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• CodePlex Daily Summary for Sunday, May 27, 2012

  CodePlex Daily Summary for Sunday, May 27, 2012Popular ReleasesMS CRM Rich Text box: MS CRM Rich Text box: This release contains the final JavaScript for this plug-in. It is tested and verified. Even if someone is unable to use it, can contact me. Suggestions and bug-notifications are always most welcome.Nivo Slider Web Part SharePoint 2010: Nivo Slider Web Part WSP: Web Part encapsulating nivo slider jquery web part. Download the wsp for one click install. Edit the property of the web part to point to any image library and all done. Web part includes jQuery and nivo jquery library. No configuration is required. This web part is a SharePoint 2010 farm solution. Scope for installation is site collection.iPDC - Free Phasor Data Concentrator: iPDC-v1.3.0: For more info see the iPDC-v1.3.0-Release_Notes document. Changes in iPDC-1.3 : Now iPDC has a centralized file structure. Only a single file for each iPDC and that will store with iPDC-ID. File structure will be explained in release notes document. A setup file for a iPDC will contains the information about: iPDC Server, Connected Source Devices, Connected Destination Devices, and finally configuration frames of sources. Because of this single Setup File previously generated ....Net Code Samples: Code Samples: Code samples (SLNs).Tweetz - Windows Twitter Client Gadget: Tweetz 3.1.5.4: Changed from screen names to regular names in all timelines except search Minor correction in German translation Updated Italian translationSubExtractor: Release 1027: Fix: out-of-memory exception when reading DVDs with very large (over 1GB) cells Fix: AltGr key toggling Italics during OCR Feature: use centered alignment SSA tag for centered text in the upper part of the frame Feature: increased number of subtitle tracks visible in Choose Subtitles step listbox Feature: allow change of palette for entire movieLINQ_Koans: LinqKoans v.02: Cleaned up a bitAutoFixture: 2.11.1: This is an automatically published release created from the latest successful build. Versioning is based on Semantic Versioning. Read more here: http://blog.ploeh.dk/2011/09/06/AutoFixtureGoesContinuousDeliveryWithSemanticVersioning.aspxBlueGem: BlueGem-v1.B Source: Description This is the source of BlueGem -v1.B.XML Schema Documenter: 1.9.4.0: Compatibility fixes for SHFB 1.9.4.0 and Visual Studio 11 Third-Party References Reference Required Used For Sandcastle Help File Builder (version 1.9.4.0) Yes Underlying platform Windows Installer XML (WiX) v3.6 RC0 No Only required to build source code ZXMAK2: Version 2.6.2.1: - fix contended timings for ULA 48/128 early/late - small refactoring for ULA code - fix mistake in timing for CBXX opcodes (thanks to Pegaz for report) - save early/late flag when saving to SZX (works with original ULA's 48/128 only) Use ZXMAK-SPRINTER-2621 package to get emulator with SPRINTER files (select Sprinter model from VM->Settings->Wizard)totalem: version 2012.05.25.1: Beta version speed improvements memory usage improvements smoothness list scrollingJayData - The cross-platform HTML5 data-management library for JavaScript: JayData 1.0 RC1 Refresh 2: JayData is a unified data access library for JavaScript developers to query and update data from different sources like webSQL, indexedDB, OData, Facebook or YQL. See it in action in this 6 minutes video: http://www.youtube.com/watch?v=LlJHgj1y0CU RC1 R2 Release highlights Knockout.js integrationUsing the Knockout.js module, your UI can be automatically refreshed when the data model changes, so you can develop the front-end of your data manager app even faster. Querying 1:N relations in W...Christoc's DotNetNuke Module Development Template: 00.00.08 for DNN6: BEFORE USE YOU need to install the MSBuild Community Tasks available from http://msbuildtasks.tigris.org For best results you should configure your development environment as described in this blog post Then read this latest blog post about customizing and using these custom templates. Installation is simple To use this template place the ZIP (not extracted) file in your My Documents\Visual Studio 2010\Templates\ProjectTemplates\Visual C#\Web OR for VB My Documents\Visual Studio 2010\Te...Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.53: fix issue #18106, where member operators on numeric literals caused the member part to be duplicated when not minifying numeric literals ADD NEW FEATURE: ability to create source map files! The first mapfile format to be supported is the Script# format. Use the new -map filename switch to create map files when building your sources.myManga: Initial Release - Version 1.0.0.1 - BETA: Leave a Review! This is the initial release of myManga. Please report any bugs. NOTE: There is a bug with MangaReader.net where images are reported 403 Forbidden, this is NOT the fault of myManga but, myManga will through an error and will not download the image.BlackJumboDog: Ver5.6.3: 2012.05.22 Ver5.6.3 　(1) HTTP????????、ftp://??????????????????????LogicCircuit: LogicCircuit 2.12.5.22: Logic Circuit - is educational software for designing and simulating logic circuits. Intuitive graphical user interface, allows you to create unrestricted circuit hierarchy with multi bit buses, debug circuits behavior with oscilloscope, and navigate running circuits hierarchy. Changes of this versionThis release is fixing start up issue.Orchard Project: Orchard 1.4.2: This is a service release to address 1.4 and 1.4.1 bugs. Please read our release notes for Orchard 1.4.2: http://docs.orchardproject.net/Documentation/Orchard-1-4-Release-NotesSharePoint Euro 2012 - UEFA European Football Predictor: havivi.euro2012.wsp (1.0): New fetures:View other users predictions Hide/Show background image (web part property) Installing SharePoint Euro 2012 PredictorSharePoint Euro 2012 Predictor has been developed as a SharePoint Sandbox solution to support SharePoint Online (Office 365) Download the solution havivi.euro2012.wsp from the download page: Downloads Upload this solution to your Site Collection via the solutions area. Click on Activate to make the web parts in the solution available for use in the Site C...New ProjectsAdvStopWatch: This is an wpf project to build a stop watchBlueGem: BlueGem is a simple Rich Text Editor. It also has a system resource monitor.Db4o Extensions: Db4o Extensions is a .NET library to ease database routines like creating composite keys, defining deletion behavior, data validation and transparent persistance.Financial Advisor Toolbox: An attempt to build a set of tools that can be used by a Financial Advisor to help automate some of their daily tasks. The initial release will aim to include "client management" to track clients and their financial profile. ImpresionesJL: This is a great project!K-Dock: K-Dock is a basic WPF library built to allow developers to implement a docking system in their applications. Written in Visual Basic. mouse: ignoreopencv: a personal git mirror for opencvOpenLaunch: OpenLaunch is a new way to make your companies' software more popular. By using a simple framework, developers can integrate their software into OpenLaunch by either their existing project, or by a new project. All help on this project is greatly appreciated, and we are looking for a web developer to create a web interface to the store.Smart Setup: Smart Setup is a PowerShell-based deployment program with using a XML document. It is very flexible with supporting multiple extensions and different configurations for different environment. It's smart and light.UusAhi: Teeme jälle ahju!Win7 Style TreeView: A TreeView with win7 styleWindows Phone 7 Feedback Control: Windows Phone user control for sending feedback directly from the applicationWindows Phone SignalR Helper: Windows Phone SignalR Helper makes it easier for WPDevs to leverage SignalR in making connected real-time Windows Phone applications. Various modes of communication between phone and server will be stubbed out - like real-time Mapping, Chat, Stocks, Game Scores, Object Sync etc.; Re-use or extend to make it work for your own needs. Iterative feature addition planned. Hope this helps!

