Search Results

Search found 50247 results on 2010 pages for 'base class'.

Page 618/2010 | < Previous Page | 614 615 616 617 618 619 620 621 622 623 624 625  | Next Page >

  • Eclipse vs. Aptana

    - by RPK
    I know that Eclipse is a universal IDE and variety of plugins are available to scale it. What is the difference between: The original Eclipse IDE, Aptana and NetBeans. I looked into Wikipedia and came to know that the latter two originate from the main Eclipse. For Aptana specially, what was the need to reproduce a new variant that resembles too much with its base IDE? If your preferred choice is Eclipse itself, what makes it unique as compared to the other two.

    Read the article

  • Formation Actuate BIRT gratuite le 11 juin à Paris, pour apprendre à faire des rapports avec BIRT Open Source et BIRT iHub

    Il s'agit d'une journée de formation gratuite avec des démos et des ateliers pour apprendre à faire des rapports interactifs, Ad Hoc, OLAP en mémoire, dashboards, mashboards avec BIRT Open Source et BIRT iHub. BIRT (Business Intelligence and Reporting Tools) est un projet open source de la fondation Eclipse, basé sur la technologie Java, d'Informatique décisionnelle. La solution s'intègre avec votre application Java EE pour produire des rapports interactifs.Cette journée de formation est l'occasion...

    Read the article

  • Workflow with Flash Pro CS6 and FlashDevelop: Using fla and swc to store assets

    - by Arthur Wulf White
    I am using this tutorial: http://www.flashdevelop.org/wikidocs/index.php?title=AS3:FlexAndFlashCS3Workflow In the past older versions of Flash Pro I was able to complete these steps: right-click on the symbol in the Library panel, select "Linkage..." dialog, check "Export for ActionScript" and fill in the symbol name (ie. MySymbol_design or assets.MySymbol_design), do not change the base class (ie. flash.display.MovieClip). Right now, I am stuck at that part. Any hints? What I wish to do is: Use fla for the artist to store assets. Publish to swc Extract the assets in FlashDevelop by creating an instance of their class. ... How is this done in CS6? To clear things up, this is what I see when I right click a Flash symbol:

    Read the article

  • Strategies to Defeat Memory Editors for Cheating - Desktop Games

    - by ashes999
    I'm assuming we're talking about desktop games -- something the player downloads and runs on their local computer. Many are the memory editors that allow you to detect and freeze values, like your player's health. How do you prevent cheating via memory-modifiation? What strategies are effective to combat this kind of cheating? For reference, I know that players can: - Search for something by value or range - Search for something that changed value - Set memory values - Freeze memory values I'm looking for some good ones. Two I use that are mediocre are: Displaying values as a percentage instead of the number (eg. 46/50 = 92% health) A low-level class that holds values in an array and moves them with each change. (For example, instead of an int, I have a class that's an array of ints, and whenever the value changes, I use a different, randomly-chosen array item to hold the value)

    Read the article

  • Silverlight Training Montreal in January 2011

    - by pluginbaby
    Start the new year with an awesome Silverlight training! The Silverlight Tour has one more class in Montreal, and provide top Silverlight 4 content!!! >> This course will be taught in French * << What: Silverlight training When: January 17-20 (4 days) Where: Montreal, Qc Registration/info: http://www.runatserver.com/SilverlightTraining.aspx Also note that we offer a free license of Telerik's RadControls for Silverlight to every attendee ($999 value)!! For more information on RadControls, visit: http://www.telerik.com/products/silverlight.aspx.  * We do english class as well… check our website!

    Read the article

  • Sort method versus OrderBy LINQ extension method

    - by nmarun
    I have a class Product with an Id and a Name as properties. There are multiple ways of getting a list of products to display in sorted/ordered fashion, say, by the Name of the product. The two I’m concerned about here are the Sort and the OrderBy extension method through LINQ and the difference between them. 1: public class Product 2: { 3: public int Id { get; set; } 4: public string Name { get; set; } 5: } Below is the list of products that I’ll be using and is defined somewhere in the Program.cs...(read more)

