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• CQRS &ndash; Questions and Concerns

  - by Dylan Smith

  I’ve been doing a lot of learning on CQRS and Event Sourcing over the last little while and I have a number of questions that I haven’t been able to answer. 1. What is the benefit of CQRS when compared to a typical DDD architecture that uses Event Sourcing and properly captures intent and behavior via verb-based commands? (other than Scalability) 2. When using CQRS what do you do with complex query-based logic? I’m going to elaborate on #1 in this blog post and I’ll do a follow-up post on #2. I watched through Greg Young’s video on the business benefits of CQRS + Event Sourcing and first let me say that I thought it was an excellent presentation that really drives home a lot of the benefits to this approach to architecture (I watched it twice in a row I enjoyed it so much!). But it didn’t answer some of my questions fully (I wish I had been there to ask these of Greg in person!). So let me pick apart some of the points he makes and how they relate to my first question above. I’m completely sold on the idea of event sourcing and have a clear understanding of the benefits that it brings to the table, so I’m not going to question that. But you can use event sourcing without going to a CQRS architecture, so my main question is around the benefits of CQRS + Event Sourcing vs Event Sourcing + Typical DDD architecture Architecture with Event Sourcing + Commands on Left, CQRS on Right Greg talks about how the stereotypical architecture doesn’t support DDD, but is that only because his diagram shows DTO’s coming up from the client. If we use the same diagram but allow the client to send commands doesn’t that remove a lot of the arguments that Greg makes against the stereotypical architecture? We can now introduce verbs into the system. We can capture intent now (storing it still requires event sourcing, but you can implement event sourcing without doing CQRS) We can create a rich domain model (as opposed to an anemic domain model) Scalability is obviously a benefit that CQRS brings to the table, but like Greg says, very few of the systems we create truly need significant scalability Greg talks about the ability to scale your development efforts. He says CQRS allows you to split the system into 3 parts (Client, Domain/Commands, Reads) and assign 3 teams of developers to work on them in parallel; letting you scale your development efforts by 3x with nearly linear gains. But in the stereotypical architecture don’t you already have 2 separate modules that you can split your dev efforts between: The client that sends commands/queries and receives DTO’s, and the Domain which accepts commands/queries, and generates events/DTO’s. If this is true it’s not really a 3x scaling you achieve with CQRS but merely a 1.5x scaling which while great doesn’t sound nearly as dramatic (“I can do it with 10 devs in 12 months – let me hire 5 more and we can have it done in 8 months”). Making the Query side “stupid simple” such that you can assign junior developers (or even outsource it) sounds like a valid benefit, but I have some concerns over what you do with complex query-based logic/behavior. I’m going to go into more detail on this in a follow-up blog post shortly. He also seemed to focus on how “stupid-simple” it is doing queries against the de-normalized data store, but I imagine there is still significant complexity in the event handlers that interpret the events and apply them to the de-normalized tables. It sounds like Greg suggests that because we’re doing CQRS that allows us to apply Event Sourcing when we otherwise wouldn’t be able to (~33:30 in the video). I don’t believe this is true. I don’t see why you wouldn’t be able to apply Event Sourcing without separating out the Commands and Queries. The queries would just operate against the domain model instead of the database. But you’d still get the benefits of Event Sourcing. Without CQRS the queries would only be able to operate against the current state rather than the event history, but even in CQRS the domain behaviors can only operate against the current state and I don’t see that being a big limiting factor. If some query needs to operate against something that is not captured by the current state you would just have to update the domain model to capture that information (no different than if that statement were made about a Command under CQRS). Some of the benefits I do see being applicable are that your domain model might end up being simpler/smaller since it only needs to represent the state needed to process commands and not worry about the reads (like the Deactivate Inventory Item and associated comment example that Greg provides). And also commands that can be handled in a Transaction Script style manner by the command handler simply generating events and not touching the domain model. It also makes it easier for your senior developers to focus on the command behavior and ignore the queries, which is usually going to be a better use of their time. And of course scalability. If anybody out there has any thoughts on this and can help educate me further, please either leave a comment or feel free to get in touch with me via email:

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• SQLAuthority News – Great Time Spent at Great Indian Developers Summit 2014

  - by Pinal Dave

  The Great Indian Developer Conference (GIDS) is one of the most popular annual event held in Bangalore. This year GIDS is scheduled on April 22, 25. I will be presented total four sessions at this event and each session is very different from each other. Here are the details of four of my sessions, which I presented there. Pluralsight Shades This event was a great event and I had fantastic fun presenting a technology over here. I was indeed very excited that along with me, I had many of my friends presenting at the event as well. I want to thank all of you to attend my session and having standing room every single time. I have already sent resources in my newsletter. You can sign up for the newsletter over here. Indexing is an Art I was amazed with the crowd present in the sessions at GIDS. There was a great interest in the subject of SQL Server and Performance Tuning. Audience at GIDS I believe event like such provides a great platform to meet and share knowledge. Pinal at Pluralsight Booth Here are the abstract of the sessions which I had presented. They were recorded so at some point in time they will be available, but if you want the content of all the courses immediately, I suggest you check out my video courses on the same subject on Pluralsight. Indexes, the Unsung Hero Relevant Pluralsight Course Slow Running Queries are the most common problem that developers face while working with SQL Server. While it is easy to blame SQL Server for unsatisfactory performance, the issue often persists with the way queries have been written, and how Indexes has been set up. The session will focus on the ways of identifying problems that slow down SQL Server, and Indexing tricks to fix them. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. Indexes are the most crucial objects of the database. They are the first stop for any DBA and Developer when it is about performance tuning. There is a good side as well evil side to indexes. To master the art of performance tuning one has to understand the fundamentals of indexes and the best practices associated with the same. We will cover various aspects of Indexing such as Duplicate Index, Redundant Index, Missing Index as well as best practices around Indexes. SQL Server Performance Troubleshooting: Ancient Problems and Modern Solutions Relevant Pluralsight Course Many believe Performance Tuning and Troubleshooting is an art which has been lost in time. However, truth is that art has evolved with time and there are more tools and techniques to overcome ancient troublesome scenarios. There are three major resources that when bottlenecked creates performance problems: CPU, IO, and Memory. In this session we will focus on High CPU scenarios detection and their resolutions. If time permits we will cover other performance related tips and tricks. At the end of this session, attendees will have a clear idea as well as action items regarding what to do when facing any of the above resource intensive scenarios. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. To master the art of performance tuning one has to understand the fundamentals of performance, tuning and the best practices associated with the same. We will discuss about performance tuning in this session with the help of Demos. Pinal Dave at GIDS MySQL Performance Tuning – Unexplored Territory Relevant Pluralsight Course Performance is one of the most essential aspects of any application. Everyone wants their server to perform optimally and at the best efficiency. However, not many people talk about MySQL and Performance Tuning as it is an extremely unexplored territory. In this session, we will talk about how we can tune MySQL Performance. We will also try and cover other performance related tips and tricks. At the end of this session, attendees will not only have a clear idea, but also carry home action items regarding what to do when facing any of the above resource intensive scenarios. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. To master the art of performance tuning one has to understand the fundamentals of performance, tuning and the best practices associated with the same. You will also witness some impressive performance tuning demos in this session. Hidden Secrets and Gems of SQL Server We Bet You Never Knew Relevant Pluralsight Course SQL Trio Session! It really amazes us every time when someone says SQL Server is an easy tool to handle and work with. Microsoft has done an amazing work in making working with complex relational database a breeze for developers and administrators alike. Though it looks like child’s play for some, the realities are far away from this notion. The basics and fundamentals though are simple and uniform across databases, the behavior and understanding the nuts and bolts of SQL Server is something we need to master over a period of time. With a collective experience of more than 30+ years amongst the speakers on databases, we will try to take a unique tour of various aspects of SQL Server and bring to you life lessons learnt from working with SQL Server. We will share some of the trade secrets of performance, configuration, new features, tuning, behaviors, T-SQL practices, common pitfalls, productivity tips on tools and more. This is a highly demo filled session for practical use if you are a SQL Server developer or an Administrator. The speakers will be able to stump you and give you answers on almost everything inside the Relational database called SQL Server. I personally attended the session of Vinod Kumar, Balmukund Lakhani, Abhishek Kumar and my favorite Govind Kanshi. Summary If you have missed this event here are two action items 1) Sign up for Resource Newsletter 2) Watch my video courses on Pluralsight Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: MySQL, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, T SQL Tagged: GIDS

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• C#/.NET Little Wonders &ndash; Cross Calling Constructors