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• Is this project Structure Valid?

  - by rafuru

  I have a dilemma: In the university we learn to create modular software (on java), but this modularity is explained using a single project with packages (a package for business, another one for DAOS and another one for the model, oh and a last package for frontend). But in my work we use the next structure: I will try to explain: First we create a java library project where the model (entities classes) are created in a package. Next we create an EJB named DAOS and using the netbeans wizard we store the DAOS interfaces in the library project in another package , these interfaces are implemented in the DAOS bean. So the next part is the business logic, we create a business EJB for each group of functions , again using the wizard we store the interface in the java library project in another package then is implemented on the business bean. The final part (for the backend) is a bean that I have suggested: a Facade bean who will gather every method of the business beans in a single bean and this has an interface too that is created in our library project and implemented in the bean. So the next part is call the facade module on the web project. But I don't know how valid or viable is this, maybe I'm doing everything wrong and I don't even know! so I want to ask your opinion about this.

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• How do I trust an off site application

  - by Pieter

  I need to implement something similar to a license server. This will have to be installed off site at the customers' location and needs to communicate with other applications at the customers' site (the applications that use the licenses) and an application running in our hosting center (for reporting and getting license information). My question is how to set this up in a way I can trust that: The license server is really our application and not something that just simulates it; and There is no "man in the middle" (i.e. a proxy or something that alters the traffic). The first thing I thought of was to use with client certificates and that would solve at least 2. However, what I'm worried about is that someone just decompiles (this is build in .NET) the license server, alters some logic and recompiles it. This would be hard to detect from both connecting applications. This doesn't have to be absolutely secure since we have a limited number of customers whom we have a trust relationship with. However, I do want to make it more difficult than a simple decompile/recompile of the license server. I primarily want to protect against an employee or nephew of the boss trying to be smart.

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• CodePlex Daily Summary for Thursday, July 25, 2013