    Read the article

  • Beware of const members

    - by nmarun
    I happened to learn a new thing about const today and how one needs to be careful with its usage. Let’s say I have a third-party assembly ‘ConstVsReadonlyLib’ with a class named ConstSideEffect.cs: 1: public class ConstSideEffect 2: { 3: public static readonly int StartValue = 10; 4: public const int EndValue = 20; 5: } In my project, I reference the above assembly as follows: 1: static void Main(string[] args) 2: { 3: for (int i = ConstSideEffect.StartValue; i < ConstSideEffect.EndValue; i++) 4: { 5: Console.WriteLine(i); 6: } 7: Console.ReadLine(); 8: } You’ll see values 10 through 19 as expected. Now, let’s say I receive a new version of the ConstVsReadonlyLib. 1: public class ConstSideEffect 2: { 3: public static readonly int StartValue = 5; 4: public const int EndValue = 30; 5: } If I just drop this new assembly in the bin folder and run the application, without rebuilding my console application, my thinking was that the output would be from 5 to 29. Of course I was wrong… if not you’d not be reading this blog. The actual output is from 5 through 19. The reason is due to the behavior of const and readonly members. To begin with, const is the compile-time constant and readonly is a runtime constant. Next, when you compile the code, a compile-time constant member is replaced with the value of the constant in the code. But, the IL generated when you reference a read-only constant, references the readonly variable, not its value. So, the IL version of the Main method, after compilation actually looks something like: 1: static void Main(string[] args) 2: { 3: for (int i = ConstSideEffect.StartValue; i < 20; i++) 4: { 5: Console.WriteLine(i); 6: } 7: Console.ReadLine(); 8: } I’m no expert with this IL thingi, but when I look at the disassembled code of the exe file (using IL Disassembler), I see the following: I see our readonly member still being referenced by the variable name (ConstVsReadonlyLib.ConstSideEffect::StartValue) in line 0001. Then there’s the Console.WriteLine in line 000b and finally, see the value of 20 in line 0017. This, I’m pretty sure is our const member being replaced by its value which marks the upper bound of the ‘for’ loop. Now you know why the output was from 5 through 19. This definitely is a side-effect of having const members and one needs to be aware of it. While we’re here, I’d like to add a few other points about const and readonly members: const is slightly faster, but is less flexible readonly cannot be declared within a method scope const can be used only on primitive types (numbers and strings) Just wanted to share this before going to bed!

    Read the article

  • How to activate subwoofer in Inspiron 17r?

    - by alfC
    I have a Dell Inspiron 17r, after a fresh install of 12.10, the subwoofer seems to be not utilized. No sound comes from it and in the Sound Control Panel the settings appear grayed out (see screenshot). How can I activate the subwoofer? I tried adding the line options snd-hda-intel model=dell in the file /etc/modprobe.d/alsa-base.conf and enable-lfe-remixing = yes default-sample-channels = 3 in the file /etc/pulse/daemon.conf, but still doesn't work.

    Read the article

  • FIX: A .NET Framework 2.0-based application that uses Remoting objects crashes and closes unexpected

    982318 ... FIX: A .NET Framework 2.0-based application that uses Remoting objects crashes and closes unexpectedlyThis RSS feed provided by kbAlerz.com.Visit kbAlertz.com to subscribe. It's 100% free and you'll be able to recieve e-mail or RSS updates for the technologies you pick from the Microsoft Knowledge Base....Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

    Read the article

  • How to deal with different programming styles in a team?

    - by user3287
    We have a small dev team (only 3 developers) and we recently got a new team member. While he is a smart coder, his coding style is completely different from ours. Our existing code base contains mostly readable, clean and maintainable code, but the new team member is quickly changing many files, introducing ugly hacks and shortcuts, using defines all over the place, adding functions in the wrong places, etc. My question is if others have experienced such a situation before, and if anyone has tips on how to talk to him.

    Read the article

  • Matrix multiplication - Scene Graphs

    - by bgarate
    I wrote a MatrixStack class in C# to use in a SceneGraph. So, to get the world matrix for an object I am suposed to use: WorldMatrix = ParentWorld * LocalTransform But, in fact, it only works as expected when I do the other way: WorldMatrix = LocalTransform * ParentWorld Mi code is: public class MatrixStack { Stack<Matrix> stack = new Stack<Matrix>(); Matrix result = Matrix.Identity; public void PushMatrix(Matrix matrix) { stack.Push(matrix); result = matrix * result; } public Matrix PopMatrix() { result = Matrix.Invert(stack.Peek()) * result; return stack.Pop(); } public Matrix Result { get { return result; } } public void Clear() { stack.Clear(); result = Matrix.Identity; } } Why it works this way and not the other? Thanks!

    Read the article

  • CVE-2014-0591 Buffer Errors vulnerability in Bind

    - by Ritwik Ghoshal
    CVE DescriptionCVSSv2 Base ScoreComponentProduct and Resolution CVE-2014-0591 Buffer Errors vulnerability 2.6 Bind Solaris 10 SPARC: 119783-28 X86: 119784-28 Solaris 11.1 11.1.16.5.0 Solaris 9 SPARC: 112837-30 X86: 114265-29 Please Note: The patches mentioned above will upgrade Bind to 9.6-ESV-R10-P2. This notification describes vulnerabilities fixed in third-party components that are included in Oracle's product distributions.Information about vulnerabilities affecting Oracle products can be found on Oracle Critical Patch Updates and Security Alerts page.

