return path - Page 163 - Developer IT

Writing Unit Tests for ASP.NET Web API Controller

- by shiju

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

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PowerShell Script to Create PowerShell Profile

- by Brian Jackett

Utilizing a PowerShell profile can help any PowerShell user save time getting up and running with their work. For those unfamiliar a PowerShell profile is a file you can store any PowerShell commands that you want to run when you fire up a PowerShell console (or ISE.) In my typical profiles (example here) I load assemblies (like SharePoint 2007 DLL), set aliases, set environment variable values (such as max history), and perform other general customizations to make my work easier. Below is a sample script that will check to see if a PowerShell profile (Console or ISE) exists and create it if not found. The .ps1 script file version can also be downloaded from my SkyDrive here. Note: if downloading the .ps1 file, be sure you have enabled unsigned scripts to run on your machine as I have not signed mine. $folderExists = test-path -path $Env:UserProfile\Documents\WindowsPowerShell if($folderExists -eq $false) { new-item -type directory -path $Env:UserProfile\Documents\WindowsPowerShell > $null echo "Containing folder for profile created at: $Env:UserProfile\Documents\WindowsPowerShell" } $profileExists = test-path -path $profile if($profileExists -eq $false) { new-item -type file -path $profile > $null echo "Profile file created at: $profile" } A few things to note while going through the above script. $Env:UserProfile represents the personal user folder (c:\documents and settings…. on older OSes like XP and c:\Users… on Win 7) so it adapts to whichever OS you are running but was tested against Windows 7 and Windows Server 2008 R2. “ > $null” sends the command to a null stream. Essentially this is equivalent to DOS scripting of “@ECHO OFF” by suppressing echoing the command just run, but only for the specific command it is appended to. I haven’t yet found a better way to accomplish command suppression, but this is definitely not required for the script to work. $profile represent a standard variable to the file path of the profile file. It is dynamic based on whether you are running PowerShell Console or ISE. Conclusion In less than two weeks (Apr. 10th to be exact) I’ll be heading down to SharePoint Saturday Charlotte (SPSCLT) to give two presentations on using PowerShell with SharePoint. Since I’ll be prepping a lot of material for PowerShell I thought it only appropriate to pass along this nice little script I recently created. If you’ve never used a PowerShell profile this is a great chance to start using one. If you’ve been using a profile before, perhaps you learned a trick or two to add to your toolbox. For those of you in the Charlotte, NC area sign up for the SharePoint Saturday and see some great content and community with great folks. -Frog Out

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Design by Contract with Microsoft .Net Code Contract

- by Fredrik N

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

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Using an alternate search platform in Commerce Server 2009

- by Lewis Benge

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

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Effectively implementing a game view using java

- by kdavis8

I am writing a 2d game in java. The game mechanics are similar to the Pokémon game boy advance series e.g. fire red, ruby, diamond and so on. I need a way to draw a huge map maybe 5000 by 5000 pixels and then load individual in game sprites to across the entirety of the map, like rendering a scene. Game sprites would be things like terrain objects, trees, rocks, bushes, also houses, castles, NPC's and so on. But i also need to implement some kind of camera view class that focuses on the player. the camera view class needs to follow the characters movements throughout the game map but it also needs to clip the rest of the map away from the user's field of view, so that the user can only see the arbitrary proximity adjacent to the player's sprite. The proximity's range could be something like 500 pixels in every direction around the player’s sprite. On top of this, i need to implement an independent resolution for the game world so that the game view will be uniform on all screen sizes and screen resolutions. I know that this does sound like a handful and may fall under the category of multiple questions, but the questions are all related and any advice would be very much appreciated. I don’t need a full source code listing but maybe some pointers to effective java API classes that could make doing what i need to do a lot simpler. Also any algorithmic/ design advice would greatly benefit me as well. example of what i am trying to do in source code form below package myPackage; /** * The Purpose of GameView is to: Render a scene using Scene class, Create a * clipping pane using CameraView class, and finally instantiate a coordinate * grid using Path class. * * Once all of these things have been done, GameView class should then be * instantiated and used jointly with its helper classes. CameraView should be * used as the main drawing image. CameraView is the the window to the game * world.Scene passes data constantly to CameraView so that the entire map flows * smoothly. Path uses the x and y coordinates from camera view to construct * cells for path finding algorithms. */ public class GameView { // Scene is a helper class to game view. it renders the entire map to memory // for the camera view. Scene scene; // Camera View is a helper class to game view. It clips the Scene into a // small image that follows the players coordinates. CameraView Camera; // Path is a helper class to game view. It observes and calculates the // coordinates of camera view and divides them into Grids/Cells for Path // finding. Path path; // this represents the player and has a getSprite() method that will return // the current frame column row combination of the passed sprite sheet. Sprite player; }

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

- by mbridge

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

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Understanding C# async / await (1) Compilation

- by Dixin

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

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Understanding C# async / await (1) Compilation

- by Dixin

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

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

- by Rhames

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

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Spritebatch drawing sprite with jagged borders

- by Mutoh

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

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A strong component keeps everything together

- by Justin Paul-Oracle

Most of the times you implement a WebCenter Content based system, you require some sort of customization. Sometimes these customizations need a Java class or two, or libraries (for example, the JavaMail API), or Database Objects (like new tables, views, indexes, etc). I have seen that libraries and Database Objects are usually put in place using manual steps. This means that the library jar files are copied to one of the common classes directory (set in the Content CLASSPATH variable) and/or the database scripts are executed manually. I have also seen people place the custom Java classes in the common classes directory. While this may seem like an easy solution, think about a scenario where you need to disable or uninstall the component or if you have to upgrade or migrate the system. You have to keep these manual steps documented and execute them every time you encounter the above scenarios. It is very common that some of these manual steps are missed when you have multiple teams and people working on the system. Here are a few points to ponder upon: Place all your custom Java classes within your component. Create a new directory, say ${COMPONENT_DIR}/classes, and place your code there. You can choose to bundle all your classes into a jar or you can place the entire class directory structure. Add a path entry to the Build Settings so that it is bundled with the component when you build it. You also need to update the Custom Class Path and the Custom Class Path Load Order under the Advanced Build Settings. This will ensure that the system CLASSPATH is updated to add this new directory. Create a new component for any new library that you want to add. Add the appropriate path entries to the Build Settings so that it is bundled with the component when you build it. You also need to update the Custom Class Path, Custom Class Path Load Order and/or the Custom Library Path under the Advanced Build Settings. Enter a comma separated list of features that this component will provide. When you create other components that will use the features exposed by this component, make sure that you specify a dependency to this library component by specifying the comma separated list of features in the Advanced Build Settings. The component wizard allows you to create custom install/uninstall Java code. The wizard will create a install filter class when you check the “Has Install” checkbox on the “Install/Uninstall Settings” tab. Consider using this filter class to create database objects when you install the component and drop the objects when you uninstall the component. If you do a lot of custom component development, consider creating a install/uninstall Java class, which can execute queries defined within the component. To sum up, whenever you write a new custom component, make sure that you bundle everything within the component.

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A first look at ConfORM - Part 1

- by thangchung

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

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Using R to Analyze G1GC Log Files

- by user12620111

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

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While running a batch file in Windows 7 with Admin rights from a thumb drive, how can I get the file path back to the thumb drive?

- by Jeremy DeStefano

I have a piece of software that is being distributed to several departments for installation onto Windows 7 laptops. They install software from the thumb drive and then they have to run a script to properly configure the software. Because the script is changing registry files and program files, it requires Admin rights. When running as Admin, it drops into the System32 folder and I no longer have an easy scriptable way to access files that need to be copied from the thumb drive, simply because I don't know for sure what drive letter its going to use on the various machines. Previous installations were on Windows XP and the command window file path stayed within the script folder. I've found similar questions here and I have already tried Relative Paths, but it can't seem to find the proper folder on the thumb drive or I can't seem to find the proper way to format it.