  CodePlex Daily Summary for Thursday, July 25, 2013Popular ReleasesEnglish Practice Helper: English Practice Helper Demo v1.0: The first demoTweetinvi a friendly C# Twitter API: Alpha 0.8.0.1: This is the first release of Tweetinvi. Please report any issue in the discussion or issues. Sincerely, LinviKartris E-commerce: Kartris v2.5003: This fixes an issue where search engines appear to identify as IE and so trigger the noIE page if there is not a non-responsive skin specified.VG-Ripper & PG-Ripper: VG-Ripper 2.9.45: changes NEW: Added Support for "ImgBabes.com" links NEW: Added Support for "ImagesIon.com" linksMagelia WebStore Open-source Ecommerce software: Magelia WebStore 2.4: Magelia WebStore version 2.4 introduces new and improved features: Basket and order calculation have been redesigned with a more modular approach geographic zone algorithms for tax and shipping calculations have been re-developed. The Store service has been split in three services (store, basket, order). Product start and end dates have been added. For variant products a unique code has been introduced for the top (variable) product, product attributes can now be defined at the top ...LogicCircuit: LogicCircuit 2.13.07.22: Logic Circuit - is educational software for designing and simulating logic circuits. Intuitive graphical user interface, allows you to create unrestricted circuit hierarchy with multi bit buses, debug circuits behavior with oscilloscope, and navigate running circuits hierarchy. Changes of this versionYou can make visual elements of the circuit been visible on its symbols. This way you can build composite displays, keyboards and reuse them. Please read about displays for more details http://ww...LINQ to Twitter: LINQ to Twitter v2.1.08: Supports .NET 3.5, .NET 4.0, .NET 4.5, Silverlight 4.0, Windows Phone 7.1, Windows Phone 8, Client Profile, Windows 8, and Windows Azure. 100% Twitter API coverage. Also supports Twitter API v1.1! Also on NuGet.AcDown?????: AcDown????? v4.4.3: ??●AcDown??????????、??、??、???????。????，????，?????????????????????????。???????????Acfun、????(Bilibili)、??、??、YouTube、??、???、??????、SF????、????????????。 ●??????AcPlay?????，??????、????????????????。 ● AcDown???????C#??，????.NET Framework 2.0??。?????"Acfun?????"。 ??v4.4.3 ?? ??Bilibili????????????? ???????????? ????32??64? Windows XP/Vista/7/8 ???? 32??64? ???Linux ????(1)????????Windows XP???，????????.NET Framework 2.0???(x86)，?????"?????????"??? (2)???????????Linux???，????????Mono?? ??2.10?...Magick.NET: Magick.NET 6.8.6.601: Magick.NET linked with ImageMagick 6.8.6.6. These zip files are also available as a NuGet package: https://nuget.org/profiles/dlemstra/C# Intellisense for Notepad++: Initial release: Members auto-complete Integration with native Notepad++ Auto-Completion Auto "open bracket" for methods Right-arrow to accept suggestions51Degrees.mobi - Mobile Device Detection and Redirection: 2.1.19.4: One Click Install from NuGet This release introduces the 51Degrees.mobi IIS Vary Header Fix. When Compression and Caching is used in IIS, the Vary header is overwritten, making intelligent caching with dynamic content impossible. Find out more about installing the Vary Header fix. Changes to Version 2.1.19.4Handlers now have a ‘Count’ property. This is an integer value that shows how many devices in the dataset that use that handler. Provider.cs -> GetDeviceInfoByID to address a problem w...SMSGateWay: SMSGateWayLaunch: CMPP,SGIP,SMGP ????SP?? ??,????,????,????,VPS??,?????,???. ??????,????,?????,????......????? ????SPID ,MsgSrc,???,???IP,?????? ?????,?????,??,???? ??QQ:3483305Centrify DirectControl PowerShell Module: 1.5.709: -fix- Computer password is correctly set when preparing Computer account for Self-Service join and hostname is longer than 14 charsDLog: DLog v1.0: Log v1.0SalarDbCodeGenerator: SalarDbCodeGenerator v2.1.2013.0719: Version 2.1.2013.0719 2013/7/19 Pattern Changes: * DapperContext pattern is added. * All patterns are updated to work with one-to-one relations. Changes: * One-to-one relation is supported. * Minor bug fixes.PantheR's GraphX for .NET: GraphX for .NET v0.9.5 BETA: BETA 0.9.5 + Added GraphArea.SaveAsImage() method that supports different image formats + Added GraphArea.UseNativeObjectArrange property. True by default. If set to False it will use different coordinates handling that helps to soften vertex drag issues to the top and left area sides. + Added GraphArea.Translation property. It is needed to get correct translation coordinates when determining object position from the mouse coordinates. + Added new VertexControl.PositionChanged event along wit....NET Code Migrator for Dynamics CRM: v1.0.12: Combined the main macros, generated macros from a sample organization, and the CreateVisualStudioMacros utility into a single package.Player Framework by Microsoft: Player Framework for Windows and WP (v1.3 beta 2): Includes all changes in v1.3 beta 1 Additional support for Windows 8.1 Preview New API (JS): addTextTrack New API (JS): msKeys New API (JS): msPlayToPreferredSourceUri New API (JS): msSetMediaKeys New API (JS): onmsneedkey New API (Xaml): SetMediaStreamSource method New API (Xaml): Stretch property New API (Xaml): StretchChanged event New API (Xaml): AreTransportControlsEnabled property New API (Xaml): IsFullWindow property New API (Xaml): PlayToPreferredSourceUri proper...CodeGen Code Generator: CodeGen 4.2.11: Changes in this release include: Added several new alternate forms of the <FIELD_SELWND> token to provide template developers better control over the case of field selection window names. Also added a new token <FIELD_SELWND_ORIGINAL> to preserve the case of selection window names in the same way that <FIELD_SELWND> used to. Enhanced UI Toolkit window script selection window processing (-ws) so that selection window names are no longer case sensitive (they aren't in UI Toolkit). Also the -w...Outlook 2013 Add-In: Multiple Calendars: As per popular request, this new version includes: - Support for multiple calendars. This can be enabled in the configuration by choosing which ones to show/hide appointments from. In some cases (public folders) it may time out and crash, and so far it only supports "My Calendars", so not shared ones yet. Also they're currently shown in the same font/color so there are no confusions with color categories, but please drop me a line on any suggestions you'd like to see implemented. - Added fri...New ProjectsActive Directory Web App Availability Monitor for SCOM 2012: Extend the web application availability monitoring in System Center Operations Manager 2012 with the ability to monitor Active Directory Authenticated Web SitesArgoWinform: ArgoWinform ASP.NET Routing Optional Parameters in body of Urls: This library allows ASP.NET MVC developers to have custom parameters in the body of Urls. Routes that are defined by this library accepts a LookupService that wAutomate Variations in SharePoint 2013 using C#: Automating variations settings and configuration so whenever a deployment is needed, you will be ready with your PowerShell scripts.Automate Variations in SharePoint 2013 using PowerShell: Automating variations settings and configuration so whenever a deployment is needed, you will be ready with your PowerShell scripts.BingosoftSwimming: ?????????ContentCreator for Orchard: Orchard Module that is suposed to replace the Orchard.ContentPicker module by letting you create contentItems directlyGET - General Emitter Templates: GET: General Emitter Templates. Language: C# Given a data file (in xml format), it models the data according with the directives specified in the template file.GTS Project: This project is a private personal educational project to study and learn DNN and ASP.NET MVCJustCompare: Just Compare is human made tool to help humans to compare two digital files. We are now concentrating on source code files only. Media Tool: A collection of tool to manage media files (Pictures and videos)MVVMlight Navigation Service for Windows Phone 8: A simple project to make navigation in MVVMlight on windows phone faster.Qibla Compass for Windows Phone: Qibla compass is one of the mostly used community applications/utility among Muslims. It allows users to determine the correct location / direction of Ka’aba.QuickWebLauncherWP: Una aplicación para windows phone para leer fuentes de sindicación y coleccionar enlaces a los artículos que se desean leerSimpleBingWallpaper: It's a simple project for get bingwallpaper. if you like it. please +1.. ThanksStyrApp: Template Application for technology testingTataFm: Tata FM for Windows 8 app.TimeZoneInfoForm: Exercises timezone related classes and methods in .NET. It can be used as sample code or to troubleshoot suspected timezone issues in .NET.Wix Test: *WIX Test Solution* - is a simple WIX solution for learning some new features. This project is currently in setup mode and free.