    Read the article

  • ASP.NET MVC 2 from Scratch &ndash; Part 1 Listing Data from Database

    - by Max
    Part 1 - Listing Data from Database: Let us now learn ASP.NET MVC 2 from Scratch by actually developing a front end website for the Chinook database, which is an alternative to the traditional Northwind database. You can get the Chinook database from here. As always the best way to learn something is by working on it and doing something. The Chinook database has the following schema, a quick look will help us implementing the application in a efficient way. Let us first implement a grid view table with the list of Employees with some details, this table also has the Details, Edit and Delete buttons on it to do some operations. This is series of post will concentrate on creating a simple CRUD front end for Chinook DB using ASP.NET MVC 2. In this post, we will look at listing all the possible Employees in the database in a tabular format, from which, we can then edit and delete them as required. In this post, we will concentrate on setting up our environment and then just designing a page to show a tabular information from the database. We need to first setup the SQL Server database, you can download the required version and then set it up in your localhost. Then we need to add the LINQ to SQL Classes required for us to enable interaction with our database. Now after you do the above step, just use your Server Explorer in VS 2010 to actually navigate to the database, expand the tables node and then drag drop all the tables onto the Object Relational Designer space and you go you will have the tables visualized as classes. As simple as that. Now for the purpose of displaying the data from Employee in a table, we will show only the EmployeeID, Firstname and lastname. So let us create a class to hold this information. So let us add a new class called EmployeeList to the ViewModels. We will send this data model to the View and this can be displayed in the page. public class EmployeeList { public int EmployeeID { get; set; } public string Firstname { get; set; } public string Lastname { get; set; } public EmployeeList(int empID, string fname, string lname) { this.EmployeeID = empID; this.Firstname = fname; this.Lastname = lname; } } Ok now we have got the backend ready. Let us now look at the front end view now. We will first create a master called Site.Master and reuse it across the site. The Site.Master content will be <%@ Master Language="C#" AutoEventWireup="true" CodeBehind="Site.Master.cs" Inherits="ChinookMvcSample.Views.Shared.Site" %>   <!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 id="Head1" runat="server"> <title></title> <style type="text/css"> html { background-color: gray; } .content { width: 880px; position: relative; background-color: #ffffff; min-width: 880px; min-height: 800px; float: inherit; text-align: justify; } </style> <script src="../../Scripts/jquery-1.4.1.min.js" type="text/javascript"></script> <asp:ContentPlaceHolder ID="head" runat="server"> </asp:ContentPlaceHolder> </head> <body> <center> <h1> My Website</h1> <div class="content"> <asp:ContentPlaceHolder ID="body" runat="server"> </asp:ContentPlaceHolder> </div> </center> </body> </html> The backend Site.Master.cs does not contain anything. In the actual Index.aspx view, we add the code to simply iterate through the collection of EmployeeList that was sent to the View via the Controller. So in the top of the Index.aspx view, we have this inherits which says Inherits="System.Web.Mvc.ViewPage<IEnumerable<ChinookMvcSample.ViewModels.EmployeeList>>" In this above line, we dictate that the page is consuming a IEnumerable collection of EmployeeList. So once we specify this and compile the project. Then in our Index.aspx page, we can consume the EmployeeList object and access all its methods and properties. <table class="styled" cellpadding="3" border="0" cellspacing="0"> <tr> <th colspan="3"> </th> <th> First Name </th> <th> Last Name </th> </tr> <% foreach (var item in Model) { %> <tr> <td align="center"> <%: Html.ActionLink("Edit", "Edit", new { id = item.EmployeeID }, new { id = "links" })%> </td> <td align="center"> <%: Html.ActionLink("Details", "Details", new { id = item.EmployeeID }, new { id = "links" })%> </td> <td align="center"> <%: Html.ActionLink("Delete", "Delete", new { id = item.EmployeeID }, new { id = "links" })%> </td> <td> <%: item.Firstname %> </td> <td> <%: item.Lastname %> </td> </tr> <% } %> <tr> <td colspan="5"> <%: Html.ActionLink("Create New", "Create") %> </td> </tr> </table> The Html.ActionLink is a Html Helper to a create a hyperlink in the page, in the one we have used, the first parameter is the text that is to be used for the hyperlink, second one is the action name, third one is the parameter to be passed, last one is the attributes to be added while the hyperlink is rendered in the page. Here we are adding the id=”links” to the hyperlinks that is created in the page. In the index.aspx page, we add some jQuery stuff add alternate row colours and highlight colours for rows on mouse over. Now the Controller that handles the requests and directs the request to the right view. For the index view, the controller would be public ActionResult Index() { //var Employees = from e in data.Employees select new EmployeeList(e.EmployeeId,e.FirstName,e.LastName); //return View(Employees.ToList()); return View(_data.Employees.Select(p => new EmployeeList(p.EmployeeId, p.FirstName, p.LastName))); } Let us also write a unit test using NUnit for the above, just testing EmployeeController’s Index. DataClasses1DataContext _data; public EmployeeControllerTest() { _data = new DataClasses1DataContext("Data Source=(local);Initial Catalog=Chinook;Integrated Security=True"); }   [Test] public void TestEmployeeIndex() { var e = new EmployeeController(_data); var result = e.Index() as ViewResult; var employeeList = result.ViewData.Model; Assert.IsNotNull(employeeList, "Result is null."); } In the first EmployeeControllerTest constructor, we set the data context to be used while running the tests. And then in the actual test, We just ensure that the View results returned by Index is not null. Here is the zip of the entire solution files until this point. Let me know if you have any doubts or clarifications. Cheers! Have a nice day.

