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CodePlex Daily Summary for Friday, November 23, 2012

CodePlex Daily Summary for Friday, November 23, 2012Popular ReleasesLiberty: v3.4.3.0 Release 23rd November 2012: Change Log -Added -H4 A dialog which gives further instructions when attempting to open a "Halo 4 Data" file -H4 Added a short note to the weapon editor stating that dropping your weapons will cap their ammo -Reach Edit the world's gravity -Reach Fine invincibility controls in the object editor -Reach Edit object velocity -Reach Change the teams of AI bipeds and vehicles -Reach Enable/disable fall damage on the biped editor screen -Reach Make AIs deaf and/or blind in the objec...Umbraco CMS: Umbraco 4.11.0: NugetNuGet BlogRead the release blog post for 4.11.0. Whats new50 bugfixes (see the issue tracker for a complete list) Read the documentation for the MVC bits. Breaking changesNone since 4.10.0 NoteIf you need Courier use the release candidate (as of build 26). The code editor has been greatly improved, but is sometimes problematic in Internet Explorer 9 and lower. Previously it was just disabled for IE and we recommend you disable it in umbracoSettings.config (scriptDisableEditor) if y...VidCoder: 1.4.8 Beta: Fixed encode failures when including chapter markers (Regression in 1.4.7).Audio Pitch & Shift: Audio Pitch And Shift 5.1.0.3: Fixed supported files list on open dialog (added .pls and .m3u) Impulse Media Player splash message (can be disabled anyway)LiveChat Starter Kit: LCSK 2.0 alpha: This is an early preview of the LiveChat Starter Kit version 2 using SignalR as the core communication mechanism. To add LCSK to an existing ASP.NET app do the following: Copy the LCSK folder to your ASP.NET project Install SignalR form your package manager window Install-Package SignalR Include the following javascript tags where you want the visitor to see the chat box: <script src="/Scripts/jquery.signalR-0.5.3.min.js" type="text/javascript"></script> <script src="/signalr/hubs" typ...Impulse Media Player: Impulse Media Player 1.0.0.0: Impulse Media Player is born !!!patterns & practices - HiloJS: a Windows Store app using JavaScript: Source with Unit Tests: This source is also available under the _Source Code tab. See the folder Hilo.Specifications.Rackspace Cloud Files Manager: Rackspace Cloud Files Manager v1: Rackspace Cloud Files Manager v1MJPEG Decoder: MJPEG Decoder v1.2: Added support for WinRT (ARM and x86/x64) Added support for Windows Phone 8 Added Error event to catch connection exceptions (thanks to Mirek Czerwinski for the idea) Note that the XNA and WP7 assemblies remain at v1.1 and do not contain this addition Samples for WinRT in C#/XAML and HTML/JavaScript (in source code repository) Sample for Windows Phone 8 in C#/XAML (in source code repository)ServiceMon - Extensible Real-time, Service Monitoring Utility for Windows: ServiceMon Release 1.2.0.58: Auto-uploaded from build serverImapX 2: ImapX 2.0.0.6: An updated release of the ImapX 2 library, containing many bugfixes for both, the library and the sample application.WiX Toolset: WiX v3.7 RC: WiX v3.7 RC (3.7.1119.0) provides feature complete Bundle update and reference tracking plus several bug fixes. For more information see Rob's blog post about the release: http://robmensching.com/blog/posts/2012/11/20/WiX-v3.7-Release-Candidate-availablePicturethrill: Version 2.11.20.0: Fixed up Bing image provider on Windows 8Excel AddIn to reset the last worksheet cell: XSFormatCleaner.xla: Modified the commandbar code to use CommandBar IDs instead of English names.Json.NET: Json.NET 4.5 Release 11: New feature - Added ITraceWriter, MemoryTraceWriter, DiagnosticsTraceWriter New feature - Added StringEscapeHandling with options to escape HTML and non-ASCII characters New feature - Added non-generic JToken.ToObject methods New feature - Deserialize ISet<T> properties as HashSet<T> New feature - Added implicit conversions for Uri, TimeSpan, Guid New feature - Missing byte, char, Guid, TimeSpan and Uri explicit conversion operators added to JToken New feature - Special case...EntitiesToDTOs - Entity Framework DTO Generator: EntitiesToDTOs.v3.0: DTOs and Assemblers can be generated inside project folders! Choose the types you want to generate! Support for Visual Studio 2012 !!! Support for new Entity Framework EDMX (format used by VS2012) ! Support for Enum Types! Optional automatic check for updates! Added the following methods to Assemblers! IEnumerable<DTO>.ToEntities() : ICollection<Entity> IEnumerable<Entity>.ToDTOs() : ICollection<DTO> Indicate class identifier for DTOs and Assemblers! Cleaner Assemblers code....mojoPortal: 2.3.9.4: see release notes on mojoportal.com http://www.mojoportal.com/mojoportal-2394-released Note that we have separate deployment packages for .NET 3.5 and .NET 4.0, but we recommend you to use .NET 4, we will probably drop support for .NET 3.5 once .NET 4.5 is available The deployment package downloads on this page are pre-compiled and ready for production deployment, they contain no C# source code and are not intended for use in Visual Studio. To download the source code see getting the lates...DotNetNuke® Store: 03.01.07: What's New in this release? IMPORTANT: this version requires DotNetNuke 04.06.02 or higher! DO NOT REPORT BUGS HERE IN THE ISSUE TRACKER, INSTEAD USE THE DotNetNuke Store Forum! Bugs corrected: - Replaced some hard coded references to the default address provider classes by the corresponding interfaces to allow the creation of another address provider with a different name. New Features: - Added the 'pickup' delivery option at checkout. - Added the 'no delivery' option in the Store Admin ...ExtJS based ASP.NET 2.0 Controls: FineUI v3.2.0: +2012-11-18 v3.2.0 -?????????????????SelectedValueArray????????（◇?◆:）。 -???????????????????RecoverPropertiesFromJObject????（〓?〓、????、??、Vian_Pan）。 -????????????，?????????????，???SelectedValueArray???????（sam.chang）。 -??Alert.Show???????????（swtseaman）。 -???????????????，??Icon??IconUrl????（swtseaman）。 -?????????TimePicker（??）。 -?????????，??/res.axd?css=blue.css&v=1。 -????????，?????????????，???????。 -????MenuCheckBox（???????）。 -?RadioButton??AutoPostBack??。 -???????FCKEditor?????????...BugNET Issue Tracker: BugNET 1.2: Please read our release notes for BugNET 1.2: http://blog.bugnetproject.com/bugnet-1-2-has-been-released Please do not post questions as reviews. Questions should be posted in the Discussions tab, where they will usually get promptly responded to. If you post a question as a review, you will pollute the rating, and you won't get an answer.New Projects1123case1325: Face everything you enccounting bravely and optimistically1123case1327: blessbestgifts4us1: Gift registry v2CPE-in: A LinkedIn like for CPE Lyon engineering schoolcsanid_cs_db: mvc db operatedurrrguffy: Example project in C# This project has a wide scope and will cover the basics of the dot net framework as it applies to office environment (including sharepoint). At the end of this project, you will be able to call yourself a sharepoint developer. Epic Life: Achievements: An attempt to adapt the achievement system from games to the real life. Something between a to-do manager and a "done-in-this-year"-list. NOT A TO-DO MANAGERGeoVIP: ??????? ??? ?????????????? ?????????? ??????? ???????? ????? ?????????GTcfla KM: ??????????????????????????.??????Oracle????Java????Harlinn Windows: A C++ library targeting Windows 7 and aboveIdentityModel.Tools: Tools to support WIF with .NET 4.5jean1123-1326: rLOLSimulator: AMacroprocesos: Gestión de los procesos existentes en una empresa, así como del control de su ocumentaciónMakeQuestionaryProject: Projeto de geração de questionários dinâmicosMrCMS - ASP.NET MVC Open source CMS: MrCMS is an open source ASP.NET MVC content management system. MyWebApplication: WebApplication Next Code Generator: Next.CodeGen project is a simple application generator that offers a command line interface in order to help developers create WPF applications.Orchard backend additions: Proof of concept for combining translated contenitems and version in the backend content item listProgrammer's Color Picker for C# and WPF: Wybór koloru dla programisty C# i WPFProjet Flux RSS EPSI W: It's a project for windows 8 applicationSpander: Spander ist ein Open-Source VOS (Virtual Operating System).SQLServer Database Browser: It's a simple SQLServer Database Browser for simple query .TemplateCodeGenerator: ????????。???????。Vector Rumble WP7: navmesh navigation demo running on wp7VSDBM - Viral Sequence Data Base Manager: VSDBM - Viral Sequence Database ManagerWebApp2013: Please develop HTML5 mobile web apps rater than native mobile apps! This project is used in my training as MCT for microsoft certified WebApp Developer 70-480.Windows Phone Streaming Media: HTTP Live Streaming (HLS) for Windows Phone.WixDeploymentExtension: Extension support Biztalk Application deployment, Business Activity Monitor (BAM) Deployment and VSDBCMD based SQL deployment and SQLCMD script execution.

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CodePlex Daily Summary for Saturday, November 24, 2012

CodePlex Daily Summary for Saturday, November 24, 2012Popular ReleasesBlackJumboDog: Ver5.7.3: 2012.11.24 Ver5.7.3 (1)SMTP???????、?????????、??????????????????????? (2)?????????、?????????????????????????? (3)DNS???????CNAME????CNAME????????????????? (4)DNS????????????TTL???????? (5)???????????????????????、?????????????????? (6)???????????????????????????????MySqlBackup.NET - MySQL Backup Solution for C#, VB.NET, ASP.NET: MySqlBackup.NET 1.5.4 beta: Fix bug: When setting AddCreateDatabase = true, the database name in CREATE DATABASE sql statement is converted into Upper Case. (It should not) Fix minor bug: When exporting with custom SELECT sql statements, total rows calculation is not based on new specified conditioned SELECT sql statement.FileSystemExplorerExample: 1.0.0.1: Stable ready to downloadTEncoder: 3.1: -Added: Turkish translation (Translators, please see "To translators.txt") -Added: Profiles are now stored in different files under "Profiles" folder -Added: User created Profiles will be saved in a differen directory -Added: Custom video and audio options to profiles -Added: Container options to profiles -Added: Parent folder of input file will be created in the output folder -Added: Option to use 32bit FFmpeg eventhough the OS is 64bit -Added: New skin "Mint" -Fixed: FFMpeg could not open A...Liberty: v3.4.3.0 Release 23rd November 2012: Change Log -Added -H4 A dialog which gives further instructions when attempting to open a "Halo 4 Data" file -H4 Added a short note to the weapon editor stating that dropping your weapons will cap their ammo -Reach Edit the world's gravity -Reach Fine invincibility controls in the object editor -Reach Edit object velocity -Reach Change the teams of AI bipeds and vehicles -Reach Enable/disable fall damage on the biped editor screen -Reach Make AIs deaf and/or blind in the objec...Umbraco CMS: Umbraco 4.11.0: NugetNuGet BlogRead the release blog post for 4.11.0. Whats new50 bugfixes (see the issue tracker for a complete list) Read the documentation for the MVC bits. Breaking changesNone since 4.10.0 NoteIf you need Courier use the release candidate (as of build 26). The code editor has been greatly improved, but is sometimes problematic in Internet Explorer 9 and lower. Previously it was just disabled for IE and we recommend you disable it in umbracoSettings.config (scriptDisableEditor) if y...VidCoder: 1.4.8 Beta: Fixed encode failures when including chapter markers (Regression in 1.4.7).SCCM,Active Directory,Exchange & Powershell customisation,scripts,Web Services: SCCM 2007 - RIS Style naming console extension: CM 2007 console extension Finally giving you power of computer name generation directly from TS ! Something that Microsoft forgot to includeNeonMika.Webserver: Version 1.0: This version has now everything built in what you need to get you started. From working with digital and analog pins over PWM to file down- and upload. Please let me know if you find any bugs etc., so I can try to fix them. I work on this project in my spare time, so I hope you enjoy using it =)Audio Pitch & Shift: Audio Pitch And Shift 5.1.0.3: Fixed supported files list on open dialog (added .pls and .m3u) Impulse Media Player splash message (can be disabled anyway)ImapX 2: ImapX 2.0.0.6: An updated release of the ImapX 2 library, containing many bugfixes for both, the library and the sample application.WiX Toolset: WiX v3.7 RC: WiX v3.7 RC (3.7.1119.0) provides feature complete Bundle update and reference tracking plus several bug fixes. For more information see Rob's blog post about the release: http://robmensching.com/blog/posts/2012/11/20/WiX-v3.7-Release-Candidate-availablePicturethrill: Version 2.11.20.0: Fixed up Bing image provider on Windows 8Excel AddIn to reset the last worksheet cell: XSFormatCleaner.xla: Modified the commandbar code to use CommandBar IDs instead of English names.Json.NET: Json.NET 4.5 Release 11: New feature - Added ITraceWriter, MemoryTraceWriter, DiagnosticsTraceWriter New feature - Added StringEscapeHandling with options to escape HTML and non-ASCII characters New feature - Added non-generic JToken.ToObject methods New feature - Deserialize ISet<T> properties as HashSet<T> New feature - Added implicit conversions for Uri, TimeSpan, Guid New feature - Missing byte, char, Guid, TimeSpan and Uri explicit conversion operators added to JToken New feature - Special case...EntitiesToDTOs - Entity Framework DTO Generator: EntitiesToDTOs.v3.0: DTOs and Assemblers can be generated inside project folders! Choose the types you want to generate! Support for Visual Studio 2012 !!! Support for new Entity Framework EDMX (format used by VS2012) ! Support for Enum Types! Optional automatic check for updates! Added the following methods to Assemblers! IEnumerable<DTO>.ToEntities() : ICollection<Entity> IEnumerable<Entity>.ToDTOs() : ICollection<DTO> Indicate class identifier for DTOs and Assemblers! Cleaner Assemblers code....mojoPortal: 2.3.9.4: see release notes on mojoportal.com http://www.mojoportal.com/mojoportal-2394-released Note that we have separate deployment packages for .NET 3.5 and .NET 4.0, but we recommend you to use .NET 4, we will probably drop support for .NET 3.5 once .NET 4.5 is available The deployment package downloads on this page are pre-compiled and ready for production deployment, they contain no C# source code and are not intended for use in Visual Studio. To download the source code see getting the lates...DotNetNuke® Store: 03.01.07: What's New in this release? IMPORTANT: this version requires DotNetNuke 04.06.02 or higher! DO NOT REPORT BUGS HERE IN THE ISSUE TRACKER, INSTEAD USE THE DotNetNuke Store Forum! Bugs corrected: - Replaced some hard coded references to the default address provider classes by the corresponding interfaces to allow the creation of another address provider with a different name. New Features: - Added the 'pickup' delivery option at checkout. - Added the 'no delivery' option in the Store Admin ...ExtJS based ASP.NET 2.0 Controls: FineUI v3.2.0: +2012-11-18 v3.2.0 -?????????????????SelectedValueArray????????（◇?◆:）。 -???????????????????RecoverPropertiesFromJObject????（〓?〓、????、??、Vian_Pan）。 -????????????，?????????????，???SelectedValueArray???????（sam.chang）。 -??Alert.Show???????????（swtseaman）。 -???????????????，??Icon??IconUrl????（swtseaman）。 -?????????TimePicker（??）。 -?????????，??/res.axd?css=blue.css&v=1。 -????????，?????????????，???????。 -????MenuCheckBox（???????）。 -?RadioButton??AutoPostBack??。 -???????FCKEditor?????????...BugNET Issue Tracker: BugNET 1.2: Please read our release notes for BugNET 1.2: http://blog.bugnetproject.com/bugnet-1-2-has-been-released Please do not post questions as reviews. Questions should be posted in the Discussions tab, where they will usually get promptly responded to. If you post a question as a review, you will pollute the rating, and you won't get an answer.New ProjectsAntenna Tracking Unit - Projet Tuteuré /w RFTronic: 5 étudiantsAspectMVVM: A simple Aspected Oriented Programming (AOP) MVVM library.AssemblyLinePrompt: AssemblyLinePromptBing Map V7 ASP.NET Control: More information in relation to Bing Maps can be obtained from the following sites: http://www.microsoft.com/maps/isdk/ajax/ and http://www.bingmapsportal.com/eyeGuitarsWebService: Webservice to be accessed by the Android and iOS versions of our eyeGuitars application. (school project)HTML5Game: HTML5 Canvas GAMEJsonLDotnet: JsonLD Java Port for .netMap Tile Store: Store map tiles from different map content providers, such as OpenStreetMap to sql server database.Math Millionaire: This Project is a math quiz with use of random funciton for generating questions and answersMembros: Provamemory profiling for direct 3d apps for Windows Phone 8: Memory profiling for direct 3d apps for Windows Phone 8MessageSystem Network Library: MessageSystem is a network library,which can be mostly used in your cpp and c# projects.MSc thesis on global travel modelling: Project on modellingOneInstance: ?dotNet?????????，???????????。 ??????????? OneInstance ????，??????，?????????????。PCHenry: Providing technical information from a slight slanted standpoint. pzpp_ath_2a: This is a Hotel Management project. Main task of this ASP.NET project is to build a system which provides easy and intuitive management of the hotel. RiverTech API: The RiverTech API is a Development API for Visual Studio Developers. We Are looking for Help, and hope to release a stable, feature-rich API by the end of 2012!SCSM and Orchestrator Runbooks: This project will contain sample System Center Orchestrator 2012 Runbooks which integrate with System Center Service Manager 2012.testingpermiasmilwaukee: testingvDesktop: A virtual desktop programVisual Studio Settings Switcher: Switches between Visual Studio settings automatically when a solution is opened. Also switches or exports settings at the click of a button.??: ????Helper?，???????Website???????/??????，??????。

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Working with Timelines with LINQ to Twitter

