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  • Azure - Part 4 - Table Storage Service in Windows Azure

    - by Shaun
    In Windows Azure platform there are 3 storage we can use to save our data on the cloud. They are the Table, Blob and Queue. Before the Chinese New Year Microsoft announced that Azure SDK 1.1 had been released and it supports a new type of storage – Drive, which allows us to operate NTFS files on the cloud. I will cover it in the coming few posts but now I would like to talk a bit about the Table Storage.   Concept of Table Storage Service The most common development scenario is to retrieve, create, update and remove data from the data storage. In the normal way we communicate with database. When we attempt to move our application over to the cloud the most common requirement should be have a storage service. Windows Azure provides a in-build service that allow us to storage the structured data, which is called Windows Azure Table Storage Service. The data stored in the table service are like the collection of entities. And the entities are similar to rows or records in the tradtional database. An entity should had a partition key, a row key, a timestamp and set of properties. You can treat the partition key as a group name, the row key as a primary key and the timestamp as the identifer for solving the concurrency problem. Different with a table in a database, the table service does not enforce the schema for tables, which means you can have 2 entities in the same table with different property sets. The partition key is being used for the load balance of the Azure OS and the group entity transaction. As you know in the cloud you will never know which machine is hosting your application and your data. It could be moving based on the transaction weight and the number of the requests. If the Azure OS found that there are many requests connect to your Book entities with the partition key equals “Novel” it will move them to another idle machine to increase the performance. So when choosing the partition key for your entities you need to make sure they indecate the category or gourp information so that the Azure OS can perform the load balance as you wish.   Consuming the Table Although the table service looks like a database, you cannot access it through the way you are using now, neither ADO.NET nor ODBC. The table service exposed itself by ADO.NET Data Service protocol, which allows you can consume it through the RESTful style by Http requests. The Azure SDK provides a sets of classes for us to connect it. There are 2 classes we might need: TableServiceContext and TableServiceEntity. The TableServiceContext inherited from the DataServiceContext, which represents the runtime context of the ADO.NET data service. It provides 4 methods mainly used by us: CreateQuery: It will create a IQueryable instance from a given type of entity. AddObject: Add the specified entity into Table Service. UpdateObject: Update an existing entity in the Table Service. DeleteObject: Delete an entity from the Table Service. Beofre you operate the table service you need to provide the valid account information. It’s something like the connect string of the database but with your account name and the account key when you created the storage service on the Windows Azure Development Portal. After getting the CloudStorageAccount you can create the CloudTableClient instance which provides a set of methods for using the table service. A very useful method would be CreateTableIfNotExist. It will create the table container for you if it’s not exsited. And then you can operate the eneities to that table through the methods I mentioned above. Let me explain a bit more through an exmaple. We always like code rather than sentence.   Straightforward Accessing to the Table Here I would like to build a WCF service on the Windows Azure platform, and for now just one requirement: it would allow the client to create an account entity on the table service. The WCF service would have a method named Register and accept an instance of the account which the client wants to create. After perform some validation it will add the entity into the table service. So the first thing I should do is to create a Cloud Application on my VIstial Studio 2010 RC. (The Azure SDK 1.1 only supports VS2008 and VS2010 RC.) The solution should be like this below. Then I added a configuration items for the storage account through the Settings section under the cloud project. (Double click the Services file under Roles folder and navigate to the Setting section.) This setting will be used when to retrieve my storage account information. Since for now I just in the development phase I will select “UseDevelopmentStorage=true”. And then I navigated to the WebRole.cs file under my WCF project. If you have read my previous posts you would know that this file defines the process when the application start, and terminate on the cloud. What I need to do is to when the application start, set the configuration publisher to load my config file with the config name I specified. So the code would be like below. I removed the original service and contract created by the VS template and add my IAccountService contract and its implementation class - AccountService. And I add the service method Register with the parameters: email, password and it will return a boolean value to indicates the result which is very simple. At this moment if I press F5 the application will be established on my local development fabric and I can see my service runs well through the browser. Let’s implement the service method Rigister, add a new entity to the table service. As I said before the entities you want to store in the table service must have 3 properties: partition key, row key and timespan. You can create a class with these 3 properties. The Azure SDK provides us a base class for that named TableServiceEntity in Microsoft.WindowsAzure.StorageClient namespace. So what we need to do is more simply, create a class named Account and let it derived from the TableServiceEntity. And I need to add my own properties: Email, Password, DateCreated and DateDeleted. The DateDeleted is a nullable date time value to indecate whether this entity had been deleted and when. Do you notice that I missed something here? Yes it’s the partition key and row key I didn’t assigned. The TableServiceEntity base class defined 2 constructors one was a parameter-less constructor which will be used to fill values into the properties from the table service when retrieving data. The other was one with 2 parameters: partition key and row key. As I said below the partition key may affect the load balance and the row key must be unique so here I would like to use the email as the parition key and the email plus a Guid as the row key. OK now we finished the entity class we need to store onto the table service. The next step is to create a data access class for us to add it. Azure SDK gives us a base class for it named TableServiceContext as I mentioned below. So let’s create a class for operate the Account entities. The TableServiceContext need the storage account information for its constructor. It’s the combination of the storage service URI that we will create on Windows Azure platform, and the relevant account name and key. The TableServiceContext will use this information to find the related address and verify the account to operate the storage entities. Hence in my AccountDataContext class I need to override this constructor and pass the storage account into it. All entities will be saved in the table storage with one or many tables which we call them “table containers”. Before we operate an entity we need to make sure that the table container had been created on the storage. There’s a method we can use for that: CloudTableClient.CreateTableIfNotExist. So in the constructor I will perform it firstly to make sure all method will be invoked after the table had been created. Notice that I passed the storage account enpoint URI and the credentials to specify where my storage is located and who am I. Another advise is that, make your entity class name as the same as the table name when create the table. It will increase the performance when you operate it over the cloud especially querying. Since the Register WCF method will add a new account into the table service, here I will create a relevant method to add the account entity. Before implement, I should add a reference - System.Data.Services.Client to the project. This reference provides some common method within the ADO.NET Data Service which can be used in the Windows Azure Table Service. I will use its AddObject method to create my account entity. Since the table service are not fully implemented the ADO.NET Data Service, there are some methods in the System.Data.Services.Client that TableServiceContext doesn’t support, such as AddLinks, etc. Then I implemented the serivce method to add the account entity through the AccountDataContext. You can see in the service implmentation I load the storage account information through my configuration file and created the account table entity from the parameters. Then I created the AccountDataContext. If it’s my first time to invoke this method the constructor of the AccountDataContext will create a table container for me. Then I use Add method to add the account entity into the table. Next, let’s create a farely simple client application to test this service. I created a windows console application and added a service reference to my WCF service. The metadata information of the WCF service cannot be retrieved if it’s deployed on the Windows Azure even though the <serviceMetadata httpGetEnabled="true"/> had been set. If we need to get its metadata we can deploy it on the local development service and then changed the endpoint to the address which is on the cloud. In the client side app.config file I specified the endpoint to the local development fabric address. And the just implement the client to let me input an email and a password then invoke the WCF service to add my acocunt. Let’s run my application and see the result. Of course it should return TRUE to me. And in the local SQL Express I can see the data had been saved in the table.   Summary In this post I explained more about the Windows Azure Table Storage Service. I also created a small application for demostration of how to connect and consume it through the ADO.NET Data Service Managed Library provided within the Azure SDK. I only show how to create an eneity in the storage service. In the next post I would like to explain about how to query the entities with conditions thruogh LINQ. I also would like to refactor my AccountDataContext class to make it dyamic for any kinds of entities.   Hope this helps, Shaun   All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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  • Entity Framework version 1- Brief Synopsis and Tips &ndash; Part 1