  - by James Michael Hare

  Just a small post today, it’s the final iteration before our release and things are crazy here!  This is another little tidbit that I love using, and it should be fairly common knowledge, yet I’ve noticed many times that less experienced developers tend to have redundant constructor code when they overload their constructors. The Problem – repetitive code is less maintainable Let’s say you were designing a messaging system, and so you want to create a class to represent the properties for a Receiver, so perhaps you design a ReceiverProperties class to represent this collection of properties. Perhaps, you decide to make ReceiverProperties immutable, and so you have several constructors that you can use for alternative construction: 1: // Constructs a set of receiver properties. 2: public ReceiverProperties(ReceiverType receiverType, string source, bool isDurable, bool isBuffered) 3: { 4: ReceiverType = receiverType; 5: Source = source; 6: IsDurable = isDurable; 7: IsBuffered = isBuffered; 8: } 9: 10: // Constructs a set of receiver properties with buffering on by default. 11: public ReceiverProperties(ReceiverType receiverType, string source, bool isDurable) 12: { 13: ReceiverType = receiverType; 14: Source = source; 15: IsDurable = isDurable; 16: IsBuffered = true; 17: } 18:  19: // Constructs a set of receiver properties with buffering on and durability off. 20: public ReceiverProperties(ReceiverType receiverType, string source) 21: { 22: ReceiverType = receiverType; 23: Source = source; 24: IsDurable = false; 25: IsBuffered = true; 26: } Note: keep in mind this is just a simple example for illustration, and in same cases default parameters can also help clean this up, but they have issues of their own. While strictly speaking, there is nothing wrong with this code, logically, it suffers from maintainability flaws.  Consider what happens if you add a new property to the class?  You have to remember to guarantee that it is set appropriately in every constructor call. This can cause subtle bugs and becomes even uglier when the constructors do more complex logic, error handling, or there are numerous potential overloads (especially if you can’t easily see them all on one screen’s height). The Solution – cross-calling constructors I’d wager nearly everyone knows how to call your base class’s constructor, but you can also cross-call to one of the constructors in the same class by using the this keyword in the same way you use base to call a base constructor. 1: // Constructs a set of receiver properties. 2: public ReceiverProperties(ReceiverType receiverType, string source, bool isDurable, bool isBuffered) 3: { 4: ReceiverType = receiverType; 5: Source = source; 6: IsDurable = isDurable; 7: IsBuffered = isBuffered; 8: } 9: 10: // Constructs a set of receiver properties with buffering on by default. 11: public ReceiverProperties(ReceiverType receiverType, string source, bool isDurable) 12: : this(receiverType, source, isDurable, true) 13: { 14: } 15:  16: // Constructs a set of receiver properties with buffering on and durability off. 17: public ReceiverProperties(ReceiverType receiverType, string source) 18: : this(receiverType, source, false, true) 19: { 20: } Notice, there is much less code.  In addition, the code you have has no repetitive logic.  You can define the main constructor that takes all arguments, and the remaining constructors with defaults simply cross-call the main constructor, passing in the defaults. Yes, in some cases default parameters can ease some of this for you, but default parameters only work for compile-time constants (null, string and number literals).  For example, if you were creating a TradingDataAdapter that relied on an implementation of ITradingDao which is the data access object to retreive records from the database, you might want two constructors: one that takes an ITradingDao reference, and a default constructor which constructs a specific ITradingDao for ease of use: 1: public TradingDataAdapter(ITradingDao dao) 2: { 3: _tradingDao = dao; 4:  5: // other constructor logic 6: } 7:  8: public TradingDataAdapter() 9: { 10: _tradingDao = new SqlTradingDao(); 11:  12: // same constructor logic as above 13: }   As you can see, this isn’t something we can solve with a default parameter, but we could with cross-calling constructors: 1: public TradingDataAdapter(ITradingDao dao) 2: { 3: _tradingDao = dao; 4:  5: // other constructor logic 6: } 7:  8: public TradingDataAdapter() 9: : this(new SqlTradingDao()) 10: { 11: }   So in cases like this where you have constructors with non compiler-time constant defaults, default parameters can’t help you and cross-calling constructors is one of your best options. Summary When you have just one constructor doing the job of initializing the class, you can consolidate all your logic and error-handling in one place, thus ensuring that your behavior will be consistent across the constructor calls. This makes the code more maintainable and even easier to read.  There will be some cases where cross-calling constructors may be sub-optimal or not possible (if, for example, the overloaded constructors take completely different types and are not just “defaulting” behaviors). You can also use default parameters, of course, but default parameter behavior in a class hierarchy can be problematic (default values are not inherited and in fact can differ) so sometimes multiple constructors are actually preferable. Regardless of why you may need to have multiple constructors, consider cross-calling where you can to reduce redundant logic and clean up the code.   Technorati Tags: C#,.NET,Little Wonders

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• Is this how dynamic language copes with dynamic requirement?

  - by Amumu

  The question is in the title. I want to have my thinking verified by experienced people. You can add more or disregard my opinion, but give me a reason. Here is an example requirement: Suppose you are required to implement a fighting game. Initially, the game only includes fighters, who can attack each other. Each fighter can punch, kick or block incoming attacks. Fighters can have various fighting styles: Karate, Judo, Kung Fu... That's it for the simple universe of the game. In an OO like Java, it can be implemented similar to this way: abstract class Fighter { int hp, attack; void punch(Fighter otherFighter); void kick(Fighter otherFighter); void block(Figther otherFighter); }; class KarateFighter extends Fighter { //...implementation...}; class JudoFighter extends Fighter { //...implementation... }; class KungFuFighter extends Fighter { //...implementation ... }; This is fine if the game stays like this forever. But, somehow the game designers decide to change the theme of the game: instead of a simple fighting game, the game evolves to become a RPG, in which characters can not only fight but perform other activities, i.e. the character can be a priest, an accountant, a scientist etc... At this point, to make it more generic, we have to change the structure of our original design: Fighter is not used to refer to a person anymore; it refers to a profession. The specialized classes of Fighter (KaraterFighter, JudoFighter, KungFuFighter) . Now we have to create a generic class named Person. However, to adapt this change, I have to change the method signatures of the original operations: class Person { int hp, attack; List<Profession> skillSet; }; abstract class Profession {}; class Fighter extends Profession { void punch(Person otherFighter); void kick(Person otherFighter); void block(Person otherFighter); }; class KarateFighter extends Fighter { //...implementation...}; class JudoFighter extends Fighter { //...implementation... }; class KungFuFighter extends Fighter { //...implementation ... }; class Accountant extends Profession { void calculateTax(Person p) { //...implementation...}; void calculateTax(Company c) { //...implementation...}; }; //... more professions... Here are the problems: To adapt to the method changes, I have to fix the places where the changed methods are called (refactoring). Every time a new requirement is introduced, the current structural design has to be broken to adapt the changes. This leads to the first problem. Rigid structure makes it hard for code reuse. A function can only accept the predefined types, but it cannot accept future unknown types. A written function is bound to its current universe and has no way to accommodate to the new types, without modifications or rewrite from scratch. I see Java has a lot of deprecated methods. OO is an extreme case because it has inheritance to add up the complexity, but in general for statically typed language, types are very strict. In contrast, a dynamic language can handle the above case as follow: ;;fighter1 punch fighter2 (defun perform-punch (fighter1 fighter2) ...implementation... ) ;;fighter1 kick fighter2 (defun perform-kick (fighter1 fighter2) ...implementation... ) ;;fighter1 blocks attacks from fighter2 (defun perform-block (fighter1 fighter2) ...implementation... ) fighter1 and fighter2 can be anything as long as it has the required data for calculation; or methods (duck typing). You don't have to change from the type Fighter to Person. In the case of Lisp, because Lisp only has a single data structure: list, it's even easier to adapt to changes. However, other dynamic languages can have similar behaviors as well. I work primarily with static languages (mainly C and Java, but working with Java was a long time ago). I started learning Lisp and some other dynamic languages this year. I can see how it helps improving my productivity.

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• Windows in StreamInsight: Hopping vs. Snapshot

  - by Roman Schindlauer

  Three weeks ago, we explained the basic concept of windows in StreamInsight: defining sets of events that serve as arguments for set-based operations, like aggregations. Today, we want to discuss the so-called Hopping Windows and compare them with Snapshot Windows. We will compare these two, because they can serve similar purposes with different behaviors; we will discuss the remaining window type, Count Windows, another time. Hopping (and its syntactic-sugar-sister Tumbling) windows are probably the most straightforward windowing concept in StreamInsight. A hopping window is defined by its length, and the offset from one window to the next. They are aligned with some absolute point on the timeline (which can also be given as a parameter to the window) and create sets of events. The diagram below shows an example of a hopping window with length of 1h and hop size (the offset) of 15 minutes, hence creating overlapping windows:   Two aspects in this diagram are important: Since this window is overlapping, an event can fall into more than one windows. If an (interval) event spans a window boundary, its lifetime will be clipped to the window, before it is passed to the set-based operation. That’s the default and currently only available window input policy. (This should only concern you if you are using a time-sensitive user-defined aggregate or operator.) The set-based operation will be applied to each of these sets, yielding a result. This result is: A single scalar value in case of built-in or user-defined aggregates. A subset of the input payloads, in case of the TopK operator. Arbitrary events, when using a user-defined operator. The timestamps of the result are almost always the ones of the windows. Only the user-defined  operator can create new events with timestamps. (However, even these event lifetimes are subject to the window’s output policy, which is currently always to clip to the window end.) Let’s assume we were calculating the sum over some payload field: var result = from window in source.HoppingWindow( TimeSpan.FromHours(1), TimeSpan.FromMinutes(15), HoppingWindowOutputPolicy.ClipToWindowEnd) select new { avg = window.Avg(e => e.Value) }; Now each window is reflected by one result event:   As you can see, the window definition defines the output frequency. No matter how many or few events we got from the input, this hopping window will produce one result every 15 minutes – except for those windows that do not contain any events at all, because StreamInsight window operations are empty-preserving (more about that another time). The “forced” output for every window can become a performance issue if you have a real-time query with many events in a wide group & apply – let me explain: imagine you have a lot of events that you group by and then aggregate within each group – classical streaming pattern. The hopping window produces a result in each group at exactly the same point in time for all groups, since the window boundaries are aligned with the timeline, not with the event timestamps. This means that the query output will become very bursty, delivering the results of all the groups at the same point in time. This becomes especially obvious if the events are long-lasting, spanning multiple windows each, so that the produced result events do not change their value very often. In such a case, a snapshot window can remedy. Snapshot windows are more difficult to explain than hopping windows: they represent those periods in time, when no event changes occur. In other words, if you mark all event start and and times on your timeline, then you are looking at all snapshot window boundaries:   If your events are never overlapping, the snapshot window will not make much sense. It is commonly used together with timestamp modification, which make it a very powerful tool. Or as Allan Mitchell expressed in in a recent tweet: “I used to look at SnapshotWindow() with disdain. Now she is my mistress, the one I turn to in times of trouble and need”. Let’s look at a simple example: I want to compute the average of some value in my events over the last minute. I don’t want this output be produced at fixed intervals, but at soon as it changes (that’s the true event-driven spirit!). The snapshot window will include all currently active event at each point in time, hence we need to extend our original events’ lifetimes into the future: Applying the Snapshot window on these events, it will appear to be “looking back into the past”: If you look at the result produced in this diagram, you can easily prove that, at each point in time, the current event value represents the average of all original input event within the last minute. Here is the LINQ representation of that query, applying the lifetime extension before the snapshot window: var result = from window in source .AlterEventDuration(e => TimeSpan.FromMinutes(1)) .SnapshotWindow(SnapshotWindowOutputPolicy.Clip) select new { avg = window.Avg(e => e.Value) }; With more complex modifications of the event lifetimes you can achieve many more query patterns. For instance “running totals” by keeping the event start times, but snapping their end times to some fixed time, like the end of the day. Each snapshot then “sees” all events that have happened in the respective time period so far. Regards, The StreamInsight Team