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LibGDX onTouch() method Array and flip method

- by johnny-b

How can I add this on my application. i want to use the onTouch() method from the implementation of the InputProcessor to kill the enemies on screen. how do i do that? do i have to do anything to the enemy class? also i am trying to add a Array of enemies and it keeps throwing exceptions or the bullet now is facing LEFT <--- again after I used the flip method in the bullet class. All the code is below so please anyone feel free to have a look thanks. please help Thank you M // This is the bullet class. public class Bullet extends Sprite { public static final float BULLET_HOMING = 6000; public static final float BULLET_SPEED = 300; private Vector2 velocity; private float lifetime; private Rectangle bul; public Bullet(float x, float y) { velocity = new Vector2(0, 0); setPosition(x, y); AssetLoader.bullet1.flip(true, false); AssetLoader.bullet2.flip(true, false); setSize(AssetLoader.bullet1.getWidth(), AssetLoader.bullet1.getHeight()); bul = new Rectangle(); } public void update(float delta) { float targetX = GameWorld.getBall().getX(); float targetY = GameWorld.getBall().getY(); float dx = targetX - getX(); float dy = targetY - getY(); float distToTarget = (float) Math.sqrt(dx * dx + dy * dy); dx /= distToTarget; dy /= distToTarget; dx *= BULLET_HOMING; dy *= BULLET_HOMING; velocity.x += dx * delta; velocity.y += dy * delta; float vMag = (float) Math.sqrt(velocity.x * velocity.x + velocity.y * velocity.y); velocity.x /= vMag; velocity.y /= vMag; velocity.x *= BULLET_SPEED; velocity.y *= BULLET_SPEED; bul.set(getX(), getY(), getOriginX(), getOriginY()); Vector2 v = velocity.cpy().scl(delta); setPosition(getX() + v.x, getY() + v.y); setOriginCenter(); setRotation(velocity.angle()); } public Rectangle getBounds() { return bul; } public Rectangle getBounds1() { return this.getBoundingRectangle(); } } // This is the class where i load all the images from public class AssetLoader { public static Texture texture; public static TextureRegion bg, ball1, ball2; public static Animation bulletAnimation, ballAnimation; public static Sprite bullet1, bullet2; public static void load() { texture = new Texture(Gdx.files.internal("SpriteN1.png")); texture.setFilter(TextureFilter.Nearest, TextureFilter.Nearest); bg = new TextureRegion(texture, 80, 421, 395, 30); bg.flip(false, true); ball1 = new TextureRegion(texture, 0, 321, 32, 32); ball1.flip(false, true); ball2 = new TextureRegion(texture, 32, 321, 32, 32); ball2.flip(false, true); bullet1 = new Sprite(texture, 380, 350, 45, 20); bullet1.flip(false, true); bullet2 = new Sprite(texture, 425, 350, 45, 20); bullet2.flip(false, true); TextureRegion[] balls = { ball1, ball2 }; ballAnimation = new Animation(0.16f, balls); ballAnimation.setPlayMode(Animation.PlayMode.LOOP); } Sprite[] bullets = { bullet1, bullet2 }; bulletAnimation = new Animation(0.06f, aims); bulletAnimation.setPlayMode(Animation.PlayMode.LOOP); } public static void dispose() { texture.dispose(); } // This is for the rendering or drawing onto the screen/canvas. public class GameRenderer { private Bullet bullet; private Ball ball; public GameRenderer(GameWorld world) { myWorld = world; cam = new OrthographicCamera(); cam.setToOrtho(true, 480, 320); batcher = new SpriteBatch(); // Attach batcher to camera batcher.setProjectionMatrix(cam.combined); shapeRenderer = new ShapeRenderer(); shapeRenderer.setProjectionMatrix(cam.combined); // Call helper methods to initialize instance variables initGameObjects(); initAssets(); } private void initGameObjects() { ball = GameWorld.getBall(); bullet = myWorld.getBullet(); scroller = myWorld.getScroller(); } private void initAssets() { ballAnimation = AssetLoader.ballAnimation; bulletAnimation = AssetLoader.bulletAnimation; } public void render(float runTime) { Gdx.gl.glClearColor(0, 0, 0, 1); Gdx.gl.glClear(GL30.GL_COLOR_BUFFER_BIT); batcher.begin(); batcher.disableBlending(); batcher.enableBlending(); batcher.draw(AssetLoader.ballAnimation.getKeyFrame(runTime), ball.getX(), ball.getY(), ball.getWidth(), ball.getHeight()); batcher.draw(AssetLoader.bulletAnimation.getKeyFrame(runTime), bullet.getX(), bullet.getY(), bullet.getOriginX(), bullet.getOriginY(), bullet.getWidth(), bullet.getHeight(), 1.0f, 1.0f, bullet.getRotation()); // End SpriteBatch batcher.end(); } } // this is to load the image etc on the screen i guess public class GameWorld { public static Ball ball; private Bullet bullet; private ScrollHandler scroller; public GameWorld() { ball = new Ball(480, 273, 32, 32); bullet = new Bullet(10, 10); scroller = new ScrollHandler(0); } public void update(float delta) { ball.update(delta); bullet.update(delta); scroller.update(delta); } public static Ball getBall() { return ball; } public ScrollHandler getScroller() { return scroller; } public Bullet getBullet() { return bullet; } } //This is the input handler class public class InputHandler implements InputProcessor { private Ball myBall; private Bullet bullet; private GameRenderer aims; // Ask for a reference to the Soldier when InputHandler is created. public InputHandler(Ball ball) { myBall = ball; } @Override public boolean touchDown(int screenX, int screenY, int pointer, int button) { return false; } @Override public boolean keyDown(int keycode) { return false; } @Override public boolean keyUp(int keycode) { return false; } @Override public boolean keyTyped(char character) { return false; } @Override public boolean touchUp(int screenX, int screenY, int pointer, int button) { return false; } @Override public boolean touchDragged(int screenX, int screenY, int pointer) { return false; } @Override public boolean mouseMoved(int screenX, int screenY) { return false; } @Override public boolean scrolled(int amount) { return false; } } i am rendering all graphics in a GameRender class and a gameworld class if you need more info please let me know I am trying to make the array work but keep finding that when an array is initialized then the bullet fips back to the original and ends up being backwards???? and if I create an array I keep getting Exceptions throw??? Thank you for any help given.

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LINQ – SequenceEqual() method

- by nmarun

I have been looking at LINQ extension methods and have blogged about what I learned from them in my blog space. Next in line is the SequenceEqual() method. Here’s the description about this method: “Determines whether two sequences are equal by comparing the elements by using the default equality comparer for their type.” Let’s play with some code: 1: int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 }; 2: // int[] numbersCopy = numbers; 3: int[] numbersCopy = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 }; 4: 5: Console.WriteLine(numbers.SequenceEqual(numbersCopy)); This gives an output of ‘True’ – basically compares each of the elements in the two arrays and returns true in this case. The result is same even if you uncomment line 2 and comment line 3 (I didn’t need to say that now did I?). So then what happens for custom types? For this, I created a Product class with the following definition: 1: class Product 2: { 3: public int ProductId { get; set; } 4: public string Name { get; set; } 5: public string Category { get; set; } 6: public DateTime MfgDate { get; set; } 7: public Status Status { get; set; } 8: } 9: 10: public enum Status 11: { 12: Active = 1, 13: InActive = 2, 14: OffShelf = 3, 15: } In my calling code, I’m just adding a few product items: 1: private static List<Product> GetProducts() 2: { 3: return new List<Product> 4: { 5: new Product 6: { 7: ProductId = 1, 8: Name = "Laptop", 9: Category = "Computer", 10: MfgDate = new DateTime(2003, 4, 3), 11: Status = Status.Active, 12: }, 13: new Product 14: { 15: ProductId = 2, 16: Name = "Compact Disc", 17: Category = "Water Sport", 18: MfgDate = new DateTime(2009, 12, 3), 19: Status = Status.InActive, 20: }, 21: new Product 22: { 23: ProductId = 3, 24: Name = "Floppy", 25: Category = "Computer", 26: MfgDate = new DateTime(1993, 3, 7), 27: Status = Status.OffShelf, 28: }, 29: }; 30: } Now for the actual check: 1: List<Product> products1 = GetProducts(); 2: List<Product> products2 = GetProducts(); 3: 4: Console.WriteLine(products1.SequenceEqual(products2)); This one returns ‘False’ and the reason is simple – this one checks for reference equality and the products in the both the lists get different ‘memory addresses’ (sounds like I’m talking in ‘C’). In order to modify this behavior and return a ‘True’ result, we need to modify the Product class as follows: 1: class Product : IEquatable<Product> 2: { 3: public int ProductId { get; set; } 4: public string Name { get; set; } 5: public string Category { get; set; } 6: public DateTime MfgDate { get; set; } 7: public Status Status { get; set; } 8: 9: public override bool Equals(object obj) 10: { 11: return Equals(obj as Product); 12: } 13: 14: public bool Equals(Product other) 15: { 16: //Check whether the compared object is null. 17: if (ReferenceEquals(other, null)) return false; 18: 19: //Check whether the compared object references the same data. 20: if (ReferenceEquals(this, other)) return true; 21: 22: //Check whether the products' properties are equal. 23: return ProductId.Equals(other.ProductId) 24: && Name.Equals(other.Name) 25: && Category.Equals(other.Category) 26: && MfgDate.Equals(other.MfgDate) 27: && Status.Equals(other.Status); 28: } 29: 30: // If Equals() returns true for a pair of objects 31: // then GetHashCode() must return the same value for these objects. 32: // read why in the following articles: 33: // http://geekswithblogs.net/akraus1/archive/2010/02/28/138234.aspx 34: // http://stackoverflow.com/questions/371328/why-is-it-important-to-override-gethashcode-when-equals-method-is-overriden-in-c 35: public override int GetHashCode() 36: { 37: //Get hash code for the ProductId field. 38: int hashProductId = ProductId.GetHashCode(); 39: 40: //Get hash code for the Name field if it is not null. 41: int hashName = Name == null ? 0 : Name.GetHashCode(); 42: 43: //Get hash code for the ProductId field. 44: int hashCategory = Category.GetHashCode(); 45: 46: //Get hash code for the ProductId field. 47: int hashMfgDate = MfgDate.GetHashCode(); 48: 49: //Get hash code for the ProductId field. 50: int hashStatus = Status.GetHashCode(); 51: //Calculate the hash code for the product. 52: return hashProductId ^ hashName ^ hashCategory & hashMfgDate & hashStatus; 53: } 54: 55: public static bool operator ==(Product a, Product b) 56: { 57: // Enable a == b for null references to return the right value 58: if (ReferenceEquals(a, b)) 59: { 60: return true; 61: } 62: // If one is null and the other not. Remember a==null will lead to Stackoverflow! 63: if (ReferenceEquals(a, null)) 64: { 65: return false; 66: } 67: return a.Equals((object)b); 68: } 69: 70: public static bool operator !=(Product a, Product b) 71: { 72: return !(a == b); 73: } 74: } Now THAT kinda looks overwhelming. But lets take one simple step at a time. Ok first thing you’ve noticed is that the class implements IEquatable<Product> interface – the key step towards achieving our goal. This interface provides us with an ‘Equals’ method to perform the test for equality with another Product object, in this case. This method is called in the following situations: when you do a ProductInstance.Equals(AnotherProductInstance) and when you perform actions like Contains<T>, IndexOf() or Remove() on your collection Coming to the Equals method defined line 14 onwards. The two ‘if’ blocks check for null and referential equality using the ReferenceEquals() method defined in the Object class. Line 23 is where I’m doing the actual check on the properties of the Product instances. This is what returns the ‘True’ for us when we run the application. I have also overridden the Object.Equals() method which calls the Equals() method of the interface. One thing to remember is that anytime you override the Equals() method, its’ a good practice to override the GetHashCode() method and overload the ‘==’ and the ‘!=’ operators. For detailed information on this, please read this and this. Since we’ve overloaded the operators as well, we get ‘True’ when we do actions like: 1: Console.WriteLine(products1.Contains(products2[0])); 2: Console.WriteLine(products1[0] == products2[0]); This completes the full circle on the SequenceEqual() method. See the code used in the article here.