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• Building a Redundant / Distributed Application

  - by MattW

  This is more of a "point me in the right direction" question. My team of three and I have built a hosted web app that queues and routes customer chat requests to available customer service agents (It does other things as well, but this is enough background to illustrate the issue). The basic dev architecture today is: a single page ajax web UI (ASP.NET MVC) with floating chat windows (think Gmail) a backend Windows service to queue and route the chat requests this service also logs the chats, calculates service levels, etc a Comet server product that routes data between the web frontend and the backend Windows service this also helps us detect which Agents are still connected (online) And our hardware architecture today is: 2 servers to host the web UI portion of the application a load balancer to route requests to the 2 different web app servers a third server to host the SQL Server DB and the backend Windows service responsible for queuing / delivering chats So as it stands today, one of the web app servers could go down and we would be ok. However, if something would happen to the SQL Server / Windows Service server we would be boned. My question - how can I make this backend Windows service logic be able to be spread across multiple machines (distributed)? The Windows service is written to accept requests from the Comet server, check for available Agents, and route the chat to those agents. How can I make this more distributed? How can I make it so that I can distribute the work of the backend Windows service can be spread across multiple machines for redundancy and uptime purposes? Will I need to re-write it with distributed computing in mind? I should also note that I am hosting all of this on Rackspace Cloud instances - so maybe it is something I should be less concerned about? Thanks in advance for any help!

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• Technology Choice for a Client Application [on hold]

  - by AK_

  Not sure this is the right place to ask... I'm involved in the development of a new system, and now we are passing the demos stage. We need to build a proper client application. The platform we care most about is Windows, for now at least, but we would love to support other platforms, as long as it's free :-). Or at least very cheap. We anticipate two kinds of users: Occasional, coming mostly from the web. Professional, who would probably require more features, and better performance, and probably would prefer to see a native client. Our server exposes two APIs: A SOAP API, WCF behind the scenes, that supports 100% of the functionality. A small and very fast UDP + Binary API, that duplicates some of the functionality and is intended for the sake of performance for certain real-time scenarios. Our team is mostly proficient in .Net, C#, C++ development, and rather familiar with Web development (HTML, JavaScript). We are probably intending to develop two clients (for both user profiles), a web app, and a native app. Architecturally, we would like to have as many common components as possible. We would like to have several layers: Communication, Client Model, Client Logic, shared by both of the clients. We would also like to be able to add features to both clients when only the actual UI is a dual cost, and the rest is shared. We are looking at several technologies: WPF + Silverlight, Pure HTML, Flash / Flex (AIR?), Java (JavaFx?), and we are considering poking at WinRT(or whatever the proper name is). The question is which technology would you recommend and why? And which advantages or disadvantages will it have regarding our requirements?

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• Distinguishing between UI command & domain commands

  - by SonOfPirate

  I am building a WPF client application using the MVVM pattern that provides an interface on top of an existing set of business logic residing in a library which is shared with other applications. The business library followed a domain-driven architecture using CQRS to separate the read and write models (no event sourcing). The combination of technologies and patterns has brought up an interesting conundrum: The MVVM pattern uses the command pattern for handling user-interaction with the view models. .NET provides an ICommand interface which is implemented by most MVVM frameworks, like MVVM Light's RelayCommand and Prism's DelegateCommand. For example, the view model would expose a number of command objects as properties that are bound to the UI and respond when the user performs actions like clicking buttons. Many implementations of the CQRS use the command pattern to isolate and encapsulate individual behaviors. In my business library, we have implemented the write model as command / command-handler pairs. As such, when we want to do some work, such as create a new order, we 'issue' a command (CreateOrderCommand) which is routed to the command-handler responsible for executing the command. This is great, clearly explained in many sources and I am good with it. However, take this scenario: I have a ToolbarViewModel which exposes a CreateNewOrderCommand property. This ICommand object is bound to a button in the UI. When clicked, the UI command creates and issues a new CreateOrderCommand object to the domain which is handled by the CreateOrderCommandHandler. This is difficult to explain to other developers and I am finding myself getting tongue-tied because everything is a command. I'm sure I'm not the first developer to have patterns overlap like this where the naming/terminology also overlap. How have you approached distinguishing your commands used in the UI from those used in the domain? (Edit: I should mention that the business library is UI-agnostic, i.e. no UI technology-specific code exists, or will exists, in this library.)

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• Showing Egde Shaped Event Duration in StreamInsight using Debugger

  Whilst writing some courseware I wanted to be able to see the start and end times of Edge shaped events from within the debugger.  A quick recap on Edge events At the start of the event you do not know the end time and most probably cannot work it out or you should be using one of the other shapes. You enqueue an event (Start Edge) with the start time and payload of the event.  The end time of the event is set to infinity When you see the end edge come through, you enqueue another event (End Edge) with the previous start time and payload and restate the event’s end time.  This is the Retract Event All seems simple enough.  The problem is the debugger is a little shy about showing you what you need but you can get it to show you everything by also reading this article Here’s what I mean. Here is what the Event Debugger looks like by default when viewing 2 complete edge events.  Notice how all the end times are set to infinity   The above does not tell you for how long an event was valid.  I then add the “NewEndTime” column to the debugger output and there I can now see the duration of events.  You will see the Retract events (End Edge) have the same start time and payload as their respective start events (Start Edge)   You can follow the exact same logic when looking at Interval shape events.  They look a little different on the output adapter but using this article you can easily see what is happening.

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• Inside the DLR – Invoking methods