- by Joe Mayo

When first working with the Twitter API, I thought that using SinceID would be an effective way to page through timelines. In practice it doesn’t work well for various reasons. To explain why, Twitter published an excellent document that is a must-read for anyone working with timelines: Twitter Documentation: Working with Timelines This post shows how to implement the recommended strategies in that document by using LINQ to Twitter. You should read the document in it’s entirety before moving on because my explanation will start at the bottom and work back up to the top in relation to the Twitter document. What follows is an explanation of SinceID, MaxID, and how they come together to help you efficiently work with Twitter timelines. The Role of SinceID Specifying SinceID says to Twitter, “Don’t return tweets earlier than this”. What you want to do is store this value after every timeline query set so that it can be reused on the next set of queries. The next section will explain what I mean by query set, but a quick explanation is that it’s a loop that gets all new tweets. The SinceID is a backstop to avoid retrieving tweets that you already have. Here’s some initialization code that includes a variable named sinceID that will be used to populate the SinceID property in subsequent queries: // last tweet processed on previous query set ulong sinceID = 210024053698867204; ulong maxID; const int Count = 10; var statusList = new List<status>(); Here, I’ve hard-coded the sinceID variable, but this is where you would initialize sinceID from whatever storage you choose (i.e. a database). The first time you ever run this code, you won’t have a value from a previous query set. Initially setting it to 0 might sound like a good idea, but what if you’re querying a timeline with lots of tweets? Because of the number of tweets and rate limits, your query set might take a very long time to run. A caveat might be that Twitter won’t return an entire timeline back to Tweet #0, but rather only go back a certain period of time, the limits of which are documented for individual Twitter timeline API resources. So, to initialize SinceID at too low of a number can result in a lot of initial tweets, yet there is a limit to how far you can go back. What you’re trying to accomplish in your application should guide you in how to initially set SinceID. I have more to say about SinceID later in this post. The other variables initialized above include the declaration for MaxID, Count, and statusList. The statusList variable is a holder for all the timeline tweets collected during this query set. You can set Count to any value you want as the largest number of tweets to retrieve, as defined by individual Twitter timeline API resources. To effectively page results, you’ll use the maxID variable to set the MaxID property in queries, which I’ll discuss next. Initializing MaxID On your first query of a query set, MaxID will be whatever the most recent tweet is that you get back. Further, you don’t know what MaxID is until after the initial query. The technique used in this post is to do an initial query and then use the results to figure out what the next MaxID will be. Here’s the code for the initial query: var userStatusResponse = (from tweet in twitterCtx.Status where tweet.Type == StatusType.User && tweet.ScreenName == "JoeMayo" && tweet.SinceID == sinceID && tweet.Count == Count select tweet) .ToList(); statusList.AddRange(userStatusResponse); // first tweet processed on current query maxID = userStatusResponse.Min( status => ulong.Parse(status.StatusID)) - 1; The query above sets both SinceID and Count properties. As explained earlier, Count is the largest number of tweets to return, but the number can be less. A couple reasons why the number of tweets that are returned could be less than Count include the fact that the user, specified by ScreenName, might not have tweeted Count times yet or might not have tweeted at least Count times within the maximum number of tweets that can be returned by the Twitter timeline API resource. Another reason could be because there aren’t Count tweets between now and the tweet ID specified by sinceID. Setting SinceID constrains the results to only those tweets that occurred after the specified Tweet ID, assigned via the sinceID variable in the query above. The statusList is an accumulator of all tweets receive during this query set. To simplify the code, I left out some logic to check whether there were no tweets returned. If the query above doesn’t return any tweets, you’ll receive an exception when trying to perform operations on an empty list. Yeah, I cheated again. Besides querying initial tweets, what’s important about this code is the final line that sets maxID. It retrieves the lowest numbered status ID in the results. Since the lowest numbered status ID is for a tweet we already have, the code decrements the result by one to keep from asking for that tweet again. Remember, SinceID is not inclusive, but MaxID is. The maxID variable is now set to the highest possible tweet ID that can be returned in the next query. The next section explains how to use MaxID to help get the remaining tweets in the query set. Retrieving Remaining Tweets Earlier in this post, I defined a term that I called a query set. Essentially, this is a group of requests to Twitter that you perform to get all new tweets. A single query might not be enough to get all new tweets, so you’ll have to start at the top of the list that Twitter returns and keep making requests until you have all new tweets. The previous section showed the first query of the query set. The code below is a loop that completes the query set: do { // now add sinceID and maxID userStatusResponse = (from tweet in twitterCtx.Status where tweet.Type == StatusType.User && tweet.ScreenName == "JoeMayo" && tweet.Count == Count && tweet.SinceID == sinceID && tweet.MaxID == maxID select tweet) .ToList(); if (userStatusResponse.Count > 0) { // first tweet processed on current query maxID = userStatusResponse.Min( status => ulong.Parse(status.StatusID)) - 1; statusList.AddRange(userStatusResponse); } } while (userStatusResponse.Count != 0 && statusList.Count < 30); Here we have another query, but this time it includes the MaxID property. The SinceID property prevents reading tweets that we’ve already read and Count specifies the largest number of tweets to return. Earlier, I mentioned how it was important to check how many tweets were returned because failing to do so will result in an exception when subsequent code runs on an empty list. The code above protects against this problem by only working with the results if Twitter actually returns tweets. Reasons why there wouldn’t be results include: if the first query got all the new tweets there wouldn’t be more to get and there might not have been any new tweets between the SinceID and MaxID settings of the most recent query. The code for loading the returned tweets into statusList and getting the maxID are the same as previously explained. The important point here is that MaxID is being reset, not SinceID. As explained in the Twitter documentation, paging occurs from the newest tweets to oldest, so setting MaxID lets us move from the most recent tweets down to the oldest as specified by SinceID. The two loop conditions cause the loop to continue as long as tweets are being read or a max number of tweets have been read. Logically, you want to stop reading when you’ve read all the tweets and that’s indicated by the fact that the most recent query did not return results. I put the check to stop after 30 tweets are reached to keep the demo from running too long – in the console the response scrolls past available buffer and I wanted you to be able to see the complete output. Yet, there’s another point to be made about constraining the number of items you return at one time. The Twitter API has rate limits and making too many queries per minute will result in an error from twitter that LINQ to Twitter raises as an exception. To use the API properly, you’ll have to ensure you don’t exceed this threshold. Looking at the statusList.Count as done above is rather primitive, but you can implement your own logic to properly manage your rate limit. Yeah, I cheated again. Summary Now you know how to use LINQ to Twitter to work with Twitter timelines. After reading this post, you have a better idea of the role of SinceID - the oldest tweet already received. You also know that MaxID is the largest tweet ID to retrieve in a query. Together, these settings allow you to page through results via one or more queries. You also understand what factors affect the number of tweets returned and considerations for potential error handling logic. The full example of the code for this post is included in the downloadable source code for LINQ to Twitter. @JoeMayo

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Passing Strings by Ref

- by SGWellens

Humbled yet again…DOH! No matter how much experience you acquire, no matter how smart you may be, no matter how hard you study, it is impossible to keep fully up to date on all the nuances of the technology we are exposed to. There will always be gaps in our knowledge: Little 'dead zones' of uncertainty. For me, this time, it was about passing string parameters to functions. I thought I knew this stuff cold. First, a little review... Value Types and Ref Integers and structs are value types (as opposed to reference types). When declared locally, their memory storage is on the stack; not on the heap. When passed to a function, the function gets a copy of the data and works on the copy. If a function needs to change a value type, you need to use the ref keyword. Here's an example: // ---- declaration ----------------- public struct MyStruct { public string StrTag; } // ---- functions ----------------------- void SetMyStruct(MyStruct myStruct) // pass by value { myStruct.StrTag = "BBB"; } void SetMyStruct(ref MyStruct myStruct) // pass by ref { myStruct.StrTag = "CCC"; } // ---- Usage ----------------------- protected void Button1_Click(object sender, EventArgs e) { MyStruct Data; Data.StrTag = "AAA"; SetMyStruct(Data); // Data.StrTag is still "AAA" SetMyStruct(ref Data); // Data.StrTag is now "CCC" } No surprises here. All value types like ints, floats, datetimes, enums, structs, etc. work the same way. And now on to... Class Types and Ref // ---- Declaration ----------------------------- public class MyClass { public string StrTag; } // ---- Functions ---------------------------- void SetMyClass(MyClass myClass) // pass by 'value' { myClass.StrTag = "BBB"; } void SetMyClass(ref MyClass myClass) // pass by ref { myClass.StrTag = "CCC"; } // ---- Usage --------------------------------------- protected void Button2_Click(object sender, EventArgs e) { MyClass Data = new MyClass(); Data.StrTag = "AAA"; SetMyClass(Data); // Data.StrTag is now "BBB" SetMyClass(ref Data); // Data.StrTag is now "CCC" } No surprises here either. Since Classes are reference types, you do not need the ref keyword to modify an object. What may seem a little strange is that with or without the ref keyword, the results are the same: The compiler knows what to do. So, why would you need to use the ref keyword when passing an object to a function? Because then you can change the reference itself…ie you can make it refer to a completely different object. Inside the function you can do: myClass = new MyClass() and the old object will be garbage collected and the new object will be returned to the caller. That ends the review. Now let's look at passing strings as parameters. The String Type and Ref Strings are reference types. So when you pass a String to a function, you do not need the ref keyword to change the string. Right? Wrong. Wrong, wrong, wrong. When I saw this, I was so surprised that I fell out of my chair. Getting up, I bumped my head on my desk (which really hurt). My bumping the desk caused a large speaker to fall off of a bookshelf and land squarely on my big toe. I was screaming in pain and hopping on one foot when I lost my balance and fell. I struck my head on the side of the desk (once again) and knocked myself out cold. When I woke up, I was in the hospital where due to a database error (thanks Oracle) the doctors had put casts on both my hands. I'm typing this ever so slowly with just my ton..tong ..tongu…tongue. But I digress. Okay, the only true part of that story is that I was a bit surprised. Here is what happens passing a String to a function. // ---- Functions ---------------------------- void SetMyString(String myString) // pass by 'value' { myString = "BBB"; } void SetMyString(ref String myString) // pass by ref { myString = "CCC"; } // ---- Usage --------------------------------- protected void Button3_Click(object sender, EventArgs e) { String MyString = "AAA"; SetMyString(MyString); // MyString is still "AAA" What!!!! SetMyString(ref MyString); // MyString is now "CCC" } What the heck. We should not have to use the ref keyword when passing a String because Strings are reference types. Why didn't the string change? What is going on? I spent hours unssuccessfully researching this anomaly until finally, I had a Eureka moment: This code: String MyString = "AAA"; Is semantically equivalent to this code (note this code doesn't actually compile): String MyString = new String(); MyString = "AAA"; Key Point: In the function, the copy of the reference is pointed to a new object and THAT object is modified. The original reference and what it points to is unchanged. You can simulate this behavior by modifying the class example code to look like this: void SetMyClass(MyClass myClass) // call by 'value' { //myClass.StrTag = "BBB"; myClass = new MyClass(); myClass.StrTag = "BBB"; } Now when you call the SetMyClass function without using ref, the parameter is unchanged...just like the string example. I hope someone finds this useful. Steve Wellens

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When someone deletes a shared data source in SSRS

- by Rob Farley

SQL Server Reporting Services plays nicely. You can have things in the catalogue that get shared. You can have Reports that have Links, Datasets that can be used across different reports, and Data Sources that can be used in a variety of ways too. So if you find that someone has deleted a shared data source, you potentially have a bit of a horror story going on. And this works for this month’s T-SQL Tuesday theme, hosted by Nick Haslam, who wants to hear about horror stories. I don’t write about LobsterPot client horror stories, so I’m writing about a situation that a fellow MVP friend asked me about recently instead. The best thing to do is to grab a recent backup of the ReportServer database, restore it somewhere, and figure out what’s changed. But of course, this isn’t always possible. And it’s much nicer to help someone with this kind of thing, rather than to be trying to fix it yourself when you’ve just deleted the wrong data source. Unfortunately, it lets you delete data sources, without trying to scream that the data source is shared across over 400 reports in over 100 folders, as was the case for my friend’s colleague. So, suddenly there’s a big problem – lots of reports are failing, and the time to turn it around is small. You probably know which data source has been deleted, but getting the shared data source back isn’t the hard part (that’s just a connection string really). The nasty bit is all the re-mapping, to get those 400 reports working again. I know from exploring this kind of stuff in the past that the ReportServer database (using its default name) has a table called dbo.Catalog to represent the catalogue, and that Reports are stored here. However, the information about what data sources these deployed reports are configured to use is stored in a different table, dbo.DataSource. You could be forgiven for thinking that shared data sources would live in this table, but they don’t – they’re catalogue items just like the reports. Let’s have a look at the structure of these two tables (although if you’re reading this because you have a disaster, feel free to skim past). Frustratingly, there doesn’t seem to be a Books Online page for this information, sorry about that. I’m also not going to look at all the columns, just ones that I find interesting enough to mention, and that are related to the problem at hand. These fields are consistent all the way through to SQL Server 2012 – there doesn’t seem to have been any changes here for quite a while. dbo.Catalog The Primary Key is ItemID. It’s a uniqueidentifier. I’m not going to comment any more on that. A minor nice point about using GUIDs in unfamiliar databases is that you can more easily figure out what’s what. But foreign keys are for that too… Path, Name and ParentID tell you where in the folder structure the item lives. Path isn’t actually required – you could’ve done recursive queries to get there. But as that would be quite painful, I’m more than happy for the Path column to be there. Path contains the Name as well, incidentally. Type tells you what kind of item it is. Some examples are 1 for a folder and 2 a report. 4 is linked reports, 5 is a data source, 6 is a report model. I forget the others for now (but feel free to put a comment giving the full list if you know it). Content is an image field, remembering that image doesn’t necessarily store images – these days we’d rather use varbinary(max), but even in SQL Server 2012, this field is still image. It stores the actual item definition in binary form, whether it’s actually an image, a report, whatever. LinkSourceID is used for Linked Reports, and has a self-referencing foreign key (allowing NULL, of course) back to ItemID. Parameter is an ntext field containing XML for the parameters of the report. Not sure why this couldn’t be a separate table, but I guess that’s just the way it goes. This field gets changed when the default parameters get changed in Report Manager. There is nothing in dbo.Catalog that describes the actual data sources that the report uses. The default data sources would be part of the Content field, as they are defined in the RDL, but when you deploy reports, you typically choose to NOT replace the data sources. Anyway, they’re not in this table. Maybe it was already considered a bit wide to throw in another ntext field, I’m not sure. They’re in dbo.DataSource instead. dbo.DataSource The Primary key is DSID. Yes it’s a uniqueidentifier... ItemID is a foreign key reference back to dbo.Catalog Fields such as ConnectionString, Prompt, UserName and Password do what they say on the tin, storing information about how to connect to the particular source in question. Link is a uniqueidentifier, which refers back to dbo.Catalog. This is used when a data source within a report refers back to a shared data source, rather than embedding the connection information itself. You’d think this should be enforced by foreign key, but it’s not. It does allow NULLs though. Flags this is an int, and I’ll come back to this. When a Data Source gets deleted out of dbo.Catalog, you might assume that it would be disallowed if there are references to it from dbo.DataSource. Well, you’d be wrong. And not because of the lack of a foreign key either. Deleting anything from the catalogue is done by calling a stored procedure called dbo.DeleteObject. You can look at the definition in there – it feels very much like the kind of Delete stored procedures that many people write, the kind of thing that means they don’t need to worry about allowing cascading deletes with foreign keys – because the stored procedure does the lot. Except that it doesn’t quite do that. If it deleted everything on a cascading delete, we’d’ve lost all the data sources as configured in dbo.DataSource, and that would be bad. This is fine if the ItemID from dbo.DataSource hooks in – if the report is being deleted. But if a shared data source is being deleted, you don’t want to lose the existence of the data source from the report. So it sets it to NULL, and it marks it as invalid. We see this code in that stored procedure. UPDATE [DataSource] SET [Flags] = [Flags] & 0x7FFFFFFD, -- broken link [Link] = NULL FROM [Catalog] AS C INNER JOIN [DataSource] AS DS ON C.[ItemID] = DS.[Link] WHERE (C.Path = @Path OR C.Path LIKE @Prefix ESCAPE '*') Unfortunately there’s no semi-colon on the end (but I’d rather they fix the ntext and image types first), and don’t get me started about using the table name in the UPDATE clause (it should use the alias DS). But there is a nice comment about what’s going on with the Flags field. What I’d LIKE it to do would be to set the connection information to a report-embedded copy of the connection information that’s in the shared data source, the one that’s about to be deleted. I understand that this would cause someone to lose the benefit of having the data sources configured in a central point, but I’d say that’s probably still slightly better than LOSING THE INFORMATION COMPLETELY. Sorry, rant over. I should log a Connect item – I’ll put that on my todo list. So it sets the Link field to NULL, and marks the Flags to tell you they’re broken. So this is your clue to fixing it. A bitwise AND with 0x7FFFFFFD is basically stripping out the ‘2’ bit from a number. So numbers like 2, 3, 6, 7, 10, 11, etc, whose binary representation ends in either 11 or 10 get turned into 0, 1, 4, 5, 8, 9, etc. We can test for it using a WHERE clause that matches the SET clause we’ve just used. I’d also recommend checking for Link being NULL and also having no ConnectionString. And join back to dbo.Catalog to get the path (including the name) of broken reports are – in case you get a surprise from a different data source being broken in the past. SELECT c.Path, ds.Name FROM dbo.[DataSource] AS ds JOIN dbo.[Catalog] AS c ON c.ItemID = ds.ItemID WHERE ds.[Flags] = ds.[Flags] & 0x7FFFFFFD AND ds.[Link] IS NULL AND ds.[ConnectionString] IS NULL; When I just ran this on my own machine, having deleted a data source to check my code, I noticed a Report Model in the list as well – so if you had thought it was just going to be reports that were broken, you’d be forgetting something. So to fix those reports, get your new data source created in the catalogue, and then find its ItemID by querying Catalog, using Path and Name to find it. And then use this value to fix them up. To fix the Flags field, just add 2. I prefer to use bitwise OR which should do the same. Use the OUTPUT clause to get a copy of the DSIDs of the ones you’re changing, just in case you need to revert something later after testing (doing it all in a transaction won’t help, because you’ll just lock out the table, stopping you from testing anything). UPDATE ds SET [Flags] = [Flags] | 2, [Link] = '3AE31CBA-BDB4-4FD1-94F4-580B7FAB939D' /*Insert your own GUID*/ OUTPUT deleted.Name, deleted.DSID, deleted.ItemID, deleted.Flags FROM dbo.[DataSource] AS ds JOIN dbo.[Catalog] AS c ON c.ItemID = ds.ItemID WHERE ds.[Flags] = ds.[Flags] & 0x7FFFFFFD AND ds.[Link] IS NULL AND ds.[ConnectionString] IS NULL; But please be careful. Your mileage may vary. And there’s no reason why 400-odd broken reports needs to be quite the nightmare that it could be. Really, it should be less than five minutes. @rob_farley

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CodePlex Daily Summary for Thursday, October 31, 2013