    - by Rohit Gupta
    To Do Eager loading use Projections (for e.g. from c in context.Contacts select c, c.Addresses)  or use Include Query Builder Methods (Include(“Addresses”)) If there is multi-level hierarchical Data then to eager load all the relationships use Include Query Builder methods like customers.Include("Order.OrderDetail") to include Order and OrderDetail collections or use customers.Include("Order.OrderDetail.Location") to include all Order, OrderDetail and location collections with a single include statement =========================================================================== If the query uses Joins then Include() Query Builder method will be ignored, use Nested Queries instead If the query does projections then Include() Query Builder method will be ignored Use Address.ContactReference.Load() OR Contact.Addresses.Load() if you need to Deferred Load Specific Entity – This will result in extra round trips to the database ObjectQuery<> cannot return anonymous types... it will return a ObjectQuery<DBDataRecord> Only Include method can be added to Linq Query Methods Any Linq Query method can be added to Query Builder methods. If you need to append a Query Builder Method (other than Include) after a LINQ method  then cast the IQueryable<Contact> to ObjectQuery<Contact> and then append the Query Builder method to it =========================================================================== Query Builder methods are Select, Where, Include Methods which use Entity SQL as parameters e.g. "it.StartDate, it.EndDate" When Query Builder methods do projection then they return ObjectQuery<DBDataRecord>, thus to iterate over this collection use contact.Item[“Name”].ToString() When Linq To Entities methods do projection, they return collection of anonymous types --- thus the collection is strongly typed and supports Intellisense EF Object Context can track changes only on Entities, not on Anonymous types. If you use a Defining Query for a EntitySet then the EntitySet becomes readonly since a Defining Query is the same as a View (which is treated as a ReadOnly by default). However if you want to use this EntitySet for insert/update/deletes then we need to map stored procs (as created in the DB) to the insert/update/delete functions of the Entity in the Designer You can use either Execute method or ToList() method to bind data to datasources/bindingsources If you use the Execute Method then remember that you can traverse through the ObjectResult<> collection (returned by Execute) only ONCE. In WPF use ObservableCollection to bind to data sources , for keeping track of changes and letting EF send updates to the DB automatically. Use Extension Methods to add logic to Entities. For e.g. create extension methods for the EntityObject class. Create a method in ObjectContext Partial class and pass the entity as a parameter, then call this method as desired from within each entity. ================================================================ DefiningQueries and Stored Procedures: For Custom Entities, one can use DefiningQuery or Stored Procedures. Thus the Custom Entity Collection will be populated using the DefiningQuery (of the EntitySet) or the Sproc. If you use Sproc to populate the EntityCollection then the query execution is immediate and this execution happens on the Server side and any filters applied will be applied in the Client App. If we use a DefiningQuery then these queries are composable, meaning the filters (if applied to the entityset) will all be sent together as a single query to the DB, returning only filtered results. If the sproc returns results that cannot be mapped to existing entity, then we first create the Entity/EntitySet in the CSDL using Designer, then create a dummy Entity/EntitySet using XML in the SSDL. When creating a EntitySet in the SSDL for this dummy entity, use a TSQL that does not return any results, but does return the relevant columns e.g. select ContactID, FirstName, LastName from dbo.Contact where 1=2 Also insure that the Entity created in the SSDL uses the SQL DataTypes and not .NET DataTypes. If you are unable to open the EDMX file in the designer then note the Errors ... they will give precise info on what is wrong. The Thrid option is to simply create a Native Query in the SSDL using <Function Name="PaymentsforContact" IsComposable="false">   <CommandText>SELECT ActivityId, Activity AS ActivityName, ImagePath, Category FROM dbo.Activities </CommandText></FuncTion> Then map this Function to a existing Entity. This is a quick way to get a custom Entity which is regular Entity with renamed columns or additional columns (which are computed columns). The disadvantage to using this is that It will return all the rows from the Defining query and any filter (if defined) will be applied only at the Client side (after getting all the rows from DB). If you you DefiningQuery instead then we can use that as a Composable Query. The Fourth option (for mapping a READ stored proc results to a non-existent Entity) is to create a View in the Database which returns all the fields that the sproc also returns, then update the Model so that the model contains this View as a Entity. Then map the Read Sproc to this View Entity. The other option would be to simply create the View and remove the sproc altogether. ================================================================ To Execute a SProc that does not return a entity, use a EntityCommand to execute that proc. You cannot call a sproc FunctionImport that does not return Entities From Code, the only way is to use SSDL function calls using EntityCommand.  This changes with EntityFramework Version 4 where you can return Scalar Types, Complex Types, Entities or NonQuery ================================================================ UDF when created as a Function in SSDL, we need to set the Name & IsComposable properties for the Function element. IsComposable is always false for Sprocs, for UDF's set this to true. You cannot call UDF "Function" from within code since you cannot import a UDF Function into the CSDL Model (with Version 1 of EF). only stored procedures can be imported and then mapped to a entity ================================================================ Entity Framework requires properties that are involved in association mappings to be mapped in all of the function mappings for the entity (Insert, Update and Delete). Because Payment has an association to Reservation... hence we need to pass both the paymentId and reservationId to the Delete sproc even though just the paymentId is the PK on the Payment Table. ================================================================ When mapping insert, update and delete procs to a Entity, insure that all the three or none are mapped. Further if you have a base class and derived class in the CSDL, then you must map (ins, upd, del) sprocs to all parent and child entities in the inheritance relationship. Note that this limitation that base and derived entity methods must all must be mapped does not apply when you are mapping Read Stored Procedures.... ================================================================ You can write stored procedures SQL directly into the SSDL by creating a Function element in the SSDL and then once created, you can map this Function to a CSDL Entity directly in the designer during Function Import ================================================================ You can do Entity Splitting such that One Entity maps to multiple tables in the DB. For e.g. the Customer Entity currently derives from Contact Entity...in addition it also references the ContactPersonalInfo Entity. One can copy all properties from the ContactPersonalInfo Entity into the Customer Entity and then Delete the CustomerPersonalInfo entity, finall one needs to map the copied properties to the ContactPersonalInfo Table in Table Mapping (by adding another table (ContactPersonalInfo) to the Table Mapping... this is called Entity Splitting. Thus now when you insert a Customer record, it will automatically create SQL to insert records into the Contact, Customers and ContactPersonalInfo tables even though you have a Single Entity called Customer in the CSDL =================================================================== There is Table by Type Inheritance where another EDM Entity can derive from another EDM entity and absorb the inherted entities properties, for example in the Break Away Geek Adventures EDM, the Customer entity derives (inherits) from the Contact Entity and absorbs all the properties of Contact entity. Thus when you create a Customer Entity in Code and then call context.SaveChanges the Object Context will first create the TSQL to insert into the Contact Table followed by a TSQL to insert into the Customer table =================================================================== Then there is the Table per Hierarchy Inheritance..... where different types are created based on a condition (similar applying a condition to filter a Entity to contain filtered records)... the diference being that the filter condition populates a new Entity Type (derived from the base Entity). In the BreakAway sample the example is Lodging Entity which is a Abstract Entity and Then Resort and NonResort Entities which derive from Lodging Entity and records are filtered based on the value of the Resort Boolean field =================================================================== Then there is Table per Concrete Type Hierarchy where we create a concrete Entity for each table in the database. In the BreakAway sample there is a entity for the Reservation table and another Entity for the OldReservation table even though both the table contain the same number of fields. The OldReservation Entity can then inherit from the Reservation Entity and configure the OldReservation Entity to remove all Scalar Properties from the Entity (since it inherits the properties from Reservation and filters based on ReservationDate field) =================================================================== Complex Types (Complex Properties) Entities in EF can also contain Complex Properties (in addition to Scalar Properties) and these Complex Properties reference a ComplexType (not a EntityType) DropdownList, ListBox, RadioButtonList, CheckboxList, Bulletedlist are examples of List server controls (not data bound controls) these controls cannot use Complex properties during databinding, they need Scalar Properties. So if a Entity contains Complex properties and you need to bind those to list server controls then use projections to return Scalar properties and bind them to the control (the disadvantage is that projected collections are not tracked by the Object Context and hence cannot persist changes to the projected collections bound to controls) ObjectDataSource and EntityDataSource do account for Complex properties and one can bind entities with Complex Properties to Data Source controls and they will be tracked for changes... with no additional plumbing needed to persist changes to these collections bound to controls So DataBound controls like GridView, FormView need to use EntityDataSource or ObjectDataSource as a datasource for entities that contain Complex properties so that changes to the datasource done using the GridView can be persisted to the DB (enabling the controls for updates)....if you cannot use the EntityDataSource you need to flatten the ComplexType Properties using projections With EF Version 4 ComplexTypes are supported by the Designer and can add/remove/compose Complex Types directly using the Designer =================================================================== Conditional Mapping ... is like Table per Hierarchy Inheritance where Entities inherit from a base class and then used conditions to populate the EntitySet (called conditional Mapping). Conditional Mapping has limitations since you can only use =, is null and IS NOT NULL Conditions to do conditional mapping. If you need more operators for filtering/mapping conditionally then use QueryView(or possibly Defining Query) to create a readonly entity. QueryView are readonly by default... the EntitySet created by the QueryView is enabled for change tracking by the ObjectContext, however the ObjectContext cannot create insert/update/delete TSQL statements for these Entities when SaveChanges is called since it is QueryView. One way to get around this limitation is to map stored procedures for the insert/update/delete operations in the Designer. =================================================================== Difference between QueryView and Defining Query : QueryView is defined in the (MSL) Mapping File/section of the EDM XML, whereas the DefiningQuery is defined in the store schema (SSDL). QueryView is written using Entity SQL and is this database agnostic and can be used against any database/Data Layer. DefiningQuery is written using Database Lanaguage i.e. TSQL or PSQL thus you have more control =================================================================== Performance: Lazy loading is deferred loading done automatically. lazy loading is supported with EF version4 and is on by default. If you need to turn it off then use context.ContextOptions.lazyLoadingEnabled = false To improve Performance consider PreCompiling the ObjectQuery using the CompiledQuery.Compile method

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  • C#: Why Decorate When You Can Intercept