  - by Simon Cooper

  So, we’ve looked at how a dynamic call is represented in a compiled assembly, and how the dynamic lookup is performed at runtime. The last piece of the puzzle is how the resolved method gets invoked, and that is the subject of this post. Invoking methods As discussed in my previous posts, doing a full lookup and bind at runtime each and every single time the callsite gets invoked would be far too slow to be usable. The results obtained from the callsite binder must to be cached, along with a series of conditions to determine whether the cached result can be reused. So, firstly, how are the conditions represented? These conditions can be anything; they are determined entirely by the semantics of the language the binder is representing. The binder has to be able to return arbitary code that is then executed to determine whether the conditions apply or not. Fortunately, .NET 4 has a neat way of representing arbitary code that can be easily combined with other code – expression trees. All the callsite binder has to return is an expression (called a ‘restriction’) that evaluates to a boolean, returning true when the restriction passes (indicating the corresponding method invocation can be used) and false when it does’t. If the bind result is also represented in an expression tree, these can be combined easily like so: if ([restriction is true]) { [invoke cached method] } Take my example from my previous post: public class ClassA { public static void TestDynamic() { CallDynamic(new ClassA(), 10); CallDynamic(new ClassA(), "foo"); } public static void CallDynamic(dynamic d, object o) { d.Method(o); } public void Method(int i) {} public void Method(string s) {} } When the Method(int) method is first bound, along with an expression representing the result of the bind lookup, the C# binder will return the restrictions under which that bind can be reused. In this case, it can be reused if the types of the parameters are the same: if (thisArg.GetType() == typeof(ClassA) && arg1.GetType() == typeof(int)) { thisClassA.Method(i); } Caching callsite results So, now, it’s up to the callsite to link these expressions returned from the binder together in such a way that it can determine which one from the many it has cached it should use. This caching logic is all located in the System.Dynamic.UpdateDelegates class. It’ll help if you’ve got this type open in a decompiler to have a look yourself. For each callsite, there are 3 layers of caching involved: The last method invoked on the callsite. All methods that have ever been invoked on the callsite. All methods that have ever been invoked on any callsite of the same type. We’ll cover each of these layers in order Level 1 cache: the last method called on the callsite When a CallSite<T> object is first instantiated, the Target delegate field (containing the delegate that is called when the callsite is invoked) is set to one of the UpdateAndExecute generic methods in UpdateDelegates, corresponding to the number of parameters to the callsite, and the existance of any return value. These methods contain most of the caching, invoke, and binding logic for the callsite. The first time this method is invoked, the UpdateAndExecute method finds there aren’t any entries in the caches to reuse, and invokes the binder to resolve a new method. Once the callsite has the result from the binder, along with any restrictions, it stitches some extra expressions in, and replaces the Target field in the callsite with a compiled expression tree similar to this (in this example I’m assuming there’s no return value): if ([restriction is true]) { [invoke cached method] return; } if (callSite._match) { _match = false; return; } else { UpdateAndExecute(callSite, arg0, arg1, ...); } Woah. What’s going on here? Well, this resulting expression tree is actually the first level of caching. The Target field in the callsite, which contains the delegate to call when the callsite is invoked, is set to the above code compiled from the expression tree into IL, and then into native code by the JIT. This code checks whether the restrictions of the last method that was invoked on the callsite (the ‘primary’ method) match, and if so, executes that method straight away. This means that, the next time the callsite is invoked, the first code that executes is the restriction check, executing as native code! This makes this restriction check on the primary cached delegate very fast. But what if the restrictions don’t match? In that case, the second part of the stitched expression tree is executed. What this section should be doing is calling back into the UpdateAndExecute method again to resolve a new method. But it’s slightly more complicated than that. To understand why, we need to understand the second and third level caches. Level 2 cache: all methods that have ever been invoked on the callsite When a binder has returned the result of a lookup, as well as updating the Target field with a compiled expression tree, stitched together as above, the callsite puts the same compiled expression tree in an internal list of delegates, called the rules list. This list acts as the level 2 cache. Why use the same delegate? Stitching together expression trees is an expensive operation. You don’t want to do it every time the callsite is invoked. Ideally, you would create one expression tree from the binder’s result, compile it, and then use the resulting delegate everywhere in the callsite. But, if the same delegate is used to invoke the callsite in the first place, and in the caches, that means each delegate needs two modes of operation. An ‘invoke’ mode, for when the delegate is set as the value of the Target field, and a ‘match’ mode, used when UpdateAndExecute is searching for a method in the callsite’s cache. Only in the invoke mode would the delegate call back into UpdateAndExecute. In match mode, it would simply return without doing anything. This mode is controlled by the _match field in CallSite<T>. The first time the callsite is invoked, _match is false, and so the Target delegate is called in invoke mode. Then, if the initial restriction check fails, the Target delegate calls back into UpdateAndExecute. This method sets _match to true, then calls all the cached delegates in the rules list in match mode to try and find one that passes its restrictions, and invokes it. However, there needs to be some way for each cached delegate to inform UpdateAndExecute whether it passed its restrictions or not. To do this, as you can see above, it simply re-uses _match, and sets it to false if it did not pass the restrictions. This allows the code within each UpdateAndExecute method to check for cache matches like so: foreach (T cachedDelegate in Rules) { callSite._match = true; cachedDelegate(); // sets _match to false if restrictions do not pass if (callSite._match) { // passed restrictions, and the cached method was invoked // set this delegate as the primary target to invoke next time callSite.Target = cachedDelegate; return; } // no luck, try the next one... } Level 3 cache: all methods that have ever been invoked on any callsite with the same signature The reason for this cache should be clear – if a method has been invoked through a callsite in one place, then it is likely to be invoked on other callsites in the codebase with the same signature. Rather than living in the callsite, the ‘global’ cache for callsite delegates lives in the CallSiteBinder class, in the Cache field. This is a dictionary, typed on the callsite delegate signature, providing a RuleCache<T> instance for each delegate signature. This is accessed in the same way as the level 2 callsite cache, by the UpdateAndExecute methods. When a method is matched in the global cache, it is copied into the callsite and Target cache before being executed. Putting it all together So, how does this all fit together? Like so (I’ve omitted some implementation & performance details): That, in essence, is how the DLR performs its dynamic calls nearly as fast as statically compiled IL code. Extensive use of expression trees, compiled to IL and then into native code. Multiple levels of caching, the first of which executes immediately when the dynamic callsite is invoked. And a clever re-use of compiled expression trees that can be used in completely different contexts without being recompiled. All in all, a very fast and very clever reflection caching mechanism.

