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• 2D Platformer Collision Handling

  - by defender-zone

  Hello, everyone! I am trying to create a 2D platformer (Mario-type) game and I am some having some issues with handling collisions properly. I am writing this game in C++, using SDL for input, image loading, font loading, etcetera. I am also using OpenGL via the FreeGLUT library in conjunction with SDL to display graphics. My method of collision detection is AABB (Axis-Aligned Bounding Box), which is really all I need to start with. What I need is an easy way to both detect which side the collision occurred on and handle the collisions properly. So, basically, if the player collides with the top of the platform, reposition him to the top; if there is a collision to the sides, reposition the player back to the side of the object; if there is a collision to the bottom, reposition the player under the platform. I have tried many different ways of doing this, such as trying to find the penetration depth and repositioning the player backwards by the penetration depth. Sadly, nothing I've tried seems to work correctly. Player movement ends up being very glitchy and repositions the player when I don't want it to. Part of the reason is probably because I feel like this is something so simple but I'm over-thinking it. If anyone thinks they can help, please take a look at the code below and help me try to improve on this if you can. I would like to refrain from using a library to handle this (as I want to learn on my own) or the something like the SAT (Separating Axis Theorem) if at all possible. Thank you in advance for your help! void world1Level1CollisionDetection() { for(int i; i < blocks; i++) { if (de2dCheckCollision(ball,block[i],0.0f,0.0f)==true) { int up = 0; int left = 0; int right = 0; int down = 0; if(ball.coords[0] < block[i].coords[0] && block[i].coords[0] < ball.coords[2] && ball.coords[2] < block[i].coords[2]) { left = 1; } if(block[i].coords[0] < ball.coords[0] && ball.coords[0] < block[i].coords[2] && block[i].coords[2] < ball.coords[2]) { right = 1; } if(ball.coords[1] < block[i].coords[1] && block[i].coords[1] < ball.coords[3] && ball.coords[3] < block[i].coords[3]) { up = 1; } if(block[i].coords[1] < ball.coords[1] && ball.coords[1] < block[i].coords[3] && block[i].coords[3] < ball.coords[3]) { down = 1; } cout << left << ", " << right << ", " << up << ", " << down << ", " << endl; if (left == 1) { ball.coords[0] = block[i].coords[0] - 16.0f; ball.coords[2] = block[i].coords[0] - 0.0f; } if (right == 1) { ball.coords[0] = block[i].coords[2] + 0.0f; ball.coords[2] = block[i].coords[2] + 16.0f; } if (down == 1) { ball.coords[1] = block[i].coords[3] + 0.0f; ball.coords[3] = block[i].coords[3] + 16.0f; } if (up == 1) { ball.yspeed = 0.0f; ball.gravity = 0.0f; ball.coords[1] = block[i].coords[1] - 16.0f; ball.coords[3] = block[i].coords[1] - 0.0f; } } if (de2dCheckCollision(ball,block[i],0.0f,0.0f)==false) { ball.gravity = -0.5f; } } } To explain what some of this code means: The blocks variable is basically an integer that is storing the amount of blocks, or platforms. I am checking all of the blocks using a for loop, and the number that the loop is currently on is represented by integer i. The coordinate system might seem a little weird, so that's worth explaining. coords[0] represents the x position (left) of the object (where it starts on the x axis). coords[1] represents the y position (top) of the object (where it starts on the y axis). coords[2] represents the width of the object plus coords[0] (right). coords[3] represents the height of the object plus coords[1] (bottom). de2dCheckCollision performs an AABB collision detection. Up is negative y and down is positive y, as it is in most games. Hopefully I have provided enough information for someone to help me successfully. If there is something I left out that might be crucial, let me know and I'll provide the necessary information. Finally, for anyone who can help, providing code would be very helpful and much appreciated. Thank you again for your help!

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• Oracle CRM On Demand Release 24 is Generally Available

  - by Richard Lefebvre

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 We are pleased to announce that Oracle CRM On Demand Release 24 is Generally Available as of October 25, 2013 Get smarter, more productive and the best value with Oracle CRM On Demand Release 24. Oracle CRM On Demand continues to be the most complete Software-as-a-Service (SaaS) CRM solution available. Now, with Release 24, organizations of all types and sizes benefit from actionable insight anywhere, anytime, as well as key enhancements in mobility, embedded social, analytics, integration and extensibility, and ease of use.Next Generation Mobile and Desktop Solutions : Oracle CRM On Demand Release 24 offers a complete set of mobile and desktop solutions that improve productivity by enabling reps to access and update information anywhere, anytime. Capabilities include: Oracle CRM On Demand Disconnected Mobile Sales (DMS) – A disconnected native iPad solution, DMS has been further streamlined mobile sales process by adding Structured Product Messaging to record brand specific call objectives, enhancements in HTML5 eDetailing including message response tracking and improvements in administration and configuration such as more field management options for read only fields, role management and enhanced logging. Oracle CRM On Demand Connected Mobile Sales. This add-on mobile service provides a configurable mobile solution on iOS, BlackBerry and now Android devices. You can access data from CRM On Demand in real time with a rich, native user experience, that is comfortable and familiar to current iOS, BlackBerry and Android users. New features also include Single Sign On to enhance security for mobile users.  Oracle CRM On Demand Desktop: This application centralizes essential CRM information in the familiar Microsoft Outlook environment,increasing user adoption and decreasing training costs. Users can manage CRM data while disconnected, then synchronize bi-directionally when they are back on the network. New in Oracle CRM On Demand Desktop Version 3 is the ability to synchronize by Books of Business, and improved Online Lookup. Mobile Browser Support: The following mobile device browsers are now supported: Apple iPhone, Apple iPad, Windows 8 Tablets, and Google Android. Leverage the Social Enterprise Engaging customers via social channels is rapidly becoming a significant key to enhanced customer experience as it provides proactive customer service, targeted messaging and greater intimacy throughout the entire customer lifecycle. Listening to customers on the social channels can identify a customers’ sphere of influence and the real value they bring to their organization, or the impact they can have on the opportunity. Servicing the customer’s need is the first step towards loyalty to a brand, integrating with social channels allows us to maximize brand affinity and virally expand customer engagements thus increasing revenue. Oracle CRM On Demand is leveraging the Social Enterprise through its integration with Oracle’s Social Relationship Management (SRM) product suite by providing out-of-the-box integration with Social Engagement and Monitoring (SEM), Social Marketing (SM) and Oracle Social Network (OSN). With Oracle CRM On Demand Release 24, users are able to create a service request from a social post via SEM and have leads entered on a SM lead form automatically entered into Oracle CRM On Demand along with the campaign, streamlining the lead qualification process. Get Smarter with Actionable Insight The difference between making good decisions and great decisions depends heavily upon the quality, structure, and availability of information at hand. Oracle CRM On Demand Release 24 expands upon its industry-leading analytics capabilities to provide greater business insight than ever before. New capabilities include flexible permissions on analytics reports folders, allowing for read only access to reports, and additional field and object coverage. Get More Productive with Powerful Tools Oracle CRM On Demand Release 24 introduces a new set of powerful capabilities designed to maximize productivity. A significant new feature for customizing Oracle CRM On Demand is a JavaScript API. The JS API allows customers to add new buttons, suppress existing buttons and even change what happens when a user clicks an existing button. Other usability enhancements, such as personalized related information applets, extended case insensitive search provide users with better, more intuitive, experience. Additional privileges for viewing private activities and notes allow administrators to reassign records as needed, and Custom Object management. Workflow has been added to the Order Item object; and now tasks can be assigned to a relative user, such as an Account Owner, allowing more complex business processes to be automated and adhered to. Get the Best Value Oracle CRM On Demand delivers unprecedented value with the broadest set of capabilities from a single-provider solution, the industry’s lowest total cost of ownership, the most on-demand deployment options, the deepest CRM expertise and experience of any CRM provider, and the most secure CRM in the cloud. With Release 24, Oracle CRM On Demand now includes even more enterprise-grade security, integration, and extensibility features, along with enhanced industry editions to save you time and money. New features include: Business Process Administration: A new privilege has been added that allows administrators to override a Business Process Administration rule.This privilege permits users to edit a locked record, or unlock a record, in the event of a material change that needs to be reflected per corporatepolicy. Additionally, the Products Detailed object has been added to Business Process Administration, enabling record locking and logic to be applied. Expanded Integration: Oracle continues to improve Web Services each release, by adding more object coverage enabling customers and partners to easily integrate with CRM On Demand. Bottom Line Oracle CRM On Demand Release 24 enables organizations to get smarter, get more productive, and get the best value, period. For more information on Oracle CRM On Demand Release 24, please visit oracle.com/crmondemand

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• CodePlex Daily Summary for Saturday, May 10, 2014