CodePlex Daily Summary for Thursday, October 31, 2013Popular ReleasesTCPEssentials: TCPEssentials 1.0.0.1: Changed the name of method SplitArray to Split. Standardization is important...Community Forums NNTP bridge: Community Forums NNTP Bridge V54 (LiveConnect): This is the first release which can be used with the new LiveConnect authentication. Fixes the problem that the authentication will not work after 1 hour. Also a logfile will now be stored in "%AppData%\Community\CommunityForumsNNTPServer". If you have any problems please feel free to sent me the file "LogFile.txt".WPF Extended DataGrid: WPF Extended DataGrid 2.0.0.9 binaries: Fixed issue with ICollectionView containg null values (AutoFilter issue)Community TFS Build Extensions: October 2013: The October 2013 release contains Scripts - a new addition to our delivery. These are a growing library of PowerShell scripts to use with VS2013. See our documentation for more on scripting. VS2010 Activities(target .NET 4.0) VS2012 Activities (target .NET 4.5) VS2013 Activities (target .NET 4.5.1) Community TFS Build Manager VS2012 Community TFS Build Manager VS2013 The Community TFS Build Managers for VS2010, 2012 and 2013 can also be found in the Visual Studio Gallery where upda...SuperSocket, an extensible socket server framework: SuperSocket 1.6 stable: Changes included in this release: Process level isolation SuperSocket ServerManager (include server and client) Connect to client from server side initiatively Client certificate validation New configuration attributes "textEncoding", "defaultCulture", and "storeLocation" (certificate node) Many bug fixes http://docs.supersocket.net/v1-6/en-US/New-Features-and-Breaking-ChangesBarbaTunnel: BarbaTunnel 8.1: Check Version History for more information about this release.Mugen MVVM Toolkit: Mugen MVVM Toolkit 2.1: v 2.1 Added the 'Should' class instead of the 'Validate' class. The 'Validate' class is now obsolete. Added 'Toolkit.Annotations' to support the Mugen MVVM Toolkit ReSharper plugin. Updated JetBrains annotations within the project. Added the 'GlobalSettings.DefaultActivationPolicy' property to represent the default activation policy. Removed the 'GetSettings' method from the 'ViewModelBase' class. Instead of it, the 'GlobalSettings.DefaultViewModelSettings' property is used. Updated...NAudio: NAudio 1.7: full release notes available at http://mark-dot-net.blogspot.co.uk/2013/10/naudio-17-release-notes.htmlLayered Architecture Solution Guidance (LASG): LASG 1.0.1.0 for Visual Studio 2012: PRE-REQUISITES Open GAX (Please install Oct 4, 2012 version) Microsoft® System CLR Types for Microsoft® SQL Server® 2012 Microsoft® SQL Server® 2012 Shared Management Objects Microsoft Enterprise Library 6.0 (for the generated code) Windows Azure SDK (for layered cloud applications) Silverlight 5 SDK (for Silverlight applications) THE RELEASE This release only works on Visual Studio 2012. Known Issue If you choose the Database project, the solution unfolding time will be slow....DirectX Tool Kit: October 2013: October 28, 2013 Updated for Visual Studio 2013 and Windows 8.1 SDK RTM Added DGSLEffect, DGSLEffectFactory, VertexPositionNormalTangentColorTexture, and VertexPositionNormalTangentColorTextureSkinning Model loading and effect factories support loading skinned models MakeSpriteFont now has a smooth vs. sharp antialiasing option: /sharp Model loading from CMOs now handles UV transforms for texture coordinates A number of small fixes for EffectFactory Minor code and project cleanup ...ExtJS based ASP.NET Controls: FineUI v4.0beta1: +2013-10-28 v4.0 beta1 +?????Collapsed???????????????。 -????：window/group_panel.aspx??，???????，???????，?????????。 +??????SelectedNodeIDArray???????????????。 -????：tree/checkbox/tree_checkall.aspx??，?????，?????，????????????。 -??TimerPicker???????（????、????ing）。 -??????????????????????（???）。 -?????????????，??type=text/css（??~`）。 -MsgTarget???MessageTarget，???None。 -FormOffsetRight?????20px??5px。 -?Web.config?PageManager??FormLabelAlign???。 -ToolbarPosition??Left/Right。 -??Web.conf...CODE Framework: 4.0.31028.0: See change notes in the documentation section for details on what's new. Note: If you download the class reference help file with, you have to right-click the file, pick "Properties", and then unblock the file, as many browsers flag the file as blocked during download (for security reasons) and thus hides all content.VidCoder: 1.5.10 Beta: Broke out all the encoder-specific passthrough options into their own dropdown. This should make what they do a bit more clear and clean up the codec list a bit. Updated HandBrake core to SVN 5855.Indent Guides for Visual Studio: Indent Guides v14: ImportantThis release has a separate download for Visual Studio 2010. The first link is for VS 2012 and later. Version History Changed in v14 Improved performance when scrolling and editing Fixed potential crash when Resharper is installed Fixed highlight of guides split around pragmas in C++/C# Restored VS 2010 support as a separate download Changed in v13 Added page width guide lines Added guide highlighting options Fixed guides appearing over collapsed blocks Fixed guides not...ASP.net MVC Awesome - jQuery Ajax Helpers: 3.5.3 (mvc5): version 3.5.3 - support for mvc5 version 3.5.2 - fix for setting single value to multivalue controls - datepicker min max date offset fix - html encoding for keys fix - enable Column.ClientFormatFunc to be a function call that will return a function version 3.5.1 ========================== - fixed html attributes rendering - fixed loading animation rendering - css improvements version 3.5 ========================== - autosize for all popups ( can be turned off by calling in js...Media Companion: Media Companion MC3.585b: IMDB plot scraping Fixed. New* Movie - Rename Folder using Movie Set, option to move ignored articles to end of Movie Set, only for folder renaming. Fixed* Media Companion - Fixed if using profiles, config files would blown up in size due to some settings duplicating. * Ignore Article of An was cutting of last character of movie title. * If Rescraping title, sort title changed depending on 'Move article to end of Sort Title' setting. * Movie - If changing Poster source order, list would beco...MoreTerra (Terraria World Viewer): MoreTerra 1.11.4: Release 1.11.4 =========== = Compatibility = =========== Updated to add the new tiles/walls in 1.2.1Emptycanvas: Emptycanvas v21: Maintenant plusieurs lumières possibles.PowerShell App Deployment Toolkit: PowerShell App Deployment Toolkit v3.0.7: This is a bug fix release, containing some important fixes! Fixed issue where Session 0 was not detected correctly, resulting in issues when attempting to display a UI when none was allowed Fixed Installation Prompt and Installation Restart Prompt appearing when deploy mode was non-interactive or silent Fixed issue where defer prompt is displayed after force closing multiple applications Fixed issue executing blocked app execution dialog from UNC path (executed instead from local tempo...BlackJumboDog: Ver5.9.7: 2013.10.24 Ver5.9.7 (1)FTP???????、２?????????????shift-jis????????????? (2)????HTTP????、???????POST??????????????????New ProjectsBF4Rcon.NET: BF4Rcon.NET is a .NET library for Battlefield 4's remote server administration interface.Command Processor: Command Processor with "Command Query Responsibility" prencipleDqyt.sk: a solution for sk project.Edit Visual Studio LoadTest Results' Name and Description: A simple addin to Visual Studio 2012 and Visual Studio 2010, which enables a LoadTest user to be able to give custom name and description for their loadtest.Grauers Set Metadata Properties: Use this to automatically set ISSUE, APPROVED BY and APPROVED DATEIkeCode WP7.1+ Toolkit: IkeCode WP7.1+ Toolkit is an initiative to create methods that facilitate the development of application.MongoDAO: MongoDB C#NB_Store Payment On Delivery Gateway: NB_Store Payment On Delivery Gateway allows you to add "Paymeny On Delivery" to your NB_Store webshop on DNN.occupie: // to doOffice and PDF API for .NET Components: As an independent .NET component, Spire.Office doesn't need Microsoft Office to be installed on System. It supports C# word, C# Excel and C# PDF.SharePoint Workflow Manager | Bulk Start or Terminate workflows: SharePoint Workflow Manager allows you bulk start or terminate SharePoint workflows on all items in a list.System App: The System App is a sleek, smart and open-source IT mapping and monitoring tool by Zalando.TCPEssentials: TCPEssentials is a C# Library that helps simplify the task of managing TCP connections, and also gives you a few tools that may be useful.Wangls: ???WindowSMART: WindowSMART 2013 and Home Server SMART 2013 are powerful hard disk and SSD health monitoring, reporting and alerting tools for Windows.

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Farseer tutorial for the absolute beginners

- by Bil Simser

This post is inspired (and somewhat a direct copy) of a couple of posts Emanuele Feronato wrote back in 2009 about Box2D (his tutorial was ActionScript 3 based for Box2D, this is C# XNA for the Farseer Physics Engine). Here’s what we’re building: What is Farseer The Farseer Physics Engine is a collision detection system with realistic physics responses to help you easily create simple hobby games or complex simulation systems. Farseer was built as a .NET version of Box2D (based on the Box2D.XNA port of Box2D). While the constructs and syntax has changed over the years, the principles remain the same. This tutorial will walk you through exactly what Emanuele create for Flash but we’ll be doing it using C#, XNA and the Windows Phone platform. The first step is to download the library from its home on CodePlex. If you have NuGet installed, you can install the library itself using the NuGet package that but we’ll also be using some code from the Samples source that can only be obtained by downloading the library. Once you download and unpacked the zip file into a folder and open the solution, this is what you will get: The Samples XNA WP7 project (and content) have all the demos for Farseer. There’s a wealth of info here and great examples to look at to learn. The Farseer Physics XNA WP7 project contains the core libraries that do all the work. DebugView XNA contains an XNA-ready class to let you view debug data and information in the game draw loop (which you can copy into your project or build the source and reference the assembly). The downloaded version has to be compiled as it’s only available in source format so you can do that now if you want (open the solution file and rebuild everything). If you’re using the NuGet package you can just install that. We only need the core library and we’ll be copying in some code from the samples later. Your first Farseer experiment Start Visual Studio and create a new project using the Windows Phone template can call it whatever you want. It’s time to edit Game1.cs 1 public class Game1 : Game 2 { 3 private readonly GraphicsDeviceManager _graphics; 4 private DebugViewXNA _debugView; 5 private Body _floor; 6 private SpriteBatch _spriteBatch; 7 private float _timer; 8 private World _world; 9 10 public Game1() 11 { 12 _graphics = new GraphicsDeviceManager(this) 13 { 14 PreferredBackBufferHeight = 800, 15 PreferredBackBufferWidth = 480, 16 IsFullScreen = true 17 }; 18 19 Content.RootDirectory = "Content"; 20 21 // Frame rate is 30 fps by default for Windows Phone. 22 TargetElapsedTime = TimeSpan.FromTicks(333333); 23 24 // Extend battery life under lock. 25 InactiveSleepTime = TimeSpan.FromSeconds(1); 26 } 27 28 protected override void LoadContent() 29 { 30 // Create a new SpriteBatch, which can be used to draw textures. 31 _spriteBatch = new SpriteBatch(_graphics.GraphicsDevice); 32 33 // Load our font (DebugViewXNA needs it for the DebugPanel) 34 Content.Load<SpriteFont>("font"); 35 36 // Create our World with a gravity of 10 vertical units 37 if (_world == null) 38 { 39 _world = new World(Vector2.UnitY*10); 40 } 41 else 42 { 43 _world.Clear(); 44 } 45 46 if (_debugView == null) 47 { 48 _debugView = new DebugViewXNA(_world); 49 50 // default is shape, controller, joints 51 // we just want shapes to display 52 _debugView.RemoveFlags(DebugViewFlags.Controllers); 53 _debugView.RemoveFlags(DebugViewFlags.Joint); 54 55 _debugView.LoadContent(GraphicsDevice, Content); 56 } 57 58 // Create and position our floor 59 _floor = BodyFactory.CreateRectangle( 60 _world, 61 ConvertUnits.ToSimUnits(480), 62 ConvertUnits.ToSimUnits(50), 63 10f); 64 _floor.Position = ConvertUnits.ToSimUnits(240, 775); 65 _floor.IsStatic = true; 66 _floor.Restitution = 0.2f; 67 _floor.Friction = 0.2f; 68 } 69 70 protected override void Update(GameTime gameTime) 71 { 72 // Allows the game to exit 73 if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed) 74 Exit(); 75 76 // Create a random box every second 77 _timer += (float) gameTime.ElapsedGameTime.TotalSeconds; 78 if (_timer >= 1.0f) 79 { 80 // Reset our timer 81 _timer = 0f; 82 83 // Determine a random size for each box 84 var random = new Random(); 85 var width = random.Next(20, 100); 86 var height = random.Next(20, 100); 87 88 // Create it and store the size in the user data 89 var box = BodyFactory.CreateRectangle( 90 _world, 91 ConvertUnits.ToSimUnits(width), 92 ConvertUnits.ToSimUnits(height), 93 10f, 94 new Point(width, height)); 95 96 box.BodyType = BodyType.Dynamic; 97 box.Restitution = 0.2f; 98 box.Friction = 0.2f; 99 100 // Randomly pick a location along the top to drop it from 101 box.Position = ConvertUnits.ToSimUnits(random.Next(50, 400), 0); 102 } 103 104 // Advance all the elements in the world 105 _world.Step(Math.Min((float) gameTime.ElapsedGameTime.TotalMilliseconds*0.001f, (1f/30f))); 106 107 // Clean up any boxes that have fallen offscreen 108 foreach (var box in from box in _world.BodyList 109 let pos = ConvertUnits.ToDisplayUnits(box.Position) 110 where pos.Y > _graphics.GraphicsDevice.Viewport.Height 111 select box) 112 { 113 _world.RemoveBody(box); 114 } 115 116 base.Update(gameTime); 117 } 118 119 protected override void Draw(GameTime gameTime) 120 { 121 GraphicsDevice.Clear(Color.FromNonPremultiplied(51, 51, 51, 255)); 122 123 _spriteBatch.Begin(); 124 125 var projection = Matrix.CreateOrthographicOffCenter( 126 0f, 127 ConvertUnits.ToSimUnits(_graphics.GraphicsDevice.Viewport.Width), 128 ConvertUnits.ToSimUnits(_graphics.GraphicsDevice.Viewport.Height), 0f, 0f, 129 1f); 130 _debugView.RenderDebugData(ref projection); 131 132 _spriteBatch.End(); 133 134 base.Draw(gameTime); 135 } 136 } 137 Lines 4: Declare the debug view we’ll use for rendering (more on that later). Lines 8: Declare _world variable of type class World. World is the main object to interact with the Farseer engine. It stores all the joints and bodies, and is responsible for stepping through the simulation. Lines 12-17: Create the graphics device we’ll be rendering on. This is an XNA component and we’re just setting it to be the same size as the phone and toggling it to be full screen (no system tray). Lines 34: We create a SpriteFont here by adding it to the project. It’s called “font” because that’s what the DebugView uses but you can name it whatever you want (and if you’re not using DebugView for your production app you might have several fonts). Lines 37-44: We create the physics environment that Farseer uses to contain all the objects by specifying it here. We’re using Vector2.UnitY*10 to represent the gravity to be used in the environment. In other words, 10 units going in a downward motion. Lines 46-56: We create the DebugViewXNA here. This is copied from the […] from the code you downloaded and provides the ability to render all entities onto the screen. In a production release you’ll be doing the rendering yourself of each object but we cheat a bit for the demo and let the DebugView do it for us. The other thing it can provide is to render out a panel of debugging information while the simulation is going on. This is useful in tracking down objects, figuring out how something works, or just keeping track of what’s in the engine. Lines 49-67: Here we create a rigid body (Farseer only supports rigid bodies) to represent the floor that we’ll drop objects onto. We create it by using one of the Farseer factories and specifying the width and height. The ConvertUnits class is copied from the samples code as-is and lets us toggle between display units (pixels) and simulation units (usually metres). We’re creating a floor that’s 480 pixels wide and 50 pixels high (converting them to SimUnits for the engine to understand). We also position it near the bottom of the screen. Values are in metres and when specifying values they refer to the centre of the body object. Lines 77-78: The game Update method fires 30 times a second, too fast to be creating objects this quickly. So we use a variable to track the elapsed seconds since the last update, accumulate that value, then create a new box to drop when 1 second has passed. Lines 89-94: We create a box the same way we created our floor (coming up with a random width and height for the box). Lines 96-101: We set the box to be Dynamic (rather than Static like the floor object) and position it somewhere along the top of the screen. And now you created the world. Gravity does the rest and the boxes fall to the ground. Here’s the result: Farseer Physics Engine Demo using XNA Lines 105: We must update the world at every frame. We do this with the Step method which takes in the time interval. [more] Lines 108-114: Body objects are added to the world but never automatically removed (because Farseer doesn’t know about the display world, it has no idea if an item is on the screen or not). Here we just loop through all the entities and anything that’s dropped off the screen (below the bottom) gets removed from the World. This keeps our entity count down (the simulation never has more than 30 or 40 objects in the world no matter how long you run it for). Too many entities and the app will grind to a halt. Lines 125-130: Farseer knows nothing about the UI so that’s entirely up to you as to how to draw things. Farseer is just tracking the objects and moving them around using the physics engine and it’s rules. You’ll still use XNA to draw items (using the SpriteBatch.Draw method) so you can load up your usual textures and draw items and pirates and dancing zombies all over the screen. Instead in this demo we’re going to cheat a little. In the sample code for Farseer you can download there’s a project called DebugView XNA. This project contains the DebugViewXNA class which just handles iterating through all the bodies in the world and drawing the shapes. So we call the RenderDebugData method here of that class to draw everything correctly. In the case of this demo, we just want to draw Shapes so take a look at the source code for the DebugViewXNA class as to how it extracts all the vertices for the shapes created (in this case simple boxes) and draws them. You’ll learn a *lot* about how Farseer works just by looking at this class. That’s it, that’s all. Simple huh? Hope you enjoy the code and library. Physics is hard and requires some math skills to really grok. The Farseer Physics Engine makes it pretty easy to get up and running and start building games. In future posts we’ll get more in-depth with things you can do with the engine so this is just the beginning. Enjoy!