    Read the article

  • Help with "Cannot find ContentTypeReader BB.HeightMapInfoReader, BB, Version=1.0.0.0, Culture=neutral." needed

    - by rFactor
    Hi, I have this irritating problem in XNA that I have spent my Saturday with: Cannot find ContentTypeReader BB.HeightMapInfoReader, BB, Version=1.0.0.0, Culture=neutral. It throws me that when I do (within the game assembly's Renderer.cs class): this.terrain = this.game.Content.Load<Model>("heightmap"); There is a heightmap.bmp and I don't think there's anything wrong with it, because I used it in a previous version which I switched to this new better system. So, I have a GeneratedGeometryPipeline assembly that has these classes: HeightMapInfoContent, HeightMapInfoWriter, TerrainProcessor. The GeneratedGeometryPipeline assembly does not reference any other assemblies under the solution. Then I have the game assembly that neither references any other solution assemblies and has these classes: HeightMapInfo, HeightMapInfoReader. All game assembly classes are under namespace BB and the GeneratedGeometryPipeline classes are under the namespace GeneratedGeometryPipeline. I do not understand why it does not find it. Here's some code from the GeneratedGeometryPipeline.HeightMapInfoWriter: /// <summary> /// A TypeWriter for HeightMapInfo, which tells the content pipeline how to save the /// data in HeightMapInfo. This class should match HeightMapInfoReader: whatever the /// writer writes, the reader should read. /// </summary> [ContentTypeWriter] public class HeightMapInfoWriter : ContentTypeWriter<HeightMapInfoContent> { protected override void Write(ContentWriter output, HeightMapInfoContent value) { output.Write(value.TerrainScale); output.Write(value.Height.GetLength(0)); output.Write(value.Height.GetLength(1)); foreach (float height in value.Height) { output.Write(height); } foreach (Vector3 normal in value.Normals) { output.Write(normal); } } /// <summary> /// Tells the content pipeline what CLR type the /// data will be loaded into at runtime. /// </summary> public override string GetRuntimeType(TargetPlatform targetPlatform) { return "BB.HeightMapInfo, BB, Version=1.0.0.0, Culture=neutral"; } /// <summary> /// Tells the content pipeline what worker type /// will be used to load the data. /// </summary> public override string GetRuntimeReader(TargetPlatform targetPlatform) { return "BB.HeightMapInfoReader, BB, Version=1.0.0.0, Culture=neutral"; } } Can someone help me out?

    Read the article

  • managing information/functionality on shared common project classes

    - by ilansch
    In my company, we have a common solution the contains common projects (2 projects so far, one for .net 3.5 and one for .net 4.5). My main problem is that during time, a lot of code is added, for example hosting a process as windows service is a class called ServiceManagement, But no one but the developer knows it, and if someone wants to use this shared class, he does not know it exist. So i am looking for a way to document and manage all the classes with tags, a 3rd party util/web util, that i can search for tags and maybe find common classes that i can use (if we keep all our code well-documented). Does anyone familiar with sort of tools ?

    Read the article

  • Why is Spritebatch drawing my Textures out of order?