    - by James Michael Hare
    We've all heard of the old Decorator Design Pattern (here) or used it at one time or another either directly or indirectly.  A decorator is a class that wraps a given abstract class or interface and presents the same (or a superset) public interface but "decorated" with additional functionality.   As a really simplistic example, consider the System.IO.BufferedStream, it itself is a descendent of System.IO.Stream and wraps the given stream with buffering logic while still presenting System.IO.Stream's public interface:   1: Stream buffStream = new BufferedStream(rawStream); Now, let's take a look at a custom-code example.  Let's say that we have a class in our data access layer that retrieves a list of products from a database:  1: // a class that handles our CRUD operations for products 2: public class ProductDao 3: { 4: ... 5:  6: // a method that would retrieve all available products 7: public IEnumerable<Product> GetAvailableProducts() 8: { 9: var results = new List<Product>(); 10:  11: // must create the connection 12: using (var con = _factory.CreateConnection()) 13: { 14: con.ConnectionString = _productsConnectionString; 15: con.Open(); 16:  17: // create the command 18: using (var cmd = _factory.CreateCommand()) 19: { 20: cmd.Connection = con; 21: cmd.CommandText = _getAllProductsStoredProc; 22: cmd.CommandType = CommandType.StoredProcedure; 23:  24: // get a reader and pass back all results 25: using (var reader = cmd.ExecuteReader()) 26: { 27: while(reader.Read()) 28: { 29: results.Add(new Product 30: { 31: Name = reader["product_name"].ToString(), 32: ... 33: }); 34: } 35: } 36: } 37: }            38:  39: return results; 40: } 41: } Yes, you could use EF or any myriad other choices for this sort of thing, but the germaine point is that you have some operation that takes a non-trivial amount of time.  What if, during the production day I notice that my application is performing slowly and I want to see how much of that slowness is in the query versus my code.  Well, I could easily wrap the logic block in a System.Diagnostics.Stopwatch and log the results to log4net or other logging flavor of choice: 1:     // a class that handles our CRUD operations for products 2:     public class ProductDao 3:     { 4:         private static readonly ILog _log = LogManager.GetLogger(typeof(ProductDao)); 5:         ... 6:         7:         // a method that would retrieve all available products 8:         public IEnumerable<Product> GetAvailableProducts() 9:         { 10:             var results = new List<Product>(); 11:             var timer = Stopwatch.StartNew(); 12:             13:             // must create the connection 14:             using (var con = _factory.CreateConnection()) 15:             { 16:                 con.ConnectionString = _productsConnectionString; 17:                 18:                 // and all that other DB code... 19:                 ... 20:             } 21:             22:             timer.Stop(); 23:             24:             if (timer.ElapsedMilliseconds > 5000) 25:             { 26:                 _log.WarnFormat("Long query in GetAvailableProducts() took {0} ms", 27:                     timer.ElapsedMillseconds); 28:             } 29:             30:             return results; 31:         } 32:     } In my eye, this is very ugly.  It violates Single Responsibility Principle (SRP), which says that a class should only ever have one responsibility, where responsibility is often defined as a reason to change.  This class (and in particular this method) has two reasons to change: If the method of retrieving products changes. If the method of logging changes. Well, we could “simplify” this using the Decorator Design Pattern (here).  If we followed the pattern to the letter, we'd need to create a base decorator that implements the DAOs public interface and forwards to the wrapped instance.  So let's assume we break out the ProductDAO interface into IProductDAO using your refactoring tool of choice (Resharper is great for this). Now, ProductDao will implement IProductDao and get rid of all logging logic: 1:     public class ProductDao : IProductDao 2:     { 3:         // this reverts back to original version except for the interface added 4:     } 5:  And we create the base Decorator that also implements the interface and forwards all calls: 1:     public class ProductDaoDecorator : IProductDao 2:     { 3:         private readonly IProductDao _wrappedDao; 4:         5:         // constructor takes the dao to wrap 6:         public ProductDaoDecorator(IProductDao wrappedDao) 7:         { 8:             _wrappedDao = wrappedDao; 9:         } 10:         11:         ... 12:         13:         // and then all methods just forward their calls 14:         public IEnumerable<Product> GetAvailableProducts() 15:         { 16:             return _wrappedDao.GetAvailableProducts(); 17:         } 18:     } This defines our base decorator, then we can create decorators that add items of interest, and for any methods we don't decorate, we'll get the default behavior which just forwards the call to the wrapper in the base decorator: 1:     public class TimedThresholdProductDaoDecorator : ProductDaoDecorator 2:     { 3:         private static readonly ILog _log = LogManager.GetLogger(typeof(TimedThresholdProductDaoDecorator)); 4:         5:         public TimedThresholdProductDaoDecorator(IProductDao wrappedDao) : 6:             base(wrappedDao) 7:         { 8:         } 9:         10:         ... 11:         12:         public IEnumerable<Product> GetAvailableProducts() 13:         { 14:             var timer = Stopwatch.StartNew(); 15:             16:             var results = _wrapped.GetAvailableProducts(); 17:             18:             timer.Stop(); 19:             20:             if (timer.ElapsedMilliseconds > 5000) 21:             { 22:                 _log.WarnFormat("Long query in GetAvailableProducts() took {0} ms", 23:                     timer.ElapsedMillseconds); 24:             } 25:             26:             return results; 27:         } 28:     } Well, it's a bit better.  Now the logging is in its own class, and the database logic is in its own class.  But we've essentially multiplied the number of classes.  We now have 3 classes and one interface!  Now if you want to do that same logging decorating on all your DAOs, imagine the code bloat!  Sure, you can simplify and avoid creating the base decorator, or chuck it all and just inherit directly.  But regardless all of these have the problem of tying the logging logic into the code itself. Enter the Interceptors.  Things like this to me are a perfect example of when it's good to write an Interceptor using your class library of choice.  Sure, you could design your own perfectly generic decorator with delegates and all that, but personally I'm a big fan of Castle's Dynamic Proxy (here) which is actually used by many projects including Moq. What DynamicProxy allows you to do is intercept calls into any object by wrapping it with a proxy on the fly that intercepts the method and allows you to add functionality.  Essentially, the code would now look like this using DynamicProxy: 1: // Note: I like hiding DynamicProxy behind the scenes so users 2: // don't have to explicitly add reference to Castle's libraries. 3: public static class TimeThresholdInterceptor 4: { 5: // Our logging handle 6: private static readonly ILog _log = LogManager.GetLogger(typeof(TimeThresholdInterceptor)); 7:  8: // Handle to Castle's proxy generator 9: private static readonly ProxyGenerator _generator = new ProxyGenerator(); 10:  11: // generic form for those who prefer it 12: public static object Create<TInterface>(object target, TimeSpan threshold) 13: { 14: return Create(typeof(TInterface), target, threshold); 15: } 16:  17: // Form that uses type instead 18: public static object Create(Type interfaceType, object target, TimeSpan threshold) 19: { 20: return _generator.CreateInterfaceProxyWithTarget(interfaceType, target, 21: new TimedThreshold(threshold, level)); 22: } 23:  24: // The interceptor that is created to intercept the interface calls. 25: // Hidden as a private inner class so not exposing Castle libraries. 26: private class TimedThreshold : IInterceptor 27: { 28: // The threshold as a positive timespan that triggers a log message. 29: private readonly TimeSpan _threshold; 30:  31: // interceptor constructor 32: public TimedThreshold(TimeSpan threshold) 33: { 34: _threshold = threshold; 35: } 36:  37: // Intercept functor for each method invokation 38: public void Intercept(IInvocation invocation) 39: { 40: // time the method invocation 41: var timer = Stopwatch.StartNew(); 42:  43: // the Castle magic that tells the method to go ahead 44: invocation.Proceed(); 45:  46: timer.Stop(); 47:  48: // check if threshold is exceeded 49: if (timer.Elapsed > _threshold) 50: { 51: _log.WarnFormat("Long execution in {0} took {1} ms", 52: invocation.Method.Name, 53: timer.ElapsedMillseconds); 54: } 55: } 56: } 57: } Yes, it's a bit longer, but notice that: This class ONLY deals with logging long method calls, no DAO interface leftovers. This class can be used to time ANY class that has an interface or virtual methods. Personally, I like to wrap and hide the usage of DynamicProxy and IInterceptor so that anyone who uses this class doesn't need to know to add a Castle library reference.  As far as they are concerned, they're using my interceptor.  If I change to a new library if a better one comes along, they're insulated. Now, all we have to do to use this is to tell it to wrap our ProductDao and it does the rest: 1: // wraps a new ProductDao with a timing interceptor with a threshold of 5 seconds 2: IProductDao dao = TimeThresholdInterceptor.Create<IProductDao>(new ProductDao(), 5000); Automatic decoration of all methods!  You can even refine the proxy so that it only intercepts certain methods. This is ideal for so many things.  These are just some of the interceptors we've dreamed up and use: Log parameters and returns of methods to XML for auditing. Block invocations to methods and return default value (stubbing). Throw exception if certain methods are called (good for blocking access to deprecated methods). Log entrance and exit of a method and the duration. Log a message if a method takes more than a given time threshold to execute. Whether you use DynamicProxy or some other technology, I hope you see the benefits this adds.  Does it completely eliminate all need for the Decorator pattern?  No, there may still be cases where you want to decorate a particular class with functionality that doesn't apply to the world at large. But for all those cases where you are using Decorator to add functionality that's truly generic.  I strongly suggest you give this a try!

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  • Why unhandled exceptions are useful

    - by Simon Cooper
    It’s the bane of most programmers’ lives – an unhandled exception causes your application or webapp to crash, an ugly dialog gets displayed to the user, and they come complaining to you. Then, somehow, you need to figure out what went wrong. Hopefully, you’ve got a log file, or some other way of reporting unhandled exceptions (obligatory employer plug: SmartAssembly reports an application’s unhandled exceptions straight to you, along with the entire state of the stack and variables at that point). If not, you have to try and replicate it yourself, or do some psychic debugging to try and figure out what’s wrong. However, it’s good that the program crashed. Or, more precisely, it is correct behaviour. An unhandled exception in your application means that, somewhere in your code, there is an assumption that you made that is actually invalid. Coding assumptions Let me explain a bit more. Every method, every line of code you write, depends on implicit assumptions that you have made. Take this following simple method, that copies a collection to an array and includes an item if it isn’t in the collection already, using a supplied IEqualityComparer: public static T[] ToArrayWithItem( ICollection<T> coll, T obj, IEqualityComparer<T> comparer) { // check if the object is in collection already // using the supplied comparer foreach (var item in coll) { if (comparer.Equals(item, obj)) { // it's in the collection already // simply copy the collection to an array // and return it T[] array = new T[coll.Count]; coll.CopyTo(array, 0); return array; } } // not in the collection // copy coll to an array, and add obj to it // then return it T[] array = new T[coll.Count+1]; coll.CopyTo(array, 0); array[array.Length-1] = obj; return array; } What’s all the assumptions made by this fairly simple bit of code? coll is never null comparer is never null coll.CopyTo(array, 0) will copy all the items in the collection into the array, in the order defined for the collection, starting at the first item in the array. The enumerator for coll returns all the items in the collection, in the order defined for the collection comparer.Equals returns true if the items are equal (for whatever definition of ‘equal’ the comparer uses), false otherwise comparer.Equals, coll.CopyTo, and the coll enumerator will never throw an exception or hang for any possible input and any possible values of T coll will have less than 4 billion items in it (this is a built-in limit of the CLR) array won’t be more than 2GB, both on 32 and 64-bit systems, for any possible values of T (again, a limit of the CLR) There are no threads that will modify coll while this method is running and, more esoterically: The C# compiler will compile this code to IL according to the C# specification The CLR and JIT compiler will produce machine code to execute the IL on the user’s computer The computer will execute the machine code correctly That’s a lot of assumptions. Now, it could be that all these assumptions are valid for the situations this method is called. But if this does crash out with an exception, or crash later on, then that shows one of the assumptions has been invalidated somehow. An unhandled exception shows that your code is running in a situation which you did not anticipate, and there is something about how your code runs that you do not understand. Debugging the problem is the process of learning more about the new situation and how your code interacts with it. When you understand the problem, the solution is (usually) obvious. The solution may be a one-line fix, the rewrite of a method or class, or a large-scale refactoring of the codebase, but whatever it is, the fix for the crash will incorporate the new information you’ve gained about your own code, along with the modified assumptions. When code is running with an assumption or invariant it depended on broken, then the result is ‘undefined behaviour’. Anything can happen, up to and including formatting the entire disk or making the user’s computer sentient and start doing a good impression of Skynet. You might think that those can’t happen, but at Halting problem levels of generality, as soon as an assumption the code depended on is broken, the program can do anything. That is why it’s important to fail-fast and stop the program as soon as an invariant is broken, to minimise the damage that is done. What does this mean in practice? To start with, document and check your assumptions. As with most things, there is a level of judgement required. How you check and document your assumptions depends on how the code is used (that’s some more assumptions you’ve made), how likely it is a method will be passed invalid arguments or called in an invalid state, how likely it is the assumptions will be broken, how expensive it is to check the assumptions, and how bad things are likely to get if the assumptions are broken. Now, some assumptions you can assume unless proven otherwise. You can safely assume the C# compiler, CLR, and computer all run the method correctly, unless you have evidence of a compiler, CLR or processor bug. You can also assume that interface implementations work the way you expect them to; implementing an interface is more than simply declaring methods with certain signatures in your type. The behaviour of those methods, and how they work, is part of the interface contract as well. For example, for members of a public API, it is very important to document your assumptions and check your state before running the bulk of the method, throwing ArgumentException, ArgumentNullException, InvalidOperationException, or another exception type as appropriate if the input or state is wrong. For internal and private methods, it is less important. If a private method expects collection items in a certain order, then you don’t necessarily need to explicitly check it in code, but you can add comments or documentation specifying what state you expect the collection to be in at a certain point. That way, anyone debugging your code can immediately see what’s wrong if this does ever become an issue. You can also use DEBUG preprocessor blocks and Debug.Assert to document and check your assumptions without incurring a performance hit in release builds. On my coding soapbox… A few pet peeves of mine around assumptions. Firstly, catch-all try blocks: try { ... } catch { } A catch-all hides exceptions generated by broken assumptions, and lets the program carry on in an unknown state. Later, an exception is likely to be generated due to further broken assumptions due to the unknown state, causing difficulties when debugging as the catch-all has hidden the original problem. It’s much better to let the program crash straight away, so you know where the problem is. You should only use a catch-all if you are sure that any exception generated in the try block is safe to ignore. That’s a pretty big ask! Secondly, using as when you should be casting. Doing this: (obj as IFoo).Method(); or this: IFoo foo = obj as IFoo; ... foo.Method(); when you should be doing this: ((IFoo)obj).Method(); or this: IFoo foo = (IFoo)obj; ... foo.Method(); There’s an assumption here that obj will always implement IFoo. If it doesn’t, then by using as instead of a cast you’ve turned an obvious InvalidCastException at the point of the cast that will probably tell you what type obj actually is, into a non-obvious NullReferenceException at some later point that gives you no information at all. If you believe obj is always an IFoo, then say so in code! Let it fail-fast if not, then it’s far easier to figure out what’s wrong. Thirdly, document your assumptions. If an algorithm depends on a non-trivial relationship between several objects or variables, then say so. A single-line comment will do. Don’t leave it up to whoever’s debugging your code after you to figure it out. Conclusion It’s better to crash out and fail-fast when an assumption is broken. If it doesn’t, then there’s likely to be further crashes along the way that hide the original problem. Or, even worse, your program will be running in an undefined state, where anything can happen. Unhandled exceptions aren’t good per-se, but they give you some very useful information about your code that you didn’t know before. And that can only be a good thing.