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GeoIP and Nginx

- by JavierMartinez

I have a nginx with geoip, but it is not working rightly. The issue is the next: Nginx are getting geodata from $_SERVER['REMOTE_ADDR'] instead of $_SERVER['HTTP_X_HAPROXY_IP'], which have the real client ip. So, the reported geodata belongs to my server ip instead of client ip. Does anybody where could be the error to fix it? Nginx version and compiled modules: nginx -V nginx version: nginx/1.2.3 TLS SNI support enabled configure arguments: --prefix=/etc/nginx --conf-path=/etc/nginx/nginx.conf --error-log- path=/var/log/nginx/error.log --http-client-body-temp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-log-path=/var/log/nginx/access.log --http-proxy-temp-path=/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --lock-path=/var/lock/nginx.lock --pid-path=/var/run/nginx.pid --with-pcre-jit --with-debug --with-file-aio --with-http_addition_module --with-http_dav_module --with-http_geoip_module --with-http_gzip_static_module --with-http_image_filter_module --with-http_realip_module --with-http_secure_link_module --with-http_stub_status_module --with-http_ssl_module --with-http_sub_module --with-http_xslt_module --with-ipv6 --with-sha1=/usr/include/openssl --with-md5=/usr/include/openssl --with-mail --with-mail_ssl_module --add-module=/usr/src/nginx/source/nginx-1.2.3/debian/modules/nginx-auth-pam --add-module=/usr/src/nginx/source/nginx-1.2.3/debian/modules/nginx-echo --add-module=/usr/src/nginx/source/nginx-1.2.3/debian/modules/nginx-upstream-fair --add-module=/usr/src/nginx/source/nginx-1.2.3/debian/modules/nginx-dav-ext-module --add-module=/usr/src/nginx/source/nginx-1.2.3/debian/modules/nginx-syslog --add-module=/usr/src/nginx/source/nginx-1.2.3/debian/modules/nginx-cache-purge nginx site conf (frontend machine) server { root /var/www/storage; server_name ~^.*(\.)?mydomain.com$; if ($host ~ ^(.*)\.mydomain\.com$) { set $new_host $1.mydomain.com; } if ($host !~ ^(.*)\.mydomain\.com$) { set $new_host www.mydomain.com; } add_header Staging true; real_ip_header X-HAProxy-IP; set_real_ip_from 10.5.0.10/32; location /files { expires 30d; if ($uri !~ ^/files/([a-fA-F0-9]+)_(220|45)\.jpg$) { return 403; } rewrite ^/files/([a-fA-F0-9][a-fA-F0-9])([a-fA-F0-9][a-fA-F0-9])([a-fA-F0-9][a-fA-F0-9])([a-fA-F0-9][a-fA-F0-9])([a-fA-F0-9]+)_(220|45)\.jpg$ /files/$1/$2/$3/$4/$1$2$3$4$5_$6.jpg break; try_files $uri @to_backend; } location /assets { if ($uri ~ ^/assets/r([a-zA-Z0-9]+[^/])(/(css|js|fonts)/.*)) { rewrite ^/assets/r([a-zA-Z0-9]+[^/])/(css|js|fonts)/(.*)$ /assets/$2/$3 break; } try_files $uri @to_backend; } location / { proxy_set_header Host $new_host; proxy_set_header X-HAProxy-IP $remote_addr; proxy_pass http://10.5.0.10:8080; } location @to_backend { proxy_set_header Host $new_host; proxy_pass http://10.5.0.10:8080; } } nginx.conf (backend machine) http{ ... ## # GeoIP Config ## geoip_country /etc/nginx/geoip/GeoIP.dat; # the country IP database geoip_city /etc/nginx/geoip/GeoLiteCity.dat; # the city IP database ... } fastcgi_params (backend machine) ### SET GEOIP Variables ### fastcgi_param GEOIP_COUNTRY_CODE $geoip_country_code; fastcgi_param GEOIP_COUNTRY_CODE3 $geoip_country_code3; fastcgi_param GEOIP_COUNTRY_NAME $geoip_country_name; fastcgi_param GEOIP_CITY_COUNTRY_CODE $geoip_city_country_code; fastcgi_param GEOIP_CITY_COUNTRY_CODE3 $geoip_city_country_code3; fastcgi_param GEOIP_CITY_COUNTRY_NAME $geoip_city_country_name; fastcgi_param GEOIP_REGION $geoip_region; fastcgi_param GEOIP_CITY $geoip_city; fastcgi_param GEOIP_POSTAL_CODE $geoip_postal_code; fastcgi_param GEOIP_CITY_CONTINENT_CODE $geoip_city_continent_code; fastcgi_param GEOIP_LATITUDE $geoip_latitude; fastcgi_param GEOIP_LONGITUDE $geoip_longitude; haproxy.conf (frontend machine) defaults log global option forwardfor option httpclose mode http retries 3 option redispatch maxconn 4096 contimeout 100000 clitimeout 100000 srvtimeout 100000 listen cluster_webs *:8080 mode http option tcpka option httpchk option httpclose option forwardfor balance roundrobin server backend-stage 10.5.0.11:80 weight 1 $_SERVER dump: http://paste.laravel.com/7dy Where 10.5.0.10 is frontend private ip and 10.5.0.11 backend private ip

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cannt run phpunit tests on bash ubuntu 11.10