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Reading OpenDocument spreadsheets using C#

- by DigiMortal

Excel with its file formats is not the only spreadsheet application that is widely used. There are also users on Linux and Macs and often they are using OpenOffice and other open-source office packages that use ODF instead of OpenXML. In this post I will show you how to read Open Document spreadsheet in C#. Importer as example My previous post about importers showed you how to build flexible importers support to your web application. This post introduces you practical example of one of my importers. Of course, sensitive code is omitted. We start with ODS importer class and we add new methods as we go. public class OdsImporter : ImporterBase { public OdsImporter() { } public override string[] SupportedFileExtensions { get { return new[] { "ods" }; } } public override ImportResult Import(Stream fileStream, long companyId, short year) { string contentXml = GetContentXml(fileStream); var result = new ImportResult(); var doc = XDocument.Parse(contentXml); var rows = doc.Descendants("{urn:oasis:names:tc:opendocument:xmlns:table:1.0}table-row").Skip(1); foreach (var row in rows) { ImportRow(row, companyId, year, result); } return result; } } The class given here just extends base class for importers (previous post uses interface but as I already told there you move to abstract base class when writing code for real projects). Import method reads data from *.ods file, parses it (it is XML), finds all data rows and imports data. As you may see then first row is skipped. This is because the first row on my sheet is always headers row. Reading ODS file Our import method starts with getting XML from *.ods file. ODS files like OpenXml files are zipped containers that contain different files. We need content.xml as all data is kept there. To get the contents of file we use SharpZipLib library to read uploaded file as *.zip file. private static string GetContentXml(Stream fileStream) { var contentXml = ""; using (var zipInputStream = new ZipInputStream(fileStream)) { ZipEntry contentEntry = null; while ((contentEntry = zipInputStream.GetNextEntry()) != null) { if (!contentEntry.IsFile) continue; if (contentEntry.Name.ToLower() == "content.xml") break; } if (contentEntry.Name.ToLower() != "content.xml") { throw new Exception("Cannot find content.xml"); } var bytesResult = new byte[] { }; var bytes = new byte[2000]; var i = 0; while ((i = zipInputStream.Read(bytes, 0, bytes.Length)) != 0) { var arrayLength = bytesResult.Length; Array.Resize<byte>(ref bytesResult, arrayLength + i); Array.Copy(bytes, 0, bytesResult, arrayLength, i); } contentXml = Encoding.UTF8.GetString(bytesResult); } return contentXml; } If here is content.xml file then we stop browsing the file. We read this file to memory and return it as UTF-8 format string. Importing rows Our last task is to import rows. We use special method for this as we have to handle some tricks here. To keep files smaller the cell count on row is not always the same. If we have more than one empty cell one after another then ODS keeps only one cell for sequential empty cells. This cell has attribute called number-columns-repeated and it’s value is set to the number of sequential empty cells. This is why we use two indexers for cells collection. private void ImportRow(XElement row, ImportResult result) { var cells = (from c in row.Descendants() where c.Name == "{urn:oasis:names:tc:opendocument:xmlns:table:1.0}table-cell" select c).ToList(); var dto = new DataDto(); var count = cells.Count; var j = -1; for (var i = 0; i < count; i++) { j++; var cell = cells[i]; var attr = cell.Attribute("{urn:oasis:names:tc:opendocument:xmlns:table:1.0}number-columns-repeated"); if (attr != null) { var numToSkip = 0; if (int.TryParse(attr.Value, out numToSkip)) { j += numToSkip - 1; } } if (i > 30) break; if (j == 0) { dto.SomeProperty = cells[i].Value; } if (j == 1) { dto.SomeOtherProperty = cells[i].Value; } // some more data reading } // save data } You can define your own class for import results and add there all problems found during data import. Your application gets the results and shows them to user. Conclusion Reading ODS files may seem to complex task but actually it is very easy if we need only data from those documents. We can use some zip-library to get the content file and then parse it to XML. It is not hard to go through the XML but there are some optimization tricks we have to know. The code here is safe to use in web applications as it is not using any API-s that may have special needs to server and infrastructure.

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Are your personal insecurities screwing up your internal communications?

- by Lucy Boyes

I do some internal comms as part of my job. Quite a lot of it involves talking to people about stuff. I’m spending the next couple of weeks talking to lots of people about internal comms itself, because we haven’t done a lot of audience/user feedback gathering, and it turns out that if you talk to people about how they feel and what they think, you get some pretty interesting insights (and an idea of what to do next that isn’t just based on guesswork and generalising from self). Three things keep coming up from talking to people about what we suck at in terms of internal comms. And, as far as I can tell, they’re all examples where personal insecurity on the part of the person doing the communicating makes the experience much worse for the people on the receiving end. 1. Spending time telling people how you’re going to do something, not what you’re doing and why Imagine you’ve got to give an update to a lot of people who don’t work in your area or department but do have an interest in what you’re doing (either because they want to know because they’re curious or because they need to know because it’s going to affect their work too). You don’t want to look bad at your job. You want to make them think you’ve got it covered – ideally because you do*. And you want to reassure them that there’s lots of exciting work going on in your area to make [insert thing of choice] happen to [insert thing of choice] so that [insert group of people] will be happy. That’s great! You’re doing a good job and you want to tell people about it. This is good comms stuff right here. However, you’re slightly afraid you might secretly be stupid or lazy or incompetent. And you’re exponentially more afraid that the people you’re talking to might think you’re stupid or lazy or incompetent. Or pointless. Or not-adding-value. Or whatever the thing that’s the worst possible thing to be in your company is. So you open by mentioning all the stuff you’re going to do, spending five minutes or so making sure that everyone knows that you’re DOING lots of STUFF. And the you talk for the rest of the time about HOW you’re going to do the stuff, because that way everyone will know that you’ve thought about this really hard and done tons of planning and had lots of great ideas about process and that you’ve got this one down. That’s the stuff you’ve got to say, right? To prove you’re not fundamentally worthless as a human being? Well, maybe. But probably not. See, the people who need to know how you’re going to do the stuff are the people doing the stuff. And those are the people in your area who you’ve (hopefully-please-for-the-love-of-everything-holy) already talked to in depth about how you’re going to do the thing (because else how could they help do it?). They are the only people who need to know the how**. It’s the difference between strategy and tactics. The people outside of your bubble of stuff-doing need to know the strategy – what it is that you’re doing, why, where you’re going with it, etc. The people on the ground with you need the strategy and the tactics, because else they won’t know how to do the stuff. But the outside people don’t really need the tactics at all. Don’t bother with the how unless your audience needs it. They probably don’t. It might make you feel better about yourself, but it’s much more likely that Bob and Jane are thinking about how long this meeting has gone on for already than how personally impressive and definitely-not-an-idiot you are for knowing how you’re going to do some work. Feeling marginally better about yourself (but, let’s face it, still insecure as heck) is not worth the cost, which in this case is the alienation of your audience. 2. Talking for too long about stuff This is kinda the same problem as the previous problem, only much less specific, and I’ve more or less covered why it’s bad already. Basic motivation: to make people think you’re not an idiot. What you do: talk for a very long time about what you’re doing so as to make it sound like you know what you’re doing and lots about it. What your audience wants: the shortest meaningful update. Some of this is a kill your darlings problem – the stuff you’re doing that seems really nifty to you seems really nifty to you, and thus you want to share it with everyone to show that you’re a smart person who thinks up nifty things to do. The downside to this is that it’s mostly only interesting to you – if other people don’t need to know, they likely also don’t care. Think about how you feel when someone is talking a lot to you about a lot of stuff that they’re doing which is at best tangentially interesting and/or relevant. You’re probably not thinking that they’re really smart and clearly know what they’re doing (unless they’re talking a lot and being really engaging about it, which is not the same as talking a lot). You’re probably thinking about something totally unrelated to the thing they’re talking about. Or the fact that you’re bored. You might even – and this is the opposite of what they’re hoping to achieve by talking a lot about stuff – be thinking they’re kind of an idiot. There’s another huge advantage to paring down what you’re trying to say to the barest possible points – it clarifies your thinking. The lightning talk format, as well as other formats which limit the time and/or number of slides you have to say a thing, are really good for doing this. It’s incredibly likely that your audience in this case (the people who need to know some things about your thing but not all the things about your thing) will get everything they need to know from five minutes of you talking about it, especially if trying to condense ALL THE THINGS into a five-minute talk has helped you get clear in your own mind what you’re doing, what you’re trying to say about what you’re doing and why you’re doing it. The bonus of this is that by being clear in your thoughts and in what you say, and in not taking up lots of people’s time to tell them stuff they don’t really need to know, you actually come across as much, much smarter than the person who talks for half an hour or more about things that are semi-relevant at best. 3. Waiting until you’ve got every detail sorted before announcing a big change to the people affected by it This is the worst crime on the list. It’s also human nature. Announcing uncertainty – that something important is going to happen (big reorganisation, product getting canned, etc.) but you’re not quite sure what or when or how yet – is scary. There are risks to it. Uncertainty makes people anxious. It might even paralyse them. You can’t run a business while you’re figuring out what to do if you’ve paralysed everyone with fear over what the future might bring. And you’re scared that they might think you’re not the right person to be in charge of [thing] if you don’t even know what you’re doing with it. Best not to say anything until you know exactly what’s going to happen and you can reassure them all, right? Nope. The people who are going to be affected by whatever it is that you don’t quite know all the details of yet aren’t stupid***. You wouldn’t have hired them if they were. They know something’s up because you’ve got your guilty face on and you keep pulling people into meeting rooms and looking vaguely worried. Here’s the deal: it’s a lot less stressful for everyone (including you) if you’re up front from the beginning. We took this approach during a recent company-wide reorganisation and got really positive feedback. People would much, much rather be told that something is going to happen but you’re not entirely sure what it is yet than have you wait until it’s all fixed up and then fait accompli the heck out of them. They will tell you this themselves if you ask them. And here’s why: by waiting until you know exactly what’s going on to communicate, you remove any agency that the people that the thing is going to happen to might otherwise have had. I know you’re scared that they might get scared – and that’s natural and kind of admirable – but it’s also patronising and infantilising. Ask someone whether they’d rather work on a project which has an openly uncertain future from the beginning, or one where everything’s great until it gets shut down with no forewarning, and very few people are going to tell you they’d prefer the latter. Uncertainty is humanising. It’s you admitting that you don’t have all the answers, which is great, because no one does. It allows you to be consultative – you can actually ask other people what they think and how they feel and what they’d like to do and what they think you should do, and they’ll thank you for it and feel listened to and respected as people and colleagues. Which is a really good reason to start talking to them about what’s going on as soon as you know something’s going on yourself. All of the above assumes you actually care about talking to the people who work with you and for you, and that you’d like to do the right thing by them. If that’s not the case, you can cheerfully disregard the advice here, but if it is, you might want to think about the ways above – and the inevitable countless other ways – that making internal communication about you and not about your audience could actually be doing the people you’re trying to communicate with a huge disservice. So take a deep breath and talk. For five minutes or so. About the important things. Not the other things. As soon as you possibly can. And you’ll be fine. *Of course you do. You’re good at your job. Don’t worry. **This might not always be true, but it is most of the time. Other people who need to know the how will either be people who you’ve already identified as needing-to-know and thus part of the same set as the people in you’re area you’ve already discussed this with, or else they’ll ask you. But don’t bring this stuff up unless someone asks for it, because most of the people in the audience really don’t care and you’re wasting their time. ***I mean, they might be. But let’s give them the benefit of the doubt and assume they’re not.

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Towards Ultra-Reusability for ADF - Adaptive Bindings

- by Duncan Mills

The task flow mechanism embodies one of the key value propositions of the ADF Framework, it's primary contribution being the componentization of your applications and implicitly the introduction of a re-use culture, particularly in large applications. However, what if we could do more? How could we make task flows even more re-usable than they are today? Well one great technique is to take advantage of a feature that is already present in the framework, a feature which I will call, for want of a better name, "adaptive bindings". What's an adaptive binding? well consider a simple use case. I have several screens within my application which display tabular data which are all essentially identical, the only difference is that they happen to be based on different data collections (View Objects, Bean collections, whatever) , and have a different set of columns. Apart from that, however, they happen to be identical; same toolbar, same key functions and so on. So wouldn't it be nice if I could have a single parametrized task flow to represent that type of UI and reuse it? Hold on you say, great idea, however, to do that we'd run into problems. Each different collection that I want to display needs different entries in the pageDef file and: I want to continue to use the ADF Bindings mechanism rather than dropping back to passing the whole collection into the taskflow If I do use bindings, there is no way I want to have to declare iterators and tree bindings for every possible collection that I might want the flow to handle Ah, joy! I reply, no need to panic, you can just use adaptive bindings. Defining an Adaptive Binding It's easiest to explain with a simple before and after use case. Here's a basic pageDef definition for our familiar Departments table. <executables> <iterator Binds="DepartmentsView1" DataControl="HRAppModuleDataControl" RangeSize="25" id="DepartmentsView1Iterator"/> </executables> <bindings> <tree IterBinding="DepartmentsView1Iterator" id="DepartmentsView1"> <nodeDefinition DefName="oracle.demo.model.vo.DepartmentsView" Name="DepartmentsView10"> <AttrNames> <Item Value="DepartmentId"/> <Item Value="DepartmentName"/> <Item Value="ManagerId"/> <Item Value="LocationId"/> </AttrNames> </nodeDefinition> </tree> </bindings> Here's the adaptive version: <executables> <iterator Binds="${pageFlowScope.voName}" DataControl="HRAppModuleDataControl" RangeSize="25" id="TableSourceIterator"/> </executables> <bindings> <tree IterBinding="TableSourceIterator" id="GenericView"> <nodeDefinition Name="GenericViewNode"/> </tree> </bindings> You'll notice three changes here. Most importantly, you'll see that the hard-coded View Object name that formally populated the iterator Binds attribute is gone and has been replaced by an expression (${pageFlowScope.voName}). This of course, is key, you can see that we can pass a parameter to the task flow, telling it exactly what VO to instantiate to populate this table! I've changed the IDs of the iterator and the tree binding, simply to reflect that they are now re-usable The tree binding itself has simplified and the node definition is now empty. Now what this effectively means is that the #{node} map exposed through the tree binding will expose every attribute of the underlying iterator's collection - neat! (kudos to Eugene Fedorenko at this point who reminded me that this was even possible in his excellent "deep dive" session at OpenWorld this year) Using the adaptive binding in the UI Now we have a parametrized binding we have to make changes in the UI as well, first of all to reflect the new ID that we've assigned to the binding (of course) but also to change the column list from being a fixed known list to being a generic metadata driven set: <af:table value="#{bindings.GenericView.collectionModel}" rows="#{bindings.GenericView.rangeSize}" fetchSize="#{bindings.GenericView.rangeSize}" emptyText="#{bindings.GenericView.viewable ? 'No data to display.' : 'Access Denied.'}" var="row" rowBandingInterval="0" selectedRowKeys="#{bindings.GenericView.collectionModel.selectedRow}" selectionListener="#{bindings.GenericView.collectionModel.makeCurrent}" rowSelection="single" id="t1"> <af:forEach items="#{bindings.GenericView.attributeDefs}" var="def"> <af:column headerText="#{bindings.GenericView.labels[def.name]}" sortable="true" sortProperty="#{def.name}" id="c1"> <af:outputText value="#{row[def.name]}" id="ot1"/> </af:column> </af:forEach> </af:table> Of course you are not constrained to a simple read only table here. It's a normal tree binding and iterator that you are using behind the scenes so you can do all the usual things, but you can see the value of using ADFBC as the back end model as you have the rich pantheon of UI hints to use to derive things like labels (and validators and converters...) One Final Twist To finish on a high note I wanted to point out that you can take this even further and achieve the ultra-reusability I promised. Here's the new version of the pageDef iterator, see if you can notice the subtle change? <iterator Binds="{pageFlowScope.voName}" DataControl="${pageFlowScope.dataControlName}" RangeSize="25" id="TableSourceIterator"/> Yes, as well as parametrizing the collection (VO) name, we can also parametrize the name of the data control. So your task flow can graduate from being re-usable within an application to being truly generic. So if you have some really common patterns within your app you can wrap them up and reuse then across multiple developments without having to dictate data control names, or connection names. This also demonstrates the importance of interacting with data only via the binding layer APIs. If you keep any code in the task flow generic in that way you can deal with data from multiple types of data controls, not just one flavour. Enjoy!

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Project Jigsaw: Late for the train: The Q&A

- by Mark Reinhold

I recently proposed, to the Java community in general and to the SE 8 (JSR 337) Expert Group in particular, to defer Project Jigsaw from Java 8 to Java 9. I also proposed to aim explicitly for a regular two-year release cycle going forward. Herewith a summary of the key questions I’ve seen in reaction to these proposals, along with answers. Making the decision Q Has the Java SE 8 Expert Group decided whether to defer the addition of a module system and the modularization of the Platform to Java SE 9? A No, it has not yet decided. Q By when do you expect the EG to make this decision? A In the next month or so. Q How can I make sure my voice is heard? A The EG will consider all relevant input from the wider community. If you have a prominent blog, column, or other communication channel then there’s a good chance that we’ve already seen your opinion. If not, you’re welcome to send it to the Java SE 8 Comments List, which is the EG’s official feedback channel. Q What’s the overall tone of the feedback you’ve received? A The feedback has been about evenly divided as to whether Java 8 should be delayed for Jigsaw, Jigsaw should be deferred to Java 9, or some other, usually less-realistic, option should be taken. Project Jigsaw Q Why is Project Jigsaw taking so long? A Project Jigsaw started at Sun, way back in August 2008. Like many efforts during the final years of Sun, it was not well staffed. Jigsaw initially ran on a shoestring, with just a handful of mostly part-time engineers, so progress was slow. During the integration of Sun into Oracle all work on Jigsaw was halted for a time, but it was eventually resumed after a thorough consideration of the alternatives. Project Jigsaw was really only fully staffed about a year ago, around the time that Java 7 shipped. We’ve added a few more engineers to the team since then, but that can’t make up for the inadequate initial staffing and the time lost during the transition. Q So it’s really just a matter of staffing limitations and corporate-integration distractions? A Aside from these difficulties, the other main factor in the duration of the project is the sheer technical difficulty of modularizing the JDK. Q Why is modularizing the JDK so hard? A There are two main reasons. The first is that the JDK code base is deeply interconnected at both the API and the implementation levels, having been built over many years primarily in the style of a monolithic software system. We’ve spent considerable effort eliminating or at least simplifying as many API and implementation dependences as possible, so that both the Platform and its implementations can be presented as a coherent set of interdependent modules, but some particularly thorny cases remain. Q What’s the second reason? A We want to maintain as much compatibility with prior releases as possible, most especially for existing classpath-based applications but also, to the extent feasible, for applications composed of modules. Q Is modularizing the JDK even necessary? Can’t you just put it in one big module? A Modularizing the JDK, and more specifically modularizing the Java SE Platform, will enable standard yet flexible Java runtime configurations scaling from large servers down to small embedded devices. In the long term it will enable the convergence of Java SE with the higher-end Java ME Platforms. Q Is Project Jigsaw just about modularizing the JDK? A As originally conceived, Project Jigsaw was indeed focused primarily upon modularizing the JDK. The growing demand for a truly standard module system for the Java Platform, which could be used not just for the Platform itself but also for libraries and applications built on top of it, later motivated expanding the scope of the effort. Q As a developer, why should I care about Project Jigsaw? A The introduction of a modular Java Platform will, in the long term, fundamentally change the way that Java implementations, libraries, frameworks, tools, and applications are designed, built, and deployed. Q How much progress has Project Jigsaw made? A We’ve actually made a lot of progress. Much of the core functionality of the module system has been prototyped and works at both compile time and run time. We’ve extended the Java programming language with module declarations, worked out a structure for modular source trees and corresponding compiled-class trees, and implemented these features in javac. We’ve defined an efficient module-file format, extended the JVM to bootstrap a modular JRE, and designed and implemented a preliminary API. We’ve used the module system to make a good first cut at dividing the JDK and the Java SE API into a coherent set of modules. Among other things, we’re currently working to retrofit the java.util.ServiceLoader API to support modular services. Q I want to help! How can I get involved? A Check out the project page, read the draft requirements and design overview documents, download the latest prototype build, and play with it. You can tell us what you think, and follow the rest of our work in real time, on the jigsaw-dev list. The Java Platform Module System JSR Q What’s the relationship between Project Jigsaw and the eventual Java Platform Module System JSR? A At a high level, Project Jigsaw has two phases. In the first phase we’re exploring an approach to modularity that’s markedly different from that of existing Java modularity solutions. We’ve assumed that we can change the Java programming language, the virtual machine, and the APIs. Doing so enables a design which can strongly enforce module boundaries in all program phases, from compilation to deployment to execution. That, in turn, leads to better usability, diagnosability, security, and performance. The ultimate goal of the first phase is produce a working prototype which can inform the work of the Module-System JSR EG. Q What will happen in the second phase of Project Jigsaw? A The second phase will produce the reference implementation of the specification created by the Module-System JSR EG. The EG might ultimately choose an entirely different approach than the one we’re exploring now. If and when that happens then Project Jigsaw will change course as necessary, but either way I think that the end result will be better for having been informed by our current work. Maven & OSGi Q Why not just use Maven? A Maven is a software project management and comprehension tool. As such it can be seen as a kind of build-time module system but, by its nature, it does nothing to support modularity at run time. Q Why not just adopt OSGi? A OSGi is a rich dynamic component system which includes not just a module system but also a life-cycle model and a dynamic service registry. The latter two facilities are useful to some kinds of sophisticated applications, but I don’t think they’re of wide enough interest to be standardized as part of the Java SE Platform. Q Okay, then why not just adopt the module layer of OSGi? A The OSGi module layer is not operative at compile time; it only addresses modularity during packaging, deployment, and execution. As it stands, moreover, it’s useful for library and application modules but, since it’s built strictly on top of the Java SE Platform, it can’t be used to modularize the Platform itself. Q If Maven addresses modularity at build time, and the OSGi module layer addresses modularity during deployment and at run time, then why not just use the two together, as many developers already do? A The combination of Maven and OSGi is certainly very useful in practice today. These systems have, however, been built on top of the existing Java platform; they have not been able to change the platform itself. This means, among other things, that module boundaries are weakly enforced, if at all, which makes it difficult to diagnose configuration errors and impossible to run untrusted code securely. The prototype Jigsaw module system, by contrast, aims to define a platform-level solution which extends both the language and the JVM in order to enforce module boundaries strongly and uniformly in all program phases. Q If the EG chooses an approach like the one currently being taken in the Jigsaw prototype, will Maven and OSGi be made obsolete? A No, not at all! No matter what approach is taken, to ensure wide adoption it’s essential that the standard Java Platform Module System interact well with Maven. Applications that depend upon the sophisticated features of OSGi will no doubt continue to use OSGi, so it’s critical that implementations of OSGi be able to run on top of the Java module system and, if suitably modified, support OSGi bundles that depend upon Java modules. Ideas for how to do that are currently being explored in Project Penrose. Java 8 & Java 9 Q Without Jigsaw, won’t Java 8 be a pretty boring release? A No, far from it! It’s still slated to include the widely-anticipated Project Lambda (JSR 335), work on which has been going very well, along with the new Date/Time API (JSR 310), Type Annotations (JSR 308), and a set of smaller features already in progress. Q Won’t deferring Jigsaw to Java 9 delay the eventual convergence of the higher-end Java ME Platforms with Java SE? A It will slow that transition, but it will not stop it. To allow progress toward that convergence to be made with Java 8 I’ve suggested to the Java SE 8 EG that we consider specifying a small number of Profiles which would allow compact configurations of the SE Platform to be built and deployed. Q If Jigsaw is deferred to Java 9, would the Oracle engineers currently working on it be reassigned to other Java 8 features and then return to working on Jigsaw again after Java 8 ships? A No, these engineers would continue to work primarily on Jigsaw from now until Java 9 ships. Q Why not drop Lambda and finish Jigsaw instead? A Even if the engineers currently working on Lambda could instantly switch over to Jigsaw and immediately become productive—which of course they can’t—there are less than nine months remaining in the Java 8 schedule for work on major features. That’s just not enough time for the broad review, testing, and feedback which such a fundamental change to the Java Platform requires. Q Why not ship the module system in Java 8, and then modularize the platform in Java 9? A If we deliver a module system in one release but don’t use it to modularize the JDK until some later release then we run a big risk of getting something fundamentally wrong. If that happens then we’d have to fix it in the later release, and fixing fundamental design flaws after the fact almost always leads to a poor end result. Q Why not ship Jigsaw in an 8.5 release, less than two years after 8? Or why not just ship a new release every year, rather than every other year? A Many more developers work on the JDK today than a couple of years ago, both because Oracle has dramatically increased its own investment and because other organizations and individuals have joined the OpenJDK Community. Collectively we don’t, however, have the bandwidth required to ship and then provide long-term support for a big JDK release more frequently than about every other year. Q What’s the feedback been on the two-year release-cycle proposal? A For just about every comment that we should release more frequently, so that new features are available sooner, there’s been another asking for an even slower release cycle so that large teams of enterprise developers who ship mission-critical applications have a chance to migrate at a comfortable pace.