  CodePlex Daily Summary for Saturday, May 10, 2014Popular ReleasesTerraMap (Terraria World Map Viewer): TerraMap 1.0.3.14652: Added support for the new Terraria v1.2.4 update. New items, walls, and tiles The setup file will make sure .NET 4 is installed, install TerraMap, create desktop and start menu shortcuts, add a .wld file association, and launch TerraMap. If you prefer the zip file, make sure you have .NET Framework v4.5 installed, then just download and extract the ZIP file, and run TerraMap.exe.R.NET: R.NET 1.5.12: R.NET 1.5.12 is a beta release towards R.NET 1.6. You are encouraged to use 1.5.12 now and give feedback. See the documentation for setup and usage instructions. Main changes for R.NET 1.5.12: The C stack limit was not disabled on Windows. For reasons possibly peculiar to R, this means that non-concurrent access to R from multiple threads was not stable. This is now fixed, with the fix validated with a unit test. Thanks to Odugen, skyguy94, and previously others (evolvedmicrobe, tomasp) fo...CTI Text Encryption: CTI Text Encryption 5.2: Change log: 5.2 - Remove Cut button. - Fixed Reset All button does not reset encrypted text column. - Switch button location between Copy and Paste. - Enable users to use local fonts to display characters of their language correctly. (A font settings file will be saved at the same folder of this program.) 5.1 - Improve encryption process. - Minor UI update. - Version 5.1 is not compatible with older version. 5.0 - Improve encryption algorithm. - Simply inner non-encryption related mec...SEToolbox: SEToolbox 01.029.006 Release 1: Fix to allow keyboard search on load dialog. (type the first few letters of your save) Fixed check for new release. Changed the way ship details are loaded to alleviate load time for worlds with very large ships (100,000+ blocks). Fixed Image importer, was incorrectly listing 'Asteroid' as import option. Minor changes to menus (text and appearance) for clarity and OS consistency. Added in reading of world palette for color dialog editor. WIP on subsystem editor. Can now multiselec...Media Companion: Media Companion MC3.597b: Thank you for being patient, againThere are a number of fixes in place with this release. and some new features added. Most are self explanatory, so check out the options in Preferences. Couple of new Features:* Movie - Allow save Title and Sort Title in Title Case format. * Movie - Allow save fanart.jpg if movie in folder. * TV - display episode source. Get episode source from episode filename. Fixed:* Movie - Added Fill Tags from plot keywords to Batch Rescraper. * Movie - Fixed TMDB s...SimCityPak: SimCityPak 0.3.0.0: Contains several bugfixes, newly identified properties and some UI improvements. Main new features UI overhaul for the main index list: Icons for each different index, including icons for different property files Tooltips for all relevant fields Removed clutter Identified hundreds of additional properties (thanks to MaxisGuillaume) - this should make modding gameplay easierSeal Report: Seal Report 1.4: New Features: Report Designer: New option to convert a Report Source into a Repository Source. Report Designer: New contextual helper menus to select, remove, copy, prompt elements in a model. Web Server: New option to expand sub-folders displayed in the tree view. Web Server: Web Folder Description File can be a .cshtml file to display a MVC View. Views: additional CSS parameters for some DIVs. NVD3 Chart: Some default configuration values have been changed. Issues Addressed:16 ...Magick.NET: Magick.NET 6.8.9.002: Magick.NET linked with ImageMagick 6.8.9.0.VidCoder: 1.5.22 Beta: Added ability to burn SRT subtitles. Updated to HandBrake SVN 6169. Added checks to prevent VidCoder from running with a database version newer than it expects. Tooltips in the Advanced Video panel now trigger on the field labels as well as the fields themselves. Fixed updating preset/profile/tune/level settings on changing video encoder. This should resolve some problems with QSV encoding. Fixed tunes and profiles getting set to blank when switching between x264 and x265. Fixed co...NuGet: NuGet 2.8.2: We will be releasing a 2.8.2 version of our own NuGet packages and the NuGet.exe command-line tool. The 2.8.2 release will not include updated VS or WebMatrix extensions. NuGet.Server.Extensions.dll needs to be used alongside NuGet-Signed.exe to provide the NuGet.exe mirror functionality.DNN CMS Platform: 07.03.00 BETA (Not For Production Use): DNN 7.3 release is focused on performance and we have made a variety of changes to improve the run-time characteristics of the platform. End users will notice faster page response time and administrators will appreciate a more responsive user experience, especially on larger scale web sites. This is a BETA release and is NOT recommended for production use. There is no upgrade path offered from this release to the final DNN 7.3 release. Known Issues - The Telerik RAD Controls for ASP.NET AJA...SmartStore.NET - Free ASP.NET MVC Ecommerce Shopping Cart Solution: SmartStore.NET 2.0.2: SmartStore.NET 2.0.2 is primarily a maintenance release for version 2.0.0, which has been released on April 04 2014. It contains several improvements & important fixes. BugfixesIMPORTANT FIX: Memory leak leads to OutOfMemoryException in application after a while Installation fix: some varchar(MAX) columns get created as varchar(4000). Added a migration to fix the column specs. Installation fix: Setup fails with exception Value cannot be null. Parameter name: stream Bugfix for stock iss...Channel9's Absolute Beginner Series: Windows Phone 8.1: Entire source code for Windows Phone 8.1 Absolute Beginner Series.BIDS Helper: BIDS Helper 1.6.6: This BIDS Helper beta release brings support for SQL Server 2014 and SSDTBI for Visual Studio 2013. (Note that SSDTBI for Visual Studio 2013 is currently unavailable to download from Microsoft. We are releasing BIDS Helper support to help those who downloaded it before it became unavailable, and we will recheck BIDS Helper 2014 is compatible after SSDTBI becomes available to download again.) BIDS Helper 2014 Beta Limitations: SQL Server 2014 support for Biml is still in progress, so this bet...Windows Phone IsoStoreSpy (a cool WP8.1 + WP8 Isolated Storage Explorer): IsoStoreSpy WP8.1 3.0.0.0 (Win8 only): 3.0.0.0 + WP8.1 & WP8 device allowed + Local, Roaming or Temp directory Selector for WindowsRuntime apps + Version number in the title :)CS-Script for Notepad++ (C# intellisense and code execution): Release v1.0.24.0: ShortcutMapping panel now allows direct modification of the shortcuts. Custom updater dropped support for MSI installation but it still allows downloading of MSI http://www.csscript.net/npp/codeplex/non_msi_update.pngProDinner - ASP.NET MVC Sample (EF5, N-Tier, jQuery): 8.2: upgrade to mvc 5 upgrade to ASP.net MVC Awesome 4.0, EF 6.1, latest jcrop, Windsor Castle etc. ability to show/hide the dog using tinymce for the feedback page mobile friendly uiASP.net MVC Awesome - jQuery Ajax Helpers: 4.0: version 4.0 ========================== - added InitPopup, InitPopupForm helpers, open initialized popups using awe.open(name, params) - added Tag or Tags for all helpers, usable in mod code - added popup aweclose, aweresize events - popups have api accessible via .data('api'), with methods open, close and destroy - all popups have .awe-popup class - popups can be grouped using .Group(string), only 1 popup in the same group can exist at the same time - added awebeginload event for...ScreenToGif: Release 1.0: What's new: • Small UI tweaks everywhere. • You can add Text, Subtitles and Title Frames. • Processing the gif now takes less time. • Languages: Spanish, Italian and Tamil added. • Single .exe multi language. • Takes less time to apply blur and pixelated efect. • Restart button. • Language picker. (If the user wants to select a diferent language than the system's) • "Encoding Finished" page with a link to open the file. • GreenScreen unchanged pixels to save kilobytes. • "Check for Updates" t...Touchmote: Touchmote 1.0 beta 11: Changes Support for multiple monitor setup Additional settings for analog sticks More reliable pairing Bug fixes and improvementsNew ProjectsADO: copy rightAntilop: Antilop is a professionnal C# business and data access framework.Bit Consulting Business Information Technology Blog: Espacio creado para todos los interesados en intercambiar información, opinar, preguntar todo lo relacionado con los productos ofrecidos por BIT CONSULTING.Black Desert C# emulator(Necroz Project): Development Black Desert emulatorDSLK: bai tap ctdl&gtFreelancerWebSecurity: FreelancerWebSecurityGlobal Machine Access: The project provides an intuitive interface computer control via the command line window. Features: - Login, logout, change password. - Execute commands inHeadTS: An alternative to the HeadJS script loader that provides a more focused, robust, promise-based script management system.How to develop an autodialer / predictive dialer in C#: This project demonstrates how to build a VoIP autodialer in C# in order to be able to make a huge amount of simultaneous calls automatically.html5demo: demo web app.NetPipe: A new piece of software in python that will allow programs to be executed on other computers / servers over a network.Observer Pattern: This project shows how the observer design pattern works.Our wedding: Ruben y Sarahi wedding 19-09-2014SpreadsheetComputations: Good stuffSpurnUI: jQuery based professional ASP.NET Controls for moblieStrategy Pattern: This project shows how the strategy design pattern works.TagIt-MP3: TagIt-MP3 is a free audio file data tagging ID3 format editor, support ID3 tag version, this audio tool can read and write metadata tags for MP3 audio files.TeamProjectDaNang: Ðà N?ng nhóm l?p trình :DThaumcraft4 Research: A small application to help players of Minecraft / Thaumcraft 4 complete their research projects.Visualize and Analyze Demand for Coding Skills, Using WPF: Use data visualization app to figure-out which job skills are most in demand. WPlayer: This project using ffmpeg library, based on Media Foundation. Yammer API SDK: A C# Yammer API SDK?????-?????【??】???????: ????????????????、?????????,??????、??????????????????,???????.??????????,????????。 ??????-??????【??】??????????: ??????????????????,???????、????、????、??????、???????,??????,???????????。?????-?????【??】???????: ??????????1992?,????????????????。??????????????????????。????????????,????，????????！ ?????-?????【??】?????????: ???????????????,???????、???????????,????????,????,?????????,??????,??????! ?????-?????【??】?????????: ???????,??????,?????????????????????,???????????????????????。?????-?????【??】???????: ???????????:?????,??????!???????????????,???????、?????、??????“??”????,????,????!?????-?????【??】???????: ???????????????????,???,??????????、???????????????????。??????,????、????，??????！ ?????-?????【??】???????: ???????????????,????,?????、???、?????,???????,?????,???????????100%。??????！ ?????-?????【??】????? ??: ?????????????????????????,???????????,??????,??????????????...????????。??????！??????-??????【??】??????????: ??????????????????,??:??????,????,????,????,?????,??????????????.??????-??????【??】??????????: ????????????????????,?????????????,???????????.????????????,????????????! ?????-?????【??】???????: ?????????????????????????,???????????,??????,??????????????...????????。??????！????-????【??】????????: ????????????????、?????、?????、????、?????,??????????。????????????????!?????-?????【??】?????????: ??????,??,????????。 ... ??????????????????、??????????????????...?????-?????【??】?????????: ?????????????:????,????,????,???????,????????,??????:????????,?????!??????-??????【??】????????: ?????????????????????、????、????、??????、???????,??????、??????。??????-??????【??】??????????: ????????,??????,?????????????????????,???????????????????????。 ?????-?????【??】???????: ??????????????????????????,??????,???????????,????????????????,????????.??????. ????-????【??】????????: ??????????????,???????、???????????,????????,????,?????????,??????,??????!?????-?????【??】?????: ?????????????????,???????、????、????、??????、???????,??????,???????????。?????-?????【??】???????: ????????????、????、????、??????、????、???????,?????,?????????!?????-?????【??】?????????: ???????????????????????、??????,????、?????、????， ?????????，?????????????！ ??????-??????【??】??????????: ?????????????????????、????、????、??????、???????,??????、??????。?????-??????【??】???????: ?????????,???????????,??????????,????:??,????,???????? ??????????,????????。??????！?????-?????【??】?????????: ???????????????????????、??????,????、?????、????， ?????????，?????????????！?????-?????【??】?????????: ??????????????、????、????、??????、????、???????,?????,?????????!??????-??????【??】??????????: ?????????????????"????,????"???,????????????????????????,??????????????。 ?????-?????【??】???????: ????????????????、?????????,??????、??????????????????,???????.??????????,????????。 ????-????【??】????????: ????????????????????????,???????????????,????????????????！ ?????-?????【??】?????????: ?????,?????????,?????????????。?????????????,?????????,???????。??????-??????【??】??????????: ????????????????,????:????,????,????,??????,?????,???????????????!?????-?????【??】???????: ???????????:?????,??????!???????????????,???????、?????、??????“??”????,????,????! ?????-?????【??】?????????: ?????????????????????????、??????????????,??????????????。?????-?????【??】?????????: ???????????????,????????????,?????????????????,??????,????????!?????-?????【??】?????????: ??????????????????????,????????????,?????、??、????,?????,??????！ ?????-?????【??】???????: ????????????????????????,????,????“???、???、???”?????,?????,?????????????????。??????！ ??????-??????【??】????????: ??????????????????????????、??????????????,??????????????。??????-??????【??】??????????: ?????????????????"????,????"???,????????????????????????,??????????????。????-????【??】????????: ????,?????????,?????????????。?????????????,?????????,???????。 ?????-?????【??】???????: ?????????????????、????、??????、????????,????????????,???????????！?????-?????【??】???????: ???????????????,????????????,?????????????????,??????,????????!?????-?????【??】?????????: ???????????????,????:????,????,????,??????,?????,???????????????! ??????-??????【??】????: ???????????????:?????? ???? ??????,???????,??????,???????。??????-??????【??】????????: ??????????????????、????、??????、????????,????????????,???????????！?????-?????【??】???????: ???????????????????,????????????,????????,???,???????????,????,????。?????,??????.????-????【??】??????: ?????????????????????????,???????????????????????,???????。?????-?????【??】???????: ???????????,????,??????????? ???? ???? ?????????,???,??,?????!

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• Difference between Factory Method and Abstract Factory design patterns using C#.Net

  - by nijhawan.saurabh

  First of all I'll just put both these patterns in context and describe their intent as in the GOF book: Factory Method: Define an interface for creating an object, but let subclasses decide which class to instantiate. Factory Method lets a class defer instantiation to subclasses.   Abstract Factory: Provide an interface for creating families of related or dependent objects without specifying their concrete classes.   Points to note:   Abstract factory pattern adds a layer of abstraction to the factory method pattern. The type of factory is not known to the client at compile time, this information is passed to the client at runtime (How it is passed is again dependent on the system, you may store this information in configuration files and the client can read it on execution). While implementing Abstract factory pattern, the factory classes can have multiple factory methods. In Abstract factory, a factory is capable of creating more than one type of product (Simpilar products are grouped together in a factory)   Sample implementation of factory method pattern   Let's see the class diagram first:                   ProductFactory.cs // ----------------------------------------------------------------------- // <copyright file="ProductFactory.cs" company=""> // TODO: Update copyright text. // </copyright> // -----------------------------------------------------------------------   namespace FactoryMethod {     using System;     using System.Collections.Generic;     using System.Linq;     using System.Text;       /// <summary>     /// TODO: Update summary.     /// </summary>     public abstract class ProductFactory     {         /// <summary>         /// </summary>         /// <returns>         /// </returns>         public abstract Product CreateProductInstance();     } }     ProductAFactory.cs // ----------------------------------------------------------------------- // <copyright file="ProductAFactory.cs" company=""> // TODO: Update copyright text. // </copyright> // -----------------------------------------------------------------------   namespace FactoryMethod {     using System;     using System.Collections.Generic;     using System.Linq;     using System.Text;       /// <summary>     /// TODO: Update summary.     /// </summary>     public class ProductAFactory:ProductFactory     {         public override Product CreateProductInstance()         {             return new ProductA();         }     } }         // ----------------------------------------------------------------------- // <copyright file="ProductBFactory.cs" company=""> // TODO: Update copyright text. // </copyright> // -----------------------------------------------------------------------   namespace FactoryMethod {     using System;     using System.Collections.Generic;     using System.Linq;     using System.Text;       /// <summary>     /// TODO: Update summary.     /// </summary>     public class ProductBFactory:ProductFactory     {         public override Product CreateProductInstance()         {             return new ProductB();           }     } }     // ----------------------------------------------------------------------- // <copyright file="Product.cs" company=""> // TODO: Update copyright text. // </copyright> // -----------------------------------------------------------------------   namespace FactoryMethod {     using System;     using System.Collections.Generic;     using System.Linq;     using System.Text;       /// <summary>     /// TODO: Update summary.     /// </summary>     public abstract class Product     {         public abstract string Name { get; set; }     } }     // ----------------------------------------------------------------------- // <copyright file="ProductA.cs" company=""> // TODO: Update copyright text. // </copyright> // -----------------------------------------------------------------------   namespace FactoryMethod {     using System;     using System.Collections.Generic;     using System.Linq;     using System.Text;       /// <summary>     /// TODO: Update summary.     /// </summary>     public class ProductA:Product     {         public ProductA()         {               Name = "ProductA";         }           public override string Name { get; set; }     } }       // ----------------------------------------------------------------------- // <copyright file="ProductB.cs" company=""> // TODO: Update copyright text. // </copyright> // -----------------------------------------------------------------------   namespace FactoryMethod {     using System;     using System.Collections.Generic;     using System.Linq;     using System.Text;       /// <summary>     /// TODO: Update summary.     /// </summary>     public class ProductB:Product     {          public ProductB()         {               Name = "ProductA";         }         public override string Name { get; set; }     } }     Program.cs using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace FactoryMethod {     class Program     {         static void Main(string[] args)         {             ProductFactory pf = new ProductAFactory();               Product product = pf.CreateProductInstance();             Console.WriteLine(product.Name);         }     } }       Normal 0 false false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

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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 II