- by Mohamad Elbialy

i'm working with ubuntu 11.10 as root on my local machine, i've installed xampp 1.7.7 and i'm a newbie to ubuntu, while following a tutorial on sitepoint(http://www.sitepoint.com/getting-started-with-pear/) on how to install pear to use PhpUnit, i didnt notice it then, but it seems that i installed or used an existing php version 5.3.6 in CL to do that, also the pear installation was built on this version, while xampp being installed,i now have two versions of php,xampp's 5.3.8 and the 5.3.6, anyway, what i want to do is to use the existing xampp php version and build pear on that, to make all my work through xampp.so my questions are: how to uninstall the php V5.3.6 and it's pear installation? how to link the CL with the php ver. of xampp? how to build the next pear installation on the php ver. of xampp? i want all my web dev. work through xampp, is there anything else i need to unistall, to avoid this confusion? 4. i did the following in attampet to solve the problem: i wrote this in bash: gedit ~/.bashrc i added that to the end of ~/.bashrc file in attempt to change environment path: export PATH=/opt/lampp/bin:$PATH export PATH=/opt/lampp/lib/php:$PATH export PATH=/opt/lampp/lib/php/PHPUnit/pearcmd.php:$PATH i checked the php and pear version using 'php -v' and 'pear list' i got an ouput of: PHP 5.3.8 (cli) (built: Sep 19 2011 13:29:27) Copyright (c) 1997-2011 The PHP Group Zend Engine v2.3.0, Copyright (c) 1998-2011 Zend Technologies and for pear: Installed packages, channel pear.php.net: ========================================= Package Version State Archive_Tar 1.3.9 stable Console_Getopt 1.3.1 stable PEAR 1.9.4 stable PHPUnit 1.3.2 stable Structures_Graph 1.0.4 stable XML_Util 1.2.1 stable when i run: 'phpunit MessageTest.php': i get PHP Warning: require_once(PHP/CodeCoverage/Filter.php): failed to open stream: No such file or directory in /usr/bin/phpunit on line 38 Warning: require_once(PHP/CodeCoverage/Filter.php): failed to open stream: No such file or directory in /usr/bin/phpunit on line 38 PHP Fatal error: require_once(): Failed opening required 'PHP/CodeCoverage/Filter.php' (include_path='.:/php/includes:/opt/lampp/lib/php:/opt/lampp/bin:/opt/lampp/lib/php/PEAR') in /usr/bin/phpunit on line 38 5.i ran the following commands as reported in other questions as a solution to that error: sudo apt-get remove phpunit sudo pear channel-discover pear.phpunit.de sudo pear channel-discover pear.symfony-project.com sudo pear channel-discover components.ez.no sudo pear update-channels sudo pear upgrade-all sudo pear install --alldeps phpunit/PHPUnit sudo apt-get install phpunit and updated include path of php.ini to be: include_path = ".:/php/includes:/opt/lampp/lib/php:/opt/lampp/bin:/opt/lampp/lib/php/PEAR" the php file MessageTest.php: <?php require 'PHPUnit/Autoload.php'; $path = '/opt/lampp/lib/php/PEAR'; set_include_path(get_include_path() . PATH_SEPARATOR . $path); require_once 'PHPUnit/Framework/TestCase.php'; require_once 'Message/Controller/MessageController.php'; class MessageTest extends PHPUnit_Framework_TestCase{ private $message; public function setUp() { $this->message = new MessageController(); } public function tearDown() { } public function testRepeat(){ $yell = "Hello, Any One Out There?"; $this->message->repeat($yell); //sending a request $returnedMessage = $this->message->repeat($yell);//get a response $this->assertEquals($returnedMessage, $yell); } } ?> MessageController class from MessageController.php that i'm trying to test <?php class MessageController { public function actionHelloWorld() { echo 'helloWorld'; } public function repeat($inputString){ return $inputString; } } $msg = new MessageController; ?> I'm not using any PHP framework, i just made the files and classes sounds like it that's all. and still i get the same error: PHP Warning: require_once(PHP/CodeCoverage/Filter.php): failed to open stream: No such file or directory in /usr/bin/phpunit on line Warning: require_once(PHP/CodeCoverage/Filter.php): failed to open stream: No such file or directory in /usr/bin/phpunit on line 38 PHP Fatal error: require_once(): Failed opening required 'PHP/CodeCoverage/Filter.php' (include_path='.:/php/includes:/opt/lampp/lib/php:/opt/lampp/bin:/opt/lampp/lib/php/PEAR') in /usr/bin/phpunit on line 38 sure, i'm getting demanding here, i've wasted a lot of time and got really frustrated over this, hope you guys dont get bored reading through my questions, i appreciate your help thanks in advance, Mohamad elbialy

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Improvements to Joshua Bloch's Builder Design Pattern?

- by Jason Fotinatos

Back in 2007, I read an article about Joshua Blochs take on the "builder pattern" and how it could be modified to improve the overuse of constructors and setters, especially when an object has a large number of properties, most of which are optional. A brief summary of this design pattern is articled here [http://rwhansen.blogspot.com/2007/07/theres-builder-pattern-that-joshua.html]. I liked the idea, and have been using it since. The problem with it, while it is very clean and nice to use from the client perspective, implementing it can be a pain in the bum! There are so many different places in the object where a single property is reference, and thus creating the object, and adding a new property takes a lot of time. So...I had an idea. First, an example object in Joshua Bloch's style: Josh Bloch Style: public class OptionsJoshBlochStyle { private final String option1; private final int option2; // ...other options here <<<< public String getOption1() { return option1; } public int getOption2() { return option2; } public static class Builder { private String option1; private int option2; // other options here <<<<< public Builder option1(String option1) { this.option1 = option1; return this; } public Builder option2(int option2) { this.option2 = option2; return this; } public OptionsJoshBlochStyle build() { return new OptionsJoshBlochStyle(this); } } private OptionsJoshBlochStyle(Builder builder) { this.option1 = builder.option1; this.option2 = builder.option2; // other options here <<<<<< } public static void main(String[] args) { OptionsJoshBlochStyle optionsVariation1 = new OptionsJoshBlochStyle.Builder().option1("firefox").option2(1).build(); OptionsJoshBlochStyle optionsVariation2 = new OptionsJoshBlochStyle.Builder().option1("chrome").option2(2).build(); } } Now my "improved" version: public class Options { // note that these are not final private String option1; private int option2; // ...other options here public String getOption1() { return option1; } public int getOption2() { return option2; } public static class Builder { private final Options options = new Options(); public Builder option1(String option1) { this.options.option1 = option1; return this; } public Builder option2(int option2) { this.options.option2 = option2; return this; } public Options build() { return options; } } private Options() { } public static void main(String[] args) { Options optionsVariation1 = new Options.Builder().option1("firefox").option2(1).build(); Options optionsVariation2 = new Options.Builder().option1("chrome").option2(2).build(); } } As you can see in my "improved version", there are 2 less places in which we need to add code about any addition properties (or options, in this case)! The only negative that I can see is that the instance variables of the outer class are not able to be final. But, the class is still immutable without this. Is there really any downside to this improvement in maintainability? There has to be a reason which he repeated the properties within the nested class that I'm not seeing?

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Accessing py2exe program over network in Windows 98 throws ImportErrors

- by darvids0n

I'm running a py2exe-compiled python program from one server machine on a number of client machines (mapped to a network drive on every machine, say W:). For Windows XP and later machines, have so far had zero problems with Python picking up W:\python23.dll (yes, I'm using Python 2.3.5 for W98 compatibility and all that). It will then use W:\zlib.pyd to decompress W:\library.zip containing all the .pyc files like os and such, which are then imported and the program runs no problems. The issue I'm getting is on some Windows 98 SE machines (note: SOME Windows 98 SE machines, others seem to work with no apparent issues). What happens is, the program runs from W:, the W:\python23.dll is, I assume, found (since I'm getting Python ImportErrors, we'd need to be able to execute a Python import statement), but a couple of things don't work: 1) If W:\library.zip contains the only copy of the .pyc files, I get ZipImportError: can't decompress data; zlib not available (nonsense, considering W:\zlib.pyd IS available and works fine with the XP and higher machines on the same network). 2) If the .pyc files are actually bundled INSIDE the python exe by py2exe, OR put in the same directory as the .exe, OR put into a named subdirectory which is then set as part of the PYTHONPATH variable (e.g W:\pylib), I get ImportError: no module named os (os is the first module imported, before sys and anything else). Come to think of it, sys.path wouldn't be available to search if os was imported before it maybe? I'll try switching the order of those imports but my question still stands: Why is this a sporadic issue, working on some networks but not on others? And how would I force Python to find the files that are bundled inside the very executable I run? I have immediate access to the working Windows 98 SE machine, but I only get access to the non-working one (a customer of mine) every morning before their store opens. Thanks in advance! EDIT: Okay, big step forward. After debugging with PY2EXE_VERBOSE, the problem occurring on the specific W98SE machine is that it's not using the right path syntax when looking for imports. Firstly, it doesn't seem to read the PYTHONPATH environment variable (there may be a py2exe-specific one I'm not aware of, like PY2EXE_VERBOSE). Secondly, it only looks in one place before giving up (if the files are bundled inside the EXE, it looks there. If not, it looks in library.zip). EDIT 2: In fact, according to this, there is a difference between the sys.path in the Python interpreter and that of Py2exe executables. Specifically, sys.path contains only a single entry: the full pathname of the shared code archive. Blah. No fallbacks? Not even the current working directory? I'd try adding W:\ to PATH, but py2exe doesn't conform to any sort of standards for locating system libraries, so it won't work. Now for the interesting bit. The path it tries to load atexit, os, etc. from is: W:\\library.zip\<module>.<ext> Note the single slash after library.zip, but the double slash after the drive letter (someone correct me if this is intended and should work). It looks like if this is a string literal, then since the slash isn't doubled, it's read as an (invalid) escape sequence and the raw character is printed (giving W:\library.zipos.pyd, W:\library.zipos.dll, ... instead of with a slash); if it is NOT a string literal, the double slash might not be normpath'd automatically (as it should be) and so the double slash confuses the module loader. Like I said, I can't just set PYTHONPATH=W:\\library.zip\\ because it ignores that variable. It may be worth using sys.path.append at the start of my program but hard-coding module paths is an absolute LAST resort, especially since the problem occurs in ONE configuration of an outdated OS. Any ideas? I have one, which is to normpath the sys.path.. pity I need os for that. Another is to just append os.getenv('PATH') or os.getenv('PYTHONPATH') to sys.path... again, needing the os module. The site module also fails to initialise, so I can't use a .pth file. I also recently tried the following code at the start of the program: for pth in sys.path: fErr.write(pth) fErr.write(' to ') pth.replace('\\\\','\\') # Fix Windows 98 pathing issues fErr.write(pth) fErr.write('\n') But it can't load linecache.pyc, or anything else for that matter; it can't actually execute those commands from the looks of things. Is there any way to use built-in functionality which doesn't need linecache to modify the sys.path dynamically? Or am I reduced to hard-coding the correct sys.path?