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• CodePlex Daily Summary for Saturday, December 25, 2010

  CodePlex Daily Summary for Saturday, December 25, 2010Popular ReleasesCosmos (C# Open Source Managed Operating System): Release 71246: This is the first release featuring VS2010 support. Express support (C#) should work as well. Release notes: http://www.gocosmos.org/Releases/71246/NoSimplerAccounting: NoSimplerAccounting 6.0: -Fixed a bug in expense category report.NHibernate Mapping Generator: NHibernate Mapping Generator 2.0: Added support for Postgres (Thanks to Angelo)NewLife XCode: XCode v6.5.2010.1223 ????（????v3.5??）: XCode v6.5.2010.1223 ????，??： NewLife.Core ??? NewLife.Net ??? XControl ??? XTemplate ????，??C#?????? XAgent ???? NewLife.CommonEnitty ??????（???，XCode??????） XCode?? ?????????，??????????????????，?????95% XCode v3.5.2009.0714 ??，?v3.5?v6.0???????????????，?????????。v3.5???????????，??????????????。 XCoder ??XTemplate?????????，????????XCode??? XCoder_Src ???????（????XTemplate????），??????????????????MiniTwitter: 1.64: MiniTwitter 1.64 ???? ?? 1.63 ??? URL ??????????????Ajax ASP.Net Forum: InSeCla Forum Software v0.1.9: *VERSION: 0.1.9* HAPPY CHRISTMAS FEATURES ADDED Added features customizabled per category level (Customize at ADMIN/Categories Tab) Allow Anonymous Threads, Allow Anonymous Post Virtual URLs (friendly urls) has finally added And you can have some forum (category) using virtual urls and other using normal urls. Check !, as this improve the SEO indexing results Moderation Instant On: Delete Thread, Move Thread Available to users being members of moderators or administrators InstantO...VivoSocial: VivoSocial 7.4.0: Please see changes: http://support.vivoware.com/project/ChangeLog.aspx?PROJID=48Umbraco CMS: Umbraco 4.6 Beta - codename JUNO: The Umbraco 4.6 beta (codename JUNO) release contains many new features focusing on an improved installation experience, a number of robust developer features, and contains more than 89 bug fixes since the 4.5.2 release. Improved installer experience Updated Starter Kits (Simple, Blog, Personal, Business) Beautiful, free, customizable skins included Skinning engine and Skin customization (see Skinning Documentation Kit) Default dashboards on install with hide option Updated Login t...SSH.NET Library: 2010.12.23: This release includes some bug fixes and few new fetures. Fixes Allow to retrieve big directory structures ssh-dss algorithm is fixed Populate sftp file attributes New Features Support for passhrase when private key is used Support added for diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha256 and diffie-hellman-group-exchange-sha1 key exchange algorithms Allow to provide multiple key files for authentication Add support for "keyboard-interactive" authentication method...ASP.NET MVC SiteMap provider: MvcSiteMapProvider 2.3.0: Using NuGet?MvcSiteMapProvider is also listed in the NuGet feed. Learn more... Like the project? Consider a donation!Donate via PayPal via PayPal. Release notesThis will be the last release targeting ASP.NET MVC 2 and .NET 3.5. MvcSiteMapProvider 3.0.0 will be targeting ASP.NET MVC 3 and .NET 4 Web.config setting skipAssemblyScanOn has been deprecated in favor of excludeAssembliesForScan and includeAssembliesForScan ISiteMapNodeUrlResolver is now completely responsible for generating th...SuperSocket, an extensible socket application framework: SuperSocket 1.3 beta 2: Compared with SuperSocket 1.3 beta 1, the changes listed below have been done in SuperSocket 1.3 beta 2: added supports for .NET 3.5 replaced Logging Application Block of EntLib with Log4Net improved the code about logging fixed a bug in QuickStart sample project added IPv6 supportTibiaPinger: TibiaPinger v1.0: TibiaPinger v1.0Media Companion: Media Companion 3.400: Extract the entire archive to a folder which has user access rights, eg desktop, documents etc. A manual is included to get you startedMulticore Task Framework: MTF 1.0.1: Release 1.0.1 of Multicore Task Framework.EnhSim: EnhSim 2.2.6 ALPHA: 2.2.6 ALPHAThis release supports WoW patch 4.03a at level 85 To use this release, you must have the Microsoft Visual C++ 2010 Redistributable Package installed. This can be downloaded from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=A7B7A05E-6DE6-4D3A-A423-37BF0912DB84 To use the GUI you must have the .NET 4.0 Framework installed. This can be downloaded from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=9cfb2d51-5ff4-4491-b0e5-b386f32c0992 - Fixing up some r...ASP.NET MVC Project Awesome (jQuery Ajax helpers): 1.4.3: Helpers (controls) that you can use to build highly responsive and interactive Ajax-enabled Web applications. These helpers include Autocomplete, AjaxDropdown, Lookup, Confirm Dialog, Popup Form, Popup and Pager new stuff: Improvements for confirm, popup, popup form RenderView controller extension the user experience for crud in live demo has been substantially improved + added search all the features are shown in the live demoGanttPlanner: GanttPlanner V1.0: GanttPlanner V1.0 include GanttPlanner.dll and also a Demo application.N2 CMS: 2.1 release candidate 3: * Web platform installer support available N2 is a lightweight CMS framework for ASP.NET. It helps you build great web sites that anyone can update. Major Changes Support for auto-implemented properties ({get;set;}, based on contribution by And Poulsen) A bunch of bugs were fixed File manager improvements (multiple file upload, resize images to fit) New image gallery Infinite scroll paging on news Content templates First time with N2? Try the demo site Download one of the templ...TweetSharp: TweetSharp v2.0.0.0 - Preview 6: Documentation for this release may be found at http://tweetsharp.codeplex.com/wikipage?title=UserGuide&referringTitle=Documentation. Note: This code is currently preview quality. Preview 6 ChangesMaintenance release with user reported fixes Preview 5 ChangesMaintenance release with user reported fixes Preview 4 ChangesReintroduced fluent interface support via satellite assembly Added entities support, entity segmentation, and ITweetable/ITweeter interfaces for client development Numer...Team Foundation Server Administration Tool: 2.1: TFS Administration Tool 2.1, is the first version of the TFS Administration Tool which is built on top of the Team Foundation Server 2010 object model. TFS Administration Tool 2.1 can be installed on machines that are running either Team Explorer 2010, or Team Foundation Server 2010.New ProjectsAzure Configuration File Comparer: Compares two Azure configuration files and highlights the differencesConquera: Conquera is a Xna fantasy turn-based strategy, where players capture castles and resources to expand, defend and improve their territories. eSCADA: Sistema de supervision, control y adquisicion de datos (SCADA) desarrollado sobre la plataforma .net 4.0Jing SaaS Platform: This SaaS Platform is built for fast form based project delivery.MatchChow: MatchChowMeshSharp: MeshSharp is a Navigational Mesh pathfinding library for XNA written in C#. This will use a combination of algorithms; A* (Astar), Funnel, Steering and Flocking. This will be a similar project to the recast navigation project (written in C++).MonJardin: MonJardin est une application pour le jardin. Cette application effectue l'inventaire des plantations et les récoltes d'un jardin.Open Bitrac: Open Bitrac is a asp.net blog system!PAMS: PAN Applications Management System for PAN Service Agents and AgenciesPassword Manager: Password Manager application for the Windows Phone, Desktop, ASP.NET/Silverlight platformsRandomRest: Creating a class library that is more random than the standard system.random by using crowd sourcingSimple Config Editor: A .Net Library to Create and Modify Config Files, Based on XML.SQL UML PROFILE: This project envolves the creation of an UML Profile for Visual Studio 2010 that allows creating database diagrams with UML objects in modeling projects. We will also create a T4 template to generate SQL Scripts from the modeling projectTSQL Parser based on Database Edition GDR: TSQL Parser based in Database Edition GDR, this particular implementation help in finding Tables and columns used in TSQL. For this project to work you will need to install Database Edition GDR. http://www.microsoft.com/downloads/en/details.aspx?FamilyID=bb3ad767-5f69-4db9-b1c9-8WiiScanner: A project for scanning objects into virtual environments using WiiMotes.Windows Azure Development Toys: The Windows Azure Development Toys is a collaboration of many libraries, interfaces, adapters and plug-ins for Windows Azure project development. It will accelerate your development performance of your Windows Azure based application.