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• ArchBeat Link-o-Rama for November 13, 2012

  - by Bob Rhubart

  This week on the OTN Solution Architect Homepage Make time to check out this week's features on the OTN Solution Architect Homepage, including: SOA Practitioner Guide: Identifying and Discovering Services Setting Up, Configuring, and Using an Oracle WebLogic Server Cluster OTN ArchBeat Podcast: Are You Future Proof (Conclusion) Keynote: New Paradigms for Application Architecture: From Applications to IT Services I this keynote address from the SOA, Cloud, and Service Technology Symposium, Anne Thomas Manes highlights the importance of adapting to the current trend marked by the convergence of mobile, social and cloud, moving away from app-centric design to service-based solutions. New Solaris Cluster! | Jeff Victor "Oracle Solaris Cluster 4.1 offers both High Availability (HA) and also Scalable Services capabilities," explains Jeff Victor. "HA delivers automatic restart of software on the same cluster node and/or automatic failover from a failed node to a working cluster node. Software and support is available for both x86 and SPARC systems." You'll find download links and other resources in Jeff's short post. ADF BC View Accessor To Centralize Business Logic Processing | Andrejus Baranovskis Oracle ACE Director Andrejus Baranovskis illustrates one way to implement a use case that requires a comparison between the current row status and the data returned by another query (no master-detail relationship). Thought for the Day "The danger from computers is not that they will eventually get as smart as men, but that we will meanwhile agree to meet them halfway." — Bernard Avishai Source: SoftwareQuotes.com

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• Database Backup History From MSDB in a pivot table

  - by steveh99999

  I knocked up a nice little query to display backup history for each database in a pivot table format.I wanted to display the most recent full, differential, and transaction log backup for each database. Here's the SQL :-WITH backupCTE AS (SELECT name, recovery_model_desc, d AS 'Last Full Backup', i AS 'Last Differential Backup', l AS 'Last Tlog Backup' FROM ( SELECT db.name, db.recovery_model_desc,type, backup_finish_date FROM master.sys.databases db LEFT OUTER JOIN msdb.dbo.backupset a ON a.database_name = db.name WHERE db.state_desc = 'ONLINE' ) AS Sourcetable   PIVOT (MAX (backup_finish_date) FOR type IN (D,I,L) ) AS MostRecentBackup ) SELECT * FROM backupCTE Gives output such as this :-  With this query, I can then build up some straightforward queries to ensure backups are scheduled and running as expected -For example, the following logic can be used ;-  - WHERE [Last Full Backup] IS NULL) - ie database has never been backed up.. - WHERE [Last Tlog Backup] < DATEDIFF(mm,GETDATE(),-60) AND recovery_model_desc <> 'SIMPLE') - transction log not backed up in last 60 minutes. - WHERE [Last Full Backup] < DATEDIFF(dd,GETDATE(),-1) AND [Last Differential Backup] < [Last Full Backup]) -- no backup in last day.- WHERE [Last Differential Backup] < DATEDIFF(dd,GETDATE(),-1) AND [Last Full Backup] < DATEDIFF(dd,GETDATE(),-8) ) -- no differential backup in last day when last full backup is over 8 days old.   

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• UPDATE FOR BI PUBLISHER ENTERPRISE 10.1.3.4.2 NOVEMBER 2011

  - by Tim Dexter

  It's Friday, that means its patch release time. Why do we do this to ourselves, 'we'll release on Friday!' It might 11.59 on Friday but by golly we'll have released on Friday. I can remember a release of BIP years ago that for some reason we went for 12/31 as a release date ... were we mad? I seem to remember we made it but talk about ridiculous pressure! The latest 10g rollup is out in the wild and available from Oracle support. A bug fixing rollup but worth getting to and know that support will want you to get to it and re-test before going forward on an SR. One simple but very useful fix or enhancement:[Cause of the bug] @ ================== @ Customer reports that despite the clock being shown, end users are clicking @ on the View button repeatedly as the initial generation is taking some time.   @ If the button were to be grayed out then  this would prevent the users @ requesting the report more than  once.  Repeated requests are causing a @ system overload and as this is their Production  instance this is extremely @ important to the customer. @ . @ [The Fix] @ ========= @ Added the logic to disable the button after the user clicks on the "view" @ button and re-enable it when the report is loaded. I told a group of customers once that they have a headache and we have a non-steroidal anti-inflammatory drug, alright, I actually said 'aspirin'. This little gem of a fix helps relieve another little headache that our aspirin was causing. The patch number for all this BIP pain killing is 13399232, enjoy!

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• Writing Web "server less" applications

  - by crodjer

  TL;DR What are the prospects of write applications which are completely based on a REST database server (CouchDB) and web applications which directly access the DB instead of having a web server in between? I recently started looking up some NoSQL databases. MongoDB seems to be a popular choices. I also liked the project. But I personally liked the REST interface of CouchDB. So what I wanted to know is if there was the possibility of applications (maybe cached apps in web browser, a chrome extension etc.) which could just just query the database directly with no requirement of a webserver in between. All the computational logic would reside in the client application and the database will do what it does, CRUD. Since mostly (I don't know which doesn't) client frameworks support REST quaries, it could be a good way writing applications well optimized for respective framework. These applications though won't be doing complicated computation, but still provide enough functionality which could replace lots of conventional applications. Are existing resources and projects which would help me move towards writing such applications and also the scope and moving towards developing in this way? Are their any technical/security issues with this? This post will help me decide to look into project like CouchDB (and maybe Dive into Erlang later) or stay with the conventional frameworks (like django) and SQL databases. Update A specific point of such apps I had in mind is creation of offline applications just by replicating couchdb data on client.

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• From a DDD perspective is a report generating service a domain service or an infrastructure service?

  - by Songo

  Let assume we have the following service whose responsibility is to generate Excel reports: class ExcelReportService{ public String generateReport(String fileFormatFilePath, ResultSet data){ ReportFormat reportFormat = new ReportFormat(fileFormatFilePath); ExcelDataFormatterService excelDataFormatterService = new ExcelDataFormatterService(); FormattedData formattedData = excelDataFormatterService.format(data); ExcelFileService excelFileService = new ExcelFileService(); String reportPath= excelFileService.generateReport(reportFormat,formattedData); return reportPath; } } This is pseudo code for the service I want to design where: fileFormatFilePath: path to a configuration file where I'll keep the format of my excel file (headers, column widths, number of columns,..etc) data: the actual records returned from the database. This data can't be used directly coz I might need to make further calculations to the data before inserting them to the excel file. ReportFormat: Value object to hold the report format, has methods like getHeaders(), getColumnWidth(),...etc. ExcelDataFormatterService: a service to hold any logic that need to be applied to the data returned from the database before inserting it to the file. FormattedData: Value object the represents the formatted data to be inserted. ExcelFileService: a wrapper top the 3rd party library that generates the excel file. Now how do you determine whether a service is an infrastructure or domain service? I have the following 3 services here: ExcelReportService, ExcelDataFormatterService and ExcelFileService?