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  • StreamInsight 2.1, meet LINQ

    - by Roman Schindlauer
    Someone recently called LINQ “magic” in my hearing. I leapt to LINQ’s defense immediately. Turns out some people don’t realize “magic” is can be a pejorative term. I thought LINQ needed demystification. Here’s your best demystification resource: http://blogs.msdn.com/b/mattwar/archive/2008/11/18/linq-links.aspx. I won’t repeat much of what Matt Warren says in his excellent series, but will talk about some core ideas and how they affect the 2.1 release of StreamInsight. Let’s tell the story of a LINQ query. Compile time It begins with some code: IQueryable<Product> products = ...; var query = from p in products             where p.Name == "Widget"             select p.ProductID; foreach (int id in query) {     ... When the code is compiled, the C# compiler (among other things) de-sugars the query expression (see C# spec section 7.16): ... var query = products.Where(p => p.Name == "Widget").Select(p => p.ProductID); ... Overload resolution subsequently binds the Queryable.Where<Product> and Queryable.Select<Product, int> extension methods (see C# spec sections 7.5 and 7.6.5). After overload resolution, the compiler knows something interesting about the anonymous functions (lambda syntax) in the de-sugared code: they must be converted to expression trees, i.e.,“an object structure that represents the structure of the anonymous function itself” (see C# spec section 6.5). The conversion is equivalent to the following rewrite: ... var prm1 = Expression.Parameter(typeof(Product), "p"); var prm2 = Expression.Parameter(typeof(Product), "p"); var query = Queryable.Select<Product, int>(     Queryable.Where<Product>(         products,         Expression.Lambda<Func<Product, bool>>(Expression.Property(prm1, "Name"), prm1)),         Expression.Lambda<Func<Product, int>>(Expression.Property(prm2, "ProductID"), prm2)); ... If the “products” expression had type IEnumerable<Product>, the compiler would have chosen the Enumerable.Where and Enumerable.Select extension methods instead, in which case the anonymous functions would have been converted to delegates. At this point, we’ve reduced the LINQ query to familiar code that will compile in C# 2.0. (Note that I’m using C# snippets to illustrate transformations that occur in the compiler, not to suggest a viable compiler design!) Runtime When the above program is executed, the Queryable.Where method is invoked. It takes two arguments. The first is an IQueryable<> instance that exposes an Expression property and a Provider property. The second is an expression tree. The Queryable.Where method implementation looks something like this: public static IQueryable<T> Where<T>(this IQueryable<T> source, Expression<Func<T, bool>> predicate) {     return source.Provider.CreateQuery<T>(     Expression.Call(this method, source.Expression, Expression.Quote(predicate))); } Notice that the method is really just composing a new expression tree that calls itself with arguments derived from the source and predicate arguments. Also notice that the query object returned from the method is associated with the same provider as the source query. By invoking operator methods, we’re constructing an expression tree that describes a query. Interestingly, the compiler and operator methods are colluding to construct a query expression tree. The important takeaway is that expression trees are built in one of two ways: (1) by the compiler when it sees an anonymous function that needs to be converted to an expression tree, and; (2) by a query operator method that constructs a new queryable object with an expression tree rooted in a call to the operator method (self-referential). Next we hit the foreach block. At this point, the power of LINQ queries becomes apparent. The provider is able to determine how the query expression tree is evaluated! The code that began our story was intentionally vague about the definition of the “products” collection. Maybe it is a queryable in-memory collection of products: var products = new[]     { new Product { Name = "Widget", ProductID = 1 } }.AsQueryable(); The in-memory LINQ provider works by rewriting Queryable method calls to Enumerable method calls in the query expression tree. It then compiles the expression tree and evaluates it. It should be mentioned that the provider does not blindly rewrite all Queryable calls. It only rewrites a call when its arguments have been rewritten in a way that introduces a type mismatch, e.g. the first argument to Queryable.Where<Product> being rewritten as an expression of type IEnumerable<Product> from IQueryable<Product>. The type mismatch is triggered initially by a “leaf” expression like the one associated with the AsQueryable query: when the provider recognizes one of its own leaf expressions, it replaces the expression with the original IEnumerable<> constant expression. I like to think of this rewrite process as “type irritation” because the rewritten leaf expression is like a foreign body that triggers an immune response (further rewrites) in the tree. The technique ensures that only those portions of the expression tree constructed by a particular provider are rewritten by that provider: no type irritation, no rewrite. Let’s consider the behavior of an alternative LINQ provider. If “products” is a collection created by a LINQ to SQL provider: var products = new NorthwindDataContext().Products; the provider rewrites the expression tree as a SQL query that is then evaluated by your favorite RDBMS. The predicate may ultimately be evaluated using an index! In this example, the expression associated with the Products property is the “leaf” expression. StreamInsight 2.1 For the in-memory LINQ to Objects provider, a leaf is an in-memory collection. For LINQ to SQL, a leaf is a table or view. When defining a “process” in StreamInsight 2.1, what is a leaf? To StreamInsight a leaf is logic: an adapter, a sequence, or even a query targeting an entirely different LINQ provider! How do we represent the logic? Remember that a standing query may outlive the client that provisioned it. A reference to a sequence object in the client application is therefore not terribly useful. But if we instead represent the code constructing the sequence as an expression, we can host the sequence in the server: using (var server = Server.Connect(...)) {     var app = server.Applications["my application"];     var source = app.DefineObservable(() => Observable.Range(0, 10, Scheduler.NewThread));     var query = from i in source where i % 2 == 0 select i; } Example 1: defining a source and composing a query Let’s look in more detail at what’s happening in example 1. We first connect to the remote server and retrieve an existing app. Next, we define a simple Reactive sequence using the Observable.Range method. Notice that the call to the Range method is in the body of an anonymous function. This is important because it means the source sequence definition is in the form of an expression, rather than simply an opaque reference to an IObservable<int> object. The variation in Example 2 fails. Although it looks similar, the sequence is now a reference to an in-memory observable collection: var local = Observable.Range(0, 10, Scheduler.NewThread); var source = app.DefineObservable(() => local); // can’t serialize ‘local’! Example 2: error referencing unserializable local object The Define* methods support definitions of operator tree leaves that target the StreamInsight server. These methods all have the same basic structure. The definition argument is a lambda expression taking between 0 and 16 arguments and returning a source or sink. The method returns a proxy for the source or sink that can then be used for the usual style of LINQ query composition. The “define” methods exploit the compile-time C# feature that converts anonymous functions into translatable expression trees! Query composition exploits the runtime pattern that allows expression trees to be constructed by operators taking queryable and expression (Expression<>) arguments. The practical upshot: once you’ve Defined a source, you can compose LINQ queries in the familiar way using query expressions and operator combinators. Notably, queries can be composed using pull-sequences (LINQ to Objects IQueryable<> inputs), push sequences (Reactive IQbservable<> inputs), and temporal sequences (StreamInsight IQStreamable<> inputs). You can even construct processes that span these three domains using “bridge” method overloads (ToEnumerable, ToObservable and To*Streamable). Finally, the targeted rewrite via type irritation pattern is used to ensure that StreamInsight computations can leverage other LINQ providers as well. Consider the following example (this example depends on Interactive Extensions): var source = app.DefineEnumerable((int id) =>     EnumerableEx.Using(() =>         new NorthwindDataContext(), context =>             from p in context.Products             where p.ProductID == id             select p.ProductName)); Within the definition, StreamInsight has no reason to suspect that it ‘owns’ the Queryable.Where and Queryable.Select calls, and it can therefore defer to LINQ to SQL! Let’s use this source in the context of a StreamInsight process: var sink = app.DefineObserver(() => Observer.Create<string>(Console.WriteLine)); var query = from name in source(1).ToObservable()             where name == "Widget"             select name; using (query.Bind(sink).Run("process")) {     ... } When we run the binding, the source portion which filters on product ID and projects the product name is evaluated by SQL Server. Outside of the definition, responsibility for evaluation shifts to the StreamInsight server where we create a bridge to the Reactive Framework (using ToObservable) and evaluate an additional predicate. It’s incredibly easy to define computations that span multiple domains using these new features in StreamInsight 2.1! Regards, The StreamInsight Team

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  • SharePoint 2007 Hosting :: How to Move a Document from One Lbrary to Another