  - by mbridge

  In previous post, I have discussed on how to work with ASP.NET MVC 3 and EF Code First for developing web apps. In this post, I will demonstrate on working with domain entity with deep object graph, Service Layer and View Models and will also complete the rest of the demo application. In the previous post, we have done CRUD operations against Category entity and this post will be focus on Expense entity those have an association with Category entity. Domain Model Category Entity 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 Entity 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; }     } 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. Repository class for Expense Transaction Let’s create repository class for handling CRUD operations for Expense entity public class ExpenseRepository : RepositoryBase<Expense>, IExpenseRepository     {     public ExpenseRepository(IDatabaseFactory databaseFactory)         : base(databaseFactory)         {         }                } public interface IExpenseRepository : IRepository<Expense> { } Service Layer If you are new to Service Layer, checkout Martin Fowler's article Service Layer . According to Martin Fowler, Service Layer defines an application's boundary and its set of available operations from the perspective of interfacing client layers. It encapsulates the application's business logic, controlling transactions and coordinating responses in the implementation of its operations. Controller classes should be lightweight and do not put much of business logic onto it. We can use the service layer as the business logic layer and can encapsulate the rules of the application. Let’s create a Service class for coordinates the transaction for Expense public interface IExpenseService {     IEnumerable<Expense> GetExpenses(DateTime startDate, DateTime ednDate);     Expense GetExpense(int id);             void CreateExpense(Expense expense);     void DeleteExpense(int id);     void SaveExpense(); } public class ExpenseService : IExpenseService {     private readonly IExpenseRepository expenseRepository;            private readonly IUnitOfWork unitOfWork;     public ExpenseService(IExpenseRepository expenseRepository, IUnitOfWork unitOfWork)     {                  this.expenseRepository = expenseRepository;         this.unitOfWork = unitOfWork;     }     public IEnumerable<Expense> GetExpenses(DateTime startDate, DateTime endDate)     {         var expenses = expenseRepository.GetMany(exp => exp.Date >= startDate && exp.Date <= endDate);         return expenses;     }     public void CreateExpense(Expense expense)     {         expenseRepository.Add(expense);         unitOfWork.Commit();     }     public Expense GetExpense(int id)     {         var expense = expenseRepository.GetById(id);         return expense;     }     public void DeleteExpense(int id)     {         var expense = expenseRepository.GetById(id);         expenseRepository.Delete(expense);         unitOfWork.Commit();     }     public void SaveExpense()     {         unitOfWork.Commit();     } } View Model for Expense Transactions In real world ASP.NET MVC applications, we need to design model objects especially for our views. Our domain objects are mainly designed for the needs for domain model and it is representing the domain of our applications. On the other hand, View Model objects are designed for our needs for views. We have an Expense domain entity that has an association with Category. While we are creating a new Expense, we have to specify that in which Category belongs with the new Expense transaction. The user interface for Expense transaction will have form fields for representing the Expense entity and a CategoryId for representing the Category. So let's create view model for representing the need for Expense transactions. public class ExpenseViewModel {     public int ExpenseId { get; set; }       [Required(ErrorMessage = "Category Required")]     public int CategoryId { get; set; }       [Required(ErrorMessage = "Transaction Required")]     public string Transaction { get; set; }       [Required(ErrorMessage = "Date Required")]     public DateTime Date { get; set; }       [Required(ErrorMessage = "Amount Required")]     public double Amount { get; set; }       public IEnumerable<SelectListItem> Category { get; set; } } The ExpenseViewModel is designed for the purpose of View template and contains the all validation rules. It has properties for mapping values to Expense entity and a property Category for binding values to a drop-down for list values of Category. Create Expense transaction Let’s create action methods in the ExpenseController for creating expense transactions public ActionResult Create() {     var expenseModel = new ExpenseViewModel();     var categories = categoryService.GetCategories();     expenseModel.Category = categories.ToSelectListItems(-1);     expenseModel.Date = DateTime.Today;     return View(expenseModel); } [HttpPost] public ActionResult Create(ExpenseViewModel expenseViewModel) {                      if (!ModelState.IsValid)         {             var categories = categoryService.GetCategories();             expenseViewModel.Category = categories.ToSelectListItems(expenseViewModel.CategoryId);             return View("Save", expenseViewModel);         }         Expense expense=new Expense();         ModelCopier.CopyModel(expenseViewModel,expense);         expenseService.CreateExpense(expense);         return RedirectToAction("Index");              } In the Create action method for HttpGet request, we have created an instance of our View Model ExpenseViewModel with Category information for the drop-down list and passing the Model object to View template. The extension method ToSelectListItems is shown below public static IEnumerable<SelectListItem> ToSelectListItems(         this IEnumerable<Category> categories, int  selectedId) {     return           categories.OrderBy(category => category.Name)                 .Select(category =>                     new SelectListItem                     {                         Selected = (category.CategoryId == selectedId),                         Text = category.Name,                         Value = category.CategoryId.ToString()                     }); } In the Create action method for HttpPost, our view model object ExpenseViewModel will map with posted form input values. We need to create an instance of Expense for the persistence purpose. So we need to copy values from ExpenseViewModel object to Expense object. ASP.NET MVC futures assembly provides a static class ModelCopier that can use for copying values between Model objects. ModelCopier class has two static methods - CopyCollection and CopyModel.CopyCollection method will copy values between two collection objects and CopyModel will copy values between two model objects. We have used CopyModel method of ModelCopier class for copying values from expenseViewModel object to expense object. Finally we did a call to CreateExpense method of ExpenseService class for persisting new expense transaction. List Expense Transactions We want to list expense transactions based on a date range. So let’s create action method for filtering expense transactions with a specified date range. public ActionResult Index(DateTime? startDate, DateTime? endDate) {     //If date is not passed, take current month's first and last dte     DateTime dtNow;     dtNow = DateTime.Today;     if (!startDate.HasValue)     {         startDate = new DateTime(dtNow.Year, dtNow.Month, 1);         endDate = startDate.Value.AddMonths(1).AddDays(-1);     }     //take last date of start date's month, if end date is not passed     if (startDate.HasValue && !endDate.HasValue)     {         endDate = (new DateTime(startDate.Value.Year, startDate.Value.Month, 1)).AddMonths(1).AddDays(-1);     }     var expenses = expenseService.GetExpenses(startDate.Value ,endDate.Value);     //if request is Ajax will return partial view     if (Request.IsAjaxRequest())     {         return PartialView("ExpenseList", expenses);     }     //set start date and end date to ViewBag dictionary     ViewBag.StartDate = startDate.Value.ToShortDateString();     ViewBag.EndDate = endDate.Value.ToShortDateString();     //if request is not ajax     return View(expenses); } We are using the above Index Action method for both Ajax requests and normal requests. If there is a request for Ajax, we will call the PartialView ExpenseList. Razor Views for listing Expense information Let’s create view templates in Razor for showing list of Expense information ExpenseList.cshtml @model IEnumerable<MyFinance.Domain.Expense>   <table>         <tr>             <th>Actions</th>             <th>Category</th>             <th>                 Transaction             </th>             <th>                 Date             </th>             <th>                 Amount             </th>         </tr>       @foreach (var item in Model) {              <tr>             <td>                 @Html.ActionLink("Edit", "Edit",new { id = item.ExpenseId })                 @Ajax.ActionLink("Delete", "Delete", new { id = item.ExpenseId }, new AjaxOptions { Confirm = "Delete Expense?", HttpMethod = "Post", UpdateTargetId = "divExpenseList" })             </td>              <td>                 @item.Category.Name             </td>             <td>                 @item.Transaction             </td>             <td>                 @String.Format("{0:d}", item.Date)             </td>             <td>                 @String.Format("{0:F}", item.Amount)             </td>         </tr>          }       </table>     <p>         @Html.ActionLink("Create New Expense", "Create") |         @Html.ActionLink("Create New Category", "Create","Category")     </p> Index.cshtml @using MyFinance.Helpers; @model IEnumerable<MyFinance.Domain.Expense> @{     ViewBag.Title = "Index"; }    <h2>Expense List</h2>    <script src="@Url.Content("~/Scripts/jquery.unobtrusive-ajax.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery-ui.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.ui.datepicker.js")" type="text/javascript"></script> <link href="@Url.Content("~/Content/jquery-ui-1.8.6.custom.css")" rel="stylesheet" type="text/css" />      @using (Ajax.BeginForm(new AjaxOptions{ UpdateTargetId="divExpenseList", HttpMethod="Get"})) {     <table>         <tr>         <td>         <div>           Start Date: @Html.TextBox("StartDate", Html.Encode(String.Format("{0:mm/dd/yyyy}", ViewData["StartDate"].ToString())), new { @class = "ui-datepicker" })         </div>         </td>         <td><div>            End Date: @Html.TextBox("EndDate", Html.Encode(String.Format("{0:mm/dd/yyyy}", ViewData["EndDate"].ToString())), new { @class = "ui-datepicker" })          </div></td>          <td> <input type="submit" value="Search By TransactionDate" /></td>         </tr>     </table>         }   <div id="divExpenseList">             @Html.Partial("ExpenseList", Model)     </div> <script type="text/javascript">     $().ready(function () {         $('.ui-datepicker').datepicker({             dateFormat: 'mm/dd/yy',             buttonImage: '@Url.Content("~/Content/calendar.gif")',             buttonImageOnly: true,             showOn: "button"         });     }); </script> Ajax search functionality using Ajax.BeginForm The search functionality of Index view is providing Ajax functionality using Ajax.BeginForm. The Ajax.BeginForm() method writes an opening <form> tag to the response. You can use this method in a using block. In that case, the method renders the closing </form> tag at the end of the using block and the form is submitted asynchronously by using JavaScript. The search functionality will call the Index Action method and this will return partial view ExpenseList for updating the search result. We want to update the response UI for the Ajax request onto divExpenseList element. So we have specified the UpdateTargetId as "divExpenseList" in the Ajax.BeginForm method. Add jQuery DatePicker Our search functionality is using a date range so we are providing two date pickers using jQuery datepicker. You need to add reference to the following JavaScript files to working with jQuery datepicker. - jquery-ui.js - jquery.ui.datepicker.js For theme support for datepicker, we can use a customized CSS class. In our example we have used a CSS file “jquery-ui-1.8.6.custom.css”. For more details about the datepicker component, visit jquery UI website at http://jqueryui.com/demos/datepicker . In the jQuery ready event, we have used following JavaScript function to initialize the UI element to show date picker. <script type="text/javascript">     $().ready(function () {         $('.ui-datepicker').datepicker({             dateFormat: 'mm/dd/yy',             buttonImage: '@Url.Content("~/Content/calendar.gif")',             buttonImageOnly: true,             showOn: "button"         });     }); </script> Summary In this two-part series, we have created a simple web application using ASP.NET MVC 3 RTM, Razor and EF Code First CTP 5. I have demonstrated patterns and practices  such as Dependency Injection, Repository pattern, Unit of Work, ViewModel and Service Layer. My primary objective was to demonstrate different practices and options for developing web apps using ASP.NET MVC 3 and EF Code First. You can implement these approaches in your own way for building web apps using ASP.NET MVC 3. I will refactor this demo app on later time.

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• Thread.Interrupt Is Evil

  - by Alois Kraus

  Recently I have found an interesting issue with Thread.Interrupt during application shutdown. Some application was crashing once a week and we had not really a clue what was the issue. Since it happened not very often it was left as is until we have got some memory dumps during the crash. A memory dump usually means WindDbg which I really like to use (I know I am one of the very few fans of it).  After a quick analysis I did find that the main thread already had exited and the thread with the crash was stuck in a Monitor.Wait. Strange Indeed. Running the application a few thousand times under the debugger would potentially not have shown me what the reason was so I decided to what I call constructive debugging. I did create a simple Console application project and try to simulate the exact circumstances when the crash did happen from the information I have via memory dump and source code reading. The thread that was  crashing was actually MS code from an old version of the Microsoft Caching Application Block. From reading the code I could conclude that the main thread did call the Dispose method on the CacheManger class which did call Thread.Interrupt on the cache scavenger thread which was just waiting for work to do. My first version of the repro looked like this   static void Main(string[] args) { Thread t = new Thread(ThreadFunc) { IsBackground = true, Name = "Test Thread" }; t.Start(); Console.WriteLine("Interrupt Thread"); t.Interrupt(); } static void ThreadFunc() { while (true) { object value = Dequeue(); // block until unblocked or awaken via ThreadInterruptedException } } static object WaitObject = new object(); static object Dequeue() { object lret = "got value"; try { lock (WaitObject) { } } catch (ThreadInterruptedException) { Console.WriteLine("Got ThreadInterruptException"); lret = null; } return lret; } I do start a background thread and call Thread.Interrupt on it and then directly let the application terminate. The thread in the meantime does plenty of Monitor.Enter/Leave calls to simulate work on it. This first version did not crash. So I need to dig deeper. From the memory dump I did know that the finalizer thread was doing just some critical finalizers which were closing file handles. Ok lets add some long running finalizers to the sample. class FinalizableObject : CriticalFinalizerObject { ~FinalizableObject() { Console.WriteLine("Hi we are waiting to finalize now and block the finalizer thread for 5s."); Thread.Sleep(5000); } } class Program { static void Main(string[] args) { FinalizableObject fin = new FinalizableObject(); Thread t = new Thread(ThreadFunc) { IsBackground = true, Name = "Test Thread" }; t.Start(); Console.WriteLine("Interrupt Thread"); t.Interrupt(); GC.KeepAlive(fin); // prevent finalizing it too early // After leaving main the other thread is woken up via Thread.Abort // while we are finalizing. This causes a stackoverflow in the CLR ThreadAbortException handling at this time. } With this changed Main method and a blocking critical finalizer I did get my crash just like the real application. The funny thing is that this is actually a CLR bug. When the main method is left the CLR does suspend all threads except the finalizer thread and declares all objects as garbage. After the normal finalizers were called the critical finalizers are executed to e.g. free OS handles (usually). Remember that I did call Thread.Interrupt as one of the last methods in the Main method. The Interrupt method is actually asynchronous and does wake a thread up and throws a ThreadInterruptedException only once unlike Thread.Abort which does rethrow the exception when an exception handling clause is left. It seems that the CLR does not expect that a frozen thread does wake up again while the critical finalizers are executed. While trying to raise a ThreadInterrupedException the CLR goes down with an stack overflow. Ups not so nice. Why has this nobody noticed for years is my next question. As it turned out this error does only happen on the CLR for .NET 4.0 (x86 and x64). It does not show up in earlier or later versions of the CLR. I have reported this issue on connect here but so far it was not confirmed as a CLR bug. But I would be surprised if my console application was to blame for a stack overflow in my test thread in a Monitor.Wait call. What is the moral of this story? Thread.Abort is evil but Thread.Interrupt is too. It is so evil that even the CLR of .NET 4.0 contains a race condition during the CLR shutdown. When the CLR gurus can get it wrong the chances are high that you get it wrong too when you use this constructs. If you do not believe me see what Patrick Smacchia does blog about Thread.Abort and List.Sort. Not only the CLR creators can get it wrong. The BCL writers do sometimes have a hard time with correct exception handling as well. If you do tell me that you use Thread.Abort frequently and never had problems with it I do suspect that you do not have looked deep enough into your application to find such sporadic errors.