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• Is there a better way to consume an ASP.NET Web API call in an MVC controller?

  - by davidisawesome

  In a new project I am creating for my work I am creating a fairly large ASP.NET Web API. The api will be in a separate visual studio solution that also contains all of my business logic and database interactions, Model classes as well. In the test application I am creating (which is asp.net mvc4), I want to be able to hit an api url I defined from the control and cast the return JSON to a Model class. The reason behind this is that I want to take advantage of strongly typing my views to a Model. This is all still in a proof of concept stage, so I have not done any performance testing on it, but I am curious if what I am doing is a good practice, or if I am crazy for even going down this route. Here is the code on the client controller: public class HomeController : Controller { protected string dashboardUrlBase = "http://localhost/webapi/api/StudentDashboard/"; public ActionResult Index() //This view is strongly typed against User { //testing against Joe Bob string adSAMName = "jBob"; WebClient client = new WebClient(); string url = dashboardUrlBase + "GetUserRecord?userName=" + adSAMName; //'User' is a Model class that I have defined. User result = JsonConvert.DeserializeObject<User>(client.DownloadString(url)); return View(result); } . . . } If I choose to go this route another thing to note is I am loading several partial views in this page (as I will also do in subsequent pages). The partial views are loaded via an $.ajax call that hits this controller and does basically the same thing as the code above: Instantiate a new WebClient Define the Url to hit Deserialize the result and cast it to a Model Class. So it is possible (and likely) I could be performing the same actions 4-5 times for a single page. Is there a better method to do this that will: Let me keep strongly typed views. Do my work on the server rather than on the client (this is just a preference since I can write C# faster than I can write javascript).

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• Tips about how to spread Object Oriented practices

  - by Augusto

  I work for a medium company that has around 250 developers. Unfortunately, lots of them are stuck in a procedural way of thinking and some teams constantly deliver big Transactional Script applications, when in fact the application contains rich logic. They also fail to manage the design dependencies, and end up with services which depend on another large number of services (a clean example of Big Ball of Mud). My question is: Can you suggest how to spread this type of knowledge? I know that the surface of the problem is that these applications have a poor architecture and design. Another issue is that there are some developers who are against writing any kind of test. A few things I'm doing to change this (but I'm either failing or the change is too small are) Running presentations about design principles (SOLID, clean code, etc). Workshops about TDD and BDD. Coaching teams (this includes using sonar, findbugs, jdepend and other tools). IDE & Refactoring talks. A few things I'm thinking to do in the future (but I'm concern that they might not be good) Form a team of OO evangelists, who disseminate an OO way of thinking in differet teams (these people would need to change teams every few months). Running design review sessions, to criticise the design and suggest improvements (even if the improvements are not done because of time constraints, I think this might be useful) . Something I found with the teams I coach, is that as soon as I leave them, they revert back to the old practices. I know I don't spend a lot of time with them, usually just one month. So whatever I'm doing, it doesn't stick. I'm sorry this question is spattered with frustration, but the alterative to write this was to hit my head on the wall until I pass out.

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• New CAM Editor v2.3 with Open-XDX for Open Data APIs

  - by drrwebber

  Creating actual working XML exchanges, loading data from data stores, generating XML, testing, integrating with web services and then deployment delivery takes a lot of coding and effort. Then writing the documentation, models, schema and doing naming and design rule (NDR) checks and packaging all this together (such as for NIEM IEPD use). What if there was a tool that helped you do all that easily and simply? Welcome to the new Open-XDX and the CAM Editor! Open-XDX uses code-free techniques in combination with CAM templates and visual drag and drop to rapidly design your XML exchange. Then Open-XDX will automatically generate all the SQL for you, read the database data, generate and populate the valid output XML, and filter with parameters. To complete the processing solution Open-XDX works with web services and JDBC database connections as a callable module that can be deployed plug and play with your middleware stack, all with just a few lines of Java code (about 5 actually). You can build either Query/Response or Publish/Subscribe services from existing data stores to XML literally in minutes. To see a demonstration of using Open-XDX, a MySQL data store and integrating with Oracle Web Logic server please see this short few minutes video - http://youtube.com/user/TheCameditor There is also a Quick Guide available that provides more technical insights along with a sample pack download of templates and SQL that you can try for yourself. Head on over to our project resource site to learn more, download the latest CAM Editor and see links to all the resources and materials. We look forward to seeing how the developer community is able to jump start information sharing initiatives using this new innovative approach.

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• Webserver on a rotating server with NAT IP or changing IPs

  - by hpsoftware

  i would have to elaborate my questions so please have patience Explaining the logic. if you are familiar with logmein then it installs a client software on your computer then it kinda keeps tracks where you computer is as long as it's connected to internet. So you can always access your computer no matter where it is whatever it's IP is you just go to logmein.com and then you can just access it. Now what i am asking 1. Let's assume i have a website hosted on my laptop let's call it webserver. so then i move around i have a new IP sometime even on a hotel network is it possible to do something like what logmein does so i can keep moving around my Webserver to new IP but it has some local client or something which keeps updating my IP or something i am sure i would need a gateway server somewhere which is connected to my domain name via DNS so somebody accessing my website www.mywebsite.com goes to my main server then gets routed to my laptop which could be anywhere but my gateway server is able to communicate to my webserver I will keep updating the case description based on comments to make more sense. please have patience with me. Regards

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• What is an Enterprise Resource Planning (ERP) System?

  In order to understand what an Enterprise Resource Planning System is let us look at a classic American kids snack, the Rice Krispy Treat if we conceptually view the treat as a company’s internal applications as a whole.  Furthermore we can view a company’s departmentalized software applications as the theoretical Rice Krispies in the treat. In addition, the Rice Krispies consist of a combination of ingredients that be broken down into data, user interfaces and business logic. Next, we have the margarine or butter that is used to help the marshmallows bind with the Rice Krispies; this role in our conceptual view is taken by a data source typically as a relational database management system. Finally we have the melted marshmallows which act as the ERP software that connects all of the individual departmental software applications in to one unified system that allows all user one unified system to interact with all of the individual dispersed systems. An example of this would be if a customer places an order with a telephone operator and once the orders is processed an employee in the shipping department can see the order ready for fulfillment on his order screen. The ERP acts a go between for various independent departmental systems so that they can integrate with one another.