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Examples of bad variable names and reasons [on hold]

- by user470184

I'll start with a class in the jdk package : public final class Sdp { should be : public final class SocketsDirectProtocol { Sdp is class name, this is ambigious, should be : Class<?> cl = Class.forName("java.net.SdpSocketImpl", true, null); should be : Class<?> clazz = Class.forName("java.net.SdpSocketImpl", true, null); cl is ambiguous private static void setAccessible(final AccessibleObject o) { should be : private static void setAccessible(final AccessibleObject accessibleObject) { There are various other examples in this class, do you have similar and/or differing examples of variables that were named badly ? package com.oracle.net; public final class Sdp { private Sdp() { } /** * The package-privage ServerSocket(SocketImpl) constructor */ private static final Constructor<ServerSocket> serverSocketCtor; static { try { serverSocketCtor = (Constructor<ServerSocket>) ServerSocket.class.getDeclaredConstructor(SocketImpl.class); setAccessible(serverSocketCtor); } catch (NoSuchMethodException e) { throw new AssertionError(e); } } /** * The package-private SdpSocketImpl() constructor */ private static final Constructor<SocketImpl> socketImplCtor; static { try { Class<?> cl = Class.forName("java.net.SdpSocketImpl", true, null); socketImplCtor = (Constructor<SocketImpl>)cl.getDeclaredConstructor(); setAccessible(socketImplCtor); } catch (ClassNotFoundException e) { throw new AssertionError(e); } catch (NoSuchMethodException e) { throw new AssertionError(e); } } private static void setAccessible(final AccessibleObject o) { AccessController.doPrivileged(new PrivilegedAction<Void>() { public Void run() { o.setAccessible(true); return null; } }); } /** * SDP enabled Socket. */ private static class SdpSocket extends Socket { SdpSocket(SocketImpl impl) throws SocketException { super(impl); } } /** * Creates a SDP enabled SocketImpl */ private static SocketImpl createSocketImpl() { try { return socketImplCtor.newInstance(); } catch (InstantiationException x) { throw new AssertionError(x); } catch (IllegalAccessException x) { throw new AssertionError(x); } catch (InvocationTargetException x) { throw new AssertionError(x); } } /** * Creates an unconnected and unbound SDP socket. The {@code Socket} is * associated with a {@link java.net.SocketImpl} of the system-default type. * * @return a new Socket * * @throws UnsupportedOperationException * If SDP is not supported * @throws IOException * If an I/O error occurs */ public static Socket openSocket() throws IOException { SocketImpl impl = createSocketImpl(); return new SdpSocket(impl); } /** * Creates an unbound SDP server socket. The {@code ServerSocket} is * associated with a {@link java.net.SocketImpl} of the system-default type. * * @return a new ServerSocket * * @throws UnsupportedOperationException * If SDP is not supported * @throws IOException * If an I/O error occurs */ public static ServerSocket openServerSocket() throws IOException { // create ServerSocket via package-private constructor SocketImpl impl = createSocketImpl(); try { return serverSocketCtor.newInstance(impl); } catch (IllegalAccessException x) { throw new AssertionError(x); } catch (InstantiationException x) { throw new AssertionError(x); } catch (InvocationTargetException x) { Throwable cause = x.getCause(); if (cause instanceof IOException) throw (IOException)cause; if (cause instanceof RuntimeException) throw (RuntimeException)cause; throw new RuntimeException(x); } } /** * Opens a socket channel to a SDP socket. * * <p> The channel will be associated with the system-wide default * {@link java.nio.channels.spi.SelectorProvider SelectorProvider}. * * @return a new SocketChannel * * @throws UnsupportedOperationException * If SDP is not supported or not supported by the default selector * provider * @throws IOException * If an I/O error occurs. */ public static SocketChannel openSocketChannel() throws IOException { FileDescriptor fd = SdpSupport.createSocket(); return sun.nio.ch.Secrets.newSocketChannel(fd); } /** * Opens a socket channel to a SDP socket. * * <p> The channel will be associated with the system-wide default * {@link java.nio.channels.spi.SelectorProvider SelectorProvider}. * * @return a new ServerSocketChannel * * @throws UnsupportedOperationException * If SDP is not supported or not supported by the default selector * provider * @throws IOException * If an I/O error occurs */ public static ServerSocketChannel openServerSocketChannel() throws IOException { FileDescriptor fd = SdpSupport.createSocket(); return sun.nio.ch.Secrets.newServerSocketChannel(fd); } }

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Objects in Java ArrayList don't get updated.

- by Sbm007

This is going to be a very long post, hopefully you can understand what I'm talking about and I appreciate any help. Thanks Basically, I've created a personal, non-commercial project (which I don't plan to release) that can read ZIP and RAR files. It can only read the contents in the archive, the folders inside, the files inside the folders and its properties (such as last modified date, last modified time, CRC checksum, uncompressed size, compressed size and file name). It can't extract files either, so it's really a ZIP/RAR viewer if you may. Anyway that's slightly irrelevant to my problem but I thought I'd give you some background info. Now for my problem: I can successfully list all the folders and files inside a ZIP archive, so now I want to take that raw input and link it together in some useful way. I made 2 classes: ArchiveFile (represents a file inside a ZIP) and ArchiveFolder (represents a folder inside a ZIP). They both have some useful methods such as getLastModifiedDate, getName, getPath and so on. But the difference is that ArchiveFolder can hold an ArrayList of ArchiveFile's and additional ArchiveFolder's (think of this as files and folders inside a folder). Now I want to populate my raw input into one root ArchiveFolder, which will have all the files in the root dir of the ZIP in the ArchiveFile's ArrayList and any additional folders in the root dir of the ZIP in the ArchiveFolder's ArrayList (and this process can continue on like this like a chain reaction (more files/folders in that ArchiveFolder etc etc). So I came up with the following code: while (archive.hasMore()) { String path = ""; ArchiveFolder current = root; String[] contents = archive.getName().split("/"); for (int x = 0; x < contents.length; ++x) { if (x == (contents.length - 1) && !archive.getName().endsWith("/")) { // If on last item and item is a file path += contents[x]; // Update final path ArchiveFile file = new ArchiveFile(path, contents[x], archive.getUncompressedSize(), archive.getCompressedSize(), archive.getModifiedTime(), archive.getModifiedDate(), archive.getCRC()); current.addFile(file); // Create and add the file to the current ArchiveFolder } else if (x == (contents.length - 1)) { // Else if we are on last item and it is a folder path += contents[x] + "/"; // Update final path ArchiveFolder folder = new ArchiveFolder(path, contents[x], archive.getModifiedTime(), archive.getModifiedDate()); current.addFolder(folder); // Create and add this folder to the current ArchiveFile } else { // Else if we are still traversing through the path path += contents[x] + "/"; // Update path ArchiveFolder folder = new ArchiveFolder(path, contents[x]); current.addFolder(folder); // Create and add folder (remember we do not know the modified date/time as all we know is the path, so we can deduce the name only) current = folder; // Update current ArchiveFolder to the newly created one for the next iteration of the for loop } } archive.getNext(); } Assume that root is the root ArchiveFolder (initially empty). And that archive.getName() returns the name of the current file OR folder in the following fashion: file.txt or folder1/file2.txt or folder4/folder2/ (this is a empty folder) etc. So basically the relative path from the root of the ZIP archive. Please read through the comments in the above code to familiarize yourself with it. Also assume that the addFolder method in an ArchiveFile, only adds the folder if it doesn't exist already (so there are no multiple folders) and it also updates the time and date of an existing folder if it is blank (ie it was a intermediate folder we only knew the name of, but now we know its details). The code for addFolder is (pretty self-explanitory): public void addFolder(ArchiveFolder folder) { int loc = folders.indexOf(folder); // folders is the ArrayList containing ArchiveFolder's if (loc == -1) { folders.add(folder); } else { ArchiveFolder real = folders.get(loc); if (real.time == null) { real.setTime(folder.getTime()); real.setDate(folder.getDate()); } } } So I can't see anything wrong with the code, it works and after finishing, the root ArchiveFolder contains all the files in the root of the ZIP as I want it to, and it contains all the direcories in the root folder as I want it to. So you'd think it works as expected, but no the ArchiveFolder's in the root folder don't contain the data inside those 'child' folders, it's just a blank folder with no additional files and folders (while it does really contain some more files/folders when viewed in WinZip). After debugging using Eclipse, the for loop does iterate through all the files (even those not included above), so this led me to believe that there is a problem with this line of the code: current = folder; What it does is, it updates the current folder (used as an intermediate by the loop) to the newly added folder. I thought Java passed by reference and thus all new operations and new additions in future ArchiveFile's and ArchiveFolder's are automatically updated, and parent ArchiveFolder's will be updated accordingly. But that does not appear to be the case? I know this is a long ass post and I really hope anyone can help me out with this. Thanks in advance.