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• .NET Code Evolution

  - by Alois Kraus

  Originally posted on: http://geekswithblogs.net/akraus1/archive/2013/07/24/153504.aspxAt my day job I do look at a lot of code written by other people. Most of the code is quite good and some is even a masterpiece. And there is also code which makes you think WTF… oh it was written by me. Hm not so bad after all. There are many excuses reasons for bad code. Most often it is time pressure followed by not enough ambition (who cares) or insufficient training. Normally I do care about code quality quite a lot which makes me a (perceived) slow worker who does write many tests and refines the code quite a lot because of the design deficiencies. Most of the deficiencies I do find by putting my design under stress while checking for invariants. It does also help a lot to step into the code with a debugger (sometimes also Windbg). I do this much more often when my tests are red. That way I do get a much better understanding what my code really does and not what I think it should be doing. This time I do want to show you how code can evolve over the years with different .NET Framework versions. Once there was  time where .NET 1.1 was new and many C++ programmers did switch over to get rid of not initialized pointers and memory leaks. There were also nice new data structures available such as the Hashtable which is fast lookup table with O(1) time complexity. All was good and much code was written since then. At 2005 a new version of the .NET Framework did arrive which did bring many new things like generics and new data structures. The “old” fashioned way of Hashtable were coming to an end and everyone used the new Dictionary<xx,xx> type instead which was type safe and faster because the object to type conversion (aka boxing) was no longer necessary. I think 95% of all Hashtables and dictionaries use string as key. Often it is convenient to ignore casing to make it easy to look up values which the user did enter. An often followed route is to convert the string to upper case before putting it into the Hashtable. Hashtable Table = new Hashtable(); void Add(string key, string value) { Table.Add(key.ToUpper(), value); } This is valid and working code but it has problems. First we can pass to the Hashtable a custom IEqualityComparer to do the string matching case insensitive. Second we can switch over to the now also old Dictionary type to become a little faster and we can keep the the original keys (not upper cased) in the dictionary. Dictionary<string, string> DictTable = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase); void AddDict(string key, string value) { DictTable.Add(key, value); } Many people do not user the other ctors of Dictionary because they do shy away from the overhead of writing their own comparer. They do not know that .NET has for strings already predefined comparers at hand which you can directly use. Today in the many core area we do use threads all over the place. Sometimes things break in subtle ways but most of the time it is sufficient to place a lock around the offender. Threading has become so mainstream that it may sound weird that in the year 2000 some guy got a huge incentive for the idea to reduce the time to process calibration data from 12 hours to 6 hours by using two threads on a dual core machine. Threading does make it easy to become faster at the expense of correctness. Correct and scalable multithreading can be arbitrarily hard to achieve depending on the problem you are trying to solve. Lets suppose we want to process millions of items with two threads and count the processed items processed by all threads. A typical beginners code might look like this: int Counter; void IJustLearnedToUseThreads() { var t1 = new Thread(ThreadWorkMethod); t1.Start(); var t2 = new Thread(ThreadWorkMethod); t2.Start(); t1.Join(); t2.Join(); if (Counter != 2 * Increments) throw new Exception("Hmm " + Counter + " != " + 2 * Increments); } const int Increments = 10 * 1000 * 1000; void ThreadWorkMethod() { for (int i = 0; i < Increments; i++) { Counter++; } } It does throw an exception with the message e.g. “Hmm 10.222.287 != 20.000.000” and does never finish. The code does fail because the assumption that Counter++ is an atomic operation is wrong. The ++ operator is just a shortcut for Counter = Counter + 1 This does involve reading the counter from a memory location into the CPU, incrementing value on the CPU and writing the new value back to the memory location. When we do look at the generated assembly code we will see only inc dword ptr [ecx+10h] which is only one instruction. Yes it is one instruction but it is not atomic. All modern CPUs have several layers of caches (L1,L2,L3) which try to hide the fact how slow actual main memory accesses are. Since cache is just another word for redundant copy it can happen that one CPU does read a value from main memory into the cache, modifies it and write it back to the main memory. The problem is that at least the L1 cache is not shared between CPUs so it can happen that one CPU does make changes to values which did change in meantime in the main memory. From the exception you can see we did increment the value 20 million times but half of the changes were lost because we did overwrite the already changed value from the other thread. This is a very common case and people do learn to protect their  data with proper locking.   void Intermediate() { var time = Stopwatch.StartNew(); Action acc = ThreadWorkMethod_Intermediate; var ar1 = acc.BeginInvoke(null, null); var ar2 = acc.BeginInvoke(null, null); ar1.AsyncWaitHandle.WaitOne(); ar2.AsyncWaitHandle.WaitOne(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Intermediate did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Intermediate() { for (int i = 0; i < Increments; i++) { lock (this) { Counter++; } } } This is better and does use the .NET Threadpool to get rid of manual thread management. It does give the expected result but it can result in deadlocks because you do lock on this. This is in general a bad idea since it can lead to deadlocks when other threads use your class instance as lock object. It is therefore recommended to create a private object as lock object to ensure that nobody else can lock your lock object. When you read more about threading you will read about lock free algorithms. They are nice and can improve performance quite a lot but you need to pay close attention to the CLR memory model. It does make quite weak guarantees in general but it can still work because your CPU architecture does give you more invariants than the CLR memory model. For a simple counter there is an easy lock free alternative present with the Interlocked class in .NET. As a general rule you should not try to write lock free algos since most likely you will fail to get it right on all CPU architectures. void Experienced() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); t1.Wait(); t2.Wait(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Experienced did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Experienced() { for (int i = 0; i < Increments; i++) { Interlocked.Increment(ref Counter); } } Since time does move forward we do not use threads explicitly anymore but the much nicer Task abstraction which was introduced with .NET 4 at 2010. It is educational to look at the generated assembly code. The Interlocked.Increment method must be called which does wondrous things right? Lets see: lock inc dword ptr [eax] The first thing to note that there is no method call at all. Why? Because the JIT compiler does know very well about CPU intrinsic functions. Atomic operations which do lock the memory bus to prevent other processors to read stale values are such things. Second: This is the same increment call prefixed with a lock instruction. The only reason for the existence of the Interlocked class is that the JIT compiler can compile it to the matching CPU intrinsic functions which can not only increment by one but can also do an add, exchange and a combined compare and exchange operation. But be warned that the correct usage of its methods can be tricky. If you try to be clever and look a the generated IL code and try to reason about its efficiency you will fail. Only the generated machine code counts. Is this the best code we can write? Perhaps. It is nice and clean. But can we make it any faster? Lets see how good we are doing currently. Level Time in s IJustLearnedToUseThreads Flawed Code Intermediate 1,5 (lock) Experienced 0,3 (Interlocked.Increment) Master 0,1 (1,0 for int[2]) That lock free thing is really a nice thing. But if you read more about CPU cache, cache coherency, false sharing you can do even better. int[] Counters = new int[12]; // Cache line size is 64 bytes on my machine with an 8 way associative cache try for yourself e.g. 64 on more modern CPUs void Master() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Master, 0); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Master, Counters.Length - 1); t1.Wait(); t2.Wait(); Counter = Counters[0] + Counters[Counters.Length - 1]; if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Master did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Master(object number) { int index = (int) number; for (int i = 0; i < Increments; i++) { Counters[index]++; } } The key insight here is to use for each core its own value. But if you simply use simply an integer array of two items, one for each core and add the items at the end you will be much slower than the lock free version (factor 3). Each CPU core has its own cache line size which is something in the range of 16-256 bytes. When you do access a value from one location the CPU does not only fetch one value from main memory but a complete cache line (e.g. 16 bytes). This means that you do not pay for the next 15 bytes when you access them. This can lead to dramatic performance improvements and non obvious code which is faster although it does have many more memory reads than another algorithm. So what have we done here? We have started with correct code but it was lacking knowledge how to use the .NET Base Class Libraries optimally. Then we did try to get fancy and used threads for the first time and failed. Our next try was better but it still had non obvious issues (lock object exposed to the outside). Knowledge has increased further and we have found a lock free version of our counter which is a nice and clean way which is a perfectly valid solution. The last example is only here to show you how you can get most out of threading by paying close attention to your used data structures and CPU cache coherency. Although we are working in a virtual execution environment in a high level language with automatic memory management it does pay off to know the details down to the assembly level. Only if you continue to learn and to dig deeper you can come up with solutions no one else was even considering. I have studied particle physics which does help at the digging deeper part. Have you ever tried to solve Quantum Chromodynamics equations? Compared to that the rest must be easy ;-). Although I am no longer working in the Science field I take pride in discovering non obvious things. This can be a very hard to find bug or a new way to restructure data to make something 10 times faster. Now I need to get some sleep ….

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• Add Widget via Action in Toolbar

  - by Geertjan

  The question of the day comes from Vadim, who asks on the NetBeans Platform mailing list: "Looking for example showing how to add Widget to Scene, e.g. by toolbar button click." Well, the solution is very similar to this blog entry, where you see a solution provided by Jesse Glick for VisiTrend in Boston: https://blogs.oracle.com/geertjan/entry/zoom_capability Other relevant articles to read are as follows: http://netbeans.dzone.com/news/which-netbeans-platform-action http://netbeans.dzone.com/how-to-make-context-sensitive-actions Let's go through it step by step, with this result in the end, a solution involving 4 classes split (optionally, since a central feature of the NetBeans Platform is modularity) across multiple modules: The Customer object has a "name" String and the Droppable capability has a method "doDrop" which takes a Customer object: public interface Droppable {    void doDrop(Customer c);} In the TopComponent, we use "TopComponent.associateLookup" to publish an instance of "Droppable", which creates a new LabelWidget and adds it to the Scene in the TopComponent. Here's the TopComponent constructor: public CustomerCanvasTopComponent() {    initComponents();    setName(Bundle.CTL_CustomerCanvasTopComponent());    setToolTipText(Bundle.HINT_CustomerCanvasTopComponent());    final Scene scene = new Scene();    final LayerWidget layerWidget = new LayerWidget(scene);    Droppable d = new Droppable(){        @Override        public void doDrop(Customer c) {            LabelWidget customerWidget = new LabelWidget(scene, c.getTitle());            customerWidget.getActions().addAction(ActionFactory.createMoveAction());            layerWidget.addChild(customerWidget);            scene.validate();        }    };    scene.addChild(layerWidget);    jScrollPane1.setViewportView(scene.createView());    associateLookup(Lookups.singleton(d));} The Action is displayed in the toolbar and is enabled only if a Droppable is currently in the Lookup: @ActionID(        category = "Tools",        id = "org.customer.controler.AddCustomerAction")@ActionRegistration(        iconBase = "org/customer/controler/icon.png",        displayName = "#AddCustomerAction")@ActionReferences({    @ActionReference(path = "Toolbars/File", position = 300)})@NbBundle.Messages("AddCustomerAction=Add Customer")public final class AddCustomerAction implements ActionListener {    private final Droppable context;    public AddCustomerAction(Droppable droppable) {        this.context = droppable;    }    @Override    public void actionPerformed(ActionEvent ev) {        NotifyDescriptor.InputLine inputLine = new NotifyDescriptor.InputLine("Name:", "Data Entry");        Object result = DialogDisplayer.getDefault().notify(inputLine);        if (result == NotifyDescriptor.OK_OPTION) {            Customer customer = new Customer(inputLine.getInputText());            context.doDrop(customer);        }    }} Therefore, when the Properties window, for example, is selected, the Action will be disabled. (See the Zoomable example referred to in the link above for another example of this.) As you can see above, when the Action is invoked, a Droppable must be available (otherwise the Action would not have been enabled). The Droppable is obtained in the Action and a new Customer object is passed to its "doDrop" method. The above in pictures, take note of the enablement of the toolbar button with the red dot, on the extreme left of the toolbar in the screenshots below: The above shows the JButton is only enabled if the relevant TopComponent is active and, when the Action is invoked, the user can enter a name, after which a new LabelWidget is created in the Scene. The source code of the above is here: http://java.net/projects/nb-api-samples/sources/api-samples/show/versions/7.3/misc/WidgetCreationFromAction Note: Showing this as an MVC example is slightly misleading because, depending on which model object ("Customer" and "Droppable") you're looking at, the V and the C are different. From the point of view of "Customer", the TopComponent is the View, while the Action is the Controler, since it determines when the M is displayed. However, from the point of view of "Droppable", the TopComponent is the Controler, since it determines when the Action, i.e., which is in this case the View, displays the presence of the M.