    - by Andrew
    I just started working with XNA Studio after programming 2D games in java. Because of this, I have absolutely no experience with Spritebatch and sprite sorting. In java, I could just layer the images by calling the draw methods in order. For a while, my Spritebatch was working fine in deferred sorting mode, but when I made a change to one of my textures, it suddenly started drawing them out of order. I have searched for a solution to this problem, but nothing seems to work. I have tried adding layer depths to the sprites and changing the sort mode to BackToFront or FrontToBack or even immediate, but nothing seems to work. Here is my drawing code: protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.Gray); Game1.spriteBatch.Begin(SpriteSortMode.Deferred, BlendState.AlphaBlend, SamplerState.PointClamp, null, null); for (int x = 0; x < 5; x++) { for (int y = 0; y < 5; y++) { region[x, y].draw(((float)w / aw)); // Draws the Tile-Based background } } player.draw(spriteBatch, ((float)w / aw));//draws the character (This method is where the problem occurs) enemy.draw(spriteBatch, (float)w/aw); // draws a basic enemy Game1.spriteBatch.End(); base.Draw(gameTime); } player.draw method: public void draw(SpriteBatch sb, float ratio){ //draws the player base (The character without hair or equipment) sb.Draw(playerbase[0], new Rectangle((int)(pos.X - (24 * ratio)), (int)(pos.Y - (48 * ratio)), (int)(48 * ratio), (int)(48 * ratio)), new Rectangle(orientation * 48, animFrame * 48, 48, 48), Color.White,0,Vector2.Zero,SpriteEffects.None,0); //draws the player's hair sb.Draw(playerbase[3], new Rectangle((int)(pos.X - (24 * ratio)), (int)(pos.Y - (48 * ratio)), (int)(48 * ratio), (int)(48 * ratio)), new Rectangle(orientation * 48, animFrame * 48, 48, 48), Color.White, 0, Vector2.Zero, SpriteEffects.None, 0); //draws the player's shirt sb.Draw(equipment[0], new Rectangle((int)(pos.X - (24 * ratio)), (int)(pos.Y - (48 * ratio)), (int)(48 * ratio), (int)(48 * ratio)), new Rectangle(orientation * 48, animFrame * 48, 48, 48), Color.White, 0, Vector2.Zero, SpriteEffects.None, 0); //draws the player's pants sb.Draw(equipment[1], new Rectangle((int)(pos.X - (24 * ratio)), (int)(pos.Y - (48 * ratio)), (int)(48 * ratio), (int)(48 * ratio)), new Rectangle(orientation * 48, animFrame * 48, 48, 48), Color.White, 0, Vector2.Zero, SpriteEffects.None, 0); //draws the player's shoes sb.Draw(equipment[2], new Rectangle((int)(pos.X - (24 * ratio)), (int)(pos.Y - (48 * ratio)), (int)(48 * ratio), (int)(48 * ratio)), new Rectangle(orientation * 48, animFrame * 48, 48, 48), Color.White, 0, Vector2.Zero, SpriteEffects.None, 0); } the game has a top-down perspective much like the early legend of zelda games. It draws sections of the texture depending on which direction the character is facing and the animation frame. However, instead of drawing the character in the order the draw methods are called, it ends up drawing the character out of order. Please help me with this problem.

    Read the article

  • Controllers in CodeIgniter

    - by Dileep Dil
    I little bit new to the CodeIgniter framework and this is my first project with this framework. During a chat on StackOverflow somebody said that we need to make controllers tiny as possible. Currently I have a default controller named home with 1332 lines of codes (and increasing) and a model named Profunction with 1356 lines of codes (and increasing). The controller class have about 46 functions on it and also with model class. I thought that Codeigniter can handle large Controllers or Models well, is there any problem/performance issue/security issues regarding this?

    Read the article

  • Android viole-t-il la licence du noyau Linux ? Des experts évoquent un problème encore plus complexe que le conflit avec Oracle sur Java

    Android viole-t-il la licence du noyau Linux ? Des experts avertissent contre un problème qui pourrait être encore plus complexe que le conflit avec Oracle sur Java Comme si le procès intenté par Oracle ne suffisait pas, des experts en propriété intellectuelle se sont penchés sur l'utilisation par l'OS mobile de Google de la base de code sous licence GPL Version 2 du noyau Linux. Ils mettent en garde contre une problématique encore plus complexe pour Google que le bras de fer qui l'oppose à Or...

    Read the article

  • "Building on a Solid Foundation"

    Designing the right IT infrastructure is a critical part of ensuring application availability and performance. See how companies rely on an Oracle grid infrastructure—including Oracle Database and Oracle Real Application Clusters—to provide a solid yet flexible base for their applications.

    Read the article

  • Making my own custom Ubuntu

    - by Benny
    I was wondering, is it possible to make my own customized version of Linux based on Ubuntu 10.10 ? I am thinking of calling it something different but I was wondering besides making a custom Live CD I am talking about an Linux that people can install on there computers using Ubuntu installation method. I want to base it on something other than GNOME but be able to install it latter on. Thanks in advance, Benny

    Read the article

  • LINQ: Enhancing Distinct With The SelectorEqualityComparer

    - by Paulo Morgado
    On my last post, I introduced the PredicateEqualityComparer and a Distinct extension method that receives a predicate to internally create a PredicateEqualityComparer to filter elements. Using the predicate, greatly improves readability, conciseness and expressiveness of the queries, but it can be even better. Most of the times, we don’t want to provide a comparison method but just to extract the comaprison key for the elements. So, I developed a SelectorEqualityComparer that takes a method that extracts the key value for each element. Something like this: public class SelectorEqualityComparer<TSource, Tkey> : EqualityComparer<TSource> where Tkey : IEquatable<Tkey> { private Func<TSource, Tkey> selector; public SelectorEqualityComparer(Func<TSource, Tkey> selector) : base() { this.selector = selector; } public override bool Equals(TSource x, TSource y) { Tkey xKey = this.GetKey(x); Tkey yKey = this.GetKey(y); if (xKey != null) { return ((yKey != null) && xKey.Equals(yKey)); } return (yKey == null); } public override int GetHashCode(TSource obj) { Tkey key = this.GetKey(obj); return (key == null) ? 0 : key.GetHashCode(); } public override bool Equals(object obj) { SelectorEqualityComparer<TSource, Tkey> comparer = obj as SelectorEqualityComparer<TSource, Tkey>; return (comparer != null); } public override int GetHashCode() { return base.GetType().Name.GetHashCode(); } private Tkey GetKey(TSource obj) { return (obj == null) ? (Tkey)(object)null : this.selector(obj); } } Now I can write code like this: .Distinct(new SelectorEqualityComparer<Source, Key>(x => x.Field)) And, for improved readability, conciseness and expressiveness and support for anonymous types the corresponding Distinct extension method: public static IEnumerable<TSource> Distinct<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> selector) where TKey : IEquatable<TKey> { return source.Distinct(new SelectorEqualityComparer<TSource, TKey>(selector)); } And the query is now written like this: .Distinct(x => x.Field) For most usages, it’s simpler than using a predicate.