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• 2D Particle Explosion

  - by TheBroodian

  I'm developing a 2D action game, and in said game I've given my primary character an ability he can use to throw a fireball. I'm trying to design an effect so that when said fireball collides (be it with terrain or with an enemy) that the fireball will explode. For the explosion effect I've created a particle that once placed into game space will follow random, yet autonomic behavior based on random variables. Here is my question: When I generate my explosion (essentially 90 of these particles) I get one of two behaviors, 1) They are all generated with the same random variables, and don't resemble an explosion at all, more like a large mass of clumped sprites that all follow the same randomly generated path. 2) If I assign each particle a unique seed to its random number generator, they are a little bit -more- spread out, yet clumping is still visible (they seem to fork out into 3 different directions) Does anybody have any tips for producing particle-based 2D explosions? I'll include the code for my particle and the event I'm generating them in. Fire particle class: public FireParticle(xTile.Dimensions.Location StartLocation, ContentManager content) { worldLocation = StartLocation; fireParticleAnimation = new FireParticleAnimation(content); random = new Random(); int rightorleft = random.Next(0, 3); int upordown = random.Next(1, 3); int xVelocity = random.Next(0, 101); int yVelocity = random.Next(0, 101); Vector2 tempVector2 = new Vector2(0,0); if (rightorleft == 1) { tempVector2 = new Vector2(xVelocity, tempVector2.Y); } else if (rightorleft == 2) { tempVector2 = new Vector2(-xVelocity, tempVector2.Y); } if (upordown == 1) { tempVector2 = new Vector2(tempVector2.X, -yVelocity); } else if (upordown == 2) { tempVector2 = new Vector2(tempVector2.X, yVelocity); } velocity = tempVector2; scale = random.Next(1, 11); upwardForce = -10; dead = false; } public FireParticle(xTile.Dimensions.Location StartLocation, ContentManager content, int seed) { worldLocation = StartLocation; fireParticleAnimation = new FireParticleAnimation(content); random = new Random(seed); int rightorleft = random.Next(0, 3); int upordown = random.Next(1, 3); int xVelocity = random.Next(0, 101); int yVelocity = random.Next(0, 101); Vector2 tempVector2 = new Vector2(0, 0); if (rightorleft == 1) { tempVector2 = new Vector2(xVelocity, tempVector2.Y); } else if (rightorleft == 2) { tempVector2 = new Vector2(-xVelocity, tempVector2.Y); } if (upordown == 1) { tempVector2 = new Vector2(tempVector2.X, -yVelocity); } else if (upordown == 2) { tempVector2 = new Vector2(tempVector2.X, yVelocity); } velocity = tempVector2; scale = random.Next(1, 11); upwardForce = -10; dead = false; } #endregion #region Update and Draw public void Update(GameTime gameTime) { elapsed = (float)gameTime.ElapsedGameTime.TotalSeconds; fireParticleAnimation.Update(gameTime); Vector2 moveAmount = velocity * elapsed; xTile.Dimensions.Location newPosition = new xTile.Dimensions.Location(worldLocation.X + (int)moveAmount.X, worldLocation.Y + (int)moveAmount.Y); worldLocation = newPosition; velocity.Y += upwardForce; if (fireParticleAnimation.finishedPlaying) { dead = true; } } public void Draw(SpriteBatch spriteBatch) { spriteBatch.Draw( fireParticleAnimation.image.Image, new Rectangle((int)drawLocation.X, (int)drawLocation.Y, scale, scale), fireParticleAnimation.image.SizeAndsource, Color.White * fireParticleAnimation.image.Alpha); } Fireball explosion event: public override void Update(GameTime gameTime) { if (enabled) { float elapsed = (float)gameTime.ElapsedGameTime.TotalSeconds; foreach (Heart_of_Fire.World_Objects.Particles.FireParticle particle in explosionParticles.ToList()) { particle.Update(gameTime); if (particle.Dead) { explosionParticles.Remove(particle); } } collisionRectangle = new Microsoft.Xna.Framework.Rectangle((int)wrldPstn.X, (int)wrldPstn.Y, 5, 5); explosionCheck = exploded; if (!exploded) { coreGraphic.Update(gameTime); tailGraphic.Update(gameTime); Vector2 moveAmount = velocity * elapsed; moveAmount = horizontalCollision(moveAmount, layer); moveAmount = verticalCollision(moveAmount, layer); Vector2 newPosition = new Vector2(wrldPstn.X + moveAmount.X, wrldPstn.Y + moveAmount.Y); if (hasCollidedHorizontally || hasCollidedVertically) { exploded = true; } wrldPstn = newPosition; worldLocation = new xTile.Dimensions.Location((int)wrldPstn.X, (int)wrldPstn.Y); } if (explosionCheck != exploded) { for (int i = 0; i < 90; i++) { explosionParticles.Add(new World_Objects.Particles.FireParticle( new Location( collisionRectangle.X + random.Next(0, 6), collisionRectangle.Y + random.Next(0, 6)), contentMgr)); } } if (exploded && explosionParticles.Count() == 0) { //enabled = false; } } }

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• Social Engagement: One Size Doesn't Fit Anyone

  - by Mike Stiles

  The key to achieving meaningful social engagement is to know who you’re talking to, know what they like, and consistently deliver that kind of material to them. Every magazine for women knows this. When you read the article titles promoted on their covers, there’s no mistaking for whom that magazine is intended. And yet, confusion still reigns at many brands as to exactly whom they want to talk to, what those people want to hear, and what kind of content they should be creating for them. In most instances, the root problem is brands want to be all things to all people. Their target audience…the world! Good luck with that. It’s 2012, the age of aggregation and custom content delivery. To cope with the modern day barrage of information, people have constructed technological filters so that content they regard as being “for them” is mostly what gets through. Even if your brand is for men and women, young and old, you may want to consider social properties that divide men from women, and young from old. Yes, a man might find something in a women’s magazine that interests him. But that doesn’t mean he’s going to subscribe to it, or buy even one issue. In fact he’ll probably never see the article he’d otherwise be interested in, because in his mind, “This isn’t for me.” It wasn’t packaged for him. News Flash: men and women are different. So it’s a tall order to craft your Facebook Page or Twitter handle to simultaneously exude the motivators for both. The Harris Interactive study “2012 Connecting and Communicating Online: State of Social Media” sheds light on the differing social behaviors and drivers. -65% of women (vs. 59% of men) stay glued to social because they don’t want to miss anything. -25% of women check social when they wake up, before they check email. Only 18% of men check social before e-mail. -95% of women surveyed belong to Facebook vs. 86% of men. -67% of women log in to Facebook once a day or more vs. 54% of men. -Conventional wisdom is Pinterest is mostly a woman-thing, right? That may be true for viewing, but not true for sharing. Men are actually more likely to share on Pinterest than women, 23% to 10%. -The sharing divide extends to YouTube. 68% of women use it mainly for consumption, as opposed to 52% of men. -Women are as likely to have a Twitter account as men, but they’re much less likely to check it often. 54% of women check it once a week compared to 2/3 of men. Obviously, there are some takeaways from this depending on your target. Women don’t want to miss out on anything, so serialized content might be a good idea, right? Promotional posts that lead to a big payoff could keep them hooked. Posts for women might be better served first thing in the morning. If sharing is your goal, maybe male-targeted content is more likely to get those desired shares. And maybe Twitter is a better place to aim your male-targeted content than Facebook. Some grocery stores started experimenting with male-only aisles. The results have been impressive. Why? Because while it’s true men were finding those same items in the store just fine before, now something has been created just for them. They have a place in the store where they belong. Each brand’s strategy and targets are going to differ. The point is…know who you’re talking to, know how they behave, know what they like, and deliver content using any number of social relationship management targeting tools that meets their expectations. If, however, you’re committed to a one-size-fits-all, “our content is for everybody” strategy (or even worse, a “this is what we want to put out and we expect everybody to love it” strategy), your content will miss the mark for more often than it hits. @mikestilesPhoto via stock.schng

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• WCF ReliableSession and Timeouts

  - by user80108

  I have a WCF service used mainly for managing documents in a repository. I used the chunking channel sample from MS so that I could upload/download huge files. Now I implemented reliable session with the service and I am seeing some strange behaviors. Here are the timeout values I am using. this.SendTimeout = new TimeSpan(0,10,0); this.OpenTimeout = new TimeSpan(0, 1, 0); this.CloseTimeout = new TimeSpan(0, 1, 0); this.ReceiveTimeout = new TimeSpan(0,10, 0); reliableBe.InactivityTimeout = new TimeSpan(0,2,0); I have the following issues. 1. If the Service is not up & running, the clients are not get disconnected after OpenTimeout. I tried it with my test client. Scenario 1: Without Reliable Session: I get the following exception: Could not connect to net.tcp://localhost:8788/MediaManagementService/ep1. The connection attempt lasted for a time span of 00:00:00.9848790. TCP error code 10061: No connection could be made because the target machine actively refused it 127.0.0.1:8788 This is the correct behavior as I have given the OpenTimeout as 1 sec. Scenario 2: With ReliableSession: I get the same exception: Could not connect to net.tcp://localhost:8788/MediaManagementService/ep1. The connection attempt lasted for a time span of 00:00:00.9692460. TCP error code 10061: No connection could be made because the target machine actively refused it 127.0.0.1:8788. But this message comes after around 10 mintes . (I believe after SendTimeout) So here I just have enabled the reliable session and now it looks like the OpenTimeout = SendTimeout for the client. Is this desired behavior? 2: Issue while uploading huge files with ReliableSession: The general rule is that you have to set a huge value for the maxReceivedMessageSize, SendTimeout and ReceiveTimeout. But in the case of Chunking channel, the max received message size doesn't matter as the data is sent in chunks. So I set a huge value for Send and ReceiveTimeout : say 10 hours. Now the upload is going fine, but it has a side effect that, even if the Service is not up, it takes 10 hours to timeout the client connection due to the behavior mentioned in (1). Please let me know your thoughts on this behavior.