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• Loosely coupled .NET Cache Provider using Dependency Injection

  - by Rhames

  I have recently been reading the excellent book “Dependency Injection in .NET”, written by Mark Seemann. I do not generally buy software development related books, as I never seem to have the time to read them, but I have found the time to read Mark’s book, and it was time well spent I think. Reading the ideas around Dependency Injection made me realise that the Cache Provider code I wrote about earlier (see http://geekswithblogs.net/Rhames/archive/2011/01/10/using-the-asp.net-cache-to-cache-data-in-a-model.aspx) could be refactored to use Dependency Injection, which should produce cleaner code. The goals are to: Separate the cache provider implementation (using the ASP.NET data cache) from the consumers (loose coupling). This will also mean that the dependency on System.Web for the cache provider does not ripple down into the layers where it is being consumed (such as the domain layer). Provide a decorator pattern to allow a consumer of the cache provider to be implemented separately from the base consumer (i.e. if we have a base repository, we can decorate this with a caching version). Although I used the term repository, in reality the cache consumer could be just about anything. Use constructor injection to provide the Dependency Injection, with a suitable DI container (I use Castle Windsor). The sample code for this post is available on github, https://github.com/RobinHames/CacheProvider.git ICacheProvider In the sample code, the key interface is ICacheProvider, which is in the domain layer. 1: using System; 2: using System.Collections.Generic; 3:   4: namespace CacheDiSample.Domain 5: { 6: public interface ICacheProvider<T> 7: { 8: T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry); 9: IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry); 10: } 11: }   This interface contains two methods to retrieve data from the cache, either as a single instance or as an IEnumerable. the second paramerter is of type Func<T>. This is the method used to retrieve data if nothing is found in the cache. The ASP.NET implementation of the ICacheProvider interface needs to live in a project that has a reference to system.web, typically this will be the root UI project, or it could be a separate project. The key thing is that the domain or data access layers do not need system.web references adding to them. In my sample MVC application, the CacheProvider is implemented in the UI project, in a folder called “CacheProviders”: 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Web; 5: using System.Web.Caching; 6: using CacheDiSample.Domain; 7:   8: namespace CacheDiSample.CacheProvider 9: { 10: public class CacheProvider<T> : ICacheProvider<T> 11: { 12: public T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) 13: { 14: return FetchAndCache<T>(key, retrieveData, absoluteExpiry, relativeExpiry); 15: } 16:   17: public IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) 18: { 19: return FetchAndCache<IEnumerable<T>>(key, retrieveData, absoluteExpiry, relativeExpiry); 20: } 21:   22: #region Helper Methods 23:   24: private U FetchAndCache<U>(string key, Func<U> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) 25: { 26: U value; 27: if (!TryGetValue<U>(key, out value)) 28: { 29: value = retrieveData(); 30: if (!absoluteExpiry.HasValue) 31: absoluteExpiry = Cache.NoAbsoluteExpiration; 32:   33: if (!relativeExpiry.HasValue) 34: relativeExpiry = Cache.NoSlidingExpiration; 35:   36: HttpContext.Current.Cache.Insert(key, value, null, absoluteExpiry.Value, relativeExpiry.Value); 37: } 38: return value; 39: } 40:   41: private bool TryGetValue<U>(string key, out U value) 42: { 43: object cachedValue = HttpContext.Current.Cache.Get(key); 44: if (cachedValue == null) 45: { 46: value = default(U); 47: return false; 48: } 49: else 50: { 51: try 52: { 53: value = (U)cachedValue; 54: return true; 55: } 56: catch 57: { 58: value = default(U); 59: return false; 60: } 61: } 62: } 63:   64: #endregion 65:   66: } 67: }   The FetchAndCache helper method checks if the specified cache key exists, if it does not, the Func<U> retrieveData method is called, and the results are added to the cache. Using Castle Windsor to register the cache provider In the MVC UI project (my application root), Castle Windsor is used to register the CacheProvider implementation, using a Windsor Installer: 1: using Castle.MicroKernel.Registration; 2: using Castle.MicroKernel.SubSystems.Configuration; 3: using Castle.Windsor; 4:   5: using CacheDiSample.Domain; 6: using CacheDiSample.CacheProvider; 7:   8: namespace CacheDiSample.WindsorInstallers 9: { 10: public class CacheInstaller : IWindsorInstaller 11: { 12: public void Install(IWindsorContainer container, IConfigurationStore store) 13: { 14: container.Register( 15: Component.For(typeof(ICacheProvider<>)) 16: .ImplementedBy(typeof(CacheProvider<>)) 17: .LifestyleTransient()); 18: } 19: } 20: }   Note that the cache provider is registered as a open generic type. Consuming a Repository I have an existing couple of repository interfaces defined in my domain layer: IRepository.cs 1: using System; 2: using System.Collections.Generic; 3:   4: using CacheDiSample.Domain.Model; 5:   6: namespace CacheDiSample.Domain.Repositories 7: { 8: public interface IRepository<T> 9: where T : EntityBase 10: { 11: T GetById(int id); 12: IList<T> GetAll(); 13: } 14: }   IBlogRepository.cs 1: using System; 2: using CacheDiSample.Domain.Model; 3:   4: namespace CacheDiSample.Domain.Repositories 5: { 6: public interface IBlogRepository : IRepository<Blog> 7: { 8: Blog GetByName(string name); 9: } 10: }   These two repositories are implemented in the DataAccess layer, using Entity Framework to retrieve data (this is not important though). One important point is that in the BaseRepository implementation of IRepository, the methods are virtual. This will allow the decorator to override them. The BlogRepository is registered in a RepositoriesInstaller, again in the MVC UI project. 1: using Castle.MicroKernel.Registration; 2: using Castle.MicroKernel.SubSystems.Configuration; 3: using Castle.Windsor; 4:   5: using CacheDiSample.Domain.CacheDecorators; 6: using CacheDiSample.Domain.Repositories; 7: using CacheDiSample.DataAccess; 8:   9: namespace CacheDiSample.WindsorInstallers 10: { 11: public class RepositoriesInstaller : IWindsorInstaller 12: { 13: public void Install(IWindsorContainer container, IConfigurationStore store) 14: { 15: container.Register(Component.For<IBlogRepository>() 16: .ImplementedBy<BlogRepository>() 17: .LifestyleTransient() 18: .DependsOn(new 19: { 20: nameOrConnectionString = "BloggingContext" 21: })); 22: } 23: } 24: }   Now I can inject a dependency on the IBlogRepository into a consumer, such as a controller in my sample code: 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Web; 5: using System.Web.Mvc; 6:   7: using CacheDiSample.Domain.Repositories; 8: using CacheDiSample.Domain.Model; 9:   10: namespace CacheDiSample.Controllers 11: { 12: public class HomeController : Controller 13: { 14: private readonly IBlogRepository blogRepository; 15:   16: public HomeController(IBlogRepository blogRepository) 17: { 18: if (blogRepository == null) 19: throw new ArgumentNullException("blogRepository"); 20:   21: this.blogRepository = blogRepository; 22: } 23:   24: public ActionResult Index() 25: { 26: ViewBag.Message = "Welcome to ASP.NET MVC!"; 27:   28: var blogs = blogRepository.GetAll(); 29:   30: return View(new Models.HomeModel { Blogs = blogs }); 31: } 32:   33: public ActionResult About() 34: { 35: return View(); 36: } 37: } 38: }   Consuming the Cache Provider via a Decorator I used a Decorator pattern to consume the cache provider, this means my repositories follow the open/closed principle, as they do not require any modifications to implement the caching. It also means that my controllers do not have any knowledge of the caching taking place, as the DI container will simply inject the decorator instead of the root implementation of the repository. The first step is to implement a BlogRepository decorator, with the caching logic in it. Note that this can reside in the domain layer, as it does not require any knowledge of the data access methods. BlogRepositoryWithCaching.cs 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5:   6: using CacheDiSample.Domain.Model; 7: using CacheDiSample.Domain; 8: using CacheDiSample.Domain.Repositories; 9:   10: namespace CacheDiSample.Domain.CacheDecorators 11: { 12: public class BlogRepositoryWithCaching : IBlogRepository 13: { 14: // The generic cache provider, injected by DI 15: private ICacheProvider<Blog> cacheProvider; 16: // The decorated blog repository, injected by DI 17: private IBlogRepository parentBlogRepository; 18:   19: public BlogRepositoryWithCaching(IBlogRepository parentBlogRepository, ICacheProvider<Blog> cacheProvider) 20: { 21: if (parentBlogRepository == null) 22: throw new ArgumentNullException("parentBlogRepository"); 23:   24: this.parentBlogRepository = parentBlogRepository; 25:   26: if (cacheProvider == null) 27: throw new ArgumentNullException("cacheProvider"); 28:   29: this.cacheProvider = cacheProvider; 30: } 31:   32: public Blog GetByName(string name) 33: { 34: string key = string.Format("CacheDiSample.DataAccess.GetByName.{0}", name); 35: // hard code 5 minute expiry! 36: TimeSpan relativeCacheExpiry = new TimeSpan(0, 5, 0); 37: return cacheProvider.Fetch(key, () => 38: { 39: return parentBlogRepository.GetByName(name); 40: }, 41: null, relativeCacheExpiry); 42: } 43:   44: public Blog GetById(int id) 45: { 46: string key = string.Format("CacheDiSample.DataAccess.GetById.{0}", id); 47:   48: // hard code 5 minute expiry! 49: TimeSpan relativeCacheExpiry = new TimeSpan(0, 5, 0); 50: return cacheProvider.Fetch(key, () => 51: { 52: return parentBlogRepository.GetById(id); 53: }, 54: null, relativeCacheExpiry); 55: } 56:   57: public IList<Blog> GetAll() 58: { 59: string key = string.Format("CacheDiSample.DataAccess.GetAll"); 60:   61: // hard code 5 minute expiry! 62: TimeSpan relativeCacheExpiry = new TimeSpan(0, 5, 0); 63: return cacheProvider.Fetch(key, () => 64: { 65: return parentBlogRepository.GetAll(); 66: }, 67: null, relativeCacheExpiry) 68: .ToList(); 69: } 70: } 71: }   The key things in this caching repository are: I inject into the repository the ICacheProvider<Blog> implementation, via the constructor. This will make the cache provider functionality available to the repository. I inject the parent IBlogRepository implementation (which has the actual data access code), via the constructor. This will allow the methods implemented in the parent to be called if nothing is found in the cache. I override each of the methods implemented in the repository, including those implemented in the generic BaseRepository. Each override of these methods follows the same pattern. It makes a call to the CacheProvider.Fetch method, and passes in the parentBlogRepository implementation of the method as the retrieval method, to be used if nothing is present in the cache. Configuring the Caching Repository in the DI Container The final piece of the jigsaw is to tell Castle Windsor to use the BlogRepositoryWithCaching implementation of IBlogRepository, but to inject the actual Data Access implementation into this decorator. This is easily achieved by modifying the RepositoriesInstaller to use Windsor’s implicit decorator wiring: 1: using Castle.MicroKernel.Registration; 2: using Castle.MicroKernel.SubSystems.Configuration; 3: using Castle.Windsor; 4:   5: using CacheDiSample.Domain.CacheDecorators; 6: using CacheDiSample.Domain.Repositories; 7: using CacheDiSample.DataAccess; 8:   9: namespace CacheDiSample.WindsorInstallers 10: { 11: public class RepositoriesInstaller : IWindsorInstaller 12: { 13: public void Install(IWindsorContainer container, IConfigurationStore store) 14: { 15:   16: // Use Castle Windsor implicit wiring for the block repository decorator 17: // Register the outermost decorator first 18: container.Register(Component.For<IBlogRepository>() 19: .ImplementedBy<BlogRepositoryWithCaching>() 20: .LifestyleTransient()); 21: // Next register the IBlogRepository inmplementation to inject into the outer decorator 22: container.Register(Component.For<IBlogRepository>() 23: .ImplementedBy<BlogRepository>() 24: .LifestyleTransient() 25: .DependsOn(new 26: { 27: nameOrConnectionString = "BloggingContext" 28: })); 29: } 30: } 31: }   This is all that is needed. Now if the consumer of the repository makes a call to the repositories method, it will be routed via the caching mechanism. You can test this by stepping through the code, and seeing that the DataAccess.BlogRepository code is only called if there is no data in the cache, or this has expired. The next step is to add the SQL Cache Dependency support into this pattern, this will be a future post.