    Read the article

  • A Look Inside JSR 360 - CLDC 8

    - by Roger Brinkley
    If you didn't notice during JavaOne the Java Micro Edition took a major step forward in its consolidation with Java Standard Edition when JSR 360 was proposed to the JCP community. Over the last couple of years there has been a focus to move Java ME back in line with it's big brother Java SE. We see evidence of this in JCP itself which just recently merged the ME and SE/EE Executive Committees into a single Java Executive Committee. But just before that occurred JSR 360 was proposed and approved for development on October 29. So let's take a look at what changes are now being proposed. In a way JSR 360 is returning back to the original roots of Java ME when it was first introduced. It was indeed a subset of the JDK 4 language, but as Java progressed many of the language changes were not implemented in the Java ME. Back then the tradeoff was still a functionality, footprint trade off but the major market was feature phones. Today the market has changed and CLDC, while it will still target feature phones, will have it primary emphasis on embedded devices like wireless modules, smart meters, health care monitoring and other M2M devices. The major changes will come in three areas: language feature changes, library changes, and consolidating the Generic Connection Framework.  There have been three Java SE versions that have been implemented since JavaME was first developed so the language feature changes can be divided into changes that came in JDK 5 and those in JDK 7, which mostly consist of the project Coin changes. There were no language changes in JDK 6 but the changes from JDK 5 are: Assertions - Assertions enable you to test your assumptions about your program. For example, if you write a method that calculates the speed of a particle, you might assert that the calculated speed is less than the speed of light. In the example code below if the interval isn't between 0 and and 1,00 the an error of "Invalid value?" would be thrown. private void setInterval(int interval) { assert interval > 0 && interval <= 1000 : "Invalid value?" } Generics - Generics add stability to your code by making more of your bugs detectable at compile time. Code that uses generics has many benefits over non-generic code with: Stronger type checks at compile time. Elimination of casts. Enabling programming to implement generic algorithms. Enhanced for Loop - the enhanced for loop allows you to iterate through a collection without having to create an Iterator or without having to calculate beginning and end conditions for a counter variable. The enhanced for loop is the easiest of the new features to immediately incorporate in your code. In this tip you will see how the enhanced for loop replaces more traditional ways of sequentially accessing elements in a collection. void processList(Vector<string> list) { for (String item : list) { ... Autoboxing/Unboxing - This facility eliminates the drudgery of manual conversion between primitive types, such as int and wrapper types, such as Integer.  Hashtable<Integer, string=""> data = new Hashtable<>(); void add(int id, String value) { data.put(id, value); } Enumeration - Prior to JDK 5 enumerations were not typesafe, had no namespace, were brittle because they were compile time constants, and provided no informative print values. JDK 5 added support for enumerated types as a full-fledged class (dubbed an enum type). In addition to solving all the problems mentioned above, it allows you to add arbitrary methods and fields to an enum type, to implement arbitrary interfaces, and more. Enum types provide high-quality implementations of all the Object methods. They are Comparable and Serializable, and the serial form is designed to withstand arbitrary changes in the enum type. enum Season {WINTER, SPRING, SUMMER, FALL}; } private Season season; void setSeason(Season newSeason) { season = newSeason; } Varargs - Varargs eliminates the need for manually boxing up argument lists into an array when invoking methods that accept variable-length argument lists. The three periods after the final parameter's type indicate that the final argument may be passed as an array or as a sequence of arguments. Varargs can be used only in the final argument position. void warning(String format, String... parameters) { .. for(String p : parameters) { ...process(p);... } ... } Static Imports -The static import construct allows unqualified access to static members without inheriting from the type containing the static members. Instead, the program imports the members either individually or en masse. Once the static members have been imported, they may be used without qualification. The static import declaration is analogous to the normal import declaration. Where the normal import declaration imports classes from packages, allowing them to be used without package qualification, the static import declaration imports static members from classes, allowing them to be used without class qualification. import static data.Constants.RATIO; ... double r = Math.cos(RATIO * theta); Annotations - Annotations provide data about a program that is not part of the program itself. They have no direct effect on the operation of the code they annotate. There are a number of uses for annotations including