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• Winform radiobutton data binding

  - by Rajarshi

  I am following the "Presentation Model" design pattern suggested by Martin Fowler for my GUI architecture in a Windows Forms project. "The essence of a Presentation Model is of a fully self-contained class that represents all the data and behavior of the UI window, but without any of the controls used to render that UI on the screen. A view then simply projects the state of the presentation model onto the glass...." - Martin Fowler Read more about this pattern at www.martinfowler.com/eaaDev/PresentationModel.html I am finding the concept very fluid and easy to understand except this one issue of data binding RadioButtons to properties on the Data/Domain object. Suposing I have a Windows Form with 3 radio buttons to depict some "Mode" options as - Auto Manual Import How can I use boolean properties on Data/Domain Objects to DataBind to these buttons? I have tried many ways but to no avail. For example I would like to code like - rbtnAutoMode.DataBindings.Add("Text", myBusinessObject, "IsAutoMode"); rbtnManualMode.DataBindings.Add("Text", myBusinessObject, "IsManualMode"); rbtnImportMode.DataBindings.Add("Text", myBusinessObject, "IsImportMode"); There should be a fourth property like "SelectedMode" on the data/domain object which at the end should depict a single value like "SelectedMode = Auto". I am trying to update this property when any of the "IsAutoMode", "IsManualMode" or "IsImportMode" is changed, e.g. through the property setters. I have INotifyPropertyChanged implemented on my data/domain object so, updating any data/domain object property automatically updates my UI controls, that's not an issue. There is a good example of binding 2 radio buttons here - http://stackoverflow.com/questions/344964/how-do-i-use-databinding-with-windows-forms-radio-buttons but I am missing the link while implementing the same with 3 buttons. I am having very erratic behaviors for the Radio Buttons. I hope I was able to explain reasonably. I am actually in a hurry and could not put a detailed code on post, but any help in this regard is appreciated. There is a simple solution to this issue by exposing a method like - public void SetMode(Modes mode) { this._selectedMode = mode; } which could be called from the "CheckedChanged" event of the Radio Buttons from the UI and would perfectly set the "SelectedMode" on the business object, but I need to stretch the limits to verify whether this can be done by DataBinding.

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• Use native HBitmap in C# while preserving alpha channel/transparency. Please check this code, it works on my computer...

  - by David

  Let's say I get a HBITMAP object/handle from a native Windows function. I can convert it to a managed bitmap using Bitmap.FromHbitmap(nativeHBitmap), but if the native image has transparency information (alpha channel), it is lost by this conversion. There are a few questions on Stack Overflow regarding this issue. Using information from the first answer of this question (How to draw ARGB bitmap using GDI+?), I wrote a piece of code that I've tried and it works. It basically gets the native HBitmap width, height and the pointer to the location of the pixel data using GetObject and the BITMAP structure, and then calls the managed Bitmap constructor: Bitmap managedBitmap = new Bitmap(bitmapStruct.bmWidth, bitmapStruct.bmHeight, bitmapStruct.bmWidth * 4, PixelFormat.Format32bppArgb, bitmapStruct.bmBits); As I understand (please correct me if I'm wrong), this does not copy the actual pixel data from the native HBitmap to the managed bitmap, it simply points the managed bitmap to the pixel data from the native HBitmap. And I don't draw the bitmap here on another Graphics (DC) or on another bitmap, to avoid unnecessary memory copying, especially for large bitmaps. I can simply assign this bitmap to a PictureBox control or the the Form BackgroundImage property. And it works, the bitmap is displayed correctly, using transparency. When I no longer use the bitmap, I make sure the BackgroundImage property is no longer pointing to the bitmap, and I dispose both the managed bitmap and the native HBitmap. The Question: Can you tell me if this reasoning and code seems correct. I hope I will not get some unexpected behaviors or errors. And I hope I'm freeing all the memory and objects correctly. private void Example() { IntPtr nativeHBitmap = IntPtr.Zero; /* Get the native HBitmap object from a Windows function here */ // Create the BITMAP structure and get info from our nativeHBitmap NativeMethods.BITMAP bitmapStruct = new NativeMethods.BITMAP(); NativeMethods.GetObjectBitmap(nativeHBitmap, Marshal.SizeOf(bitmapStruct), ref bitmapStruct); // Create the managed bitmap using the pointer to the pixel data of the native HBitmap Bitmap managedBitmap = new Bitmap( bitmapStruct.bmWidth, bitmapStruct.bmHeight, bitmapStruct.bmWidth * 4, PixelFormat.Format32bppArgb, bitmapStruct.bmBits); // Show the bitmap this.BackgroundImage = managedBitmap; /* Run the program, use the image */ MessageBox.Show("running..."); // When the image is no longer needed, dispose both the managed Bitmap object and the native HBitmap this.BackgroundImage = null; managedBitmap.Dispose(); NativeMethods.DeleteObject(nativeHBitmap); } internal static class NativeMethods { [StructLayout(LayoutKind.Sequential)] public struct BITMAP { public int bmType; public int bmWidth; public int bmHeight; public int bmWidthBytes; public ushort bmPlanes; public ushort bmBitsPixel; public IntPtr bmBits; } [DllImport("gdi32", CharSet = CharSet.Auto, EntryPoint = "GetObject")] public static extern int GetObjectBitmap(IntPtr hObject, int nCount, ref BITMAP lpObject); [DllImport("gdi32.dll")] internal static extern bool DeleteObject(IntPtr hObject); }

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• WCF Self Host Service - Endpoints in C#

  - by Kyle

  My first few attempts at creating a self hosted service. Trying to make something up which will accept a query string and return some text but have have a few issues: All the documentation talks about endpoints being created automatically for each base address if they are not found in a config file. This doesn't seem to be the case for me, I get the "Service has zero application endpoints..." exception. Manually specifying a base endpoint as below seems to resolve this: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.ServiceModel; using System.ServiceModel.Description; namespace TestService { [ServiceContract] public interface IHelloWorldService { [OperationContract] string SayHello(string name); } public class HelloWorldService : IHelloWorldService { public string SayHello(string name) { return string.Format("Hello, {0}", name); } } class Program { static void Main(string[] args) { string baseaddr = "http://localhost:8080/HelloWorldService/"; Uri baseAddress = new Uri(baseaddr); // Create the ServiceHost. using (ServiceHost host = new ServiceHost(typeof(HelloWorldService), baseAddress)) { // Enable metadata publishing. ServiceMetadataBehavior smb = new ServiceMetadataBehavior(); smb.HttpGetEnabled = true; smb.MetadataExporter.PolicyVersion = PolicyVersion.Policy15; host.Description.Behaviors.Add(smb); host.AddServiceEndpoint(typeof(IHelloWorldService), new BasicHttpBinding(), baseaddr + "SayHello"); //for some reason a default endpoint does not get created here host.Open(); Console.WriteLine("The service is ready at {0}", baseAddress); Console.WriteLine("Press to stop the service."); Console.ReadLine(); // Close the ServiceHost. host.Close(); } } } } I still think I'm doing something wrong as I don't get the normal "This is a web service...etc..." page when I load up the url How would I go about setting this up to return the value of name in SayHello(string name) when requested thusly: localhost:8080/HelloWorldService/SayHello?name=kyle Do I have to create an endpoing for the SayHello contract as well? I'm trying to walk before running, but this just seems like crawling...Service has zero application endpoints...

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• Need to add totals of select list, and subtract if taken away

  - by jeremy

  This is the code I am using to calculate the sum of two values (example below) http://www.healthybrighton.co.uk/wse/node/1841 This works to a degree. It will add the two together but only if #edit-submitted-test is selected first, and even then it will show NaN until I select #edit-submitted-test-1. I want it to calculate the sum of the fields and show the amount live, i.e. the value of edit-submitted-test-1 will show 500, then if i select another field it will update to 1000. If i take one selection away it will then subtract it and will be back to 500. Any ideas would be helpful thanks! Drupal.behaviors.bookingForm = function (context) { // some debugging here, remove when you're finished console.log('[bookingForm] started.'); // get number of travelers and multiply it by 100 function recalculateTotal() { var count = $('#edit-submitted-test').val(); count = parseFloat( count ); var cost = $('#edit-submitted-test-1').val(); cost = parseFloat( cost ); $('#edit-submitted-total').val( count + cost ); } // run recalculateTotal every time user enters a new value var fieldCount = $('#edit-submitted-test'); var fieldCount = $('#edit-submitted-test-1'); fieldCount.change( recalculateTotal ); // etc ... }; EDIT This is all working beautiful, however I now want to add all the values together, and automatically update a total cost field that is the sum of a the added field with code above and field with value passed from previous page. I did this where accomcost is the field that is added together, but the total cost field does update, but not automatically, it is always one selection behind. i.e. If i select options and accomodation cost updates to £900, total cost remains empty. If i then change the selection and the accomodation updates to £300, the total cost updates to the previous selection of £900. Any help on this one Felix? ;) thanks. var accomcost = $('#edit-submitted-accomodation-cost').val(); accomcost = accomcost ? parseFloat(accomcost) : 0; var coursescost = $('#edit-submitted-courses-cost-2').val(); coursescost = coursescost ? parseFloat(coursescost) : 0; $('#edit-submitted-accomodation-cost').val( w1 + w2 + w3 + w4 + w5 + w6 + w7 + w8 + w9 + w10 + w11 + w12 + w13 + w14 + w15 + w16 + w17 + w18 + w19 + w20 + w21 + w22 + w23 + w24 + w25 + w26 + w27 + w28 + w29 + w30 ); $('#edit-submitted-total-cost').val( accomcost + coursescost ); var fieldCount = $('#edit-submitted-accomodation-cost, #edit-submitted-courses-cost-2') .change( recalculateTotal );

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• GHC.Generics and Type Families