    - by mbridge
    Moving a document using a SharePoint Designer workflow involves copying the document to the SharePoint document library you want to move the document to, and then deleting the document from the current document library it is in. You can use the Copy List Item action to copy the document and the Delete item action to delete the document. To create a SharePoint Designer workflow that can move a document from one document library to another: 1. In SharePoint Designer 2007, open the SharePoint site on which the document library that contains the documents to move is located. 2. On the Define your new workflow screen of the Workflow Designer, enter a name for the workflow, select the document library you want to attach the workflow to (this would be a document library containing documents to move), select Allow this workflow to be manually started from an item, and click Next. 3. On the Step 1 screen of the Workflow Designer, click Actions, and then click More Actions from the drop-down menu. 4. On the Workflow Actions dialog box, select List Actions from the category drop-down list box, select Copy List Item from the actions list, and click Add. The following text is added to the Workflow Designer: Copy item in this list to this list 5. On the Step 1 screen of the Workflow Designer, click the first this list (representing the document library to copy the document from) in the text of the Copy List Item action. 6. On the Choose List Item dialog box, leave Current Item selected, and click OK. 7. On the Step 1 screen of the Workflow Designer, click the second this list (representing the document library to copy the document to) in the text of the Copy List Item action, and select the document library (this is the document library to where you want to move the document) from the drop-down list box that appears. 8. On the Step 1 screen of the Workflow Designer, click Actions, and then click More Actions from the drop-down menu. 9. On the Workflow Actions dialog box, select List Actions from the category drop-down list box, select Delete Item from the actions list, and click Add. The following text is added to the Workflow Designer: then Delete item in this list 10. On the Step 1 screen of the Workflow Designer, click this list in the text of the Delete Item action. 11. On the Choose List Item dialog box, leave Current Item selected and click OK. The final text for the workflow should now look like: Copy item in DocLib1 to DocLib2   then Delete item in DocLib1 where DocLib1 is the SharePoint document library containing the document to move and DocLib2 the document library to move the document to. 12. On the Step 1 screen of the Workflow Designer, click Finish. How to Test the Workflow? 1. Go to the SharePoint document library to which you attached the workflow, click on a document, and select Workflows from the drop-down menu. 2. On the Workflows page, click the name of your SharePoint Designer workflow. 3. On the workflow initiation page, click Start.

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  • How load WebView with another URL when navigated through tab bar viewController

    - by TechFusion
    Hello, I have created window based application, root controller as Tab bar controller. WebView is being loaded in Tab bar interfaced ViewController's View.WebView is created using IB.WebView object declared in ViewController as per below. //ViewController.h @interface ViewController:UIViewController{ IBOutlet UIWebview *Webview; } @property(nonatomic,retain)IBOutlet UIWebview *Webview; @end I am calling [WebView loadrequest] method in -viewDidLoad method and stopLoading will be called in -viewWillDisappear method. I am again reload it in -viewWillAppear:animated method to load it again when tab bar is pressed. //ViewController.m @implementation viewcontroller @synthesize Webview; -(void)viewDidLoad{ [super viewDidLoad]; [self.Webview loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"www.apple.com"]]]; } -(void)viewWillAppear:(BOOL)animated{ [super viewWillAppear:animated]; [self.Webview reload]; } -(void)viewWillDisappear:(BOOL)animated{ [super viewWillDisappear:animated]; [self.Webview stopLoading]; } I am releasing WebView in -ViewDidUnload method -(void)viewDidUnload{ [super viewDidUnload]; [Webview release]; } -(void)dealloc{ [Webview release]; [super dealloc]; } Does Webview released correctly ? Here how to kill connection with URL when ViewWillDisappear method called ? How to load View with Different URL then it's loaded in -viewDidLoad method when ViewController interfaced tab is pressed ? Means if naviagated from one tab to another that ViewController interface tab which has WebView should load request with another URL. Does it correct to call [self.Webview loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"www.stackoverflow.com"]]]; this method again in -viewWillAppear:animated method to load with another URL ? Thanks,

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  • Problem deleting record using Entity Framework and System.Data.SQLite

    - by jamone
    I have a SQLite DB that is set up so when I delete a Person the delete is cascaded. This works fine when I manually delete a Person (all records that reference the PersonID are deleted). But when I use Entity Framework to delete the Person I get an error: System.InvalidOperationException: The operation failed: The relationship could not be changed because one or more of the foreign-key properties is non-nullable. When a change is made to a relationship, the related foreign-key property is set to a null value. If the foreign-key does not support null values, a new relationship must be defined, the foreign-key property must be assigned another non-null value, or the unrelated object must be deleted. I don't understand why this is occurring. My trigger is set to clean up all related objects before deleting the object it was told to delete. When I go into the model editor and check the properties of the relationship it shows no action for the OnDelete property. Why isn't this set correctly by pulling it from the DB? Here's the relivent SQL for my tables. CREATE TABLE [SomeTable] ( [SomeTableID] INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, [PersonID] INTEGER NOT NULL REFERENCES [Person](PersonID) ON DELETE CASCADE ) CREATE TABLE [Person] ( [PersonID] INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT )

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  • change the value of the button of the button clicked

    - by user269431
    On inserting the new <li>, I have to set the value of the button clicked to Delete. How can I do that? With the actual code, it`s working only once, and on adding other list, the button no more has the the value 'Delete'. $("#mylist :button").click( function() { var text = $(this).val(); if (text == "Delete") { $(this).parent().remove(); } else { $(this).val("Delete"); } }); $("#mylist li:last-child").live('click', function() { $(this).parent().append('<li>' + '<input type = "textbox">' + '<input type = "button" value= "Save">' + '</li>'); }); <div> <ul id="mylist"> <li id="1">1<button id="Button3">Delete</button> </li> <li id="2">2<button id="Button2">Delete</button></li> <li id="3">3<button id="another_entry">Save</button></li> </ul>

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  • android throw InvocationTargetException,How to modify the error

    - by fonter
    ActivityManager am = (ActivityManager)this.getSystemService(this.ACTIVITY_SERVICE); try { clearMethod = am.getClass() .getMethod("clearApplicationUserData", String.class, IPackageDataObserver.class); } catch (Exception e) { Log.e("Error", "Android Error",e); clearMethod = null; } if(clearMethod!=null){ try { clearMethod.invoke(am,"com.android.browser",new ClearUserDataObserver()); } catch (Exception e) { Log.e("Error", "Android Exception",e); } } Exception 05-26 08:34:13.056: ERROR/Error(739): java.lang.reflect.InvocationTargetException 05-26 08:34:13.056: ERROR/Error(739): at android.app.ActivityManager.clearApplicationUserData(ActivityManager.java:475) 05-26 08:34:13.056: ERROR/Error(739): at java.lang.reflect.Method.invokeNative(Native Method) 05-26 08:34:13.056: ERROR/Error(739): at java.lang.reflect.Method.invoke(Method.java:521) 05-26 08:34:13.056: ERROR/Error(739): at com.iwidsets.clear.manager.AndClear.onCreate(AndClear.java:34) 05-26 08:34:13.056: ERROR/Error(739): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1123) 05-26 08:34:13.056: ERROR/Error(739): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2364) 05-26 08:34:13.056: ERROR/Error(739): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2417) 05-26 08:34:13.056: ERROR/Error(739): at android.app.ActivityThread.access$2100(ActivityThread.java:116) 05-26 08:34:13.056: ERROR/Error(739): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794) 05-26 08:34:13.056: ERROR/Error(739): at android.os.Handler.dispatchMessage(Handler.java:99) 05-26 08:34:13.056: ERROR/Error(739): at android.os.Looper.loop(Looper.java:123) 05-26 08:34:13.056: ERROR/Error(739): at android.app.ActivityThread.main(ActivityThread.java:4203) 05-26 08:34:13.056: ERROR/Error(739): at java.lang.reflect.Method.invokeNative(Native Method) 05-26 08:34:13.056: ERROR/Error(739): at java.lang.reflect.Method.invoke(Method.java:521) 05-26 08:34:13.056: ERROR/Error(739): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791) 05-26 08:34:13.056: ERROR/Error(739): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:549) 05-26 08:34:13.056: ERROR/Error(739): at dalvik.system.NativeStart.main(Native Method) 05-26 08:34:13.056: ERROR/Error(739): Caused by: java.lang.SecurityException: 739 does not have permission:android.permission.CLEAR_APP_USER_DATA to clear datafor process:com.android.browser 05-26 08:34:13.056: ERROR/Error(739): at android.os.Parcel.readException(Parcel.java:1218) 05-26 08:34:13.056: ERROR/Error(739): at android.os.Parcel.readException(Parcel.java:1206) 05-26 08:34:13.056: ERROR/Error(739): at android.app.ActivityManagerProxy.clearApplicationUserData(ActivityManagerNative.java:2016) 05-26 08:34:13.056: ERROR/Error(739): ... 17 more

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  • Nature of Lock is child table while deletion(sql server)

    - by Mubashar Ahmad
    Dear Devs From couple of days i am thinking of a following scenario Consider I have 2 tables with parent child relationship of kind one-to-many. On removal of parent row i have to delete the rows in child those are related to parents. simple right? i have to make a transaction scope to do above operation i can do this as following; (its psuedo code but i am doing this in c# code using odbc connection and database is sql server) begin transaction(read committed) Read all child where child.fk = p1 foreach(child) delete child where child.pk = cx delete parent where parent.pk = p1 commit trans OR begin transaction(read committed) delete all child where child.fk = p1 delete parent where parent.pk = p1 commit trans Now there are couple of questions in my mind Which one of above is better to use specially considering a scenario of real time system where thousands of other operations(select/update/delete/insert) are being performed within a span of seconds. does it ensure that no new child with child.fk = p1 will be added until transaction completes? If yes for 2nd question then how it ensures? do it take the table level locks or what. Is there any kind of Index locking supported by sql server if yes what it does and how it can be used. Regards Mubashar

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  • help in saving data in GP original table

    - by Rahul khanna
    Hi all, I am new to microsoft great plains technology. In this post my concern is to save the scroll window data in original sql table. I am selecting the values from lookup window and displaying in scroll window and saving it to temp table. While i am running temp table i see data is saved there, my motto is to save the data from temp table to original table while clicking the save button. for that i have written... get first table is_customer_temp; while err() = OKAY do copy from table is_customer_temp to table is_customer; save table is_customer; get next table is_customer_temp; end while; but while i see the back end nothing is stored in original table. Pls somebody help me... And 2nd problem is i want to delete the selected row from scroll window using checkbox. If i dont use check box and simply want to delete row i can do this simple way....write delete code scroll window line delete event and call that script in row delete button event. It will delete the particular row from scroll. But how can i do if i use checkbox in scroll window...Pls somebody help me.. Thanks, Rahul

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  • Writing to a file in Python inserts null bytes

    - by Javier Badia
    I'm writing a todo list program. It keeps a file with a thing to do per line, and lets the user add or delete items. The problem is that for some reason, I end up with a lot of zero bytes at the start of the file, even though the item is correctly deleted. I'll show you a couple of screenshots to make sure I'm making myself clear. This is the file in Notepad++ before running the program: This is the file after deleting item 3 (counting from 1): This is the relevant code. The actual program is bigger, but running just this part triggers the error. import os TODO_FILE = r"E:\javi\code\Python\todo-list\src\todo.txt" def del_elems(f, delete): """Takes an open file and either a number or a list of numbers, and deletes the lines corresponding to those numbers (counting from 1).""" if isinstance(delete, int): delete = [delete] lines = f.readlines() f.truncate(0) counter = 1 for line in lines: if counter not in delete: f.write(line) counter += 1 f = open(TODO_FILE, "r+") del_elems(f, 3) f.close() Could you please point out where's the mistake?