information for the compiler, compiler-time and deployment-time processing, and run-time processing. They can be applied to a program's declarations of classes, fields, methods, and other program elements. @Deprecated public void clear(); The language changes from JDK 7 are little more familiar as they are mostly the changes from Project Coin: String in switch - Hey it only took us 18 years but the String class can be used in the expression of a switch statement. Fortunately for us it won't take that long for JavaME to adopt it. switch (arg) { case "-data": ... case "-out": ... Binary integral literals and underscores in numeric literals - Largely for readability, the integral types (byte, short, int, and long) can also be expressed using the binary number system. and any number of underscore characters (_) can appear anywhere between digits in a numerical literal. byte flags = 0b01001111; long mask = 0xfff0_ff08_4fff_0fffl; Multi-catch and more precise rethrow - A single catch block can handle more than one type of exception. In addition, the compiler performs more precise analysis of rethrown exceptions than earlier releases of Java SE. This enables you to specify more specific exception types in the throws clause of a method declaration. catch (IOException | InterruptedException ex) { logger.log(ex); throw ex; } Type Inference for Generic Instance Creation - Otherwise known as the diamond operator, the type arguments required to invoke the constructor of a generic class can be replaced with an empty set of type parameters (<>) as long as the compiler can infer the type arguments from the context.  map = new Hashtable<>(); Try-with-resource statement - The try-with-resources statement is a try statement that declares one or more resources. A resource is an object that must be closed after the program is finished with it. The try-with-resources statement ensures that each resource is closed at the end of the statement.  try (DataInputStream is = new DataInputStream(...)) { return is.readDouble(); } Simplified varargs method invocation - The Java compiler generates a warning at the declaration site of a varargs method or constructor with a non-reifiable varargs formal parameter. Java SE 7 introduced a compiler option -Xlint:varargs and the annotations @SafeVarargs and @SuppressWarnings({"unchecked", "varargs"}) to supress these warnings. On the library side there are new features that will be added to satisfy the language requirements above and some to improve the currently available set of APIs.  The library changes include: Collections update - New Collection, List, Set and Map, Iterable and Iteratator as well as implementations including Hashtable and Vector. Most of the work is too support generics String - New StringBuilder and CharSequence as well as a Stirng formatter. The javac compiler  now uses the the StringBuilder instead of String Buffer. Since StringBuilder is synchronized there is a performance increase which has necessitated the wahat String constructor works. Comparable interface - The comparable interface works with Collections, making it easier to reuse. Try with resources - Closeable and AutoCloseable Annotations - While support for Annotations is provided it will only be a compile time support. SuppressWarnings, Deprecated, Override NIO - There is a subset of NIO Buffer that have been in use on the of the graphics packages and needs to be pulled in and also support for NIO File IO subset. Platform extensibility via Service Providers (ServiceLoader) - ServiceLoader interface dos late bindings of interface to existing implementations. It helpe to package an interface and behavior of the implementation at a later point in time.Provider classes must have a zero-argument constructor so that they can be instantiated during loading. They are located and instantiated on demand and are identified via a provider-configuration file in the METAINF/services resource directory. This is a mechansim from Java SE. import com.XYZ.ServiceA; ServiceLoader<ServiceA> sl1= new ServiceLoader(ServiceA.class); Resources: META-INF/services/com.XYZ.ServiceA: ServiceAProvider1 ServiceAProvider2 ServiceAProvider3 META-INF/services/ServiceB: ServiceBProvider1 ServiceBProvider2 From JSR - I would rather use this list I think The Generic Connection Framework (GCF) was previously specified in a number of different JSRs including CLDC, MIDP, CDC 1.2, and JSR 197. JSR 360 represents a rare opportunity to consolidated and reintegrate parts that were duplicated in other specifications into a single specification, upgrade the APIs as well provide new functionality. The proposal is to specify a combined GCF specification that can be used with Java ME or Java SE and be backwards compatible with previous implementations. Because of size limitations as well as the complexity of the some features like InvokeDynamic and Unicode 6 will not be included. Additionally, any language or library changes in JDK 8 will be not be included. On the upside, with all the changes being made, backwards compatibility will still be maintained. JSR 360 is a major step forward for Java ME in terms of platform modernization, language alignment, and embedded support. If you're interested in following the progress of this JSR see the JSR's java.net project for details of the email lists, discussions groups.