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Processing Kinect v2 Color Streams in Parallel

- by Chris Gardner

Originally posted on: http://geekswithblogs.net/freestylecoding/archive/2014/08/20/processing-kinect-v2-color-streams-in-parallel.aspxProcessing Kinect v2 Color Streams in Parallel I've really been enjoying being a part of the Kinect for Windows Developer's Preview. The new hardware has some really impressive capabilities. However, with great power comes great system specs. Unfortunately, my little laptop that could is not 100% up to the task; I've had to get a little creative. The most disappointing thing I've run into is that I can't always cleanly display the color camera stream in managed code. I managed to strip the code down to what I believe is the bear minimum: using( ColorFrame _ColorFrame = e.FrameReference.AcquireFrame() ) { if( null == _ColorFrame ) return; BitmapToDisplay.Lock(); _ColorFrame.CopyConvertedFrameDataToIntPtr( BitmapToDisplay.BackBuffer, Convert.ToUInt32( BitmapToDisplay.BackBufferStride * BitmapToDisplay.PixelHeight ), ColorImageFormat.Bgra ); BitmapToDisplay.AddDirtyRect( new Int32Rect( 0, 0, _ColorFrame.FrameDescription.Width, _ColorFrame.FrameDescription.Height ) ); BitmapToDisplay.Unlock(); } With this snippet, I'm placing the converted Bgra32 color stream directly on the BackBuffer of the WriteableBitmap. This gives me pretty smooth playback, but I still get the occasional freeze for half a second. After a bit of profiling, I discovered there were a few problems. The first problem is the size of the buffer along with the conversion on the buffer. At this time, the raw image format of the data from the Kinect is Yuy2. This is great for direct video processing. It would be ideal if I had a WriteableVideo object in WPF. However, this is not the case. Further digging led me to the real problem. It appears that the SDK is converting the input serially. Let's think about this for a second. The color camera is a 1080p camera. As we should all know, this give us a native resolution of 1920 x 1080. This produces 2,073,600 pixels. Yuy2 uses 4 bytes per 2 pixel, for a buffer size of 4,147,200 bytes. Bgra32 uses 4 bytes per pixel, for a buffer size of 8,294,400 bytes. The SDK appears to be doing this on one thread. I started wondering if I chould do this better myself. I mean, I have 8 cores in my system. Why can't I use them all? The first problem is converting a Yuy2 frame into a Bgra32 frame. It is NOT trivial. I spent a day of research of just how to do this. In the end, I didn't even produce the best algorithm possible, but it did work. After I managed to get that to work, I knew my next step was the get the conversion operation off the UI Thread. This was a simple process of throwing the work into a Task. Of course, this meant I had to marshal the final write to the WriteableBitmap back to the UI thread. Finally, I needed to vectorize the operation so I could run it safely in parallel. This was, mercifully, not quite as hard as I thought it would be. I had my loop return an index to a pair of pixels. From there, I had to tell the loop to do everything for this pair of pixels. If you're wondering why I did it for pairs of pixels, look back above at the specification for the Yuy2 format. I won't go into full detail on why each 4 bytes contains 2 pixels of information, but rest assured that there is a reason why the format is described in that way. The first working attempt at this algorithm successfully turned my poor laptop into a space heater. I very quickly brought and maintained all 8 cores up to about 97% usage. That's when I remembered that obscure option in the Task Parallel Library where you could limit the amount of parallelism used. After a little trial and error, I discovered 4 parallel tasks was enough for most cases. This yielded the follow code: private byte ClipToByte( int p_ValueToClip ) { return Convert.ToByte( ( p_ValueToClip < byte.MinValue ) ? byte.MinValue : ( ( p_ValueToClip > byte.MaxValue ) ? byte.MaxValue : p_ValueToClip ) ); } private void ColorFrameArrived( object sender, ColorFrameArrivedEventArgs e ) { if( null == e.FrameReference ) return; // If you do not dispose of the frame, you never get another one... using( ColorFrame _ColorFrame = e.FrameReference.AcquireFrame() ) { if( null == _ColorFrame ) return; byte[] _InputImage = new byte[_ColorFrame.FrameDescription.LengthInPixels * _ColorFrame.FrameDescription.BytesPerPixel]; byte[] _OutputImage = new byte[BitmapToDisplay.BackBufferStride * BitmapToDisplay.PixelHeight]; _ColorFrame.CopyRawFrameDataToArray( _InputImage ); Task.Factory.StartNew( () => { ParallelOptions _ParallelOptions = new ParallelOptions(); _ParallelOptions.MaxDegreeOfParallelism = 4; Parallel.For( 0, Sensor.ColorFrameSource.FrameDescription.LengthInPixels / 2, _ParallelOptions, ( _Index ) => { // See http://msdn.microsoft.com/en-us/library/windows/desktop/dd206750(v=vs.85).aspx int _Y0 = _InputImage[( _Index << 2 ) + 0] - 16; int _U = _InputImage[( _Index << 2 ) + 1] - 128; int _Y1 = _InputImage[( _Index << 2 ) + 2] - 16; int _V = _InputImage[( _Index << 2 ) + 3] - 128; byte _R = ClipToByte( ( 298 * _Y0 + 409 * _V + 128 ) >> 8 ); byte _G = ClipToByte( ( 298 * _Y0 - 100 * _U - 208 * _V + 128 ) >> 8 ); byte _B = ClipToByte( ( 298 * _Y0 + 516 * _U + 128 ) >> 8 ); _OutputImage[( _Index << 3 ) + 0] = _B; _OutputImage[( _Index << 3 ) + 1] = _G; _OutputImage[( _Index << 3 ) + 2] = _R; _OutputImage[( _Index << 3 ) + 3] = 0xFF; // A _R = ClipToByte( ( 298 * _Y1 + 409 * _V + 128 ) >> 8 ); _G = ClipToByte( ( 298 * _Y1 - 100 * _U - 208 * _V + 128 ) >> 8 ); _B = ClipToByte( ( 298 * _Y1 + 516 * _U + 128 ) >> 8 ); _OutputImage[( _Index << 3 ) + 4] = _B; _OutputImage[( _Index << 3 ) + 5] = _G; _OutputImage[( _Index << 3 ) + 6] = _R; _OutputImage[( _Index << 3 ) + 7] = 0xFF; } ); Application.Current.Dispatcher.Invoke( () => { BitmapToDisplay.WritePixels( new Int32Rect( 0, 0, Sensor.ColorFrameSource.FrameDescription.Width, Sensor.ColorFrameSource.FrameDescription.Height ), _OutputImage, BitmapToDisplay.BackBufferStride, 0 ); } ); } ); } } This seemed to yield a results I wanted, but there was still the occasional stutter. This lead to what I realized was the second problem. There is a race condition between the UI Thread and me locking the WriteableBitmap so I can write the next frame. Again, I'm writing approximately 8MB to the back buffer. Then, I started thinking I could cheat. The Kinect is running at 30 frames per second. The WPF UI Thread runs at 60 frames per second. This made me not feel bad about exploiting the Composition Thread. I moved the bulk of the code from the FrameArrived handler into CompositionTarget.Rendering. Once I was in there, I polled from a frame, and rendered it if it existed. Since, in theory, I'm only killing the Composition Thread every other hit, I decided I was ok with this for cases where silky smooth video performance REALLY mattered. This ode looked like this: private byte ClipToByte( int p_ValueToClip ) { return Convert.ToByte( ( p_ValueToClip < byte.MinValue ) ? byte.MinValue : ( ( p_ValueToClip > byte.MaxValue ) ? byte.MaxValue : p_ValueToClip ) ); } void CompositionTarget_Rendering( object sender, EventArgs e ) { using( ColorFrame _ColorFrame = FrameReader.AcquireLatestFrame() ) { if( null == _ColorFrame ) return; byte[] _InputImage = new byte[_ColorFrame.FrameDescription.LengthInPixels * _ColorFrame.FrameDescription.BytesPerPixel]; byte[] _OutputImage = new byte[BitmapToDisplay.BackBufferStride * BitmapToDisplay.PixelHeight]; _ColorFrame.CopyRawFrameDataToArray( _InputImage ); ParallelOptions _ParallelOptions = new ParallelOptions(); _ParallelOptions.MaxDegreeOfParallelism = 4; Parallel.For( 0, Sensor.ColorFrameSource.FrameDescription.LengthInPixels / 2, _ParallelOptions, ( _Index ) => { // See http://msdn.microsoft.com/en-us/library/windows/desktop/dd206750(v=vs.85).aspx int _Y0 = _InputImage[( _Index << 2 ) + 0] - 16; int _U = _InputImage[( _Index << 2 ) + 1] - 128; int _Y1 = _InputImage[( _Index << 2 ) + 2] - 16; int _V = _InputImage[( _Index << 2 ) + 3] - 128; byte _R = ClipToByte( ( 298 * _Y0 + 409 * _V + 128 ) >> 8 ); byte _G = ClipToByte( ( 298 * _Y0 - 100 * _U - 208 * _V + 128 ) >> 8 ); byte _B = ClipToByte( ( 298 * _Y0 + 516 * _U + 128 ) >> 8 ); _OutputImage[( _Index << 3 ) + 0] = _B; _OutputImage[( _Index << 3 ) + 1] = _G; _OutputImage[( _Index << 3 ) + 2] = _R; _OutputImage[( _Index << 3 ) + 3] = 0xFF; // A _R = ClipToByte( ( 298 * _Y1 + 409 * _V + 128 ) >> 8 ); _G = ClipToByte( ( 298 * _Y1 - 100 * _U - 208 * _V + 128 ) >> 8 ); _B = ClipToByte( ( 298 * _Y1 + 516 * _U + 128 ) >> 8 ); _OutputImage[( _Index << 3 ) + 4] = _B; _OutputImage[( _Index << 3 ) + 5] = _G; _OutputImage[( _Index << 3 ) + 6] = _R; _OutputImage[( _Index << 3 ) + 7] = 0xFF; } ); BitmapToDisplay.WritePixels( new Int32Rect( 0, 0, Sensor.ColorFrameSource.FrameDescription.Width, Sensor.ColorFrameSource.FrameDescription.Height ), _OutputImage, BitmapToDisplay.BackBufferStride, 0 ); } }

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Stumbling Through: Visual Studio 2010 (Part IV)

So finally we get to the fun part the fruits of all of our middle-tier/back end labors of generating classes to interface with an XML data source that the previous posts were about can now be presented quickly and easily to an end user. I think. Well see. Well be using a WPF window to display all of our various MFL information that weve collected in the two XML files, and well provide a means of adding, updating and deleting each of these entities using as little code as possible. Additionally, I would like to dig into the performance of this solution as well as the flexibility of it if were were to modify the underlying XML schema. So first things first, lets create a WPF project and include our xml data in a data folder within. On the main window, well drag out the following controls: A combo box to contain all of the teams A list box to show the players of the selected team, along with add/delete player buttons A text box tied to the selected players name, with a save button to save any changes made to the player name A combo box of all the available positions, tied to the currently selected players position A data grid tied to the statistics of the currently selected player, with add/delete statistic buttons This monstrosity of a form and its associated project will look like this (dont forget to reference the DataFoundation project from the Presentation project): To get to the visual data binding, as we learned in a previous post, you have to first make sure the project containing your bindable classes is compiled. Do so, and then open the Data Sources pane to add a reference to the Teams and Positions classes in the DataFoundation project: Why only Team and Position? Well, we will get to Players from Teams, and Statistics from Players so no need to make an interface for them as well see in a second. As for Positions, well need a way to bind the dropdown to ALL positions they dont appear underneath any of the other classes so we need to reference it directly. After adding these guys, expand every node in your Data Sources pane and see how the Team node allows you to drill into Players and then Statistics. This is why there was no need to bring in a reference to those classes for the UI we are designing: Now for the seriously hard work of binding all of our controls to the correct data sources. Drag the following items from the Data Sources pane to the specified control on the window design canvas: Team.Name > Teams combo box Team.Players.Name > Players list box Team.Players.Name > Player name text box Team.Players.Statistics > Statistics data grid Position.Name > Positions combo box That is it! Really? Well, no, not really there is one caveat here in that the Positions combo box is not bound the selected players position. To do so, we will apply a binding to the position combo boxs SelectedValue to point to the current players PositionId value: That should do the trick now, all we need to worry about is loading the actual data. Sadly, it appears as if we will need to drop to code in order to invoke our IO methods to load all teams and positions. At least Visual Studio kindly created the stubs for us to do so, ultimately the code should look like this: Note the weirdness with the InitializeDataFiles call that is my current means of telling an IO where to load the data for each of the entities. I havent thought of a more intuitive way than that yet, but do note that all data is loaded from Teams.xml besides for positions, which is loaded from Lookups.xml. I think that may be all we need to do to at least load all of the data, lets run it and see: Yay! All of our glorious data is being displayed! Er, wait, whats up with the position dropdown? Why is it red? Lets select the RB and see if everything updates: Crap, the position didnt update to reflect the selected player, but everything else did. Where did we go wrong in binding the position to the selected player? Thinking about it a bit and comparing it to how traditional data binding works, I realize that we never set the value member (or some similar property) to tell the control to join the Id of the source (positions) to the position Id of the player. I dont see a similar property to that on the combo box control, but I do see a property named SelectedValuePath that might be it, so I set it to Id and run the app again: Hey, all right! No red box around the positions combo box. Unfortunately, selecting the RB does not update the dropdown to point to Runningback. Hmmm. Now what could it be? Maybe the problem is that we are loading teams before we are loading positions, so when it binds position Id, all of the positions arent loaded yet. I went to the code behind and switched things so position loads first and no dice. Same result when I run. Why? WHY? Ok, ok, calm down, take a deep breath. Get something with caffeine or sugar (preferably both) and think rationally. Ok, gigantic chocolate chip cookie and a mountain dew chaser have never let me down in the past, so dont fail me now! Ah ha! of course! I didnt even have to finish the mountain dew and I think Ive got it: Data Context. By default, when setting on the selected value binding for the dropdown, the data context was list_team. I dont even know what the heck list_team is, we want it to be bound to our team players view source resource instead, like this: Running it now and selecting the various players: Done and done. Everything read and bound, thank you caffeine and sugar! Oh, and thank you Visual Studio 2010. Lets wire up some of those buttons now There has got to be a better way to do this, but it works for now. What the add player button does is add a new player object to the currently selected team. Unfortunately, I couldnt get the new object to automatically show up in the players list (something about not using an observable collection gotta look into this) so I just save the change immediately and reload the screen. Terrible, but it works: Lets go after something easier: The save button. By default, as we type in new text for the players name, it is showing up in the list box as updated. Cool! Why couldnt my add new player logic do that? Anyway, the save button should be as simple as invoking MFL.IO.Save for the selected player, like this: MFL.IO.Save((MFL.Player)lbTeamPlayers.SelectedItem, true); Surprisingly, that worked on the first try. Lets see if we get as lucky with the Delete player button: MFL.IO.Delete((MFL.Player)lbTeamPlayers.SelectedItem); Refresh(); Note the use of the Refresh method again I cant seem to figure out why updates to the underlying data source are immediately reflected, but adds and deletes are not. That is a problem for another day, and again my hunch is that I should be binding to something more complex than IEnumerable (like observable collection). Now that an example of the basic CRUD methods are wired up, I want to quickly investigate the performance of this beast. Im going to make a special button to add 30 teams, each with 50 players and 10 seasons worth of stats. If my math is right, that will end up with 15000 rows of data, a pretty hefty amount for an XML file. The save of all this new data took a little over a minute, but that is acceptable because we wouldnt typically be saving batches of 15k records, and the resulting XML file size is a little over a megabyte. Not huge, but big enough to see some read performance numbers or so I thought. It reads this file and renders the first team in under a second. That is unbelievable, but we are lazy loading and the file really wasnt that big. I will increase it to 50 teams with 100 players and 20 seasons each - 100,000 rows. It took a year and a half to save all of that data, and resulted in an 8 megabyte file. Seriously, if you are loading XML files this large, get a freaking database! Despite this, it STILL takes under a second to load and render the first team, which is interesting mostly because I thought that it was loading that entire 8 MB XML file behind the scenes. I have to say that I am quite impressed with the performance of the LINQ to XML approach, particularly since I took no efforts to optimize any of this code and was fairly new to the concept from the start. There might be some merit to this little project after all Look out SQL Server and Oracle, use XML files instead! Next up, I am going to completely pull the rug out from under the UI and change a number of entities in our model. How well will the code be regenerated? How much effort will be required to tie things back together in the UI?Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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Stumbling Through: Visual Studio 2010 (Part III)

