Plinq(int lowerLimit, int upperLimit) 2: { 3: // populate an array with int values from lowerLimit to the upperLimit 4: var source = Enumerable.Range(lowerLimit, upperLimit); 5:  6: // Start a timer 7: Stopwatch stopwatch = new Stopwatch(); 8: stopwatch.Start(); 9:  10: // set the expectation => build the expression tree 11: var evenNumbers = from num in source.AsParallel() 12: where IsDivisibleBy(num, 2) 13: select num; 14:  15: // iterate over and print the returned items 16: foreach (var number in evenNumbers) 17: { 18: Console.WriteLine(string.Format("** {0}", number)); 19: } 20:  21: stopwatch.Stop(); 22:  23: // check the metrics 24: Console.WriteLine(String.Format("Elapsed {0}ms", stopwatch.ElapsedMilliseconds)); 25: } That’s it, this is now in PLINQ format. Oh and if you haven’t found the difference, look line 11 a little more closely. You’ll see an extension method ‘AsParallel()’ added to the ‘source’ variable. Couldn’t be more simpler right? So this is going to improve the performance for us. Let’s test it. So in my Main method of the Console application that I’m working on, I make a call to both. 1: static void Main(string[] args) 2: { 3: // set lower and upper limits 4: int lowerLimit = 1; 5: int upperLimit = 20; 6: // call the methods 7: Console.WriteLine("Calling Linq() method"); 8: Linq(lowerLimit, upperLimit); 9: 10: Console.WriteLine(); 11: Console.WriteLine("Calling Plinq() method"); 12: Plinq(lowerLimit, upperLimit); 13:  14: Console.ReadLine(); // just so I get enough time to read the output 15: } YMMV, but here are the results that I got:    It’s quite obvious from the above results that the Plinq() method is taking considerably less time than the Linq() version. I’m sure you’ve already noticed that the output of the Plinq() method is not in order. That’s because, each of the ‘control’s we sent to fetch the results, reported with values as and when they obtained them. This is something about parallel LINQ that one needs to remember – the collection cannot be guaranteed to be undisturbed. This could be counted as a negative about PLINQ (emphasize ‘could’). Nevertheless, if we want the collection to be sorted, we can use a SortedSet (.net 4.0) or build our own custom ‘sorter’. Either way we go, there’s a good chance we’ll end up with a better performance using PLINQ. And there’s another negative of PLINQ (depending on how you see it). This is regarding the CPU cycles. See the usage for Linq() method (used ResourceMonitor): I have dual CPU’s and see the height of the peak in the bottom two blocks and now compare to what happens when I run the Plinq() method. The difference is obvious. Higher usage, but for a shorter duration (width of the peak). Both these points make sense in both cases. Linq() runs for a longer time, but uses less resources whereas Plinq() runs for a shorter time and consumes more resources. Even after knowing all these, I’m still inclined towards PLINQ. PLINQ rocks! (no hard feelings LINQ)

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