    Read the article

  • DRY and SRP

    - by Timothy Klenke
    Originally posted on: http://geekswithblogs.net/TimothyK/archive/2014/06/11/dry-and-srp.aspxKent Beck’s XP Simplicity Rules (aka Four Rules of Simple Design) are a prioritized list of rules that when applied to your code generally yield a great design.  As you’ll see from the above link the list has slightly evolved over time.  I find today they are usually listed as: All Tests Pass Don’t Repeat Yourself (DRY) Express Intent Minimalistic These are prioritized.  If your code doesn’t work (rule 1) then everything else is forfeit.  Go back to rule one and get the code working before worrying about anything else. Over the years the community have debated whether the priority of rules 2 and 3 should be reversed.  Some say a little duplication in the code is OK as long as it helps express intent.  I’ve debated it myself.  This recent post got me thinking about this again, hence this post.   I don’t think it is fair to compare “Expressing Intent” against “DRY”.  This is a comparison of apples to oranges.  “Expressing Intent” is a principal of code quality.  “Repeating Yourself” is a code smell.  A code smell is merely an indicator that there might be something wrong with the code.  It takes further investigation to determine if a violation of an underlying principal of code quality has actually occurred. For example “using nouns for method names”, “using verbs for property names”, or “using Booleans for parameters” are all code smells that indicate that code probably isn’t doing a good job at expressing intent.  They are usually very good indicators.  But what principle is the code smell of Duplication pointing to and how good of an indicator is it? Duplication in the code base is bad for a couple reasons.  If you need to make a change and that needs to be made in a number of locations it is difficult to know if you have caught all of them.  This can lead to bugs if/when one of those locations is overlooked.  By refactoring the code to remove all duplication there will be left with only one place to change, thereby eliminating this problem. With most projects the code becomes the single source of truth for a project.  If a production code base is inconsistent with a five year old requirements or design document the production code that people are currently living with is usually declared as the current reality (or truth).  Requirement or design documents at this age in a project life cycle are usually of little value. Although comparing production code to external documentation is usually straight forward, duplication within the code base muddles this declaration of truth.  When code is duplicated small discrepancies will creep in between the two copies over time.  The question then becomes which copy is correct?  As different factions debate how the software should work, trust in the software and the team behind it erodes. The code smell of Duplication points to a violation of the “Single Source of Truth” principle.  Let me define that as: A stakeholder’s requirement for a software change should never cause more than one class to change. Violation of the Single Source of Truth principle will always result in duplication in the code.  However, the inverse is not always true.  Duplication in the code does not necessarily indicate that there is a violation of the Single Source of Truth principle. To illustrate this, let’s look at a retail system where the system will (1) send a transaction to a bank and (2) print a receipt for the customer.  Although these are two separate features of the system, they are closely related.  The reason for printing the receipt is usually to provide an audit trail back to the bank transaction.  Both features use the same data:  amount charged, account number, transaction date, customer name, retail store name, and etcetera.  Because both features use much of the same data, there is likely to be a lot of duplication between them.  This duplication can be removed by making both features use the same data access layer. Then start coming the divergent requirements.  The receipt stakeholder wants a change so that the account number has the last few digits masked out to protect the customer’s privacy.  That can be solve with a small IF statement whilst still eliminating all duplication in the system.  Then the bank wants to take a picture of the customer as well as capture their signature and/or PIN number for enhanced security.  Then the receipt owner wants to pull data from a completely different system to report the customer’s loyalty program point total. After a while you realize that the two stakeholders have somewhat similar, but ultimately different responsibilities.  They have their own reasons for pulling the data access layer in different directions.  Then it dawns on you, the Single Responsibility Principle: There should never be more than one reason for a class to change. In this example we have two stakeholders giving two separate reasons for the data access class to change.  It is clear violation of the Single Responsibility Principle.  That’s a problem because it can often lead the project owner pitting the two stakeholders against each other in a vein attempt to get them to work out a mutual single source of truth.  But that doesn’t exist.  There are two completely valid truths that the developers need to support.  How is this to be supported and honour the Single Responsibility Principle?  The solution is to duplicate the data access layer and let each stakeholder control their own copy. The Single Source of Truth and Single Responsibility Principles are very closely related.  SST tells you when to remove duplication; SRP tells you when to introduce it.  They may seem to be fighting each other, but really they are not.  The key is to clearly identify the different responsibilities (or sources of truth) over a system.  Sometimes there is a single person with that responsibility, other times there are many.  This can be especially difficult if the same person has dual responsibilities.  They might not even realize they are wearing multiple hats. In my opinion Single Source of Truth should be listed as the second rule of simple design with Express Intent at number three.  Investigation of the DRY code smell should yield to the proper application SST, without violating SRP.  When necessary leave duplication in the system and let the class names express the different people that are responsible for controlling them.  Knowing all the people with responsibilities over a system is the higher priority because you’ll need to know this before you can express it.  Although it may be a code smell when there is duplication in the code, it does not necessarily mean that the coder has chosen to be expressive over DRY or that the code is bad.

    Read the article

  • How To Teach Independence

    - by Glenn Nelson
    In my IB Computer Science class I am routinely asked by... pretty much everyone how to do X or implement Y. I'm the only person with any significant programming experience in the class and I do not necessaries mind teaching people about programming but so many of the questions could be simply solved by doing a little investigating. What are some ways I could try to teach my fellow students how to be self-reliant programmers? All I can really think of is being a Google ninja & learning how to use an API.

    Read the article

< Previous Page | 614 615 616 617 618 619 620 621 622 623 624 625  | Next Page >