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• ASP.NET Multi-Select Radio Buttons

  - by Ajarn Mark Caldwell

  “HERESY!” you say, “Radio buttons are for single-select items!  If you want multi-select, use checkboxes!”  Well, I would agree, and that is why I consider this a significant bug that ASP.NET developers need to be aware of.  Here’s the situation. If you use ASP:RadioButton controls on your WebForm, then you know that in order to get them to behave properly, that is, to define a group in which only one of them can be selected by the user, you use the Group attribute and set the same value on each one.  For example: 1: <asp:RadioButton runat="server" ID="rdo1" Group="GroupName" checked="true" /> 2: <asp:RadioButton runat="server" ID="rdo2" Group="GroupName" /> With this configuration, the controls will render to the browser as HTML Input / Type=radio tags and when the user selects one, the browser will automatically deselect the other one so that only one can be selected (checked) at any time. BUT, if you user server-side code to manipulate the Checked attribute of these controls, it is possible to set them both to believe that they are checked. 1: rdo2.Checked = true; // Does NOT change the Checked attribute of rdo1 to be false. As long as you remain in server-side code, the system will believe that both radio buttons are checked (you can verify this in the debugger).  Therefore, if you later have code that looks like this 1: if (rdo1.Checked) 2: { 3: DoSomething1(); 4: } 5: else 6: { 7: DoSomethingElse(); 8: } then it will always evaluate the condition to be true and take the first action.  The good news is that if you return to the client with multiple radio buttons checked, the browser tries to clean that up for you and make only one of them really checked.  It turns out that the last one on the screen wins, so in this case, you will in fact end up with rdo2 as checked, and if you then make a trip to the server to run the code above, it will appear to be working properly.  However, if your page initializes with rdo2 checked and in code you set rdo1 to checked also, then when you go back to the client, rdo2 will remain checked, again because it is the last one and the last one checked “wins”. And this gets even uglier if you ever set these radio buttons to be disabled.  In that case, although the client browser renders the radio buttons as though only one of them is checked the system actually retains the value of both of them as checked, and your next trip to the server will really frustrate you because the browser showed rdo2 as checked, but your DoSomething1() routine keeps getting executed. The following is sample code you can put into any WebForm to test this yourself. 1: <body> 2: <form id="form1" runat="server"> 3: <h1>Radio Button Test</h1> 4: <hr /> 5: <asp:Button runat="server" ID="cmdBlankPostback" Text="Blank Postback" /> 6: &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 7: <asp:Button runat="server" ID="cmdEnable" Text="Enable All" OnClick="cmdEnable_Click" /> 8: &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 9: <asp:Button runat="server" ID="cmdDisable" Text="Disable All" OnClick="cmdDisable_Click" /> 10: &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 11: <asp:Button runat="server" ID="cmdTest" Text="Test" OnClick="cmdTest_Click" /> 12: <br /><br /><br /> 13: <asp:RadioButton ID="rdoG1R1" GroupName="Group1" runat="server" Text="Group 1 Radio 1" Checked="true" /><br /> 14: <asp:RadioButton ID="rdoG1R2" GroupName="Group1" runat="server" Text="Group 1 Radio 2" /><br /> 15: <asp:RadioButton ID="rdoG1R3" GroupName="Group1" runat="server" Text="Group 1 Radio 3" /><br /> 16: <hr /> 17: <asp:RadioButton ID="rdoG2R1" GroupName="Group2" runat="server" Text="Group 2 Radio 1" /><br /> 18: <asp:RadioButton ID="rdoG2R2" GroupName="Group2" runat="server" Text="Group 2 Radio 2" Checked="true" /><br /> 19:  20: </form> 21: </body> 1: protected void Page_Load(object sender, EventArgs e) 2: { 3:  4: } 5:  6: protected void cmdEnable_Click(object sender, EventArgs e) 7: { 8: rdoG1R1.Enabled = true; 9: rdoG1R2.Enabled = true; 10: rdoG1R3.Enabled = true; 11: rdoG2R1.Enabled = true; 12: rdoG2R2.Enabled = true; 13: } 14:  15: protected void cmdDisable_Click(object sender, EventArgs e) 16: { 17: rdoG1R1.Enabled = false; 18: rdoG1R2.Enabled = false; 19: rdoG1R3.Enabled = false; 20: rdoG2R1.Enabled = false; 21: rdoG2R2.Enabled = false; 22: } 23:  24: protected void cmdTest_Click(object sender, EventArgs e) 25: { 26: rdoG1R2.Checked = true; 27: rdoG2R1.Checked = true; 28: } 29: 30: protected void Page_PreRender(object sender, EventArgs e) 31: { 32:  33: } After you copy the markup and page-behind code into the appropriate files.  I recommend you set a breakpoint on Page_Load as well as cmdTest_Click, and add each of the radio button controls to the Watch list so that you can walk through the code and see exactly what is happening.  Use the Blank Postback button to cause a postback to the server so you can inspect things without making any changes. The moral of the story is: if you do server-side manipulation of the Checked status of RadioButton controls, then you need to set ALL of the controls in a group whenever you want to change one.

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• Web Services Example - Part 2: Programmatic

  - by Denis T

  In this edition of the ADF Mobile blog we'll tackle part 2 of our Web Service examples.  In this posting we'll take a look at using a SOAP Web Service but calling it programmatically in code and parsing the return into a bean. Getting the sample code: Just click here to download a zip of the entire project.  You can unzip it and load it into JDeveloper and deploy it either to iOS or Android.  Please follow the previous blog posts if you need help getting JDeveloper or ADF Mobile installed.  Note: This is a different workspace than WS-Part1 Defining our Web Service: Just like our first installment, we are using the same public weather forecast web service provided free by CDYNE Corporation.  Sometimes this service goes down so please ensure you know it's up before reporting this example isn't working. We're going to concentrate on the same two web service methods, GetCityForecastByZIP and GetWeatherInformation. Defing the Application: The application setup is identical to the Weather1 version.  There are some improvements to the data that is displayed as part of this example though.  Now we are able to show the associated image along with each forecast line when using the Forecast By Zip feature.  We've also added the temperature Hi/Low values into the UI. Summary of Fundamental Changes In This Application The most fundamental change is that we're binding the UI to the Bean Data Controls instead of directly to the Web Service Data Controls.  This gives us much more flexibility to control the shape of the data and allows us to do caching of the data outside of the Web Service.  This way if your application is, say offline, your bean could still populate with data from a local cache and still show you some UI as opposed to completely failing because you don't have any connectivity. In general we promote this type of programming technique with ADF Mobile to insulate your application from any issues with network connectivity. What's different with this example? We have setup the Web Service DC the same way but now we have managed beans to process the data.  The following classes define the "Model" of our application:  CityInformation-CityForecast-Forecast, WeatherInformation-WeatherDescription.  We use WeatherBean for UI interaction to the model layer.  If you look through this example, we don't really do that much with the java code except use it to grab the image URL from the weather description.  In a more realistic example, you might be using some JDBC classes to persist the data to a local database. To have a good architecture it is always good to keep your model and UI layers separate.  This gets muddied if you start to use bindings on a page invoked from Java code and this java code starts to become your "model" layer.  Since bindings are page specific, your model layer starts to become entwined with your UI.  Not good!  To help with this, we've added some utility functions that let you invoke DC methods without having a binding and thus execute methods from your "model" layer without requiring a binding in your page definition.  We do this with the invokeDataControlMethod of the AdfmfJavaUtilities class.  An example of this method call is available in line 95 of WeatherInformation.java and line 93 of CityInformation.Java. What's a GenericType? Because Web Service Data Controls (and also URL Data Controls AKA REST) use generic name/value pairs to define their structure and don't have strongly typed objects, these are actually stored internally as GenericType objects.  The GenericType class is simply a property map of name/value pairs that can be hierarchical.  There are methods like getAttribute where you supply the index of the attribute or it's string property name.  Why is this important to know?  Because invokeDataControlMethod returns GenericType objects and developers either need to parse these GenericType objects themselves or use one of our helper functions. GenericTypeBeanSerializationHelper This class does exactly what it's name implies.  It's a helper class for developers to aid in serialization of GenericTypes to/from java objects.  This is extremely handy if you have a large GenericType object with many attributes (or you're just lazy like me!) and you just want to parse it out into a real java object you can use more easily.  Here you would use the fromGenericType method.  This method takes the class of the Java object you wish to return and the GenericType as parameters.  The method then parses through each attribute in the GenericType and uses reflection to set that same attribute in the Java class.  Then the method returns that new object of the class you specified.  This is obviously very handy to avoid a lot of shuffling code between GenericType and your own Java classes.  The reverse method, toGenericType is also available when you want to go the other way.  In this case you supply the string that represents the package location in the DataControl definition (Example: "MyDC.myParams.MyCollection") and then pass in the Java object you have that holds the data and a GenericType is returned to you.  Again, it will use reflection to calculate the attributes that match between the java class and the GenericType and call the getters/setters on those. Issues and Possible Improvements: In the next installment we'll show you how to make your web service calls asynchronously so your UI will fill dynamically when the service call returns but in the meantime you show the data you have locally in your bean fed from some local cache.  This gives your users instant delivery of some data while you fetch other data in the background.

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• Proxied calls not working as expected

  - by AndyH

  I have been modifying an application to have a cleaner client/server split to allow for load splitting and resource sharing etc. Everything is written to an interface so it was easy to add a remoting layer to the interface using a proxy. Everything worked fine. The next phase was to add a caching layer to the interface and again this worked fine and speed was improved but not as much as I would have expected. On inspection it became very clear what was going on. I feel sure that this behavior has been seen many times before and there is probably a design pattern to solve the problem but it eludes me and I'm not even sure how to describe it. It is easiest explained with an example. Let's imagine the interface is interface IMyCode { List<IThing> getLots( List<String> ); IThing getOne( String id ); } The getLots() method calls getOne() and fills up the list before returning. The interface is implemented at the client which is proxied to a remoting client which then calls the remoting server which in turn calls the implementation at the server. At the client and the server layers there is also a cache. So we have :- Client interface | Client cache | Remote client | Remote server | Server cache | Server interface If we call getOne("A") at the client interface, the call is passed to the client cache which faults. This then calls the remote client which passes the call to the remote server. This then calls the server cache which also faults and so the call is eventually passed to the server interface which actually gets the IThing. In turn the server cache is filled and finally the client cache also. If getOne("A") is again called at the client interface the client cache has the data and it gets returned immediately. If a second client called getOne("B") it would fill the server cache with "B" as well as it's own client cache. Then, when the first client calls getOne("B") the client cache faults but the server cache has the data. This is all as one would expect and works well. Now lets call getLots( [ "C", "D" ] ). This works as you would expect by calling getOne() twice but there is a subtlety here. The call to getLots() cannot directly make use of the cache. Therefore the sequence is to call the client interface which in turn calls the remote client, then the remote server and eventually the server interface. This then calls getOne() to fill the list before returning. The problem is that the getOne() calls are being satisfied at the server when ideally they should be satisfied at the client. If you imagine that the client/server link is really slow then it becomes clear why the client call is more efficient than the server call once the client cache has the data. This example is contrived to illustrate the point. The more general problem is that you cannot just keep adding proxied layers to an interface and expect it to work as you would imagine. As soon as the call goes 'through' the proxy any subsequent calls are on the proxied side rather than 'self' side. Have I failed to learn or not learned something correctly? All this is implemented in Java and I haven't used EJBs. It seems that the example may be confusing. The problem is nothing to do with cache efficiencies. It is more to do with an illusion created by the use of proxies or AOP techniques in general. When you have an object whose class implements an interface there is an assumption that a call on that object might make further calls on that same object. For example, public String getInternalString() { return InetAddress.getLocalHost().toString(); } public String getString() { return getInternalString(); } If you get an object and call getString() the result depends where the code is running. If you add a remoting proxy to the class then the result could be different for calls to getString() and getInternalString() on the same object. This is because the initial call gets 'deproxied' before the actual method is called. I find this not only confusing but I wonder how I can control this behavior especially as the use of the proxy may be by a third party. The concept is fine but the practice is certainly not what I expected. Have I missed the point somewhere?

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• How to create Captcha in ASP.NET

  - by Samir R. Bhogayta

  1. Create one page with name "Captcha.aspx" 2. No any control require in this page 3. Go to Captcha.aspx.vb write the below code Protected Sub Page_Load(sender As Object, e As System.EventArgs) Handles Me.Load         'create object of Bitmap Class and set its width and height.         Dim objBMP As Bitmap = New Bitmap(180, 51)         'Create Graphics object and assign bitmap object to graphics' object.         Dim objGraphics As Graphics = Graphics.FromImage(objBMP)         objGraphics.Clear(Color.White)         objGraphics.TextRenderingHint = TextRenderingHint.AntiAlias         Dim objFont As Font = New Font("arial", 30, FontStyle.Bold)         'genetating random 6 digit random number         Dim randomStr As String = GeneratePassword()         'set this random number in session         Session.Add("randomStr", randomStr)         Session.Add("randomStrCountry", randomStr)         objGraphics.DrawString(randomStr, objFont, Brushes.Black, 2, 2)         Response.ContentType = "image/GIF"         objBMP.Save(Response.OutputStream, ImageFormat.Gif)         objFont.Dispose()         objGraphics.Dispose()         objBMP.Dispose()     End Sub     Public Function GeneratePassword() As String         ' Below code describes how to create random numbers.some of the digits and letters         ' are ommited because they look same like "i","o","1","0","I","O".         Dim allowedChars As String = "a,b,c,d,e,f,g,h,j,k,m,n,p,q,r,s,t,u,v,w,x,y,z,"         allowedChars += "A,B,C,D,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,U,V,W,X,Y,Z,"         allowedChars += "2,3,4,5,6,7,8,9"         Dim sep() As Char = {","c}         Dim arr() As String = allowedChars.Split(sep)         Dim passwordString As String = ""         Dim temp As String         Dim rand As Random = New Random()         Dim i As Integer         For i = 0 To 5 - 1 Step i + 1             temp = arr(rand.Next(0, arr.Length))             passwordString += temp         Next         Return passwordString     End Function 4. Use this page in you aspx page like this img alt="" border="0" src="Captcha.aspx" style="cursor: move; height: 60px; width: 200px;" //                                   your textbox to insert code by user.