  - by jberryman

  This is a question related to my module here, and is simplified a bit. It's also related to this previous question, in which I oversimplified my problem and didn't get the answer I was looking for. I hope this isn't too specific, and please change the title if you can think if a better one. Background My module uses a concurrent chan, split into a read side and write side. I use a special class with an associated type synonym to support polymorphic channel "joins": {-# LANGUAGE TypeFamilies #-} class Sources s where type Joined s newJoinedChan :: IO (s, Messages (Joined s)) -- NOT EXPORTED --output and input sides of channel: data Messages a -- NOT EXPORTED data Mailbox a instance Sources (Mailbox a) where type Joined (Mailbox a) = a newJoinedChan = undefined instance (Sources a, Sources b)=> Sources (a,b) where type Joined (a,b) = (Joined a, Joined b) newJoinedChan = undefined -- and so on for tuples of 3,4,5... The code above allows us to do this kind of thing: example = do (mb , msgsA) <- newJoinedChan ((mb1, mb2), msgsB) <- newJoinedChan --say that: msgsA, msgsB :: Messages (Int,Int) --and: mb :: Mailbox (Int,Int) -- mb1,mb2 :: Mailbox Int We have a recursive action called a Behavior that we can run on the messages we pull out of the "read" end of the channel: newtype Behavior a = Behavior (a -> IO (Behavior a)) runBehaviorOn :: Behavior a -> Messages a -> IO () -- NOT EXPORTED This would allow us to run a Behavior (Int,Int) on either of msgsA or msgsB, where in the second case both Ints in the tuple it receives actually came through separate Mailboxes. This is all tied together for the user in the exposed spawn function spawn :: (Sources s) => Behavior (Joined s) -> IO s ...which calls newJoinedChan and runBehaviorOn, and returns the input Sources. What I'd like to do I'd like users to be able to create a Behavior of arbitrary product type (not just tuples) , so for instance we could run a Behavior (Pair Int Int) on the example Messages above. I'd like to do this with GHC.Generics while still having a polymorphic Sources, but can't manage to make it work. spawn :: (Sources s, Generic (Joined s), Rep (Joined s) ~ ??) => Behavior (Joined s) -> IO s The parts of the above example that are actually exposed in the API are the fst of the newJoinedChan action, and Behaviors, so an acceptable solution can modify one or all of runBehaviorOn or the snd of newJoinedChan. I'll also be extending the API above to support sums (not implemented yet) like Behavior (Either a b) so I hoped GHC.Generics would work for me. Questions Is there a way I can extend the API above to support arbitrary Generic a=> Behavior a? If not using GHC's Generics, are there other ways I can get the API I want with minimal end-user pain (i.e. they just have to add a deriving clause to their type)?

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• Issues in Ajax based applications

  - by Sinuhe

  I'm very interested in developing Ajax based applications. This is, loading almost all of the content of the application via XMLHttpRequest, instead of only some combos and widgets. But if I try to do this form scratch, soon I find some problems without an easy solution. I wonder if there is some framework (both client and server side) to deal with this issues. As far as I know, there isn't (but I've searched mainly in Java world). So I am seriously thinking of doing my own framework, at least for my projects. Therefore, in this question I ask for several things. First, the possible problems of an ajax based development. Then, I'm looking for some framework or utility in order to deal with them. Finally, if there is no framework available, what features must it have. Here are the issues I thought: 1 - JavaScript must be enabled. Security paranoia isn't the only problem: a lot of mobile devices couldn't use the application, too. 2 - Sometimes you need to update more than one DIV (e.g. main content, menu and breadcrumbs). 3 - Unknown response type: when you make an Ajax call, you set the callback function too, usually specifying if expected response is a javascript object or in which DIV put the result. But this fails when you get another type of response: for example when the session has expired and the user must log in again. 4 - Browser's refresh, back and forward buttons can be a real pain. User will expect different behaviors depending on the situation. 5 - When search engines indexes a site, only follow links. Thus, content load by Ajax won't "exist" for who doesn't know about it yet. 6 - Users can ask for open a link in a different window/tab. 7 - Address bar doesn't show the "real" page you are in. So, you can't copy the location and send it to a friend or bookmark the page. 8 - If you want to monetize the site, you can put some advertisings. As you don't refresh entire page and you want to change the ad after some time, you have to refresh only the DIV where the ad is. But this can violate the Terms and Conditions of your ad service. In fact, it can go against AdSense TOS. 9 - When you refresh an entire page, all JavaScript gets "cleaned". But in Ajax calls, all JavaScript objects will remain. 10 - You can't easily change your CSS properties.

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• Showing div based on filled form field

  - by Fabio

  I have this script where I use a slider to show some elements of a form. So far so good. The way I'm doing it is by having a slider (can't use a multistep form since it uses a plugin not allowing multistep forms, plus some graphic behaviors) and a button that goes to the next slider. So now I need that button (not part of the form) to show only if a certain field is filled. I tried teh following, but it's not working, I assume some error but can't figure what. My code is as follows: $('#clientname').change(function() { var clientVal = $("input").val() == ''; $(".next").hide(); if ($('#clientname').val() != '').show(); else $('.next').hide(); }); and the html as follows: <div class="b40-right"> <h3>The Basics</h3> <div class="label"> Your Name (required)</div> <div class="inputes"> <span class="wpcf7-form-control-wrap your-name"><input id="clientname" type="text" name="your-name" value="" class="wpcf7-form-control wpcf7-text wpcf7-validates-as-required" size="40" /></span> </div> <div class="label">Your Email (required)</div> <div class="inputes"> <span class="wpcf7-form-control-wrap your-email"><input type="text" name="your-email" value="" class="wpcf7-form-control wpcf7-text wpcf7-email wpcf7-validates-as-required wpcf7-validates-as-email" size="40" /></span> </div> <div class="label">Type of Business</div> <div class="inputes"> <span class="wpcf7-form-control-wrap type-of-business"><textarea name="type-of-business" class="wpcf7-form-control wpcf7-textarea" cols="40" rows="10"></textarea></span> </div> </div> <a class="next" href="javascript:stepcarousel.stepBy('mygallery2', 1)"><img id="nextbut1" src="<?php bloginfo('template_directory'); ?>/images/next.png" alt="" /></a> any help on what am I doing wrong? Is there a better approach/solution? (I'm not a programmer as you may figure) Thank you in advance!

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• How do I mock/fake/replace/stub a base class at unit-test time in C#?

  - by MatthewMartin

  UPDATE: I've changed the wording of the question. Previously it was a yes/no question about if a base class could be changed at runtime. I may be working on mission impossible here, but I seem to be getting close. I want to extend a ASP.NET control, and I want my code to be unit testable. Also, I'd like to be able to fake behaviors of a real Label (namely things like ID generation, etc), which a real Label can't do in an nUnit host. Here a working example that makes assertions on something that depends on a real base class and something that doesn't-- in a more realistic unit test, the test would depend on both --i.e. an ID existing and some custom behavior. Anyhow the code says it better than I can: public class LabelWrapper : Label //Runtime //public class LabelWrapper : FakeLabel //Unit Test time { private readonly LabelLogic logic= new LabelLogic(); public override string Text { get { return logic.ProcessGetText(base.Text); } set { base.Text=logic.ProcessSetText(value); } } } //Ugh, now I have to test FakeLabelWrapper public class FakeLabelWrapper : FakeLabel //Unit Test time { private readonly LabelLogic logic= new LabelLogic(); public override string Text { get { return logic.ProcessGetText(base.Text); } set { base.Text=logic.ProcessSetText(value); } } } [TestFixture] public class UnitTest { [Test] public void Test() { //Wish this was LabelWrapper label = new LabelWrapper(new FakeBase()) LabelWrapper label = new LabelWrapper(); //FakeLabelWrapper label = new FakeLabelWrapper(); label.Text = "ToUpper"; Assert.AreEqual("TOUPPER",label.Text); StringWriter stringWriter = new StringWriter(); HtmlTextWriter writer = new HtmlTextWriter(stringWriter); label.RenderControl(writer); Assert.AreEqual(1,label.ID); Assert.AreEqual("<span>TOUPPER</span>", stringWriter.ToString()); } } public class FakeLabel { virtual public string Text { get; set; } public void RenderControl(TextWriter writer) { writer.Write("<span>" + Text + "</span>"); } } //System Under Test internal class LabelLogic { internal string ProcessGetText(string value) { return value.ToUpper(); } internal string ProcessSetText(string value) { return value.ToUpper(); } }

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• mySQL Optimization Suggestions