The last post ended with us just getting started on stumbling into text template file customization, a task that required a Visual Studio extension (Tangible T4 Editor) to even have a chance at completing. Despite the benefits of the Tangible T4 Editor, I still had a hard time putting together a solid text template that would be easy to explain. This is mostly due to the way the files allow you to mix code (encapsulated in <# #>) with straight-up text to generate. It is effective to be sure, but not very readable. Nevertheless, I will try and explain what was accomplished in my custom tt file, though the details of which are not really the point of this article (my way of saying dont criticize my crappy code, and certainly dont use it in any somewhat real application. You may become dumber just by looking at this code. You have been warned really the footnote I should put at the end of all of my blog posts). To begin with, there were two basic requirements that I needed the code generator to satisfy: Reading one to many entity framework files, and using the entities that were found to write one to many class files. Thankfully, using the Entity Object Generator as a starting point gave us an example on how to do exactly that by using the MetadataLoader and EntityFrameworkTemplateFileManager you include references to these items and use them like so: // Instantiate an entity framework file reader and file writer MetadataLoader loader = new MetadataLoader(this); EntityFrameworkTemplateFileManager fileManager = EntityFrameworkTemplateFileManager.Create(this); // Load the entity model metadata workspace MetadataWorkspace metadataWorkspace = null; bool allMetadataLoaded =loader.TryLoadAllMetadata("MFL.tt", out metadataWorkspace); EdmItemCollection ItemCollection = (EdmItemCollection)metadataWorkspace.GetItemCollection(DataSpace.CSpace); // Create an IO class to contain the 'get' methods for all entities in the model fileManager.StartNewFile("MFL.IO.gen.cs"); Next, we want to be able to loop through all of the entities found in the model, and then each property for each entity so we can generate classes and methods for each. The code for that is blissfully simple: // Iterate through each entity in the model foreach (EntityType entity in ItemCollection.GetItems<EntityType>().OrderBy(e => e.Name)) { // Iterate through each primitive property of the entity foreach (EdmProperty edmProperty in entity.Properties.Where(p => p.TypeUsage.EdmType is PrimitiveType && p.DeclaringType == entity)) { // TODO: Create properties } // Iterate through each relationship of the entity foreach (NavigationProperty navProperty in entity.NavigationProperties.Where(np => np.DeclaringType == entity)) { // TODO: Create associations } } There really isnt anything more advanced than that going on in the text template the only thing I had to blunder through was realizing that if you want the generator to interpret a line of code (such as our iterations above), you need to enclose the code in <# and #> while if you want the generator to interpret the VALUE of code, such as putting the entity name into the class name, you need to enclose the code in <#= and #> like so: public partial class <#=entity.Name#> To make a long story short, I did a lot of repetition of the above to come up with a text template that generates a class for each entity based on its properties, and a set of IO methods for each entity based on its relationships. The two work together to provide lazy-loading for hierarchical data (such getting Team.Players) so it should be pretty intuitive to use on a front-end. This text template is available here you can tweak the inputFiles array to load one or many different edmx models and generate the basic xml IO and class files, though it will probably only work correctly in the simplest of cases, like our MFL model described in the previous post. Additionally, there is no validation, logging or error handling which is something I want to handle later by stumbling through the enterprise library 5.0. The code that gets generated isnt anything special, though using the LINQ to XML feature was something very new and exciting for me I had only worked with XML in the past using the DOM or XML Reader objects along with XPath, and the LINQ to XML model is just so much more elegant and supposedly efficient (something to test later). For example, the following code was generated to create a Player object for each Player node in the XML: return from element in GetXmlData(_PlayerDataFile).Descendants("Player") select new Player { Id = int.Parse(element.Attribute("Id").Value) ,ParentName = element.Parent.Name.LocalName ,ParentId = long.Parse(element.Parent.Attribute("Id").Value) ,Name = element.Attribute("Name").Value ,PositionId = int.Parse(element.Attribute("PositionId").Value) }; It is all done in one line of code, no looping needed. Even though GetXmlData loads the entire xml file just like the old XML DOM approach would have, it is supposed to be much less resource intensive. I will definitely put that to the test after we develop a user interface for getting at this data. Speaking of the data where IS the data? Weve put together a pretty model and a bunch of code around it, but we dont have any data to speak of. We can certainly drop to our favorite XML editor and crank out some data, but if it doesnt totally match our model, it will not load correctly. To help with this, Ive built in a method to generate xml at any given layer in the hierarchy. So for us to get the closest possible thing to real data, wed need to invoke MFL.IO.GenerateTeamXML and save the results to file. Doing so should get us something that looks like this: <Team Id="0" Name="0"> <Player Id="0" Name="0" PositionId="0"> <Statistic Id="0" PassYards="0" RushYards="0" Year="0" /> </Player> </Team> Sadly, it is missing the Positions node (havent thought of a way to generate lookup xml yet) and the data itself isnt quite realistic (well, as realistic as MFL data can be anyway). Lets manually remedy that for now to give us a decent starter set of data. Note that this is TWO xml files Lookups.xml and Teams.xml: <Lookups Id=0> <Position Id="0" Name="Quarterback"/> <Position Id="1" Name="Runningback"/> </Lookups> <Teams Id=0> <Team Id="0" Name="Chicago"> <Player Id="0" Name="QB Bears" PositionId="0"> <Statistic Id="0" PassYards="4000" RushYards="120" Year="2008" /> <Statistic Id="1" PassYards="4200" RushYards="180" Year="2009" /> </Player> <Player Id="1" Name="RB Bears" PositionId="1"> <Statistic Id="2" PassYards="0" RushYards="800" Year="2007" /> <Statistic Id="3" PassYards="0" RushYards="1200" Year="2008" /> <Statistic Id="4" PassYards="3" RushYards="1450" Year="2009" /> </Player> </Team> </Teams> Ok, so we have some data, we have a way to read/write that data and we have a friendly way of representing that data. Now, what remains is the part that I have been looking forward to the most: present the data to the user and give them the ability to add/update/delete, and doing so in a way that is very intuitive (easy) from a development standpoint.Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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Stumbling Through: Visual Studio 2010 (Part III)

The last post ended with us just getting started on stumbling into text template file customization, a task that required a Visual Studio extension (Tangible T4 Editor) to even have a chance at completing. Despite the benefits of the Tangible T4 Editor, I still had a hard time putting together a solid text template that would be easy to explain. This is mostly due to the way the files allow you to mix code (encapsulated in <# #>) with straight-up text to generate. It is effective to be sure, but not very readable. Nevertheless, I will try and explain what was accomplished in my custom tt file, though the details of which are not really the point of this article (my way of saying dont criticize my crappy code, and certainly dont use it in any somewhat real application. You may become dumber just by looking at this code. You have been warned really the footnote I should put at the end of all of my blog posts). To begin with, there were two basic requirements that I needed the code generator to satisfy: Reading one to many entity framework files, and using the entities that were found to write one to many class files. Thankfully, using the Entity Object Generator as a starting point gave us an example on how to do exactly that by using the MetadataLoader and EntityFrameworkTemplateFileManager you include references to these items and use them like so: // Instantiate an entity framework file reader and file writer MetadataLoader loader = new MetadataLoader(this); EntityFrameworkTemplateFileManager fileManager = EntityFrameworkTemplateFileManager.Create(this); // Load the entity model metadata workspace MetadataWorkspace metadataWorkspace = null; bool allMetadataLoaded =loader.TryLoadAllMetadata("MFL.tt", out metadataWorkspace); EdmItemCollection ItemCollection = (EdmItemCollection)metadataWorkspace.GetItemCollection(DataSpace.CSpace); // Create an IO class to contain the 'get' methods for all entities in the model fileManager.StartNewFile("MFL.IO.gen.cs"); Next, we want to be able to loop through all of the entities found in the model, and then each property for each entity so we can generate classes and methods for each. The code for that is blissfully simple: // Iterate through each entity in the model foreach (EntityType entity in ItemCollection.GetItems<EntityType>().OrderBy(e => e.Name)) { // Iterate through each primitive property of the entity foreach (EdmProperty edmProperty in entity.Properties.Where(p => p.TypeUsage.EdmType is PrimitiveType && p.DeclaringType == entity)) { // TODO: Create properties } // Iterate through each relationship of the entity foreach (NavigationProperty navProperty in entity.NavigationProperties.Where(np => np.DeclaringType == entity)) { // TODO: Create associations } } There really isnt anything more advanced than that going on in the text template the only thing I had to blunder through was realizing that if you want the generator to interpret a line of code (such as our iterations above), you need to enclose the code in <# and #> while if you want the generator to interpret the VALUE of code, such as putting the entity name into the class name, you need to enclose the code in <#= and #> like so: public partial class <#=entity.Name#> To make a long story short, I did a lot of repetition of the above to come up with a text template that generates a class for each entity based on its properties, and a set of IO methods for each entity based on its relationships. The two work together to provide lazy-loading for hierarchical data (such getting Team.Players) so it should be pretty intuitive to use on a front-end. This text template is available here you can tweak the inputFiles array to load one or many different edmx models and generate the basic xml IO and class files, though it will probably only work correctly in the simplest of cases, like our MFL model described in the previous post. Additionally, there is no validation, logging or error handling which is something I want to handle later by stumbling through the enterprise library 5.0. The code that gets generated isnt anything special, though using the LINQ to XML feature was something very new and exciting for me I had only worked with XML in the past using the DOM or XML Reader objects along with XPath, and the LINQ to XML model is just so much more elegant and supposedly efficient (something to test later). For example, the following code was generated to create a Player object for each Player node in the XML: return from element in GetXmlData(_PlayerDataFile).Descendants("Player") select new Player { Id = int.Parse(element.Attribute("Id").Value) ,ParentName = element.Parent.Name.LocalName ,ParentId = long.Parse(element.Parent.Attribute("Id").Value) ,Name = element.Attribute("Name").Value ,PositionId = int.Parse(element.Attribute("PositionId").Value) }; It is all done in one line of code, no looping needed. Even though GetXmlData loads the entire xml file just like the old XML DOM approach would have, it is supposed to be much less resource intensive. I will definitely put that to the test after we develop a user interface for getting at this data. Speaking of the data where IS the data? Weve put together a pretty model and a bunch of code around it, but we dont have any data to speak of. We can certainly drop to our favorite XML editor and crank out some data, but if it doesnt totally match our model, it will not load correctly. To help with this, Ive built in a method to generate xml at any given layer in the hierarchy. So for us to get the closest possible thing to real data, wed need to invoke MFL.IO.GenerateTeamXML and save the results to file. Doing so should get us something that looks like this: <Team Id="0" Name="0"> <Player Id="0" Name="0" PositionId="0"> <Statistic Id="0" PassYards="0" RushYards="0" Year="0" /> </Player> </Team> Sadly, it is missing the Positions node (havent thought of a way to generate lookup xml yet) and the data itself isnt quite realistic (well, as realistic as MFL data can be anyway). Lets manually remedy that for now to give us a decent starter set of data. Note that this is TWO xml files Lookups.xml and Teams.xml: <Lookups Id=0> <Position Id="0" Name="Quarterback"/> <Position Id="1" Name="Runningback"/> </Lookups> <Teams Id=0> <Team Id="0" Name="Chicago"> <Player Id="0" Name="QB Bears" PositionId="0"> <Statistic Id="0" PassYards="4000" RushYards="120" Year="2008" /> <Statistic Id="1" PassYards="4200" RushYards="180" Year="2009" /> </Player> <Player Id="1" Name="RB Bears" PositionId="1"> <Statistic Id="2" PassYards="0" RushYards="800" Year="2007" /> <Statistic Id="3" PassYards="0" RushYards="1200" Year="2008" /> <Statistic Id="4" PassYards="3" RushYards="1450" Year="2009" /> </Player> </Team> </Teams> Ok, so we have some data, we have a way to read/write that data and we have a friendly way of representing that data. Now, what remains is the part that I have been looking forward to the most: present the data to the user and give them the ability to add/update/delete, and doing so in a way that is very intuitive (easy) from a development standpoint.Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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Iphone SDK - adding UITableView to UIView

- by Shashi

Hi, I am trying to learn how to use different views, for this sample test app, i have a login page, upon successful logon, the user is redirected to a table view and then upon selection of an item in the table view, the user is directed to a third page showing details of the item. the first page works just fine, but the problem occurs when i go to the second page, the table shown doesn't have title and i cannot add title or toolbar or anything other than the content of the tables themselves. and when i click on the item, needless to say nothing happens. no errors as well. i am fairly new to programming and have always worked on Java but never on C(although i have some basic knowledge of C) and Objective C is new to me. Here is the code. import @interface NavigationTestAppDelegate : NSObject { UIWindow *window; UIViewController *viewController; IBOutlet UITextField *username; IBOutlet UITextField *password; IBOutlet UILabel *loginError; //UINavigationController *navigationController; } @property (nonatomic, retain) IBOutlet UIViewController *viewController; @property (nonatomic, retain) IBOutlet UIWindow *window; @property (nonatomic, retain) IBOutlet UITextField *username; @property (nonatomic, retain) IBOutlet UITextField *password; @property (nonatomic, retain) IBOutlet UILabel *loginError; -(IBAction) login; -(IBAction) hideKeyboard: (id) sender; @end import "NavigationTestAppDelegate.h" import "RootViewController.h" @implementation NavigationTestAppDelegate @synthesize window; @synthesize viewController; @synthesize username; @synthesize password; @synthesize loginError; pragma mark - pragma mark Application lifecycle -(IBAction) hideKeyboard: (id) sender{ [sender resignFirstResponder]; } (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { // Override point for customization after app launch //RootViewController *rootViewController = [[RootViewController alloc] init]; //[window addSubview:[navigationController view]]; [window addSubview:[viewController view]]; [window makeKeyAndVisible]; return YES; } -(IBAction) login { RootViewController *rootViewController = [[RootViewController alloc] init]; //NSString *user = [[NSString alloc] username. if([username.text isEqualToString:@"test"]&&[password.text isEqualToString:@"test"]){ [window addSubview:[rootViewController view]]; //[window addSubview:[navigationController view]]; [window makeKeyAndVisible]; //rootViewController.awakeFromNib; } else { loginError.text = @"LOGIN ERROR"; [window addSubview:[viewController view]]; [window makeKeyAndVisible]; } } (void)applicationWillTerminate:(UIApplication *)application { // Save data if appropriate } pragma mark - pragma mark Memory management (void)dealloc { //[navigationController release]; [viewController release]; [window release]; [super dealloc]; } @end import @interface RootViewController : UITableViewController { IBOutlet NSMutableArray *views; } @property (nonatomic, retain) IBOutlet NSMutableArray * views; @end // // RootViewController.m // NavigationTest // // Created by guest on 4/23/10. // Copyright MyCompanyName 2010. All rights reserved. // import "RootViewController.h" import "OpportunityOne.h" @implementation RootViewController @synthesize views; //@synthesize navigationViewController; pragma mark - pragma mark View lifecycle (void)viewDidLoad { views = [ [NSMutableArray alloc] init]; OpportunityOne *opportunityOneController; for (int i=1; i<=20; i++) { opportunityOneController = [[OpportunityOne alloc] init]; opportunityOneController.title = [[NSString alloc] initWithFormat:@"Opportunity %i",i]; [views addObject:[NSDictionary dictionaryWithObjectsAndKeys: [[NSString alloc] initWithFormat:@"Opportunity %i",i], @ "title", opportunityOneController, @"controller", nil]]; self.title=@"GPS"; } /*UIBarButtonItem *temporaryBarButtonItem = [[UIBarButtonItem alloc] init]; temporaryBarButtonItem.title = @"Back"; self.navigationItem.backBarButtonItem = temporaryBarButtonItem; [temporaryBarButtonItem release]; */ //self.title =@"Global Platform for Sales"; [super viewDidLoad]; //[temporaryBarButtonItem release]; //[opportunityOneController release]; // Uncomment the following line to display an Edit button in the navigation bar for this view controller. // self.navigationItem.rightBarButtonItem = self.editButtonItem; } pragma mark - pragma mark Table view data source // Customize the number of sections in the table view. - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return 1; } // Customize the number of rows in the table view. - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return [views count]; } // Customize the appearance of table view cells. - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease]; } // Configure the cell. cell.textLabel.text = [[views objectAtIndex:indexPath.row] objectForKey:@"title"]; return cell; } pragma mark - pragma mark Table view delegate (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { //UIViewController *targetViewController = [[views objectAtIndex:indexPath.row] objectForKey:@"controller"]; UIViewController *targetViewController = [[views objectAtIndex:indexPath.row] objectForKey:@"controller"]; [[self navigationController] pushViewController:targetViewController animated:YES]; } pragma mark - pragma mark Memory management (void)didReceiveMemoryWarning { // Releases the view if it doesn't have a superview. [super didReceiveMemoryWarning]; // Relinquish ownership any cached data, images, etc that aren't in use. } (void)viewDidUnload { // Relinquish ownership of anything that can be recreated in viewDidLoad or on demand. // For example: self.myOutlet = nil; } (void)dealloc { [views release]; [super dealloc]; } @end Wow, i was finding it real hard to post the code. i apologize for the bad formatting, but i just couldn't get past the formatting rules for this text editor. Thanks, Shashi

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Is That REST API Really RPC? Roy Fielding Seems to Think So.