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  • How to map different UI views in a RESTful web application?

    - by MicE
    Hello, I'm designing a web application, which will support both standard UIs (accessed via browsers) and a RESTful API (an XML/JSON-based web service). User agents will be able to differentiate between these by using different values in the Accept HTTP header. The RESTful API will use the following URI structure (example for an "article" resource): GET /article/ - gets a list of articles POST /article/ - adds a new article PUT /article/{id} - updates an existing article based on {id} DELETE /article/{id} - deletes an existing article based on {id} The UI part of the application will however need to support multiple views, for example: a standard resource view a view for submitting a new resource a view for editing an existing resource a view for deleting an existing resource (i.e. display delete confirmation) Note that the latter three views are still accessed via GET, even though they are processed via overloaded POST. Possible solution: Introduce additional parameters (keywords) into URIs which would identify individual views - i.e. on top of the above, the application would support the following URIs (but only for Content-Type: text/html): GET /article/add - displays a form for adding a new article (fetched via GET, processed via POST) GET /article/123 - displays article 123 in "view" mode (fetched via GET) GET /article/123/edit - displays article 123 in "edit" mode (fetched via GET, processed via PUT overloaded as POST) GET /article/123/delete - displays "delete" confirmation for article 123 (fetched via GET, processed via DELETE overloaded as POST) A better implementation of the above might be to put the add/edit/delete keywords into a GET parameter - since they do not change the resource we're working with, it might be better to keep the base URI same for all of them. My question is: How would you map the above URI structure to UIs served to the regular user, considering that there can be several views per each resource, please? Do you agree with the possible solution detailed above, or would you recommend a different approach based on your experience? NB: we've already implemented an application which consists of a standalone RESTful API and a standalone web application. I'm currently looking into options for future projects where these two would be merged together (i.e. in order to reduce overhead). Thank you, M.

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  • HTML form with multiple submit options

    - by phimuemue
    Hi, I'm trying to create a small web app that is used to remove items from a MySQL table. It just shows the items in a HTML table and for each item a button [delete]: item_1 [delete] item_2 [delete] ... item_N [delete] To achieve this, I dynamically generate the table via PHP into a HTML form. This form has then obviously N [delete]-buttons. The form should use the POST-method for transfering data. For the deletion I wanted to submit the ID (primary key in the MySQL table) of the corresponding item to the executing php skript. So I introduced hidden fields (all these fields have the name='ID' that store the ID of the corresponding item. However, when pressing an arbitrary [delete], it seems to submit always just the last ID (i.e. the value of the last ID hidden field). Is there any way to submit just the ID field of the corresponding item without using multiple forms? Or is it possible to submit data from multiple forms with just one submit-button? Or should I even choose any completly different way? The point why I want to do it in just one single form is that there are some "global" parameters that shall not be placed next to each item, but just once for the whole table.

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  • security deleting a mysql row with jQuery $.post

    - by FFish
    I want to delete a row in my database and found an example on how to do this with jQuery's $.post() Now I am wondering about security though.. Can someone send a POST request to my delete-row.php script from another website? JS function deleterow(id) { // alert(typeof(id)); // number if (confirm('Are you sure want to delete?')) { $.post('delete-row.php', {album_id:+id, ajax:'true'}, function() { $("#row_"+id).fadeOut("slow"); }); } } PHP: delete-row.php <?php require_once("../db.php"); mysql_connect(DB_SERVER, DB_USER, DB_PASSWORD) or die("could not connect to database " . mysql_error()); mysql_select_db(DB_NAME) or die("could not select database " . mysql_error()); if (isset($_POST['album_id'])) { $query = "DELETE FROM albums WHERE album_id = " . $_POST['album_id']; $result = mysql_query($query); if (!$result) die('Invalid query: ' . mysql_error()); echo "album deleted!"; } ?>

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  • css problem - 'post link'

    - by csetzkorn
    Hi, I am no css expert so I am wondering whether someone could help. I have several forms to delete an item like this: <form action="/Items/DeleteItem" class="deleteForm" method="post"> Some text <input id="Id" name="Id" value="14014" type="hidden"> <input value="Delete" class="link_button" type="submit"> </form> This should look like this: Some text Delete Here ‘Some text’ describes the item and Delete is a ‘link’ which performs a post request to delete the item (as virtually all browsers only support the post and get requests). I have started to style things (CSS below) but the ‘Delete’ ‘link’ is still slightly offset in relation to ‘Some text’ (at least in firefox). I would appreciate any help with the css. Thanks! .link_button { background-color:white; border:0; color:#034af3; text-decoration:underline; font-size:1em; font-family:inherit; cursor:pointer; float:left; margin:0; padding:0; } .deleteForm { float:right; margin:0; padding:0; } Christian

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  • Deleting a resource in a Cucumber (Capybara) step doesn't work

    - by Josiah Kiehl
    Here is my Scenario: Scenario: Delete a match Given pojo is logged in And there is a match with the following: | game_id | 1 | | name | Game del Pojo | | date_and_time | 2010-02-23 17:52:00 | | players | 2 | | teams | 2 | | comment | This is an awesome comment | | user_id | 1 | And I am on the show match 1 page And show me the page When I follow "Delete" And I follow "Yes, delete it" Then there should not be a match with the following: | game_id | 1 | | name | Game del Pojo | | date_and_time | 2010-02-23 17:52:00 | | players | 2 | | teams | 2 | | comment | This is an awesome comment | | user_id | 1 | If I walk through these steps manually, they work. When I click the confirmation: Yes, delete it, then the match is deleted. Cucumber, however, fails to delete the record and the last step fails. And I follow "Yes, delete it" # features/step_definitions/web_steps.rb:32 Then there should not be a match with the following: # features/step_definitions/match_steps.rb:8 | game_id | 1 | | name | Game del Pojo | | date_and_time | 2010-02-23 17:52:00 | | players | 2 | | teams | 2 | | comment | This is an awesome comment | | user_id | 1 | <nil> expected but was <#<Match id: 1, name: "Game del Pojo", date_and_time: "2010-02-23 17:52:00", teams: 2, created_at: "2010-03-02 23:06:33", updated_at: "2010-03-02 23:06:33", comment: "This is an awesome comment", players: 2, game_id: 1, user_id: 1>>. (Test::Unit::AssertionFailedError) /usr/lib/ruby/1.8/test/unit/assertions.rb:48:in `assert_block' /usr/lib/ruby/1.8/test/unit/assertions.rb:495:in `_wrap_assertion' /usr/lib/ruby/1.8/test/unit/assertions.rb:46:in `assert_block' /usr/lib/ruby/1.8/test/unit/assertions.rb:83:in `assert_equal' /usr/lib/ruby/1.8/test/unit/assertions.rb:172:in `assert_nil' ./features/step_definitions/match_steps.rb:22:in `/^there should (not)? be a match with the following:$/' features/matches.feature:124:in `Then there should not be a match with the following:' Any clue how to debug this? Thanks!

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  • Bind button visibility to the expresion (C#)

    - by drasto
    I have a delete button in each row of GridView (component ASP.NET). I want some of the delete buttons to be invisible. The visibility of the delete button should depend on the data that are back the row. GridView is backed by EntityDataSource. GridView displays entities called Category, one instance in each row. Entity Category has (besides others) also a field of type EntityCollection. Name of that field is Items. Basically I want to allow user to delete a row only if the Items field of backing Category entity is an empty collection. I cannot make up the binding of Visible property. I have no experience with bindings and Google does not really help. This is how the button looks right now: <asp:Button ID="DeleteButton" runat="server" CommandName="Delete" Text="Delete" Visible=??? ></asp:Button> I don't know what should replace ???. The button schold be visible only when this expression evaluates to true: ((SimpleEShop.Model.Category) dataItem).Items.LongCount() <= 0 where dataItem variable contains data of current row in the table. What is the binding that I need ?

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  • Cleaning up a sparsebundle with a script

    - by nickg
    I'm using time machine to backup some servers to a sparse disk image bundle and I'd like to have a script to clean up the old back ups and re-size the image once space has been freed up. I'm fairly certain the data is protected because if I delete the old backups by right clicking, I have to enter a password to be able to delete them. To allow my script to be able to delete them, I've been running it as root. For some reason, it just won't run and every file it tries to delete I get rm: /file/: Operation not permitted Here is what I have as my script: #!/bin/bash for server in servername; do /usr/bin/hdiutil attach -mountpoint /path/to/mountpoint /path/to/sparsebundle/$server.sparsebundle/; /bin/sleep 10; /usr/bin/find /path/to/mountpoint -type d -mtime +7 -exec /bin/rm -rf {} \; /usr/bin/hdiutil unmount /path/to/mountpoint; /bin/sleep 10; /usr/bin/hdiutil compact /path/to/sparsebundle/$server.sparsebundle/; done exit; One of the problems I thought was causing this was it needed to have a mountpoint specified since the default mount was to /Volumes/Time\ Machine\ Backups/ that's why I created a mountpoint. I also thought that it was trying to delete the files to quickly after mounting and it wasn't actually mounted yet, that's why I added the sleep. I've also tried using the -delete option for find instead of -exec, but it didn't make any difference. Any help on this would be greatly appreciated because I'm out of ideas as to why this won't work.

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  • can someone help me fix my code?