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• The most mind-bending programming language? [closed]

  - by Xepoch

  From a reasonably common programming language, which do you find to be the most mind-bending? I have been listening to a lot of programming podcasts and taking some time to learn some new languages that are being considered upcoming, and important. I'm not necessarily talking about BrainFuck, but which language would you consider to be one that challenges the common programming paradigms? For me, I did some functional and logic (ex. Prolog) programming in the 90s, so can't say that I find anything special there. I am far from being an expert in it, but even today the most mind-bending programming language for me is Perl. Not because "Hello World" is hard to implement but rather there is so much lexical flexibility that some of the hardest solutions can be decomposed so poetically that I have to walk outside away from my terminal to clear my head. I'm not saying I'd likely sell a commercial software implementation, just that there is a distinct reason Perl is so (in)famous. Just look at the basic list of books on it. So, what is your mind-bending language that promotes your better programming and practices?

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• Why don't windows of the same application behave as they should?

  - by Yuttadhammo

  Somewhere along the upgrade path, Unity has developed some strange logic behind window layering. First, before Oneiric, there was a way to see all the windows of an application - I think it was when you click on the icon in the launcher. Now, clicking on the icon often does nothing. Suppose I have two terminals open, one behind this Firefox window, and one in front of it. Clicking on the launcher does nothing - the only way to find the second terminal, afaics, is to move the Firefox window or use the task switcher. Secondly, once I have both terminals on top, then I decide to close one of them, suddenly they both disappear (the second one, for some reason, has gone into hiding behind the Firefox window). Third (though I can't pin it down now), sometimes when a window is on top, focus is still on a window in back; I click on the top x to close the window in front, only to find I've closed an important window in the back. (Update: this question details the problem) I can't really believe these are bugs, since they seem too obvious to not have been fixed by now. My question is, am I missing something? Some compiz option I can set to make it act like it used to? Or is this really how Unity is supposed to act?

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• How can Agile methodologies be adapted to High Volume processing system development?

  - by luckyluke

  I am developing high volume processing systems. Like mathematical models that calculate various parameters based on millions of records, calculated derived fields over milions of records, process huge files having transactions etc... I am well aware of unit testing methodologies and if my code is in C# I have no problem in unit testing it. Problem is I often have code in T-SQL, C# code that is a SQL stored assembly, and SSIS workflow with a good amount of logic (and outcomes etc) or some SAS process. What is the approach YOu use when developing such systems. I usually develop several tests as Stored procedures in a designed schema(TEST) and then automatically run them overnight and check out the results. But this is only for T-SQL. And Continous integration IS hard. But the problem is with testing SSIS packages. How do You test it? What is Your preferred approach for stubbing data into tables (especially if You need a lot data initialization). I have some approach derived over the years but maybe I am just not reading enough articles. So Banking, Telecom, Risk developers out there. How do You test your mission critical apps that process milions of records at end day, month end etc? What frameworks do You use? How do You validate that Your ssis package is Correct (as You develop it)/ How do You achieve continous integration in such an environment (Personally I never got there)? I hope this is not to open-ended question. How do You test Your map-reduce jobs for example (i do not use hadoop but this is quite similar). luke Hope that this is not too open ended

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• Is Moving Entity Framework objects over a webservice really the best way?

  - by aceinthehole

  I've inherited a .NET project that has close to 2 thousand clients out in the field that need to push data periodically up to a central repository. The clients wake up and attempt to push the data up via a series of WCF webservices where they are passing each entity framework entity as parameter. Once the service receives this object, it preforms some business logic on the data, and then turns around and sticks it in it's own database that mirrors the database on the client machines. The trick is, is that this data is being transmitted over a metered connection, which is very expensive. So optimizing the data is a serious priority. Now, we are using a custom encoder that compresses the data (and decompresses it on the other end) while it is being transmitted, and this is reducing the data footprint. However, the amount of data that the clients are using, seem ridiculously large, given the amount of information that is actually being transmitted. It seems me that entity framework itself may be to blame. I'm suspecting that the objects are very large when serialized to be sent over wire, with a lot context information and who knows what else, when what we really need is just the 'new' inserts. Is using the entity framework and WCF services as we have done so far the correct way, architecturally, of approaching this n-tiered, asynchronous, push only problem? Or is there a different approach, that could optimize the data use?

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• We are moving an Access based corporate front-end into a Web-based App

  - by Max Vernon

  We have an enterprise application with a front end written in Microsoft Access 2003 that has evolved over the past 6 years. The back end data, and a fair amount of back-end logic is contained within several Microsoft SQL Server databases. This front end app consists of around 180 forms, and over 120,000 lines of code, and interacts with VB.Net DLLs that support various critical functions used by our sales force. The current system makes use of 3 monitors to display various information; the Access app uses COM+ to control Microsoft Outlook and Internet Explorer for various purposes. The Access front end sometimes occupies 2 screens, automatically resizing itself based on Windows API-reported screen dimensions. The app also uses a Google map to present data to our agents, and allows two-way interactivity with the map through COM+ connectivity to JavaScript contained in the Google map. At the urging of senior management, we are looking to completely rewrite this application using some web-based technology, such as ASP.Net or perhaps a LAMP stack (the thinking with the LAMP stack thing is "free" is pretty cheap). We want to move to a web-based app so we can eliminate the dependency on our physical location for hiring new sales force members. Currently, our main office is full to capacity, and we need to continue growing the company. Does anyone have any thoughts on what would be the best technology to use for a web-based app of this magnitude? Keeping in mind the app is dependent on back-end services on our existing infrastructure. The app handles financial data and personal customer data, among other things. [I've looked at Best practices for moving large MS Access application towards .Net? and read the answers, and most of the comments. Interesting reading, and has some valid points, but our C.O.O. and contracted Software Architect are pushing for a full web-based app, not a .Net Windows App]

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• StreamInsight 2.1, meet LINQ

  - by Roman Schindlauer

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

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