- by Rich Apodaca

A large amount of what I thought I knew about REST is apparently wrong - and I'm not alone. This question has a long lead-in, but it seems to be necessary because the information is a bit scattered. The actual question comes at the end if you're already familiar with this topic. From the first paragraph of Roy Fielding's REST APIs must be hypertext-driven, it's pretty clear he believes his work is being widely misinterpreted: I am getting frustrated by the number of people calling any HTTP-based interface a REST API. Today’s example is the SocialSite REST API. That is RPC. It screams RPC. There is so much coupling on display that it should be given an X rating. Fielding goes on to list several attributes of a REST API. Some of them seem to go against both common practice and common advice on SO and other forums. For example: A REST API should be entered with no prior knowledge beyond the initial URI (bookmark) and set of standardized media types that are appropriate for the intended audience (i.e., expected to be understood by any client that might use the API). ... A REST API must not define fixed resource names or hierarchies (an obvious coupling of client and server). ... A REST API should spend almost all of its descriptive effort in defining the media type(s) used for representing resources and driving application state, or in defining extended relation names and/or hypertext-enabled mark-up for existing standard media types. ... The idea of "hypertext" plays a central role - much more so than URI structure or what HTTP verbs mean. "Hypertext" is defined in one of the comments: When I [Fielding] say hypertext, I mean the simultaneous presentation of information and controls such that the information becomes the affordance through which the user (or automaton) obtains choices and selects actions. Hypermedia is just an expansion on what text means to include temporal anchors within a media stream; most researchers have dropped the distinction. Hypertext does not need to be HTML on a browser. Machines can follow links when they understand the data format and relationship types. I'm guessing at this point, but the first two points above seem to suggest that API documentation for a Foo resource that looks like the following leads to tight coupling between client and server and has no place in a RESTful system. GET /foos/{id} # read a Foo POST /foos/{id} # create a Foo PUT /foos/{id} # update a Foo Instead, an agent should be forced to discover the URIs for all Foos by, for example, issuing a GET request against /foos. (Those URIs may turn out to follow the pattern above, but that's beside the point.) The response uses a media type that is capable of conveying how to access each item and what can be done with it, giving rise to the third point above. For this reason, API documentation should focus on explaining how to interpret the hypertext contained in the response. Furthermore, every time a URI to a Foo resource is requested, the response contains all of the information needed for an agent to discover how to proceed by, for example, accessing associated and parent resources through their URIs, or by taking action after the creation/deletion of a resource. The key to the entire system is that the response consists of hypertext contained in a media type that itself conveys to the agent options for proceeding. It's not unlike the way a browser works for humans. But this is just my best guess at this particular moment. Fielding posted a follow-up in which he responded to criticism that his discussion was too abstract, lacking in examples, and jargon-rich: Others will try to decipher what I have written in ways that are more direct or applicable to some practical concern of today. I probably won’t, because I am too busy grappling with the next topic, preparing for a conference, writing another standard, traveling to some distant place, or just doing the little things that let me feel I have I earned my paycheck. So, two simple questions for the REST experts out there with a practical mindset: how do you interpret what Fielding is saying and how do you put it into practice when documenting/implementing REST APIs? Edit: this question is an example of how hard it can be to learn something if you don't have a name for what you're talking about. The name in this case is "Hypermedia as the Engine of Application State" (HATEOAS).

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LINQ 4 XML - What is the proper way to query deep in the tree structure?

- by Keith Barrows

I have an XML structure that is 4 deep: <?xml version="1.0" encoding="utf-8"?> <EmailRuleList xmlns:xsd="EmailRules.xsd"> <TargetPST name="Tech Communities"> <Parse emailAsList="true" useJustDomain="false" fromAddress="false" toAddress="true"> <EmailRule address="@aspadvice.com" folder="Lists, ASP" saveAttachments="false" /> <EmailRule address="@sqladvice.com" folder="Lists, SQL" saveAttachments="false" /> <EmailRule address="@xmladvice.com" folder="Lists, XML" saveAttachments="false" /> </Parse> <Parse emailAsList="false" useJustDomain="false" fromAddress="false" toAddress="true"> <EmailRule address="[email protected]" folder="Special Interest Groups|Northern Colorado Architects Group" saveAttachments="false" /> <EmailRule address="[email protected]" folder="Support|SpamBayes" saveAttachments="false" /> </Parse> <Parse emailAsList="false" useJustDomain="false" fromAddress="true" toAddress="false"> <EmailRule address="[email protected]" folder="Support|GoDaddy" saveAttachments="false" /> <EmailRule address="[email protected]" folder="Support|No-IP.com" saveAttachments="false" /> <EmailRule address="[email protected]" folder="Discussions|Orchard Project" saveAttachments="false" /> </Parse> <Parse emailAsList="false" useJustDomain="true" fromAddress="true" toAddress="false"> <EmailRule address="@agilejournal.com" folder="Newsletters|Agile Journal" saveAttachments="false"/> <EmailRule address="@axosoft.ccsend.com" folder="Newsletters|Axosoft Newsletter" saveAttachments="false"/> <EmailRule address="@axosoft.com" folder="Newsletters|Axosoft Newsletter" saveAttachments="false"/> <EmailRule address="@cmcrossroads.com" folder="Newsletters|CM Crossroads" saveAttachments="false" /> <EmailRule address="@urbancode.com" folder="Newsletters|Urbancode" saveAttachments="false" /> <EmailRule address="@urbancode.ccsend.com" folder="Newsletters|Urbancode" saveAttachments="false" /> <EmailRule address="@Infragistics.com" folder="Newsletters|Infragistics" saveAttachments="false" /> <EmailRule address="@zdnet.online.com" folder="Newsletters|ZDNet Tech Update Today" saveAttachments="false" /> <EmailRule address="@sqlservercentral.com" folder="Newsletters|SQLServerCentral.com" saveAttachments="false" /> <EmailRule address="@simple-talk.com" folder="Newsletters|Simple-Talk Newsletter" saveAttachments="false" /> </Parse> </TargetPST> <TargetPST name="[Sharpen the Saw]"> <Parse emailAsList="false" useJustDomain="false" fromAddress="false" toAddress="true"> <EmailRule address="[email protected]" folder="Head Geek|Job Alerts" saveAttachments="false" /> <EmailRule address="[email protected]" folder="Social|LinkedIn USMC" saveAttachments="false"/> </Parse> <Parse emailAsList="false" useJustDomain="false" fromAddress="true" toAddress="false"> <EmailRule address="[email protected]" folder="Head Geek|Job Alerts" saveAttachments="false" /> <EmailRule address="[email protected]" folder="Head Geek|Job Alerts" saveAttachments="false" /> <EmailRule address="[email protected]" folder="Social|Cruise Critic" saveAttachments="false"/> </Parse> <Parse emailAsList="false" useJustDomain="true" fromAddress="true" toAddress="false"> <EmailRule address="@moody.edu" folder="Social|5 Love Languages" saveAttachments="false" /> <EmailRule address="@postmaster.twitter.com" folder="Social|Twitter" saveAttachments="false"/> <EmailRule address="@diabetes.org" folder="Physical|American Diabetes Association" saveAttachments="false"/> <EmailRule address="@membership.webshots.com" folder="Social|Webshots" saveAttachments="false"/> </Parse> </TargetPST> </EmailRuleList> Now, I have both an FromAddress and a ToAddress that is parsed from an incoming email. I would like to do a LINQ query against a class set that was deserialized from this XML. For instance: ToAddress = [email protected] FromAddress = [email protected] Query: Get EmailRule.Include(Parse).Include(TargetPST) where address == ToAddress AND Parse.ToAddress==true AND Parse.useJustDomain==false Get EmailRule.Include(Parse).Include(TargetPST) where address == [ToAddress Domain Only] AND Parse.ToAddress==true AND Parse.useJustDomain==true Get EmailRule.Include(Parse).Include(TargetPST) where address == FromAddress AND Parse.FromAddress==true AND Parse.useJustDomain==false Get EmailRule.Include(Parse).Include(TargetPST) where address == [FromAddress Domain Only] AND Parse.FromAddress==true AND Parse.useJustDomain==true I am having a hard time figuring this LINQ query out. I can, of course, loop on all the bits in the XML like so (includes deserialization into objects): XmlSerializer s = new XmlSerializer(typeof(EmailRuleList)); TextReader r = new StreamReader(path); _emailRuleList = (EmailRuleList)s.Deserialize(r); TargetPST[] PSTList = _emailRuleList.Items; foreach (TargetPST targetPST in PSTList) { olRoot = GetRootFolder(targetPST.name); if (olRoot != null) { Parse[] ParseList = targetPST.Items; foreach (Parse parseRules in ParseList) { EmailRule[] EmailRuleList = parseRules.Items; foreach (EmailRule targetFolders in EmailRuleList) { } } } } However, this means going through all these loops for each and every address. It makes more sense to me to query against the Objects. Any tips appreciated!

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Elusive race condition in Java

- by nasufara

I am creating a graphing calculator. In an attempt to squeeze some more performance out of it, I added some multithreaded to the line calculator. Essentially what my current implementation does is construct a thread-safe Queue of X values, then start however many threads it needs, each one calculating a point on the line using the queue to get its values, and then ordering the points using a HashMap when the calculations are done. This implementation works great, and that's not where my race condition is (merely some background info). In examining the performance results from this, I found that the HashMap is a performance bottleneck, since I do that synchronously on one thread. So I figured that ordering each point as its calculated would work best. I tried a PriorityQueue, but that was slower than the HashMap. I ended up creating an algorithm that essentially works like this: I construct a list of X values to calculate, like in my current algorithm. I then copy that list of values into another class, unimaginatively and temporarily named BlockingList, which is responsible for ordering the points as they are calculated. BlockingList contains a put() method, which takes in two BigDecimals as parameters, the first the X value, the second the calculated Y value. put() will only accept a value if the X value is the next one on the list to be accepted in the list of X values, and will block until another thread gives it the next excepted value. For example, since that can be confusing, say I have two threads, Thread-1 and Thread-2. Thread-2 gets the X value 10.0 from the values queue, and Thread-1 gets 9.0. However, Thread-1 completes its calculations first, and calls put() before Thread-2 does. Because BlockingList is expecting to get 10.0 first, and not 9.0, it will block on Thread-1 until Thread-2 finishes and calls put(). Once Thread-2 gives BlockingList 10.0, it notify()s all waiting threads, and expects 9.0 next. This continues until BlockingList gets all of its expected values. (I apologise if that was hard to follow, if you need more clarification, just ask.) As expected by the question title, there is a race condition in here. If I run it without any System.out.printlns, it will sometimes lock because of conflicting wait() and notifyAll()s, but if I put a println in, it will run great. A small implementation of this is included below, and exhibits the same behavior: import java.math.BigDecimal; import java.util.concurrent.ConcurrentLinkedQueue; public class Example { public static void main(String[] args) throws InterruptedException { // Various scaling values, determined based on the graph size // in the real implementation BigDecimal xMax = new BigDecimal(10); BigDecimal xStep = new BigDecimal(0.05); // Construct the values list, from -10 to 10 final ConcurrentLinkedQueue<BigDecimal> values = new ConcurrentLinkedQueue<BigDecimal>(); for (BigDecimal i = new BigDecimal(-10); i.compareTo(xMax) <= 0; i = i.add(xStep)) { values.add(i); } // Contains the calculated values final BlockingList list = new BlockingList(values); for (int i = 0; i < 4; i++) { new Thread() { public void run() { BigDecimal x; // Keep looping until there are no more values while ((x = values.poll()) != null) { PointPair pair = new PointPair(); pair.realX = x; try { list.put(pair); } catch (Exception ex) { ex.printStackTrace(); } } } }.start(); } } private static class PointPair { public BigDecimal realX; } private static class BlockingList { private final ConcurrentLinkedQueue<BigDecimal> _values; private final ConcurrentLinkedQueue<PointPair> _list = new ConcurrentLinkedQueue<PointPair>(); public BlockingList(ConcurrentLinkedQueue<BigDecimal> expectedValues) throws InterruptedException { // Copy the values into a new queue BigDecimal[] arr = expectedValues.toArray(new BigDecimal[0]); _values = new ConcurrentLinkedQueue<BigDecimal>(); for (BigDecimal dec : arr) { _values.add(dec); } } public void put(PointPair item) throws InterruptedException { while (item.realX.compareTo(_values.peek()) != 0) { synchronized (this) { // Block until someone enters the next desired value wait(); } } _list.add(item); _values.poll(); synchronized (this) { notifyAll(); } } } } My question is can anybody help me find the threading error? Thanks!

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Getting template metaprogramming compile-time constants at runtime

- by GMan - Save the Unicorns

Background Consider the following: template <unsigned N> struct Fibonacci { enum { value = Fibonacci<N-1>::value + Fibonacci<N-2>::value }; }; template <> struct Fibonacci<1> { enum { value = 1 }; }; template <> struct Fibonacci<0> { enum { value = 0 }; }; This is a common example and we can get the value of a Fibonacci number as a compile-time constant: int main(void) { std::cout << "Fibonacci(15) = "; std::cout << Fibonacci<15>::value; std::cout << std::endl; } But you obviously cannot get the value at runtime: int main(void) { std::srand(static_cast<unsigned>(std::time(0))); // ensure the table exists up to a certain size // (even though the rest of the code won't work) static const unsigned fibbMax = 20; Fibonacci<fibbMax>::value; // get index into sequence unsigned fibb = std::rand() % fibbMax; std::cout << "Fibonacci(" << fibb << ") = "; std::cout << Fibonacci<fibb>::value; std::cout << std::endl; } Because fibb is not a compile-time constant. Question So my question is: What is the best way to peek into this table at run-time? The most obvious solution (and "solution" should be taken lightly), is to have a large switch statement: unsigned fibonacci(unsigned index) { switch (index) { case 0: return Fibonacci<0>::value; case 1: return Fibonacci<1>::value; case 2: return Fibonacci<2>::value; . . . case 20: return Fibonacci<20>::value; default: return fibonacci(index - 1) + fibonacci(index - 2); } } int main(void) { std::srand(static_cast<unsigned>(std::time(0))); static const unsigned fibbMax = 20; // get index into sequence unsigned fibb = std::rand() % fibbMax; std::cout << "Fibonacci(" << fibb << ") = "; std::cout << fibonacci(fibb); std::cout << std::endl; } But now the size of the table is very hard coded and it wouldn't be easy to expand it to say, 40. The only one I came up with that has a similiar method of query is this: template <int TableSize = 40> class FibonacciTable { public: enum { max = TableSize }; static unsigned get(unsigned index) { if (index == TableSize) { return Fibonacci<TableSize>::value; } else { // too far, pass downwards return FibonacciTable<TableSize - 1>::get(index); } } }; template <> class FibonacciTable<0> { public: enum { max = 0 }; static unsigned get(unsigned) { // doesn't matter, no where else to go. // must be 0, or the original value was // not in table return 0; } }; int main(void) { std::srand(static_cast<unsigned>(std::time(0))); // get index into sequence unsigned fibb = std::rand() % FibonacciTable<>::max; std::cout << "Fibonacci(" << fibb << ") = "; std::cout << FibonacciTable<>::get(fibb); std::cout << std::endl; } Which seems to work great. The only two problems I see are: Potentially large call stack, since calculating Fibonacci<2 requires we go through TableMax all the way to 2, and: If the value is outside of the table, it returns zero as opposed to calculating it. So is there something I am missing? It seems there should be a better way to pick out these values at runtime. A template metaprogramming version of a switch statement perhaps, that generates a switch statement up to a certain number? Thanks in advance.

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IOC Container Handling State Params in Non-Default Constructor

- by Mystagogue

For the purpose of this discussion, there are two kinds of parameters an object constructor might take: state dependency or service dependency. Supplying a service dependency with an IOC container is easy: DI takes over. But in contrast, state dependencies are usually only known to the client. That is, the object requestor. It turns out that having a client supply the state params through an IOC Container is quite painful. I will show several different ways to do this, all of which have big problems, and ask the community if there is another option I'm missing. Let's begin: Before I added an IOC container to my project code, I started with a class like this: class Foobar { //parameters are state dependencies, not service dependencies public Foobar(string alpha, int omega){...}; //...other stuff } I decide to add a Logger service depdendency to the Foobar class, which perhaps I'll provide through DI: class Foobar { public Foobar(string alpha, int omega, ILogger log){...}; //...other stuff } But then I'm also told I need to make class Foobar itself "swappable." That is, I'm required to service-locate a Foobar instance. I add a new interface into the mix: class Foobar : IFoobar { public Foobar(string alpha, int omega, ILogger log){...}; //...other stuff } When I make the service locator call, it will DI the ILogger service dependency for me. Unfortunately the same is not true of the state dependencies Alpha and Omega. Some containers offer a syntax to address this: //Unity 2.0 pseudo-ish code: myContainer.Resolve<IFoobar>( new parameterOverride[] { {"alpha", "one"}, {"omega",2} } ); I like the feature, but I don't like that it is untyped and not evident to the developer what parameters must be passed (via intellisense, etc). So I look at another solution: //This is a "boiler plate" heavy approach! class Foobar : IFoobar { public Foobar (string alpha, int omega){...}; //...stuff } class FoobarFactory : IFoobarFactory { public IFoobar IFoobarFactory.Create(string alpha, int omega){ return new Foobar(alpha, omega); } } //fetch it... myContainer.Resolve<IFoobarFactory>().Create("one", 2); The above solves the type-safety and intellisense problem, but it (1) forced class Foobar to fetch an ILogger through a service locator rather than DI and (2) it requires me to make a bunch of boiler-plate (XXXFactory, IXXXFactory) for all varieties of Foobar implementations I might use. Should I decide to go with a pure service locator approach, it may not be a problem. But I still can't stand all the boiler-plate needed to make this work. So then I try this: //code named "concrete creator" class Foobar : IFoobar { public Foobar(string alpha, int omega, ILogger log){...}; static IFoobar Create(string alpha, int omega){ //unity 2.0 pseudo-ish code. Assume a common //service locator, or singleton holds the container... return Container.Resolve<IFoobar>( new parameterOverride[] {{"alpha", alpha},{"omega", omega} } ); } //Get my instance: Foobar.Create("alpha",2); I actually don't mind that I'm using the concrete "Foobar" class to create an IFoobar. It represents a base concept that I don't expect to change in my code. I also don't mind the lack of type-safety in the static "Create", because it is now encapsulated. My intellisense is working too! Any concrete instance made this way will ignore the supplied state params if they don't apply (a Unity 2.0 behavior). Perhaps a different concrete implementation "FooFoobar" might have a formal arg name mismatch, but I'm still pretty happy with it. But the big problem with this approach is that it only works effectively with Unity 2.0 (a mismatched parameter in Structure Map will throw an exception). So it is good only if I stay with Unity. The problem is, I'm beginning to like Structure Map a lot more. So now I go onto yet another option: class Foobar : IFoobar, IFoobarInit { public Foobar(ILogger log){...}; public IFoobar IFoobarInit.Initialize(string alpha, int omega){ this.alpha = alpha; this.omega = omega; return this; } } //now create it... IFoobar foo = myContainer.resolve<IFoobarInit>().Initialize("one", 2) Now with this I've got a somewhat nice compromise with the other approaches: (1) My arguments are type-safe / intellisense aware (2) I have a choice of fetching the ILogger via DI (shown above) or service locator, (3) there is no need to make one or more seperate concrete FoobarFactory classes (contrast with the verbose "boiler-plate" example code earlier), and (4) it reasonably upholds the principle "make interfaces easy to use correctly, and hard to use incorrectly." At least it arguably is no worse than the alternatives previously discussed. One acceptance barrier yet remains: I also want to apply "design by contract." Every sample I presented was intentionally favoring constructor injection (for state dependencies) because I want to preserve "invariant" support as most commonly practiced. Namely, the invariant is established when the constructor completes. In the sample above, the invarient is not established when object construction completes. As long as I'm doing home-grown "design by contract" I could just tell developers not to test the invariant until the Initialize(...) method is called. But more to the point, when .net 4.0 comes out I want to use its "code contract" support for design by contract. From what I read, it will not be compatible with this last approach. Curses! Of course it also occurs to me that my entire philosophy is off. Perhaps I'd be told that conjuring a Foobar : IFoobar via a service locator implies that it is a service - and services only have other service dependencies, they don't have state dependencies (such as the Alpha and Omega of these examples). I'm open to listening to such philosophical matters as well, but I'd also like to know what semi-authorative reference to read that would steer me down that thought path. So now I turn it to the community. What approach should I consider that I havn't yet? Must I really believe I've exhausted my options?