    - by user267490
    Hi, I have this code I been working on but I'm having a hard time for it to work. I did one but it only works in php 5.3 and I realized my host only supports php 5.0! do I was trying to see if I could get it to work on my sever correctly, I'm just lost and tired lol <?php //Temporarily turn on error reporting @ini_set('display_errors', 1); error_reporting(E_ALL); // Set default timezone (New PHP versions complain without this!) date_default_timezone_set("GMT"); // Common set_time_limit(0); require_once('dbc.php'); require_once('sessions.php'); page_protect(); // Image settings define('IMG_FIELD_NAME', 'cons_image'); // Max upload size in bytes (for form) define ('MAX_SIZE_IN_BYTES', '512000'); // Width and height for the thumbnail define ('THUMB_WIDTH', '150'); define ('THUMB_HEIGHT', '150'); ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> <head> <title>whatever</title> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> <style type="text\css"> .validationerrorText { color:red; font-size:85%; font-weight:bold; } </style> </head> <body> <h1>Change image</h1> <?php $errors = array(); // Process form if (isset($_POST['submit'])) { // Get filename $filename = stripslashes($_FILES['cons_image']['name']); // Validation of image file upload $allowedFileTypes = array('image/gif', 'image/jpg', 'image/jpeg', 'image/png'); if ($_FILES[IMG_FIELD_NAME]['error'] == UPLOAD_ERR_NO_FILE) { $errors['img_empty'] = true; } elseif (($_FILES[IMG_FIELD_NAME]['type'] != '') && (!in_array($_FILES[IMG_FIELD_NAME]['type'], $allowedFileTypes))) { $errors['img_type'] = true; } elseif (($_FILES[IMG_FIELD_NAME]['error'] == UPLOAD_ERR_INI_SIZE) || ($_FILES[IMG_FIELD_NAME]['error'] == UPLOAD_ERR_FORM_SIZE) || ($_FILES[IMG_FIELD_NAME]['size'] > MAX_SIZE_IN_BYTES)) { $errors['img_size'] = true; } elseif ($_FILES[IMG_FIELD_NAME]['error'] != UPLOAD_ERR_OK) { $errors['img_error'] = true; } elseif (strlen($_FILES[IMG_FIELD_NAME]['name']) > 200) { $errors['img_nametoolong'] = true; } elseif ( (file_exists("\\uploads\\{$username}\\images\\banner\\{$filename}")) || (file_exists("\\uploads\\{$username}\\images\\banner\\thumbs\\{$filename}")) ) { $errors['img_fileexists'] = true; } if (! empty($errors)) { unlink($_FILES[IMG_FIELD_NAME]['tmp_name']); //cleanup: delete temp file } // Create thumbnail if (empty($errors)) { // Make directory if it doesn't exist if (!is_dir("\\uploads\\{$username}\\images\\banner\\thumbs\\")) { // Take directory and break it down into folders $dir = "uploads\\{$username}\\images\\banner\\thumbs"; $folders = explode("\\", $dir); // Create directory, adding folders as necessary as we go (ignore mkdir() errors, we'll check existance of full dir in a sec) $dirTmp = ''; foreach ($folders as $fldr) { if ($dirTmp != '') { $dirTmp .= "\\"; } $dirTmp .= $fldr; mkdir("\\".$dirTmp); //ignoring errors deliberately! } // Check again whether it exists if (!is_dir("\\uploads\\$username\\images\\banner\\thumbs\\")) { $errors['move_source'] = true; unlink($_FILES[IMG_FIELD_NAME]['tmp_name']); //cleanup: delete temp file } } if (empty($errors)) { // Move uploaded file to final destination if (! move_uploaded_file($_FILES[IMG_FIELD_NAME]['tmp_name'], "/uploads/$username/images/banner/$filename")) { $errors['move_source'] = true; unlink($_FILES[IMG_FIELD_NAME]['tmp_name']); //cleanup: delete temp file } else { // Create thumbnail in new dir if (! make_thumb("/uploads/$username/images/banner/$filename", "/uploads/$username/images/banner/thumbs/$filename")) { $errors['thumb'] = true; unlink("/uploads/$username/images/banner/$filename"); //cleanup: delete source file } } } } // Record in database if (empty($errors)) { // Find existing record and delete existing images $sql = "SELECT `bannerORIGINAL`, `bannerTHUMB` FROM `agent_settings` WHERE (`agent_id`={$user_id}) LIMIT 1"; $result = mysql_query($sql); if (!$result) { unlink("/uploads/$username/images/banner/$filename"); //cleanup: delete source file unlink("/uploads/$username/images/banner/thumbs/$filename"); //cleanup: delete thumbnail file die("<div><b>Error: Problem occurred with Database Query!</b><br /><br /><b>File:</b> " . __FILE__ . "<br /><b>Line:</b> " . __LINE__ . "<br /><b>MySQL Error Num:</b> " . mysql_errno() . "<br /><b>MySQL Error:</b> " . mysql_error() . "</div>"); } $numResults = mysql_num_rows($result); if ($numResults == 1) { $row = mysql_fetch_assoc($result); // Delete old files unlink("/uploads/$username/images/banner/" . $row['bannerORIGINAL']); //delete OLD source file unlink("/uploads/$username/images/banner/thumbs/" . $row['bannerTHUMB']); //delete OLD thumbnail file } // Update/create record with new images if ($numResults == 1) { $sql = "INSERT INTO `agent_settings` (`agent_id`, `bannerORIGINAL`, `bannerTHUMB`) VALUES ({$user_id}, '/uploads/$username/images/banner/$filename', '/uploads/$username/images/banner/thumbs/$filename')"; } else { $sql = "UPDATE `agent_settings` SET `bannerORIGINAL`='/uploads/$username/images/banner/$filename', `bannerTHUMB`='/uploads/$username/images/banner/thumbs/$filename' WHERE (`agent_id`={$user_id})"; } $result = mysql_query($sql); if (!$result) { unlink("/uploads/$username/images/banner/$filename"); //cleanup: delete source file unlink("/uploads/$username/images/banner/thumbs/$filename"); //cleanup: delete thumbnail file die("<div><b>Error: Problem occurred with Database Query!</b><br /><br /><b>File:</b> " . __FILE__ . "<br /><b>Line:</b> " . __LINE__ . "<br /><b>MySQL Error Num:</b> " . mysql_errno() . "<br /><b>MySQL Error:</b> " . mysql_error() . "</div>"); } } // Print success message and how the thumbnail image created if (empty($errors)) { echo "<p>Thumbnail created Successfully!</p>\n"; echo "<img src=\"/uploads/$username/images/banner/thumbs/$filename\" alt=\"New image thumbnail\" />\n"; echo "<br />\n"; } } if (isset($errors['move_source'])) { echo "\t\t<div>Error: Failure occurred moving uploaded source image!</div>\n"; } if (isset($errors['thumb'])) { echo "\t\t<div>Error: Failure occurred creating thumbnail!</div>\n"; } ?> <form action="" enctype="multipart/form-data" method="post"> <input type="hidden" name="MAX_FILE_SIZE" value="<?php echo MAX_SIZE_IN_BYTES; ?>" /> <label for="<?php echo IMG_FIELD_NAME; ?>">Image:</label> <input type="file" name="<?php echo IMG_FIELD_NAME; ?>" id="<?php echo IMG_FIELD_NAME; ?>" /> <?php if (isset($errors['img_empty'])) { echo "\t\t<div class=\"validationerrorText\">Required!</div>\n"; } if (isset($errors['img_type'])) { echo "\t\t<div class=\"validationerrorText\">File type not allowed! GIF/JPEG/PNG only!</div>\n"; } if (isset($errors['img_size'])) { echo "\t\t<div class=\"validationerrorText\">File size too large! Maximum size should be " . MAX_SIZE_IN_BYTES . "bytes!</div>\n"; } if (isset($errors['img_error'])) { echo "\t\t<div class=\"validationerrorText\">File upload error occured! Error code: {$_FILES[IMG_FIELD_NAME]['error']}</div>\n"; } if (isset($errors['img_nametoolong'])) { echo "\t\t<div class=\"validationerrorText\">Filename too long! 200 Chars max!</div>\n"; } if (isset($errors['img_fileexists'])) { echo "\t\t<div class=\"validationerrorText\">An image file already exists with that name!</div>\n"; } ?> <br /><input type="submit" name="submit" id="image1" value="Upload image" /> </form> </body> </html> <?php ################################# # # F U N C T I O N S # ################################# /* * Function: make_thumb * * Creates the thumbnail image from the uploaded image * the resize will be done considering the width and * height defined, but without deforming the image * * @param $sourceFile Path anf filename of source image * @param $destFile Path and filename to save thumbnail as * @param $new_w the new width to use * @param $new_h the new height to use */ function make_thumb($sourceFile, $destFile, $new_w=false, $new_h=false) { if ($new_w === false) { $new_w = THUMB_WIDTH; } if ($new_h === false) { $new_h = THUMB_HEIGHT; } // Get image extension $ext = strtolower(getExtension($sourceFile)); // Copy source switch($ext) { case 'jpg': case 'jpeg': $src_img = imagecreatefromjpeg($sourceFile); break; case 'png': $src_img = imagecreatefrompng($sourceFile); break; case 'gif': $src_img = imagecreatefromgif($sourceFile); break; default: return false; } if (!$src_img) { return false; } // Get dimmensions of the source image $old_x = imageSX($src_img); $old_y = imageSY($src_img); // Calculate the new dimmensions for the thumbnail image // 1. calculate the ratio by dividing the old dimmensions with the new ones // 2. if the ratio for the width is higher, the width will remain the one define in WIDTH variable // and the height will be calculated so the image ratio will not change // 3. otherwise we will use the height ratio for the image // as a result, only one of the dimmensions will be from the fixed ones $ratio1 = $old_x / $new_w; $ratio2 = $old_y / $new_h; if ($ratio1 > $ratio2) { $thumb_w = $new_w; $thumb_h = $old_y / $ratio1; } else { $thumb_h = $new_h; $thumb_w = $old_x / $ratio2; } // Create a new image with the new dimmensions $dst_img = ImageCreateTrueColor($thumb_w, $thumb_h); // Resize the big image to the new created one imagecopyresampled($dst_img, $src_img, 0, 0, 0, 0, $thumb_w, $thumb_h, $old_x, $old_y); // Output the created image to the file. Now we will have the thumbnail into the file named by $filename switch($ext) { case 'jpg': case 'jpeg': $result = imagepng($dst_img, $destFile); break; case 'png': $result = imagegif($dst_img, $destFile); break; case 'gif': $result = imagejpeg($dst_img, $destFile); break; default: //should never occur! } if (!$result) { return false; } // Destroy source and destination images imagedestroy($dst_img); imagedestroy($src_img); return true; } /* * Function: getExtension * * Returns the file extension from a given filename/path * * @param $str the filename to get the extension from */ function getExtension($str) { return pathinfo($str, PATHINFO_EXTENSION); } ?>

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  • ASP.NET MVC Unit Testing Controllers - Repositories

    - by Brian McCord
    This is more of an opinion seeking question, so there may not be a "right" answer, but I would welcome arguments as to why your answer is the "right" one. Given an MVC application that is using Entity Framework for the persistence engine, a repository layer, a service layer that basically defers to the repository, and a delete method on a controller that looks like this: public ActionResult Delete(State model) { try { if( model == null ) { return View( model ); } _stateService.Delete( model ); return RedirectToAction("Index"); } catch { return View( model ); } } I am looking for the proper way to Unit Test this. Currently, I have a fake repository that gets used in the service, and my unit test looks like this: [TestMethod] public void Delete_Post_Passes_With_State_4() { //Arrange var stateService = GetService(); var stateController = new StateController( stateService ); ViewResult result = stateController.Delete( 4 ) as ViewResult; var model = (State)result.ViewData.Model; //Act RedirectToRouteResult redirectResult = stateController.Delete( model ) as RedirectToRouteResult; stateController = new StateController( stateService ); var newresult = stateController.Delete( 4 ) as ViewResult; var newmodel = (State)newresult.ViewData.Model; //Assert Assert.AreEqual( redirectResult.RouteValues["action"], "Index" ); Assert.IsNull( newmodel ); } Is this overkill? Do I need to check to see if the record actually got deleted (as I already have Service and Repository tests that verify this)? Should I even use a fake repository here or would it make more sense just to mock the whole thing? The examples I'm looking at used this model of doing things, and I just copied it, but I'm really open to doing things in a "best practices" way. Thanks.