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How to Animate Text and Objects in PowerPoint 2010

- by DigitalGeekery

Are you looking for an eye catching way to keep your audience interested in your PowerPoint presentations? Today we’ll take a look at how to add animation effects to objects in PowerPoint 2010. Select the object you wish to animate and then click the More button in the Animation group of the Animation tab. Animations are grouped into four categories. Entrance effects, Exit effects, Emphasis effects, and Motion Paths. You can get a Live Preview of how the animation will look by hovering your mouse over an animation effect. When you select a Motion Path, your object will move along the dashed path line as shown on the screen. (This path is not displayed in the final output) Certain aspects of the Motion Path effects are editable. When you apply a Motion Path animation to an object, you can select the path and drag the end to change the length or size of the path. The green marker along the motion path marks the beginning of the path and the red marks the end. The effects can be rotated by clicking and the bar near the center of the effect. You can display additional effects by choosing one of the options at the bottom. This will pop up a Change Effect window. If you have Preview Effect checked at the lower left you can preview the effects by single clicking. Apply Multiple Animations to an Object Select the object and then click the Add Animation button to display the animation effects. Just as we did with the first effect, you can hover over to get a live preview. Click to apply the effect. The animation effects will happen in the order they are applied. Animation Pane You can view a list of the animations applied to a slide by opening the Animation Pane. Select the Animation Pane button from the Advanced Animation group to display the Animation Pane on the right. You’ll see that each animation effect in the animation pane has an assigned number to the left. Timing Animation Effects You can change when your animation starts to play. By default it is On Click. To change it, select the effect in the Animation Pane and then choose one of the options from the Start dropdown list. With Previous starts at the same time as the previous animation and After Previous starts after the last animation. You can also edit the duration that the animations plays and also set a delay. You can change the order in which the animation effects are applied by selecting the effect in the animation pane and clicking Move Earlier or Move Later from the Timing group on the Animation tab. Effect Options If the Effect Options button is available when your animation is selected, then that particular animation has some additional effect settings that can be configured. You can access the Effect Option by right-clicking on the the animation in the Animation Pane, or by selecting Effect Options on the ribbon. The available options will vary by effect and not all animation effects will have Effect Options settings. In the example below, you can change the amount of spinning and whether the object will spin clockwise or counterclockwise. Under Enhancements, you can add sound effects to your animation. When you’re finished click OK. Animating Text Animating Text works the same as animating an object. Simply select your text box and choose an animation. Text does have some different Effect Options. By selecting a sequence, you decide whether the text appears as one object, all at once, or by paragraph. As is the case with objects, there will be different available Effect Options depending on the animation you choose. Some animations, such as the Fly In animation, will have directional options. Testing Your Animations Click on the Preview button at any time to test how your animations look. You can also select the Play button on the Animation Pane. Conclusion Animation effects are a great way to focus audience attention on important points and hold viewers interest in your PowerPoint presentations. Another cool way to spice up your PPT 2010 presentations is to add video from the web. What tips do you guys have for making your PowerPoint presentations more interesting? Similar Articles Productive Geek Tips Center Pictures and Other Objects in Office 2007 & 2010Preview Before You Paste with Live Preview in Office 2010Embed True Type Fonts in Word and PowerPoint 2007 DocumentsHow to Add Video from the Web in PowerPoint 2010Add Artistic Effects to Your Pictures in Office 2010 TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Xobni Plus for Outlook All My Movies 5.9 CloudBerry Online Backup 1.5 for Windows Home Server Snagit 10 24 Million Sites Windows Media Player Glass Icons (icons we like) How to Forecast Weather, without Gadgets Outlook Tools, one stop tweaking for any Outlook version Zoofs, find the most popular tweeted YouTube videos Video preview of new Windows Live Essentials

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Tip #13 java.io.File Surprises

- by ByronNevins

There is an assumption that I've seen in code many times that is totally wrong. And this assumption can easily bite you. The assumption is: File.getAbsolutePath and getAbsoluteFile return paths that are not relative. Not true! Sort of. At least not in the way many people would assume. All they do is make sure that the beginning of the path is absolute. The rest of the path can be loaded with relative path elements. What do you think the following code will print? public class Main { public static void main(String[] args) { try { File f = new File("/temp/../temp/../temp/../"); File abs = f.getAbsoluteFile(); File parent = abs.getParentFile(); System.out.println("Exists: " + f.exists()); System.out.println("Absolute Path: " + abs); System.out.println("FileName: " + abs.getName()); System.out.printf("The Parent Directory of %s is %s\n", abs, parent); System.out.printf("The CANONICAL Parent Directory of CANONICAL %s is %s\n", abs, abs.getCanonicalFile().getParent()); System.out.printf("The CANONICAL Parent Directory of ABSOLUTE %s is %s\n", abs, parent.getCanonicalFile()); System.out.println("Canonical Path: " + f.getCanonicalPath()); } catch (IOException ex) { System.out.println("Got an exception: " + ex); } }} Output: Exists: trueAbsolute Path: D:\temp\..\temp\..\temp\..FileName: ..The Parent Directory of D:\temp\..\temp\..\temp\.. is D:\temp\..\temp\..\tempThe CANONICAL Parent Directory of CANONICAL D:\temp\..\temp\..\temp\.. is nullThe CANONICAL Parent Directory of ABSOLUTE D:\temp\..\temp\..\temp\.. is D:\tempCanonical Path: D:\ Notice how it says that the parent of d:\ is d:\temp !!!The file, f, is really the root directory. The parent is supposed to be null. I learned about this the hard way! getParentXXX simply hacks off the final item in the path. You can get totally unexpected results like the above. Easily. I filed a bug on this behavior a few years ago[1]. Recommendations: (1) Use getCanonical instead of getAbsolute. There is a 1:1 mapping of files and canonical filenames. I.e each file has one and only one canonical filename and it will definitely not have relative path elements in it. There are an infinite number of absolute paths for each file. (2) To get the parent file for File f do the following instead of getParentFile: File parent = new File(f, ".."); [1] http://bt2ws.central.sun.com/CrPrint?id=6687287

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Using the ASP.NET Cache to cache data in a Model or Business Object layer, without a dependency on System.Web in the layer - Part One.