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MySQL Binary Storage using BLOB VS OS File System: large files, large quantities, large problems.

- by Quantico773

Hi Guys, Versions I am running (basically latest of everything): PHP: 5.3.1 MySQL: 5.1.41 Apache: 2.2.14 OS: CentOS (latest) Here is the situation. I have thousands of very important documents, ranging from customer contracts to voice signatures (recordings of customer authorisation for contracts), with file types including, but not limited to jpg, gif, png, tiff, doc, docx, xls, wav, mp3, pdf, etc. All of these documents are currently stored on several servers including Windows 32 bit, CentOS and Mac, among others. Some files are also stored on employees desktop computers and laptops, and some are still hard copies stored in hundreds of boxes and filing cabinets. Now because customers or lawyers could demand evidence of contracts at any time, my company has to be able to search and locate the correct document(s) effectively, for this reason ALL of these files have to be digitised (if not already) and correlated into some sort of order for searching and accessing. As the programmer, I have created a full Customer Relations Management tool that the whole company uses. This includes Customer Profiles management, Order and job Tracking tools, Job/sale creation and management modules, etc, and at the moment any file that is needed at a customer profile level (drivers licence, credit authority, etc) or at a job/sale level (contracts, voice signatures, etc) can be uploaded to the server and sits in a parent/child hierarchy structure, just like Windows Explorer or any other typical file managment model. The structure appears as such: drivers_license |- DL_123.jpg voice_signatures |- VS_123.wav |- VS_4567.wav contracts So the files are uplaoded using PHP and Apache, and are stored in the file system of the OS. At the time of uploading, certain information about the file(s) is stored in a MySQL database. Some of the information stored is: TABLE: FileUploads FileID CustomerID (the customer id that the file belongs to, they all have this.) JobID/SaleID (the id of the job/sale associated, if any.) FileSize FileType UploadedDateTime UploadedBy FilePath (the directory path the file is stored in.) FileName (current file name of uploaded file, combination of CustomerID and JobID/SaleID if applicable.) FileDescription OriginalFileName (original name of the source file when uploaded, including extension.) So as you can see, the file is linked to the database by the File Name. When I want to provide a customers' files for download to a user all I have to do is "SELECT * FROM FileUploads WHERE CustomerID = 123 OR JobID = 2345;" and this will output all the file details I require, and with the FilePath and FileName I can provide the link for download. http... server / FilePath / FileName There are a number of problems with this method: Storing files in this "database unconcious" environment means data integrity is not kept. If a record is deleted, the file may not be deleted also, or vice versa. Files are strewn all over the place, different servers, computers, etc. The file name is the ONLY thing matching the binary to the database and customer profile and customer records. etc, etc. There are so many reasons, some of which are described here: http://www.dreamwerx.net/site/article01 . Also there is an interesting article here too: sietch.net/ViewNewsItem.aspx?NewsItemID=124 . SO, after much research I have pretty much decided I am going to store ALL of these files in the database, as a BLOB or LONGBLOB, but there are still many considerations before I do this. I know that storing them in the database is a viable option, however there are a number of methods of storing them. I also know storing them is one thing; correlating and accessing them in a manageable way is another thing entirely. The article provided at this link: dreamwerx.net/site/article01 describes a way of splitting the uploaded binary files into 64kb chunks and storing each chunk with the FileID, and then streaming the actual binary file to the client using headers. This is a really cool idea since it alleviates preassure on the servers memory; instead of loading an entire 100mb file into the RAM and then sending it to the client, it is doing it 64kb at a time. I have tried this (and updated his scripts) and this is totally successful, in a very small frame of testing. So if you are in agreeance that this method is a viable, stable and robust long-term option to store moderately large files (1kb to couple hundred megs), and large quantities of these files, let me know what other considerations or ideas you have. Also, I am considering getting a current "File Management" PHP script that gives an interface for managing files stored in the File System and converting it to manage files stored in the database. If there is already any software out there that does this, please let me know. I guess there are many questions I could ask, and all the information is up there ^^ so please, discuss all aspects of this and we can pass ideas back and forth and teach each other. Cheers, Quantico773

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Parsing error when using getSearchResultsForQuery of MGTwitterEngine

- by deep8981

Hi everyone I am doing a search using getSearchResultsForQuery method and i get searchresult too but when i try to print the parsed data i dont get text of all the tweets i am doing this [twitterEngine getSearchResultsForQuery:@"#joke" sinceID:twitterUserId startingAtPage:1 count:5]; and below is the result in console and it shows that i do get data properly but after parsing it does not parse properly.I have not done any change in parsing can anyone say why i am getting this? {"results":[{"profile_image_url":"http://a1.twimg.com/profile_images/580724970/pro_normal.jpg","created_at":"Wed, 21 Apr 2010 19:06:52 +0000","from_user":"Kousani","metadata":{"result_type":"recent"},"to_user_id":null,"text":"#ipl3 has hit hard all other General Entertainment Channels. If this continues every year, may be I will learn play cricket! :D #joke","id":12592706500,"from_user_id":13391246,"geo":null,"iso_language_code":"en","source":"<a href="http://www.tweetdeck.com" rel="nofollow">TweetDeck</a>"},{"profile_image_url":"http://a3.twimg.com/profile_images/815058343/iphone_1_059_normal.JPG","created_at":"Wed, 21 Apr 2010 19:00:59 +0000","from_user":"anamou","metadata":{"result_type":"recent"},"to_user_id":null,"text":"comedyclipsblog: Recent research has shown that six out of seven dwarves aren't happy #joke","id":12592456010,"from_user_id":7635571,"geo":null,"iso_language_code":"en","source":"<a href="http://echofon.com/" rel="nofollow">Echofon</a>"},{"profile_image_url":"http://a1.twimg.com/profile_images/636112472/Jane_New_normal.jpg","created_at":"Wed, 21 Apr 2010 18:55:49 +0000","from_user":"janeprinsep","metadata":{"result_type":"recent"},"to_user_id":20741695,"text":"@grahamtcousins DON'T DOOOOOOO ITTTTT!!!!! #joke","id":12592234721,"from_user_id":74969091,"to_user":"grahamtcousins","geo":null,"iso_language_code":"en","source":"<a href="http://www.tweetdeck.com" rel="nofollow">TweetDeck</a>"},{"profile_image_url":"http://a1.twimg.com/profile_images/779334170/sander_normal.jpg","created_at":"Wed, 21 Apr 2010 18:53:55 +0000","from_user":"SndR22","metadata":{"result_type":"recent"},"to_user_id":null,"text":"RT @MocroDeluxe: Willen jullie lachen?- kom met een #joke dan!","id":12592155790,"from_user_id":85863646,"geo":null,"iso_language_code":"nl","source":"<a href="http://ubertwitter.com" rel="nofollow">UberTwitter</a>"},{"profile_image_url":"http://a1.twimg.com/profile_images/513318990/1257454275_package_toys_normal.png","created_at":"Wed, 21 Apr 2010 18:53:33 +0000","from_user":"Fun_Jokes_Video","metadata":{"result_type":"recent"},"to_user_id":null,"text":"#joke What's Clintons new nick name?: Q. What's Clintons new nick name?\nA. Drippy Dick http://bit.ly/bZWSlJ","id":12592141067,"from_user_id":76430125,"geo":null,"iso_language_code":"en","source":"<a href="http://twitterfeed.com" rel="nofollow">twitterfeed</a>"}],"max_id":12592706500,"since_id":47543983,"refresh_url":"?since_id=12592706500&q=%23joke","next_page":"?page=2&max_id=12592706500&rpp=5&q=%23joke","results_per_page":5,"page":1,"completed_in":0.039389,"warning":"since_id removed for pagination.","query":"%23joke"} 2010-04-22 00:45:53.319 Twitter-Facebook[2090:20b] Got search results for FF1D610A-499C-41B6-B0BA-5D94989F9CF0: ( { "created_at" = 1271876812; "from_user" = Kousani; "profile_image_url" = "http://a1.twimg.com/profile_images/580724970/pro_normal.jpg"; "result_type" = recent; "source_api_request_type" = 35; }, { "created_at" = 1271876459; "from_user" = anamou; "profile_image_url" = "http://a3.twimg.com/profile_images/815058343/iphone_1_059_normal.JPG"; "result_type" = recent; "source_api_request_type" = 35; }, { "created_at" = 1271876149; "from_user" = janeprinsep; "profile_image_url" = "http://a1.twimg.com/profile_images/636112472/Jane_New_normal.jpg"; "result_type" = recent; "source_api_request_type" = 35; }, { "created_at" = 1271876035; "from_user" = SndR22; "profile_image_url" = "http://a1.twimg.com/profile_images/779334170/sander_normal.jpg"; "result_type" = recent; "source_api_request_type" = 35; }, { "created_at" = 1271876013; "from_user" = "Fun_Jokes_Video"; "profile_image_url" = "http://a1.twimg.com/profile_images/513318990/1257454275_package_toys_normal.png"; "result_type" = recent; "source_api_request_type" = 35; }, { "completed_in" = 0; "from_user_id" = 76430125; geo = ; id = 12592141067; "iso_language_code" = en; "max_id" = 12592706500; "next_page" = "?page=2&max_id=12592706500&rpp=5&q=%23joke"; page = 1; query = "%23joke"; "refresh_url" = "?since_id=12592706500&q=%23joke"; "results_per_page" = 5; "since_id" = 47543983; source = "twitterfeed"; "source_api_request_type" = 35; text = "#joke What's Clintons new nick name?: Q. What's Clintons new nick name?\nA. Drippy Dick http://bit.ly/bZWSlJ"; "to_user" = grahamtcousins; "to_user_id" = ; warning = "since_id removed for pagination."; } ) 2010-04-22 00:45:53.320 Twitter-Facebook[2090:20b] TEXT is #joke What's Clintons new nick name?: Q. What's Clintons new nick name? A. Drippy Dick http://bit.ly/bZWSlJ

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Android programming - How to acces [to draw on] XML view in main.xml layout, using code

- by user556248

Ok I'm a newbie at Android programming, have a hard time with the graphics part. Understand the beauty of creating layout in XML file, but lost how to access various elements, especially a View element to draw on it. See example of my layout main.xml here; <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/root" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="wrap_content"> <TextView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/Title" android:text="App title" android:layout_width="fill_parent" android:layout_height="wrap_content" android:textColor="#000000" android:background="#A0A0FF"/> </LinearLayout> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/PaperLayout" android:layout_width="fill_parent" android:layout_height="0dp" android:layout_weight="1" android:orientation="horizontal" android:focusable="true"> <View android:id="@+id/Paper" android:layout_width="fill_parent" android:layout_height="fill_parent" /> </LinearLayout> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="wrap_content"> <Button android:id="@+id/File" android:layout_width="fill_parent" android:layout_weight="1" android:layout_height="34dp" android:layout_alignParentTop="true" android:layout_centerInParent="true" android:clickable="true" android:textSize="10sp" android:text="File" /> <Button android:id="@+id/Edit" android:layout_width="fill_parent" android:layout_weight="1" android:layout_height="34dp" android:clickable="true" android:textSize="10sp" android:text="Edit" /> </LinearLayout> </LinearLayout> As you can see I have a custom app title bar, then a View filling middle, and finally two buttons in bottom. Catching button events and responding to, for example changing title bar text and changing View background color works fine, but how the heck do I access and more importantly draw on the view defined in main.xml UPDATE: That for your suggestion, however besides that I need a View, not ImageView and you are missing a parameter on canvas.drawText and an ending bracket, it does not work. Now this is most likely because you missed the fact that I am a newbie and assuming I can fill in any blanks. Now first of all I do NOT understand why in my main.xml layout file I can create a View or even a SurfaceView element, which is what I need, but according to your solution I don't even specify the View like Anyways I edited my main.xml according to your solution, and slimmed it down a bit for simplicity; <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/root" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="wrap_content"> <TextView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/Title" android:text="App title" android:layout_width="fill_parent" android:layout_height="wrap_content" android:textColor="#000000" android:background="#A0A0FF"/> </LinearLayout> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/PaperLayout" android:layout_width="fill_parent" android:layout_height="0dp" android:layout_weight="1" android:orientation="horizontal" android:focusable="true"> <com.example.MyApp.CustomView android:id="@+id/Paper" android:layout_width="fill_parent" android:layout_height="fill_parent" /> <com.example.colorbook.CustomView/> </LinearLayout> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="wrap_content"> <Button android:id="@+id/File" android:layout_width="fill_parent" android:layout_weight="1" android:layout_height="34dp" android:layout_alignParentTop="true" android:layout_centerInParent="true" android:clickable="true" android:textSize="10sp" android:text="File" /> </LinearLayout> </LinearLayout> In my main java file, MyApp.java, I added this after OnCreate; public class CustomView extends ImageView { @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); canvas.drawText("Your Text", 1, 1, null); } } But I get error on the "CustomView" part; "Implicit super constructor ImageView() is undefined for default constructor.Must define an explicit constructor" Eclipse suggests 3 quick fixes about adding constructor, but none helps, well it removes error but gives error on app when running. I hope somebody can break this down for me and provide a solution, and perhaps explain why I can't just create a View element in my main.xml layotu file and draw on it in code.

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Qt - drag and drop with graphics view framework

- by David Davidson

I'm trying to make a simple draggable item using the graphics framework. Here's the code for what I did so far: Widget class: class Widget : public QWidget { Q_OBJECT public: Widget(QWidget *parent = 0); ~Widget(); }; Widget::Widget(QWidget *parent) : QWidget(parent) { DragScene *scene = new DragScene(); DragView *view = new DragView(); QHBoxLayout *layout = new QHBoxLayout(); DragItem *item = new DragItem(); view->setAcceptDrops(true); scene->addItem(item); view->setScene(scene); layout->addWidget(view); this->setLayout(layout); } Widget::~Widget() { } DragView class: class DragView : public QGraphicsView { public: DragView(QWidget *parent = 0); }; DragView::DragView(QWidget *parent) : QGraphicsView(parent) { setRenderHints(QPainter::Antialiasing); } DragScene class: class DragScene : public QGraphicsScene { public: DragScene(QObject* parent = 0); protected: void dragEnterEvent(QGraphicsSceneDragDropEvent *event); void dragMoveEvent(QGraphicsSceneDragDropEvent *event); void dragLeaveEvent(QGraphicsSceneDragDropEvent *event); void dropEvent(QGraphicsSceneDragDropEvent *event); }; DragScene::DragScene(QObject* parent) : QGraphicsScene(parent) { } void DragScene::dragEnterEvent(QGraphicsSceneDragDropEvent *event){ } void DragScene::dragMoveEvent(QGraphicsSceneDragDropEvent *event){ } void DragScene::dragLeaveEvent(QGraphicsSceneDragDropEvent *event){ } void DragScene::dropEvent(QGraphicsSceneDragDropEvent *event){ qDebug() << event->pos(); event->acceptProposedAction(); DragItem *item = new DragItem(); this->addItem(item); item->setPos(event->pos()); } DragItem class: class DragItem : public QGraphicsItem { public: DragItem(QGraphicsItem *parent = 0); QRectF boundingRect() const; void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = 0); protected: void mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event); void mouseMoveEvent(QGraphicsSceneMouseEvent *event); void mousePressEvent(QGraphicsSceneMouseEvent *event); void mouseReleaseEvent(QGraphicsSceneMouseEvent *event); }; DragItem::DragItem(QGraphicsItem *parent) : QGraphicsItem(parent) { setFlag(QGraphicsItem::ItemIsMovable); } QRectF DragItem::boundingRect() const{ const QPointF *p0 = new QPointF(-10,-10); const QPointF *p1 = new QPointF(10,10); return QRectF(*p0,*p1); } void DragItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget){ if(painter == 0) painter = new QPainter(); painter->drawEllipse(QPoint(0,0),10,10); } void DragItem::mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event){ } void DragItem::mouseMoveEvent(QGraphicsSceneMouseEvent *event){ } void DragItem::mousePressEvent(QGraphicsSceneMouseEvent *event){ QMimeData* mime = new QMimeData(); QDrag* drag = new QDrag(event->widget()); drag->setMimeData(mime); drag->exec(); } void DragItem::mouseReleaseEvent(QGraphicsSceneMouseEvent *event){ } main.cpp instantiates a Widget and shows it. When I try to drag the circle, the app just creates another circle over the original one, regardless of where I release the drag. qDebug() in DragScene's dropEvent() shows QPointF(0,0) everytime the drag ends. I'm having a hard time trying to understand exactly what I have to do, which classes I should subclass, which methods needs to be overriden, to make this work. The documentation on this isn't very detailed. I'd like to know how to make this work, and if there's some other, more comprehensive resource to learn about the graphics view framework, besides the official documentation (which is excellent btw, but it would be great if there was a more detailed treatise on the subject). EDIT: Following badgerr's advice, I replaced item-pos() in DragScene::dropEvent() with item-scenePos(), now the drop event creates a new circle in the drop site, which is more or less what I wanted. But the original circle is still in place, and while the drag is in progress, the item doesn't follow the mouse cursor. The QGraphicsSceneDragDropEvent documentation says that pos() should return the cursor position in relation to the view that sent the event, which, unless I got it wrong, shouldn't be (0,0) all the time. Weird. I've read in a forum post that you can use QDrag::setPixMap() to show something during the drag, and in examples I've seen pictures being set as pixmaps, but how do I make the pixmap just like the graphics item I'm supposed to be dragging?

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