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• c# display DB table structure

  - by user3529643

  I have a question. My code is the following : public partial class Form1 : Form { public OleDbConnection datCon; public string MyDataFile; public ArrayList tblArray; public ArrayList fldArray; public Form1() { InitializeComponent(); lvData.Clear(); lvData.View = View.Details; lvData.LabelEdit = false; lvData.FullRowSelect = true; lvData.GridLines = true; } private void DataConnection() { MyDataFile = Application.StartupPath + @"\studenti.mdb"; string MyCon = @"provider=microsoft.jet.oledb.4.0;data source=" + MyDataFile; try { datCon = new OleDbConnection(MyCon); } catch (Exception ex) { MessageBox.Show(ex.Message); } FillTreeView(); } private void GetTables(OleDbConnection cnn) { try { cnn.Open(); DataTable schTable = cnn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, new Object[] { null, null, null, "TABLE" }); tblArray = new ArrayList(); foreach (DataRow datrow in schTable.Rows) { tblArray.Add(datrow["TABLE_NAME"].ToString()); } cnn.Close(); } catch (Exception ex) { MessageBox.Show(ex.Message); } } private void GetFields(OleDbConnection cnn, string tabNode) { string tabName; try { tabName = tabNode; cnn.Open(); DataTable schTable = cnn.GetOleDbSchemaTable(OleDbSchemaGuid.Columns, new Object[] { null, null, tabName }); fldArray = new ArrayList(); foreach (DataRow datRow in schTable.Rows) { fldArray.Add(datRow["COLUMN_NAME"].ToString()); } cnn.Close(); } catch (Exception ex) { MessageBox.Show(ex.Message); } } private void FillTreeView() { tvData.Nodes.Clear(); tvData.Nodes.Add("Database"); tvData.Nodes[0].Tag = "RootDB"; GetTables(datCon); // add table node for (int i = 0; i < tblArray.Count; i++) { tvData.Nodes[0].Nodes.Add(tblArray[i].ToString()); tvData.Nodes[0].Nodes[i].Tag = "Tables"; } // add field node for (int i = 0; i < tblArray.Count; i++) { GetFields(datCon, tblArray[i].ToString()); for (int j = 0; j < fldArray.Count; j++) { tvData.Nodes[0].Nodes[i].Nodes.Add(fldArray[j].ToString()); tvData.Nodes[0].Nodes[i].Nodes[j].Tag = "Fields"; } } this.tvData.ContextMenuStrip = contextMenuStrip1; contextMenuStrip1.ItemClicked +=contextMenuStrip1_ItemClicked; } public void FillListView(OleDbConnection cnn, string tabName) { OleDbCommand cmdRead; OleDbDataReader datReader; string strField; lblTableName.Text = tabName; strField = "SELECT * FROM [" + tabName + "]"; // Initi cmdRead obiect cmdRead = new OleDbCommand(strField, cnn); cnn.Open(); datReader = cmdRead.ExecuteReader(); // fill ListView while (datReader.Read()) { ListViewItem objListItem = new ListViewItem(datReader.GetValue(0).ToString()); for (int c = 1; c < datReader.FieldCount; c++) { objListItem.SubItems.Add(datReader.GetValue(c).ToString()); } lvData.Items.Add(objListItem); } datReader.Close(); cnn.Close(); } private void ViewToolStripMenuItem_Click(object sender, EventArgs e) { DataConnection(); } public void tvData_AfterExpand(object sender, System.Windows.Forms.TreeViewEventArgs e) { string tabName; int fldCount; if (e.Node.Tag.ToString() == "Tables") { fldCount = e.Node.GetNodeCount(false); //column headers. int n = lvData.Width; double wid = n / fldCount; // width columnn for (int c = 0; c < fldCount; c++) { lvData.Columns.Add(e.Node.Nodes[c].Text, (int)wid, HorizontalAlignment.Left); } // gett table name tabName = e.Node.Text; FillListView(datCon, tabName); } } public void button1_Click(object sender, EventArgs e) { //TO DO?? } } I have a treeview populated with tables (nodes) from my database, and a listview which is populated with the data from my tables when I click on a table. As you can see I have a button1 on my form. When I click it I want it to display to me the structure of the table I selected in my treeview (a treeview node). Not too many details, just the name of the columns in my table, type of columns, primary keys. I've tried to follow many tutorials but I can t seem to manage it.

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• What is wrong with Paperclip+ImageMagick on Heroku?

  - by Yuri

  UPD class User < ActiveRecord::Base Paperclip.options[:swallow_stderr] = false has_attached_file :photo, :styles => { :square => "100%", :large => "100%" }, :convert_options => { :square => "-auto-orient -geometry 70X70#", :large => "-auto-orient -geometry X300" }, :storage => :s3, :s3_credentials => "#{RAILS_ROOT}/config/s3.yml", :path => ":attachment/:id/:style.:extension", :bucket => 'mybucket' validates_attachment_size :photo, :less_than => 5.megabyte end Works great on local machine, but gives me an error on Heroku: There was an error processing the thumbnail for stream.20143 The thing is I want to auto-orient photos before resizing, so they resized properly. The only working variant now(thanks to jonnii) is resizing without auto-orient: ... as_attached_file :photo, :styles => { :square => "70X70#", :large => "X300" }, :storage => :s3, :s3_credentials => "#{RAILS_ROOT}/config/s3.yml", :path => ":attachment/:id/:style.:extension", :bucket => 'mybucket' ... How to pass additional convert options to paperclip on Heroku?

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• XNA Xbox 360 Content Manager Thread freezing Draw Thread

  - by Alikar

  I currently have a game that takes in large images, easily bigger than 1MB, to serve as backgrounds. I know exactly when this transition is supposed to take place, so I made a loader class to handle loading these large images in the background, but when I load the images it still freezes the main thread where the drawing takes place. Since this code runs on the 360 I move the thread to the 4th hardware thread, but that doesn't seem to help. Below is the class I am using. Any thoughts as to why my new content manager which should be in its own thread is interrupting the draw in my main thread would be appreciated. namespace FileSystem { /// <summary> /// This is used to reference how many objects reference this texture. /// Everytime someone references a texture we increase the iNumberOfReferences. /// When a class calls remove on a specific texture we check to see if anything /// else is referencing the class, if it is we don't remove it. If there isn't /// anything referencing the texture its safe to dispose of. /// </summary> class TextureContainer { public uint uiNumberOfReferences = 0; public Texture2D texture; } /// <summary> /// This class loads all the files from the Content. /// </summary> static class FileManager { static Microsoft.Xna.Framework.Content.ContentManager Content; static EventWaitHandle wh = new AutoResetEvent(false); static Dictionary<string, TextureContainer> Texture2DResourceDictionary; static List<Texture2D> TexturesToDispose; static List<String> TexturesToLoad; static int iProcessor = 4; private static object threadMutex = new object(); private static object Texture2DMutex = new object(); private static object loadingMutex = new object(); private static bool bLoadingTextures = false; /// <summary> /// Returns if we are loading textures or not. /// </summary> public static bool LoadingTexture { get { lock (loadingMutex) { return bLoadingTextures; } } } /// <summary> /// Since this is an static class. This is the constructor for the file loadeder. This is the version /// for the Xbox 360. /// </summary> /// <param name="_Content"></param> public static void Initalize(IServiceProvider serviceProvider, string rootDirectory, int _iProcessor ) { Content = new Microsoft.Xna.Framework.Content.ContentManager(serviceProvider, rootDirectory); Texture2DResourceDictionary = new Dictionary<string, TextureContainer>(); TexturesToDispose = new List<Texture2D>(); iProcessor = _iProcessor; CreateThread(); } /// <summary> /// Since this is an static class. This is the constructor for the file loadeder. /// </summary> /// <param name="_Content"></param> public static void Initalize(IServiceProvider serviceProvider, string rootDirectory) { Content = new Microsoft.Xna.Framework.Content.ContentManager(serviceProvider, rootDirectory); Texture2DResourceDictionary = new Dictionary<string, TextureContainer>(); TexturesToDispose = new List<Texture2D>(); CreateThread(); } /// <summary> /// Creates the thread incase we wanted to set up some parameters /// Outside of the constructor. /// </summary> static public void CreateThread() { Thread t = new Thread(new ThreadStart(StartThread)); t.Start(); } // This is the function that we thread. static public void StartThread() { //BBSThreadClass BBSTC = (BBSThreadClass)_oData; FileManager.Execute(); } /// <summary> /// This thread shouldn't be called by the outside world. /// It allows the File Manager to loop. /// </summary> static private void Execute() { // Make sure our thread is on the correct processor on the XBox 360. #if WINDOWS #else Thread.CurrentThread.SetProcessorAffinity(new int[] { iProcessor }); Thread.CurrentThread.IsBackground = true; #endif // This loop will load textures into ram for us away from the main thread. while (true) { wh.WaitOne(); // Locking down our data while we process it. lock (threadMutex) { lock (loadingMutex) { bLoadingTextures = true; } bool bContainsKey = false; for (int con = 0; con < TexturesToLoad.Count; con++) { // If we have already loaded the texture into memory reference // the one in the dictionary. lock (Texture2DMutex) { bContainsKey = Texture2DResourceDictionary.ContainsKey(TexturesToLoad[con]); } if (bContainsKey) { // Do nothing } // Otherwise load it into the dictionary and then reference the // copy in the dictionary else { TextureContainer TC = new TextureContainer(); TC.uiNumberOfReferences = 1; // We start out with 1 referece. // Loading the texture into memory. try { TC.texture = Content.Load<Texture2D>(TexturesToLoad[con]); // This is passed into the dictionary, thus there is only one copy of // the texture in memory. // There is an issue with Sprite Batch and disposing textures. // This will have to wait until its figured out. lock (Texture2DMutex) { bContainsKey = Texture2DResourceDictionary.ContainsKey(TexturesToLoad[con]); Texture2DResourceDictionary.Add(TexturesToLoad[con], TC); } // We don't have the find the reference to the container since we // already have it. } // Occasionally our texture will already by loaded by another thread while // this thread is operating. This mainly happens on the first level. catch (Exception e) { // If this happens we don't worry about it since this thread only loads // texture data and if its already there we don't need to load it. } } Thread.Sleep(100); } } lock (loadingMutex) { bLoadingTextures = false; } } } static public void LoadTextureList(List<string> _textureList) { // Ensuring that we can't creating threading problems. lock (threadMutex) { TexturesToLoad = _textureList; } wh.Set(); } /// <summary> /// This loads a 2D texture which represents a 2D grid of Texels. /// </summary> /// <param name="_textureName">The name of the picture you wish to load.</param> /// <returns>Holds the image data.</returns> public static Texture2D LoadTexture2D( string _textureName ) { TextureContainer temp; lock (Texture2DMutex) { bool bContainsKey = false; // If we have already loaded the texture into memory reference // the one in the dictionary. lock (Texture2DMutex) { bContainsKey = Texture2DResourceDictionary.ContainsKey(_textureName); if (bContainsKey) { temp = Texture2DResourceDictionary[_textureName]; temp.uiNumberOfReferences++; // Incrementing the number of references } // Otherwise load it into the dictionary and then reference the // copy in the dictionary else { TextureContainer TC = new TextureContainer(); TC.uiNumberOfReferences = 1; // We start out with 1 referece. // Loading the texture into memory. try { TC.texture = Content.Load<Texture2D>(_textureName); // This is passed into the dictionary, thus there is only one copy of // the texture in memory. } // Occasionally our texture will already by loaded by another thread while // this thread is operating. This mainly happens on the first level. catch(Exception e) { temp = Texture2DResourceDictionary[_textureName]; temp.uiNumberOfReferences++; // Incrementing the number of references } // There is an issue with Sprite Batch and disposing textures. // This will have to wait until its figured out. Texture2DResourceDictionary.Add(_textureName, TC); // We don't have the find the reference to the container since we // already have it. temp = TC; } } } // Return a reference to the texture return temp.texture; } /// <summary> /// Go through our dictionary and remove any references to the /// texture passed in. /// </summary> /// <param name="texture">Texture to remove from texture dictionary.</param> public static void RemoveTexture2D(Texture2D texture) { foreach (KeyValuePair<string, TextureContainer> pair in Texture2DResourceDictionary) { // Do our references match? if (pair.Value.texture == texture) { // Only one object or less holds a reference to the // texture. Logically it should be safe to remove. if (pair.Value.uiNumberOfReferences <= 1) { // Grabing referenc to texture TexturesToDispose.Add(pair.Value.texture); // We are about to release the memory of the texture, // thus we make sure no one else can call this member // in the dictionary. Texture2DResourceDictionary.Remove(pair.Key); // Once we have removed the texture we don't want to create an exception. // So we will stop looking in the list since it has changed. break; } // More than one Object has a reference to this texture. // So we will not be removing it from memory and instead // simply marking down the number of references by 1. else { pair.Value.uiNumberOfReferences--; } } } } /*public static void DisposeTextures() { int Count = TexturesToDispose.Count; // If there are any textures to dispose of. if (Count > 0) { for (int con = 0; con < TexturesToDispose.Count; con++) { // =!THIS REMOVES THE TEXTURE FROM MEMORY!= // This is not like a normal dispose. This will actually // remove the object from memory. Texture2D is inherited // from GraphicsResource which removes it self from // memory on dispose. Very nice for game efficency, // but "dangerous" in managed land. Texture2D Temp = TexturesToDispose[con]; Temp.Dispose(); } // Remove textures we've already disposed of. TexturesToDispose.Clear(); } }*/ /// <summary> /// This loads a 2D texture which represnets a font. /// </summary> /// <param name="_textureName">The name of the font you wish to load.</param> /// <returns>Holds the font data.</returns> public static SpriteFont LoadFont( string _fontName ) { SpriteFont temp = Content.Load<SpriteFont>( _fontName ); return temp; } /// <summary> /// This loads an XML document. /// </summary> /// <param name="_textureName">The name of the XML document you wish to load.</param> /// <returns>Holds the XML data.</returns> public static XmlDocument LoadXML( string _fileName ) { XmlDocument temp = Content.Load<XmlDocument>( _fileName ); return temp; } /// <summary> /// This loads a sound file. /// </summary> /// <param name="_fileName"></param> /// <returns></returns> public static SoundEffect LoadSound( string _fileName ) { SoundEffect temp = Content.Load<SoundEffect>(_fileName); return temp; } } }