  - by Brian Schroeter

  I'm trying to optimize our mySQL configuration for our large Magento website. The reason I believe that mySQL needs to be configured further is because New Relic has shown that our SELECT queries are taking a long time (20,000+ ms) in some categories. I ran MySQLTuner 1.3.0 and got the following results... (Disclaimer: I restarted mySQL earlier after tweaking some settings, and so the results here may not be 100% accurate): >> MySQLTuner 1.3.0 - Major Hayden <[email protected]> >> Bug reports, feature requests, and downloads at http://mysqltuner.com/ >> Run with '--help' for additional options and output filtering [OK] Currently running supported MySQL version 5.5.37-35.0 [OK] Operating on 64-bit architecture -------- Storage Engine Statistics ------------------------------------------- [--] Status: +ARCHIVE +BLACKHOLE +CSV -FEDERATED +InnoDB +MRG_MYISAM [--] Data in MyISAM tables: 7G (Tables: 332) [--] Data in InnoDB tables: 213G (Tables: 8714) [--] Data in PERFORMANCE_SCHEMA tables: 0B (Tables: 17) [--] Data in MEMORY tables: 0B (Tables: 353) [!!] Total fragmented tables: 5492 -------- Security Recommendations ------------------------------------------- [!!] User '@host5.server1.autopartsnetwork.com' has no password set. [!!] User '@localhost' has no password set. [!!] User 'root@%' has no password set. -------- Performance Metrics ------------------------------------------------- [--] Up for: 5h 3m 4s (5M q [317.443 qps], 42K conn, TX: 18B, RX: 2B) [--] Reads / Writes: 95% / 5% [--] Total buffers: 35.5G global + 184.5M per thread (1024 max threads) [!!] Maximum possible memory usage: 220.0G (174% of installed RAM) [OK] Slow queries: 0% (6K/5M) [OK] Highest usage of available connections: 5% (61/1024) [OK] Key buffer size / total MyISAM indexes: 512.0M/3.1G [OK] Key buffer hit rate: 100.0% (102M cached / 45K reads) [OK] Query cache efficiency: 66.9% (3M cached / 5M selects) [!!] Query cache prunes per day: 3486361 [OK] Sorts requiring temporary tables: 0% (0 temp sorts / 812K sorts) [!!] Joins performed without indexes: 1328 [OK] Temporary tables created on disk: 11% (126K on disk / 1M total) [OK] Thread cache hit rate: 99% (61 created / 42K connections) [!!] Table cache hit rate: 19% (9K open / 49K opened) [OK] Open file limit used: 2% (712/25K) [OK] Table locks acquired immediately: 100% (5M immediate / 5M locks) [!!] InnoDB buffer pool / data size: 32.0G/213.4G [OK] InnoDB log waits: 0 -------- Recommendations ----------------------------------------------------- General recommendations: Run OPTIMIZE TABLE to defragment tables for better performance MySQL started within last 24 hours - recommendations may be inaccurate Reduce your overall MySQL memory footprint for system stability Enable the slow query log to troubleshoot bad queries Increasing the query_cache size over 128M may reduce performance Adjust your join queries to always utilize indexes Increase table_cache gradually to avoid file descriptor limits Read this before increasing table_cache over 64: http://bit.ly/1mi7c4C Variables to adjust: *** MySQL's maximum memory usage is dangerously high *** *** Add RAM before increasing MySQL buffer variables *** query_cache_size (> 512M) [see warning above] join_buffer_size (> 128.0M, or always use indexes with joins) table_cache (> 12288) innodb_buffer_pool_size (>= 213G) My my.cnf configuration is as follows... [client] port = 3306 [mysqld_safe] nice = 0 [mysqld] tmpdir = /var/lib/mysql/tmp user = mysql port = 3306 skip-external-locking character-set-server = utf8 collation-server = utf8_general_ci event_scheduler = 0 key_buffer = 512M max_allowed_packet = 64M thread_stack = 512K thread_cache_size = 512 sort_buffer_size = 24M read_buffer_size = 8M read_rnd_buffer_size = 24M join_buffer_size = 128M # for some nightly processes client sessions set the join buffer to 8 GB auto-increment-increment = 1 auto-increment-offset = 1 myisam-recover = BACKUP max_connections = 1024 # max connect errors artificially high to support behaviors of NetScaler monitors max_connect_errors = 999999 concurrent_insert = 2 connect_timeout = 5 wait_timeout = 180 net_read_timeout = 120 net_write_timeout = 120 back_log = 128 # this table_open_cache might be too low because of MySQL bugs #16244691 and #65384) table_open_cache = 12288 tmp_table_size = 512M max_heap_table_size = 512M bulk_insert_buffer_size = 512M open-files-limit = 8192 open-files = 1024 query_cache_type = 1 # large query limit supports SOAP and REST API integrations query_cache_limit = 4M # larger than 512 MB query cache size is problematic; this is typically ~60% full query_cache_size = 512M # set to true on read slaves read_only = false slow_query_log_file = /var/log/mysql/slow.log slow_query_log = 0 long_query_time = 0.2 expire_logs_days = 10 max_binlog_size = 1024M binlog_cache_size = 32K sync_binlog = 0 # SSD RAID10 technically has a write capacity of 10000 IOPS innodb_io_capacity = 400 innodb_file_per_table innodb_table_locks = true innodb_lock_wait_timeout = 30 # These servers have 80 CPU threads; match 1:1 innodb_thread_concurrency = 48 innodb_commit_concurrency = 2 innodb_support_xa = true innodb_buffer_pool_size = 32G innodb_file_per_table innodb_flush_log_at_trx_commit = 1 innodb_log_buffer_size = 2G skip-federated [mysqldump] quick quote-names single-transaction max_allowed_packet = 64M I have a monster of a server here to power our site because our catalog is very large (300,000 simple SKUs), and I'm just wondering if I'm missing anything that I can configure further. :-) Thanks!

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• Blend for Visual Studio 2013 Prototyping Applications with SketchFlow

  - by T

  Originally posted on: http://geekswithblogs.net/tburger/archive/2014/08/10/blend-for-visual-studio-2013-prototyping-applications-with-sketchflow.aspxSketchFlow enables rapid creating of dynamic interface mockups very quickly. The SketchFlow workspace is the same as the standard Blend workspace with the inclusion of three panels: the SketchFlow Feedback panel, the SketchFlow Animation panel and the SketchFlow Map panel. By using SketchFlow to prototype, you can get feedback early in the process. It helps to surface possible issues, lower development iterations, and increase stakeholder buy in. SketchFlow prototypes not only provide an initial look but also provide a way to add additional ideas and input and make sure the team is on track prior to investing in complete development. When you have completed the prototyping, you can discard the prototype and just use the lessons learned to design the application from or extract individual elements from your prototype and include them in the application. I don’t recommend trying to transition the entire project into a development project. Objects that you add with the SketchFlow style have a hand-sketched look. The sketch style is used to remind stakeholders that this is a prototype. This encourages them to focus on the flow and functionality without getting distracted by design details. The sketchflow assets are under sketchflow in the asset panel and are identifiable by the postfix “–Sketch”. For example “Button-Sketch”. You can mix sketch and standard controls in your interface, if required. Be creative, if there is a missing control or your interface has a different look and feel than the out of the box one, reuse other sketch controls to mimic the functionality or look and feel. Only use standard controls if it doesn’t distract from the idea that this is a prototype and not a standard application. The SketchFlow Map panel provides information about the structure of your application. To create a new screen in your prototype: Right-click the map surface and choose “Create a Connected Screen”. Name the screens with names that are meaningful to the stakeholders. The start screen is the one that has the green arrow. To change the start screen, right click on any other screen and set to start screen. Only one screen can be the start screen at a time. Rounded screen are component screens to mimic reusable custom controls that will be built into the final application. You can change the colors of all of the boxes and should use colors to create functional groupings. The groupings can be identified in the SketchFlow Project Settings. To add connections between screens in the SketchFlow Map panel. Move the mouse over a screen in the SketchFlow and a menu will appear at the bottom of the screen node. In the menu, click Connect to an existing screen. Drag the arrow to another screen on the Map. You add navigation to your prototype by adding connections on the SketchFlow map or by adding navigation directly to items on your interface. To add navigation from objects on the artboard, right click the item then from the menu, choose “Navigate to”. This will expose a sub-menu with available screens, backward, or forward. When the map has connected screens, the SketchFlow Player displays the connected screens on the Navigate sidebar. All screens show in the SketchFlow Player Map. To see the SketchFlow Player, run your SketchFlow prototype. The Navigation sidebar is meant to show the desired user work flow. The map can be used to view the different screens regardless of suggested navigation in the navigation bar. The map is able to be hidden and shown. As mentioned, a component screen is a shared screen that is used in more than one screen and generally represents what will be a custom object in the application. To create a component screen, you can create a screen, right click on it in the SketchFlow Map and choose “Make into component screen”. You can mouse over a screen and from the menu that appears underneath, choose create and insert component screen. To use an existing screen, select if from the Asset panel under SketchFlow, Components. You can use Storyboards and Visual State animations in your SketchFlow project. However, SketchFlow also offers its own animation technique that is simpler and better suited for prototyping. The SketchFlow Animation panel is above your artboard by default. In SketchFlow animation, you create frames and then position the elements on your interface for each frame. You then specify elapsed time and any effects you want to apply to the transition. The + at the top is what creates new frames. Once you have a new Frame, select it and change the property you want to animate. In the example above, I changed the Text of the result box. You can adjust the time between frames in the lower area between the frames. The easing and effects functions are changed in the center between each frame. You edit the hold time for frames by clicking the clock icon in the lower left and the hold time will appear on each frame and can be edited. The FluidLayout icon (also located in the lower left) will create smooth transitions. Next to the FluidLayout icon is the name of that Animation. You can rename the animation by clicking on it and editing the name. The down arrow chevrons next to the name allow you to view the list of all animations in this prototype and select them for editing. To add the animation to the interface object (such as a button to start the animation), select the PlaySketchFlowAnimationAction from the SketchFlow behaviors in the Assets menu and drag it to an object on your interface. With the PlaySketchFlowAnimationAction that you just added selected in the Objects and Timeline, edit the properties to change the EventName to the event you want and choose the SketchFlowAnimation you want from the drop down list. You may want to add additional information to your screens that isn’t really part of the prototype but is relevant information or a request for clarification or feedback from the reviewer. You do this with annotations or notes. Both appear on the user interface, however, annotations can be switched on or off at design and review time. Notes cannot be switched off. To add an Annotation, chose the Create Annotation from the Tools menu. The annotation appears on the UI where you will add the notes. To display or Hide annotations, click the annotation toggle at the bottom right on the artboard . After to toggle annotations on, the identifier of the person who created them appears on the artboard and you must click that to expand the notes. To add a note to the artboard, simply select the Note-Sketch from Assets ->SketchFlow ->Styles ->Sketch Styles. Drag and drop it to the artboard and place where you want it. When you are ready for users to review the prototype, you have a few options available. Click File -> Export and choose one of the options from the list: Publish to Sharepoint, Package SketchFlowProject, Export to Microsoft Word, or Export as Images. I suggest you play with as many of the options as you can to see what they do. Both the Sharepoint and Packaged SketchFlowProject allow you to collect feedback from one or more users that you can import into the project. The user can make notes on the UI and in the Feedback area in the bottom left corner of the player. When the user is done adding feedback, it is exported from the right most folder icon in the My Feedback panel. Feeback is imported on a panel named SketchFlow Feedback. To get that panel to show up, select Window -> SketchFlow Feedback. Once you have the panel showing, click the + in the upper right of the panel and find the notes you exported. When imported, they will show up in a list and on the artboard. To document your prototype, use the Export to Microsoft Word option from the File menu. That should get you started with prototyping.