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  • Facebook android app keeps crashing even though there are no errors in my code. Why?

    - by user1554479
    If you import the facebook SDK library, the code works (ignore the deprecated methods for now lol) and there are no errors or warnings. However, when I run my facebook app on my Android 2.2 or 4.2 emulator, the app crashes either upon opening or after the log on screen. Why? Is it because I'm not implementing Async Task? If so, how does that work? Here's my code: package com.sara.facebookappl; import java.io.IOException; import java.net.MalformedURLException; import java.net.URL; import org.json.JSONException; import org.json.JSONObject; import android.app.Activity; import android.content.Intent; import android.content.SharedPreferences; import android.content.SharedPreferences.Editor; import android.os.Bundle; import android.os.StrictMode; import android.view.Menu; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.ImageView; import android.widget.TextView; import android.widget.Toast; import com.facebook.android.DialogError; import com.facebook.android.Facebook; import com.facebook.android.Facebook.DialogListener; import com.facebook.android.FacebookError; import com.facebook.android.Util; public class MainActivity extends Activity implements OnClickListener, DialogListener { Facebook fb; ImageView button; SharedPreferences sp; TextView welcome; Button post; @SuppressWarnings("deprecation") @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); post=(Button)findViewById(R.id.button1); String APP_ID = getString(R.string.APP_ID); fb= new Facebook(APP_ID); sp =getPreferences(MODE_PRIVATE); String access_token=sp.getString("access_token", null); long expires=sp.getLong("access_expires", 0); if (access_token !=null) { fb.setAccessToken(access_token); } if(expires !=0) { fb.setAccessExpires(expires); } button=(ImageView)findViewById(R.id.login); button.setOnClickListener((OnClickListener) this); updateButtonImage(); } @SuppressWarnings("deprecation") private void updateButtonImage() { // TODO Auto-generated method stub post.setVisibility(Button.VISIBLE); button.setImageResource(R.drawable.com_facebook_loginbutton_blue); //logout button if (fb.isSessionValid()) { button.setImageResource(R.drawable.com_facebook_loginbutton_blue); // ^logout button JSONObject obj=null; URL img_url =null; try { String jsonUser= fb.request("me"); obj = Util.parseJson(jsonUser); String id=obj.optString("id"); String name = obj.optString("name"); welcome.setText("Welcome, " + name); }catch(FacebookError e) { e.printStackTrace(); }catch (JSONException e) { e.printStackTrace(); }catch (MalformedURLException e) { e.printStackTrace(); }catch (IOException e) { e.printStackTrace(); } }else { post.setVisibility(Button.VISIBLE); button.setImageResource(R.drawable.com_facebook_loginbutton_blue); } } @SuppressWarnings("deprecation") public void buttonClicks(View v) { switch (v.getId()) { case R.id.button1: //post Bundle params= new Bundle(); params.putString("name", "User X"); params.putString("caption", "Rating"); params.putString("description", "User X Rated"); params.putString("link", "http://..."); fb.dialog(MainActivity.this, "feed", params, new Facebook.DialogListener() { @Override public void onFacebookError(FacebookError e) { // TODO Auto-generated method stub } @Override public void onError(DialogError e) { // TODO Auto-generated method stub } @Override public void onComplete(Bundle values) { // TODO Auto-generated method stub } @Override public void onCancel() { // TODO Auto-generated method stub } }); break; } } @SuppressWarnings("deprecation") public void onClick(View v) { if(fb.isSessionValid()) { try { fb.logout(getApplicationContext()); updateButtonImage(); //button will close our our session }catch(MalformedURLException e) { e.printStackTrace(); } catch(IOException e) { e.printStackTrace(); } }else{ //login into facebook fb.authorize(MainActivity.this, new String[] {"email"}, new Facebook.DialogListener() { @Override public void onFacebookError(FacebookError e) { // TODO Auto-generated method stub Toast.makeText(MainActivity.this, "fbError", Toast.LENGTH_SHORT).show(); } @Override public void onError(DialogError e) { // TODO Auto-generated method stub Toast.makeText(MainActivity.this, "onError", Toast.LENGTH_SHORT).show(); } @Override public void onComplete(Bundle values) { // TODO Auto-generated method stub Editor editor=sp.edit(); editor.putString("access_token", fb.getAccessToken()); editor.putLong("access_expires", fb.getAccessExpires()); editor.commit(); updateButtonImage(); } @Override public void onCancel() { // TODO Auto-generated method stub Toast.makeText(MainActivity.this, "onCancel", Toast.LENGTH_SHORT).show(); } }); } } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.activity_main, menu); return true; } @SuppressWarnings("deprecation") @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); fb.authorizeCallback(requestCode, resultCode, data); } @Override public void onComplete(Bundle values) { // TODO Auto-generated method stub } @Override public void onFacebookError(FacebookError e) { // TODO Auto-generated method stub } @Override public void onError(DialogError e) { // TODO Auto-generated method stub } @Override public void onCancel() { // TODO Auto-generated method stub } } LogCat Errors: 12-16 04:56:59.070: E/AndroidRuntime(822): FATAL EXCEPTION: main 12-16 04:56:59.070: E/AndroidRuntime(822): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.sara.facebookappl/com.sara.facebookappl.MainActivity}: android.os.NetworkOnMainThreadException 12-16 04:56:59.070: E/AndroidRuntime(822): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 12-16 04:56:59.070: E/AndroidRuntime(822): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 12-16 04:56:59.070: E/AndroidRuntime(822): at android.app.ActivityThread.access$600(ActivityThread.java:141) 12-16 04:56:59.070: E/AndroidRuntime(822): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 12-16 04:56:59.070: E/AndroidRuntime(822): at android.os.Handler.dispatchMessage(Handler.java:99) 12-16 04:56:59.070: E/AndroidRuntime(822): at android.os.Looper.loop(Looper.java:137) 12-16 04:56:59.070: E/AndroidRuntime(822): at android.app.ActivityThread.main(ActivityThread.java:5039) 12-16 04:56:59.070: E/AndroidRuntime(822): at java.lang.reflect.Method.invokeNative(Native Method) 12-16 04:56:59.070: E/AndroidRuntime(822): at java.lang.reflect.Method.invoke(Method.java:511) 12-16 04:56:59.070: E/AndroidRuntime(822): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 12-16 04:56:59.070: E/AndroidRuntime(822): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 12-16 04:56:59.070: E/AndroidRuntime(822): at dalvik.system.NativeStart.main(Native Method) 12-16 04:56:59.070: E/AndroidRuntime(822): Caused by: android.os.NetworkOnMainThreadException 12-16 04:56:59.070: E/AndroidRuntime(822): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117) 12-16 04:56:59.070: E/AndroidRuntime(822): at java.net.InetAddress.lookupHostByName(InetAddress.java:385) 12-16 04:56:59.070: E/AndroidRuntime(822): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236) 12-16 04:56:59.070: E/AndroidRuntime(822): at java.net.InetAddress.getAllByName(InetAddress.java:214) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpConnection.(HttpConnection.java:70) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpConnection.(HttpConnection.java:50) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:340) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:87) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpConnection.connect(HttpConnection.java:128) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:316) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpsURLConnectionImpl$HttpsEngine.makeSslConnection(HttpsURLConnectionImpl.java:461) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpsURLConnectionImpl$HttpsEngine.connect(HttpsURLConnectionImpl.java:433) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:290) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:240) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:282) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:177) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:271) 12-16 04:56:59.070: E/AndroidRuntime(822): at com.facebook.android.Util.openUrl(Util.java:219) 12-16 04:56:59.070: E/AndroidRuntime(822): at com.facebook.android.Facebook.requestImpl(Facebook.java:806) 12-16 04:56:59.070: E/AndroidRuntime(822): at com.facebook.android.Facebook.request(Facebook.java:732) 12-16 04:56:59.070: E/AndroidRuntime(822): at com.sara.facebookappl.MainActivity.updateButtonImage(MainActivity.java:83) 12-16 04:56:59.070: E/AndroidRuntime(822): at com.sara.facebookappl.MainActivity.onCreate(MainActivity.java:63) 12-16 04:56:59.070: E/AndroidRuntime(822): at android.app.Activity.performCreate(Activity.java:5104) 12-16 04:56:59.070: E/AndroidRuntime(822): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 12-16 04:56:59.070: E/AndroidRuntime(822): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 12-16 04:56:59.070: E/AndroidRuntime(822): ... 11 more 12-16 04:56:59.090: D/dalvikvm(822): GC_CONCURRENT freed 150K, 9% free 2723K/2988K, paused 7ms+58ms, total 239ms

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  • Customer wants some data to appear after you later delete rows. System giant / not my creation. Fast

    - by John Sullivan
    This is a fairly common problem, it probably has a name, I just don't know what it is. A.) User sees obscure piece of information in Row B of L_OBSCURE_INFO displayed on some screen at a certain point. It is in table L_Obscure_info. B.) Under certain circumstances we want to correctly delete data in L_OBSCURE_INFO. Unfortunately, nobody accounted for the fact that the user might want to backtrack and see some random piece of information that was most recently in L_OBSCURE_INFO. C.) The system is enormous and L_OBSCURE_INFO is used all the time. You have no idea what the ramifications are of implementing some kind of hack and whatever you do, you don't want to introduce more bugs. I think the best approach would be to create an L_OBSCURE_INFO_HISTORY table and record a record in there every time you change data. But god help your ensuring it's accurate in this system where L_OBSCURE_INFO is being touched everywhere and you don't have time to implement L_OBSCURE_INFO_HISTORY. Is there a particularly easy, clever design solution for this kind of problem -- basically an elegant database hack? If not, is this kind of design problem under a particular class of problems or have a name?

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