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• Dealing with huge SQL resultset

  - by Dave McClelland

  I am working with a rather large mysql database (several million rows) with a column storing blob images. The application attempts to grab a subset of the images and runs some processing algorithms on them. The problem I'm running into is that, due to the rather large dataset that I have, the dataset that my query is returning is too large to store in memory. For the time being, I have changed the query to not return the images. While iterating over the resultset, I run another select which grabs the individual image that relates to the current record. This works, but the tens of thousands of extra queries have resulted in a performance decrease that is unacceptable. My next idea is to limit the original query to 10,000 results or so, and then keep querying over spans of 10,000 rows. This seems like the middle of the road compromise between the two approaches. I feel that there is probably a better solution that I am not aware of. Is there another way to only have portions of a gigantic resultset in memory at a time? Cheers, Dave McClelland

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• Handling multiple column data with Java

  - by Ender

  I am writing an application that reads in a large number of basic user details in the following format; once read in it then allows the user to search for a user's details using their email: NAME ROLE EMAIL --------------------------------------------------- Joe Bloggs Manager [email protected] John Smith Consultant [email protected] Alan Wright Tester [email protected] ... The problem I am suffering is that I need to store a large number of details of all people that have worked at the company. The file containing these details will be written on a yearly basis simply for reporting purposes, but the program will need to be able to access these details quickly. The way I aim to access these files is to have a program that asks the user for the name of the unique email of the member of staff and for the program to then return the name and the role from that line of the file. I've played around with text files, but am struggling with how I would handle multiple columns of data when it comes to searching this large file. What is the best format to store such data in? A text file? XML? The size doesn't bother me, but I'd like to be able to search it as quickly as possible. The file will need to contain a lot of entries, probably over the 10K mark over time.

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• C# average function without overflow exception

  - by Ron Klein

  .NET Framework 3.5. I'm trying to calculate the average of some pretty large numbers. For instance: using System; using System.Linq; class Program { static void Main(string[] args) { var items = new long[] { long.MaxValue - 100, long.MaxValue - 200, long.MaxValue - 300 }; try { var avg = items.Average(); Console.WriteLine(avg); } catch (OverflowException ex) { Console.WriteLine("can't calculate that!"); } Console.ReadLine(); } } Obviously, the mathematical result is 9223372036854775607 (long.MaxValue - 200), but I get an exception there. This is because the implementation (on my machine) to the Average extension method, as inspected by .NET Reflector is: public static double Average(this IEnumerable<long> source) { if (source == null) { throw Error.ArgumentNull("source"); } long num = 0L; long num2 = 0L; foreach (long num3 in source) { num += num3; num2 += 1L; } if (num2 <= 0L) { throw Error.NoElements(); } return (((double) num) / ((double) num2)); } I know I can use a BigInt library (yes, I know that it is included in .NET Framework 4.0, but I'm tied to 3.5). But I still wonder if there's a pretty straight forward implementation of calculating the average of integers without an external library. Do you happen to know about such implementation? Thanks!! UPDATE: The previous example, of three large integers, was just an example to illustrate the overflow issue. The question is about calculating an average of any set of numbers which might sum to a large number that exceeds the type's max value. Sorry about this confusion. I also changed the question's title to avoid additional confusion. Thanks all!!

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• Github file size limit changed 6/18/13. Can't push now

  - by slindsey3000

  How does this change as of June 18, 2013 affect my existing repository with a file that exceeds that limit? I last pushed 2 months ago with a large file. I have a large file that I have removed locally but I can not push anything now. I get a "remote error" ... remote: error: File cron_log.log is 126.91 MB; this exceeds GitHub's file size limit of 100 MB I added the file to .gitignore after original push... But it still exists on remote (origin) Removing it locally should get rid of it at origin(Github) right? ... but ... it is not letting me push because there is a file on Github that exceeds the limit... https://github.com/blog/1533-new-file-size-limits These are the commands I issued plus error messages.. git add . git commit -m "delete cron_log.log" git push origin master remote: Error code: 40bef1f6653fd2410fb2ab40242bc879 remote: warning: Error GH413: Large files detected. remote: warning: See http://git.io/iEPt8g for more information. remote: error: File cron_log.log is 141.41 MB; this exceeds GitHub's file size limit of 100 MB remote: error: File cron_log.log is 126.91 MB; this exceeds GitHub's file size limit of 100 MB To https://github.com/slinds(omited_here)/linexxxx(omited_here).git ! [remote rejected] master - master (pre-receive hook declined) error: failed to push some refs to 'https://github.com/slinds(omited_here) I then tried things like git rm cron_log.log git rm --cached cron_log.log Same error.

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• Codeigniter image manipulation class rotates image during resize

  - by someoneinomaha

  I'm using Codeigniter's image manipulation library to re-size an uploaded image to three sizes, small, normal and large. The re-sizing is working great. However, if I'm resizing a vertical image, the library is rotating the image so it's horizontal. These are the config settings I have in place: $this->resize_config['image_library'] = 'gd2'; $this->resize_config['source_image'] = $this->file_data['full_path']; $this->resize_config['maintain_ratio'] = TRUE; // These change based on the type (small, normal, large) $this->resize_config['new_image'] = './uploads/large/'.$this->new_file_name.'.jpg'; $this->resize_config['width'] = 432; $this->resize_config['height'] = 288; I'm not setting the master_dim property because the default it set to auto, which is what I want. My assumption is that the library would take a vertical image, see that the height is greater than the width and translate the height/width config appropriately so the image remains vertical. What is happening (apparently) is that the library is rotating the image when it is vertical and sizing it per the configuration. This is the code in place I have to do the actual re-sizing: log_message('debug', 'attempting '.$size.' photo resize'); $this->CI->load->library('image_lib'); $this->CI->image_lib->initialize($this->resize_config); if ($this->CI->image_lib->resize()) { $return_value = TRUE; log_message('debug', $size.' photo resize successful'); } else { $this->errors[] = $this->CI->image_lib->display_errors(); log_message('debug', $size.' photo resize failed'); } $this->CI->image_lib->clear(); return $return_value;

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• Perl XML SAX parser emulating XML::Simple record for record

  - by DVK

  Short Q summary: I am looking a fast XML parser (most likely a wrapper around some standard SAX parser) which will produce per-record data structure 100% identical to those produced by XML::Simple. Details: We have a large code infrastructure which depends on processing records one-by-one and expects the record to be a data structure in a format produced by XML::Simple since it always used XML::Simple since early Jurassic era. An example simple XML is: <root> <rec><f1>v1</f1><f2>v2</f2></rec> <rec><f1>v1b</f1><f2>v2b</f2></rec> <rec><f1>v1c</f1><f2>v2c</f2></rec> </root> And example rough code is: sub process_record { my ($obj, $record_hash) = @_; # do_stuff } my $records = XML::Simple->XMLin(@args)->{root}; foreach my $record (@$records) { $obj->process_record($record) }; As everyone knows XML::Simple is, well, simple. And more importantly, it is very slow and a memory hog - due to being a DOM parser and needing to build/store 100% of data in memory. So, it's not the best tool for parsing an XML file consisting of large amount of small records record-by-record. However, re-writing the entire code (which consist of large amount of "process_record"-like methods) to work with standard SAX parser seems like an big task not worth the resources, even at the cost of living with XML::Simple. What I'm looking for is an existing module which will probably be based on a SAX parser (or anything fast with small memory footprint) which can be used to produce $record hashrefs one by one based on the XML pictured above that can be passed to $obj->process_record($record) and be 100% identical to what XML::Simple's hashrefs would have been. I don't care much what the interface of the new module is - e.g whether I need to call next_record() or give it a callback coderef accepting a record.

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• How to pass additional convert options to paperclip on Heroku?

  - by Yuri

  UPD class User < ActiveRecord::Base Paperclip.options[:swallow_stderr] = false has_attached_file :photo, :styles => { :square => "100%", :large => "100%" }, :convert_options => { :square => "-auto-orient -geometry 70X70#", :large => "-auto-orient -geometry X300" }, :storage => :s3, :s3_credentials => "#{RAILS_ROOT}/config/s3.yml", :path => ":attachment/:id/:style.:extension", :bucket => 'mybucket' validates_attachment_size :photo, :less_than => 5.megabyte end Works great on local machine, but gives me an error on Heroku: There was an error processing the thumbnail for stream.20143 The thing is I want to auto-orient photos before resizing, so they resized properly. The only working variant now(thanks to jonnii) is resizing without auto-orient: ... as_attached_file :photo, :styles => { :square => "70X70#", :large => "X300" }, :storage => :s3, :s3_credentials => "#{RAILS_ROOT}/config/s3.yml", :path => ":attachment/:id/:style.:extension", :bucket => 'mybucket' ... How to pass additional convert options to paperclip on Heroku?

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• Average function without overflow exception

  - by Ron Klein

  .NET Framework 3.5. I'm trying to calculate the average of some pretty large numbers. For instance: using System; using System.Linq; class Program { static void Main(string[] args) { var items = new long[] { long.MinValue + 100, long.MinValue + 200, long.MinValue + 300 }; try { var avg = items.Average(); Console.WriteLine(avg); } catch (OverflowException ex) { Console.WriteLine("can't calculate that!"); } Console.ReadLine(); } } Obviously, the mathematical result is 9223372036854775607 (long.MaxValue - 200), but I get an exception there. This is because the implementation (on my machine) to the Average extension method, as inspected by .NET Reflector is: public static double Average(this IEnumerable<long> source) { if (source == null) { throw Error.ArgumentNull("source"); } long num = 0L; long num2 = 0L; foreach (long num3 in source) { num += num3; num2 += 1L; } if (num2 <= 0L) { throw Error.NoElements(); } return (((double) num) / ((double) num2)); } I know I can use a BigInt library (yes, I know that it is included in .NET Framework 4.0, but I'm tied to 3.5). But I still wonder if there's a pretty straight forward implementation of calculating the average of integers without an external library. Do you happen to know about such implementation? Thanks!! UPDATE: The previous example, of three large integers, was just an example to illustrate the overflow issue. The question is about calculating an average of any set of numbers which might sum to a large number that exceeds the type's max value. Sorry about this confusion. I also changed the question's title to avoid additional confusion. Thanks all!!

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• How to forward a 'saved' request stream to another Action within the same controller?

  - by Moe Howard

  We have a need to chunk-up large http requests sent by our mobile devices. These smaller chunk streams are merged to a file on the server. Once all chunks are received we need a way to submit the saved merged request to an another method(Action) within the same controller that will process this large http request. How can this be done? The code we tried below results in the service hanging. Is there a way to do this without a round-trip? //Open merged chunked file FileStream fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read); //Read steam support variables int bytesRead = 0; byte[] buffer = new byte[1024]; //Build New Web Request. The target Action is called "Upload", this method we are in is called "UploadChunk" HttpWebRequest webRequest; webRequest = (HttpWebRequest)WebRequest.Create(Request.Url.ToString().Replace("Chunk", string.Empty)); webRequest.Method = "POST"; webRequest.ContentType = "text/xml"; webRequest.KeepAlive = true; webRequest.Timeout = 600000; webRequest.ReadWriteTimeout = 600000; webRequest.Credentials = System.Net.CredentialCache.DefaultCredentials; Stream webStream = webRequest.GetRequestStream(); //Hangs here, no errors, just hangs I have looked into using RedirectToAction and RedirecctToRoute but these methods don't fit well with what we are looking to do as we cannot edit the Request.InputStream (as it is read-only) to carry out large request stream. Thanks, Moe

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