- by Rhames

ASP.NET applications can make use of the System.Web.Caching.Cache object to cache data and prevent repeated expensive calls to a database or other store. However, ideally an application should make use of caching at the point where data is retrieved from the database, which typically is inside a Business Objects or Model layer. One of the key features of using a UI pattern such as Model-View-Presenter (MVP) or Model-View-Controller (MVC) is that the Model and Presenter (or Controller) layers are developed without any knowledge of the UI layer. Introducing a dependency on System.Web into the Model layer would break this independence of the Model from the View. This article gives a solution to this problem, using dependency injection to inject the caching implementation into the Model layer at runtime. This allows caching to be used within the Model layer, without any knowledge of the actual caching mechanism that will be used. Create a sample application to use the caching solution Create a test SQL Server database This solution uses a SQL Server database with the same Sales data used in my previous post on calculating running totals. The advantage of using this data is that it gives nice slow queries that will exaggerate the effect of using caching! To create the data, first create a new SQL database called CacheSample. Next run the following script to create the Sale table and populate it: USE CacheSample GO CREATE TABLE Sale(DayCount smallint, Sales money) CREATE CLUSTERED INDEX ndx_DayCount ON Sale(DayCount) go INSERT Sale VALUES (1,120) INSERT Sale VALUES (2,60) INSERT Sale VALUES (3,125) INSERT Sale VALUES (4,40) DECLARE @DayCount smallint, @Sales money SET @DayCount = 5 SET @Sales = 10 WHILE @DayCount < 5000 BEGIN INSERT Sale VALUES (@DayCount,@Sales) SET @DayCount = @DayCount + 1 SET @Sales = @Sales + 15 END Next create a stored procedure to calculate the running total, and return a specified number of rows from the Sale table, using the following script: USE [CacheSample] GO SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO -- ============================================= -- Author: Robin -- Create date: -- Description: -- ============================================= CREATE PROCEDURE [dbo].[spGetRunningTotals] -- Add the parameters for the stored procedure here @HighestDayCount smallint = null AS BEGIN -- SET NOCOUNT ON added to prevent extra result sets from -- interfering with SELECT statements. SET NOCOUNT ON; IF @HighestDayCount IS NULL SELECT @HighestDayCount = MAX(DayCount) FROM dbo.Sale DECLARE @SaleTbl TABLE (DayCount smallint, Sales money, RunningTotal money) DECLARE @DayCount smallint, @Sales money, @RunningTotal money SET @RunningTotal = 0 SET @DayCount = 0 DECLARE rt_cursor CURSOR FOR SELECT DayCount, Sales FROM Sale ORDER BY DayCount OPEN rt_cursor FETCH NEXT FROM rt_cursor INTO @DayCount,@Sales WHILE @@FETCH_STATUS = 0 AND @DayCount <= @HighestDayCount BEGIN SET @RunningTotal = @RunningTotal + @Sales INSERT @SaleTbl VALUES (@DayCount,@Sales,@RunningTotal) FETCH NEXT FROM rt_cursor INTO @DayCount,@Sales END CLOSE rt_cursor DEALLOCATE rt_cursor SELECT DayCount, Sales, RunningTotal FROM @SaleTbl END GO Create the Sample ASP.NET application In Visual Studio create a new solution and add a class library project called CacheSample.BusinessObjects and an ASP.NET web application called CacheSample.UI. The CacheSample.BusinessObjects project will contain a single class to represent a Sale data item, with all the code to retrieve the sales from the database included in it for simplicity (normally I would at least have a separate Repository or other object that is responsible for retrieving data, and probably a data access layer as well, but for this sample I want to keep it simple). The C# code for the Sale class is shown below: using System; using System.Collections.Generic; using System.Data; using System.Data.SqlClient; namespace CacheSample.BusinessObjects { public class Sale { public Int16 DayCount { get; set; } public decimal Sales { get; set; } public decimal RunningTotal { get; set; } public static IEnumerable<Sale> GetSales(int? highestDayCount) { List<Sale> sales = new List<Sale>(); SqlParameter highestDayCountParameter = new SqlParameter("@HighestDayCount", SqlDbType.SmallInt); if (highestDayCount.HasValue) highestDayCountParameter.Value = highestDayCount; else highestDayCountParameter.Value = DBNull.Value; string connectionStr = System.Configuration.ConfigurationManager .ConnectionStrings["CacheSample"].ConnectionString; using(SqlConnection sqlConn = new SqlConnection(connectionStr)) using (SqlCommand sqlCmd = sqlConn.CreateCommand()) { sqlCmd.CommandText = "spGetRunningTotals"; sqlCmd.CommandType = CommandType.StoredProcedure; sqlCmd.Parameters.Add(highestDayCountParameter); sqlConn.Open(); using (SqlDataReader dr = sqlCmd.ExecuteReader()) { while (dr.Read()) { Sale newSale = new Sale(); newSale.DayCount = dr.GetInt16(0); newSale.Sales = dr.GetDecimal(1); newSale.RunningTotal = dr.GetDecimal(2); sales.Add(newSale); } } } return sales; } } } The static GetSale() method makes a call to the spGetRunningTotals stored procedure and then reads each row from the returned SqlDataReader into an instance of the Sale class, it then returns a List of the Sale objects, as IEnnumerable<Sale>. A reference to System.Configuration needs to be added to the CacheSample.BusinessObjects project so that the connection string can be read from the web.config file. In the CacheSample.UI ASP.NET project, create a single web page called ShowSales.aspx, and make this the default start up page. This page will contain a single button to call the GetSales() method and a label to display the results. The html mark up and the C# code behind are shown below: ShowSales.aspx <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ShowSales.aspx.cs" Inherits="CacheSample.UI.ShowSales" %> <!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"> <head runat="server"> <title>Cache Sample - Show All Sales</title> </head> <body> <form id="form1" runat="server"> <div> <asp:Button ID="btnTest1" runat="server" onclick="btnTest1_Click" Text="Get All Sales" />     <asp:Label ID="lblResults" runat="server"></asp:Label> </div> </form> </body> </html> ShowSales.aspx.cs using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using CacheSample.BusinessObjects; namespace CacheSample.UI { public partial class ShowSales : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } protected void btnTest1_Click(object sender, EventArgs e) { System.Diagnostics.Stopwatch stopWatch = new System.Diagnostics.Stopwatch(); stopWatch.Start(); var sales = Sale.GetSales(null); var lastSales = sales.Last(); stopWatch.Stop(); lblResults.Text = string.Format( "Count of Sales: {0}, Last DayCount: {1}, Total Sales: {2}. Query took {3} ms", sales.Count(), lastSales.DayCount, lastSales.RunningTotal, stopWatch.ElapsedMilliseconds); } } } Finally we need to add a connection string to the CacheSample SQL Server database, called CacheSample, to the web.config file: <?xmlversion="1.0"?> <configuration> <connectionStrings> <addname="CacheSample" connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;Initial Catalog=CacheSample" providerName="System.Data.SqlClient" /> </connectionStrings> <system.web> <compilationdebug="true"targetFramework="4.0" /> </system.web> </configuration> Run the application and click the button a few times to see how long each call to the database takes. On my system, each query takes about 450ms. Next I shall look at a solution to use the ASP.NET caching to cache the data returned by the query, so that subsequent requests to the GetSales() method are much faster. Adding Data Caching Support I am going to create my caching support in a separate project called CacheSample.Caching, so the next step is to add a class library to the solution. We shall be using the application configuration to define the implementation of our caching system, so we need a reference to System.Configuration adding to the project. ICacheProvider<T> Interface The first step in adding caching to our application is to define an interface, called ICacheProvider, in the CacheSample.Caching project, with methods to retrieve any data from the cache or to retrieve the data from the data source if it is not present in the cache. Dependency Injection will then be used to inject an implementation of this interface at runtime, allowing the users of the interface (i.e. the CacheSample.BusinessObjects project) to be completely unaware of how the caching is actually implemented. As data of any type maybe retrieved from the data source, it makes sense to use generics in the interface, with a generic type parameter defining the data type associated with a particular instance of the cache interface implementation. The C# code for the ICacheProvider interface is shown below: using System; using System.Collections.Generic; namespace CacheSample.Caching { public interface ICacheProvider { } public interface ICacheProvider<T> : ICacheProvider { T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry); IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry); } } The empty non-generic interface will be used as a type in a Dictionary generic collection later to store instances of the ICacheProvider<T> implementation for reuse, I prefer to use a base interface when doing this, as I think the alternative of using object makes for less clear code. The ICacheProvider<T> interface defines two overloaded Fetch methods, the difference between these is that one will return a single instance of the type T and the other will return an IEnumerable<T>, providing support for easy caching of collections of data items. Both methods will take a key parameter, which will uniquely identify the cached data, a delegate of type Func<T> or Func<IEnumerable<T>> which will provide the code to retrieve the data from the store if it is not present in the cache, and absolute or relative expiry policies to define when a cached item should expire. Note that at present there is no support for cache dependencies, but I shall be showing a method of adding this in part two of this article. CacheProviderFactory Class We need a mechanism of creating instances of our ICacheProvider<T> interface, using Dependency Injection to get the implementation of the interface. To do this we shall create a CacheProviderFactory static class in the CacheSample.Caching project. This factory will provide a generic static method called GetCacheProvider<T>(), which shall return instances of ICacheProvider<T>. We can then call this factory method with the relevant data type (for example the Sale class in the CacheSample.BusinessObject project) to get a instance of ICacheProvider for that type (e.g. call CacheProviderFactory.GetCacheProvider<Sale>() to get the ICacheProvider<Sale> implementation). The C# code for the CacheProviderFactory is shown below: using System; using System.Collections.Generic; using CacheSample.Caching.Configuration; namespace CacheSample.Caching { public static class CacheProviderFactory { private static Dictionary<Type, ICacheProvider> cacheProviders = new Dictionary<Type, ICacheProvider>(); private static object syncRoot = new object(); ///<summary> /// Factory method to create or retrieve an implementation of the /// ICacheProvider interface for type <typeparamref name="T"/>. ///</summary> ///<typeparam name="T"> /// The type that this cache provider instance will work with ///</typeparam> ///<returns>An instance of the implementation of ICacheProvider for type ///<typeparamref name="T"/>, as specified by the application /// configuration</returns> public static ICacheProvider<T> GetCacheProvider<T>() { ICacheProvider<T> cacheProvider = null; // Get the Type reference for the type parameter T Type typeOfT = typeof(T); // Lock the access to the cacheProviders dictionary // so multiple threads can work with it lock (syncRoot) { // First check if an instance of the ICacheProvider implementation // already exists in the cacheProviders dictionary for the type T if (cacheProviders.ContainsKey(typeOfT)) cacheProvider = (ICacheProvider<T>)cacheProviders[typeOfT]; else { // There is not already an instance of the ICacheProvider in // cacheProviders for the type T // so we need to create one // Get the Type reference for the application's implementation of // ICacheProvider from the configuration Type cacheProviderType = Type.GetType(CacheProviderConfigurationSection.Current. CacheProviderType); if (cacheProviderType != null) { // Now get a Type reference for the Cache Provider with the // type T generic parameter Type typeOfCacheProviderTypeForT = cacheProviderType.MakeGenericType(new Type[] { typeOfT }); if (typeOfCacheProviderTypeForT != null) { // Create the instance of the Cache Provider and add it to // the cacheProviders dictionary for future use cacheProvider = (ICacheProvider<T>)Activator. CreateInstance(typeOfCacheProviderTypeForT); cacheProviders.Add(typeOfT, cacheProvider); } } } } return cacheProvider; } } } As this code uses Activator.CreateInstance() to create instances of the ICacheProvider<T> implementation, which is a slow process, the factory class maintains a Dictionary of the previously created instances so that a cache provider needs to be created only once for each type. The type of the implementation of ICacheProvider<T> is read from a custom configuration section in the application configuration file, via the CacheProviderConfigurationSection class, which is described below. CacheProviderConfigurationSection Class The implementation of ICacheProvider<T> will be specified in a custom configuration section in the application’s configuration. To handle this create a folder in the CacheSample.Caching project called Configuration, and add a class called CacheProviderConfigurationSection to this folder. This class will extend the System.Configuration.ConfigurationSection class, and will contain a single string property called CacheProviderType. The C# code for this class is shown below: using System; using System.Configuration; namespace CacheSample.Caching.Configuration { internal class CacheProviderConfigurationSection : ConfigurationSection { public static CacheProviderConfigurationSection Current { get { return (CacheProviderConfigurationSection) ConfigurationManager.GetSection("cacheProvider"); } } [ConfigurationProperty("type", IsRequired=true)] public string CacheProviderType { get { return (string)this["type"]; } } } } Adding Data Caching to the Sales Class We now have enough code in place to add caching to the GetSales() method in the CacheSample.BusinessObjects.Sale class, even though we do not yet have an implementation of the ICacheProvider<T> interface. We need to add a reference to the CacheSample.Caching project to CacheSample.BusinessObjects so that we can use the ICacheProvider<T> interface within the GetSales() method. Once the reference is added, we can first create a unique string key based on the method name and the parameter value, so that the same cache key is used for repeated calls to the method with the same parameter values. Then we get an instance of the cache provider for the Sales type, using the CacheProviderFactory, and pass the existing code to retrieve the data from the database as the retrievalMethod delegate in a call to the Cache Provider Fetch() method. The C# code for the modified GetSales() method is shown below: public static IEnumerable<Sale> GetSales(int? highestDayCount) { string cacheKey = string.Format("CacheSample.BusinessObjects.GetSalesWithCache({0})", highestDayCount); return CacheSample.Caching.CacheProviderFactory. GetCacheProvider<Sale>().Fetch(cacheKey, delegate() { List<Sale> sales = new List<Sale>(); SqlParameter highestDayCountParameter = new SqlParameter("@HighestDayCount", SqlDbType.SmallInt); if (highestDayCount.HasValue) highestDayCountParameter.Value = highestDayCount; else highestDayCountParameter.Value = DBNull.Value; string connectionStr = System.Configuration.ConfigurationManager. ConnectionStrings["CacheSample"].ConnectionString; using (SqlConnection sqlConn = new SqlConnection(connectionStr)) using (SqlCommand sqlCmd = sqlConn.CreateCommand()) { sqlCmd.CommandText = "spGetRunningTotals"; sqlCmd.CommandType = CommandType.StoredProcedure; sqlCmd.Parameters.Add(highestDayCountParameter); sqlConn.Open(); using (SqlDataReader dr = sqlCmd.ExecuteReader()) { while (dr.Read()) { Sale newSale = new Sale(); newSale.DayCount = dr.GetInt16(0); newSale.Sales = dr.GetDecimal(1); newSale.RunningTotal = dr.GetDecimal(2); sales.Add(newSale); } } } return sales; }, null, new TimeSpan(0, 10, 0)); } This example passes the code to retrieve the Sales data from the database to the Cache Provider as an anonymous method, however it could also be written as a lambda. The main advantage of using an anonymous function (method or lambda) is that the code inside the anonymous function can access the parameters passed to the GetSales() method. Finally the absolute expiry is set to null, and the relative expiry set to 10 minutes, to indicate that the cache entry should be removed 10 minutes after the last request for the data. As the ICacheProvider<T> has a Fetch() method that returns IEnumerable<T>, we can simply return the results of the Fetch() method to the caller of the GetSales() method. This should be all that is needed for the GetSales() method to now retrieve data from a cache after the first time the data has be retrieved from the database. Implementing a ASP.NET Cache Provider The final step is to actually implement the ICacheProvider<T> interface, and add the implementation details to the web.config file for the dependency injection. The cache provider implementation needs to have access to System.Web. Therefore it could be placed in the CacheSample.UI project, or in its own project that has a reference to System.Web. Implementing the Cache Provider in a separate project is my favoured approach. Create a new project inside the solution called CacheSample.CacheProvider, and add references to System.Web and CacheSample.Caching to this project. Add a class to the project called AspNetCacheProvider. Make the class a generic class by adding the generic parameter <T> and indicate that the class implements ICacheProvider<T>. The C# code for the AspNetCacheProvider class is shown below: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Caching; using CacheSample.Caching; namespace CacheSample.CacheProvider { public class AspNetCacheProvider<T> : ICacheProvider<T> { #region ICacheProvider<T> Members public T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) { return FetchAndCache<T>(key, retrieveData, absoluteExpiry, relativeExpiry); } public IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) { return FetchAndCache<IEnumerable<T>>(key, retrieveData, absoluteExpiry, relativeExpiry); } #endregion #region Helper Methods private U FetchAndCache<U>(string key, Func<U> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) { U value; if (!TryGetValue<U>(key, out value)) { value = retrieveData(); if (!absoluteExpiry.HasValue) absoluteExpiry = Cache.NoAbsoluteExpiration; if (!relativeExpiry.HasValue) relativeExpiry = Cache.NoSlidingExpiration; HttpContext.Current.Cache.Insert(key, value, null, absoluteExpiry.Value, relativeExpiry.Value); } return value; } private bool TryGetValue<U>(string key, out U value) { object cachedValue = HttpContext.Current.Cache.Get(key); if (cachedValue == null) { value = default(U); return false; } else { try { value = (U)cachedValue; return true; } catch { value = default(U); return false; } } } #endregion } } The two interface Fetch() methods call a private method called FetchAndCache(). This method first checks for a element in the HttpContext.Current.Cache with the specified cache key, and if so tries to cast this to the specified type (either T or IEnumerable<T>). If the cached element is found, the FetchAndCache() method simply returns it. If it is not found in the cache, the method calls the retrievalMethod delegate to get the data from the data source, and then adds this to the HttpContext.Current.Cache. The final step is to add the AspNetCacheProvider class to the relevant custom configuration section in the CacheSample.UI.Web.Config file. To do this there needs to be a <configSections> element added as the first element in <configuration>. This will match a custom section called <cacheProvider> with the CacheProviderConfigurationSection. Then we add a <cacheProvider> element, with a type property set to the fully qualified assembly name of the AspNetCacheProvider class, as shown below: <?xmlversion="1.0"?> <configuration> <configSections> <sectionname="cacheProvider" type="CacheSample.Base.Configuration.CacheProviderConfigurationSection, CacheSample.Base" /> </configSections> <connectionStrings> <addname="CacheSample" connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;Initial Catalog=CacheSample" providerName="System.Data.SqlClient" /> </connectionStrings> <cacheProvidertype="CacheSample.CacheProvider.AspNetCacheProvider`1, CacheSample.CacheProvider, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"> </cacheProvider> <system.web> <compilationdebug="true"targetFramework="4.0" /> </system.web> </configuration> One point to note is that the fully qualified assembly name of the AspNetCacheProvider class includes the notation `1 after the class name, which indicates that it is a generic class with a single generic type parameter. The CacheSample.UI project needs to have references added to CacheSample.Caching and CacheSample.CacheProvider so that the actual application is aware of the relevant cache provider implementation. Conclusion After implementing this solution, you should have a working cache provider mechanism, that will allow the middle and data access layers to implement caching support when retrieving data, without any knowledge of the actually caching implementation. If the UI is not ASP.NET based, if for example it is Winforms or WPF, the implementation of ICacheProvider<T> would be written around whatever technology is available. It could even be a standalone caching system that takes full responsibility for adding and removing items from a global store. The next part of this article will show how this caching mechanism may be extended to provide support for cache dependencies, such as the System.Web.Caching.SqlCacheDependency. Another possible extension would be to cache the cache provider implementations instead of storing them in a static Dictionary in the CacheProviderFactory. This would prevent a build up of seldom used cache providers in the application memory, as they could be removed from the cache if not used often enough, although in reality there are probably unlikely to be vast numbers of cache provider implementation instances, as most applications do not have a massive number of business object or model types.

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