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• Big Data – Is Big Data Relevant to me? – Big Data Questionnaires – Guest Post by Vinod Kumar

  - by Pinal Dave

  This guest post is by Vinod Kumar. Vinod Kumar has worked with SQL Server extensively since joining the industry over a decade ago. Working on various versions of SQL Server 7.0, Oracle 7.3 and other database technologies – he now works with the Microsoft Technology Center (MTC) as a Technology Architect. Let us read the blog post in Vinod’s own voice. I think the series from Pinal is a good one for anyone planning to start on Big Data journey from the basics. In my daily customer interactions this buzz of “Big Data” always comes up, I react generally saying – “Sir, do you really have a ‘Big Data’ problem or do you have a big Data problem?” Generally, there is a silence in the air when I ask this question. Data is everywhere in organizations – be it big data, small data, all data and for few it is bad data which is same as no data :). Wow, don’t discount me as someone who opposes “Big Data”, I am a big supporter as much as I am a critic of the abuse of this term by the people. In this post, I wanted to let my mind flow so that you can also think in the direction I want you to see these concepts. In any case, this is not an exhaustive dump of what is in my mind – but you will surely get the drift how I am going to question Big Data terms from customers!!! Is Big Data Relevant to me? Many of my customers talk to me like blank whiteboard with no idea – “why Big Data”. They want to jump into the bandwagon of technology and they want to decipher insights from their unexplored data a.k.a. unstructured data with structured data. So what are these industry scenario’s that come to mind? Here are some of them: Financials Fraud detection: Banks and Credit cards are monitoring your spending habits on real-time basis. Customer Segmentation: applies in every industry from Banking to Retail to Aviation to Utility and others where they deal with end customer who consume their products and services. Customer Sentiment Analysis: Responding to negative brand perception on social or amplify the positive perception. Sales and Marketing Campaign: Understand the impact and get closer to customer delight. Call Center Analysis: attempt to take unstructured voice recordings and analyze them for content and sentiment. Medical Reduce Re-admissions: How to build a proactive follow-up engagements with patients. Patient Monitoring: How to track Inpatient, Out-Patient, Emergency Visits, Intensive Care Units etc. Preventive Care: Disease identification and Risk stratification is a very crucial business function for medical. Claims fraud detection: There is no precise dollars that one can put here, but this is a big thing for the medical field. Retail Customer Sentiment Analysis, Customer Care Centers, Campaign Management. Supply Chain Analysis: Every sensors and RFID data can be tracked for warehouse space optimization. Location based marketing: Based on where a check-in happens retail stores can be optimize their marketing. Telecom Price optimization and Plans, Finding Customer churn, Customer loyalty programs Call Detail Record (CDR) Analysis, Network optimizations, User Location analysis Customer Behavior Analysis Insurance Fraud Detection & Analysis, Pricing based on customer Sentiment Analysis, Loyalty Management Agents Analysis, Customer Value Management This list can go on to other areas like Utility, Manufacturing, Travel, ITES etc. So as you can see, there are obviously interesting use cases for each of these industry verticals. These are just representative list. Where to start? A lot of times I try to quiz customers on a number of dimensions before starting a Big Data conversation. Are you getting the data you need the way you want it and in a timely manner? Can you get in and analyze the data you need? How quickly is IT to respond to your BI Requests? How easily can you get at the data that you need to run your business/department/project? How are you currently measuring your business? Can you get the data you need to react WITHIN THE QUARTER to impact behaviors to meet your numbers or is it always “rear-view mirror?” How are you measuring: The Brand Customer Sentiment Your Competition Your Pricing Your performance Supply Chain Efficiencies Predictive product / service positioning What are your key challenges of driving collaboration across your global business?  What the challenges in innovation? What challenges are you facing in getting more information out of your data? Note: Garbage-in is Garbage-out. Hold good for all reporting / analytics requirements Big Data POCs? A number of customers get into the realm of setting a small team to work on Big Data – well it is a great start from an understanding point of view, but I tend to ask a number of other questions to such customers. Some of these common questions are: To what degree is your advanced analytics (natural language processing, sentiment analysis, predictive analytics and classification) paired with your Big Data’s efforts? Do you have dedicated resources exploring the possibilities of advanced analytics in Big Data for your business line? Do you plan to employ machine learning technology while doing Advanced Analytics? How is Social Media being monitored in your organization? What is your ability to scale in terms of storage and processing power? Do you have a system in place to sort incoming data in near real time by potential value, data quality, and use frequency? Do you use event-driven architecture to manage incoming data? Do you have specialized data services that can accommodate different formats, security, and the management requirements of multiple data sources? Is your organization currently using or considering in-memory analytics? To what degree are you able to correlate data from your Big Data infrastructure with that from your enterprise data warehouse? Have you extended the role of Data Stewards to include ownership of big data components? Do you prioritize data quality based on the source system (that is Facebook/Twitter data has lower quality thresholds than radio frequency identification (RFID) for a tracking system)? Do your retention policies consider the different legal responsibilities for storing Big Data for a specific amount of time? Do Data Scientists work in close collaboration with Data Stewards to ensure data quality? How is access to attributes of Big Data being given out in the organization? Are roles related to Big Data (Advanced Analyst, Data Scientist) clearly defined? How involved is risk management in the Big Data governance process? Is there a set of documented policies regarding Big Data governance? Is there an enforcement mechanism or approach to ensure that policies are followed? Who is the key sponsor for your Big Data governance program? (The CIO is best) Do you have defined policies surrounding the use of social media data for potential employees and customers, as well as the use of customer Geo-location data? How accessible are complex analytic routines to your user base? What is the level of involvement with outside vendors and third parties in regard to the planning and execution of Big Data projects? What programming technologies are utilized by your data warehouse/BI staff when working with Big Data? These are some of the important questions I ask each customer who is actively evaluating Big Data trends for their organizations. These questions give you a sense of direction where to start, what to use, how to secure, how to analyze and more. Sign off Any Big data is analysis is incomplete without a compelling story. The best way to understand this is to watch Hans Rosling – Gapminder (2:17 to 6:06) videos about the third world myths. Don’t get overwhelmed with the Big Data buzz word, the destination to what your data speaks is important. In this blog post, we did not particularly look at any Big Data technologies. This is a set of questionnaire one needs to keep in mind as they embark their journey of Big Data. I did write some of the basics in my blog: Big Data – Big Hype yet Big Opportunity. Do let me know if these questions make sense?  Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• CodePlex Daily Summary for Monday, May 03, 2010

  CodePlex Daily Summary for Monday, May 03, 2010New Projects.radiko: エアログラス採用のシンプルなradiko(http://radiko.jp/)クライアントです。タスクトレイのアイコンからラジオ局の切り替えができます。7Scale: EmptyB2C MVC Plattform: The B2C MVC Plattform aims to be pluggable site framework to help small busisness accomplish basic tasks between business and customers.ElValWeb: The goal of the project to create full featured implementation of ModelValidatorProvider for Enterprise Library Application Validation Block, wich ...esatis yazilimi: asp.net yazılımı ile satış magazasi websitesi kur.IEnumerable.It sample code: IEnumerable.It sample codejQuery MicroAjax for ASP.NET: MicroAjax is a set of jQuery plugins and .NET components designed to provide simple, powerful and efficient Ajax centric web application design pat...Karbon VOS: Karbon VOS is an advanced Virtual Operating System Template for Visual Basic Express. It's developed in Visual Basic. Karbon VOS hopes to one day b...LINQ Mapper: LINQ Mapper translates simple LINQ queries between different sources. It allows you to write queries against your domain model, but have them run ...Meccano Silverlight Framework: Meccano is a new generation of frameworks for creation of LOB Silverlight applications based on MEF, RX, WCF, ADO.NET Data Services etc. It is inte...Multiuse Model View (MMV) Library: This project is an open source library for the Multiuse Model View (MMV) pattern for building robust WPF and ASP.Net applications. Visit my blog ht...Process Affinity Control: Process Affinity Control allows to set the affinity masks of processes based on rules.SilverSpatial: This project helps bridge the gap between Silverlight and Geo-Spatial data type (such as SQL Spatial). It implements the Well-Known-Binary (WKB) fo...StageAssets: Application for storing data about "things" and people in theatre. For example equipment, actors and so on.Stratosphere: Mono compatible library with set of primitives to work with scalable table, queue and block containers with corresponding implementations for Amazo...TRX Web-Viewer: A simple web-based application to upload and view VSTS 2008 and VSTS 2010 test result files with some basic lookup and feature-wise management of r...WDT2: WDT 2 is the school project to begin learning .NET enviroment, The main focus is on learning the use of almost all the componenets.WPF Behavior Library: WPF Behavior Library is a set of additional actions for WPF that allow you to add extra behaviors to a control quickly and easily. Currently the on...YouTubeEmbeddedVideo WebControl for ASP.NET: A Control to embed YouTube videos in ASP.NET pages. Works in C# and VB.NETNew Releases.radiko: beta: 東京局のみ対応 あとは手抜きActiveWorlds Managed .NET SDK: AwManaged Technology Preview - WIN32 (Alpha): This WIN32 release contains the Server Console Application. The Setup executable should be run as administrator on O.S. using UAC (Vista/Win7)AJAX Control Framework: v1.0.1.0: v1.0.1.0 - Contains a Bing Maps sample project, a number of bug fixes and a few performance improvements. - AJAX enable ANY custom control that der...App_Code (and Usercontrol) Editor (ACE): v1.0.0 alpha: The first alpha release of the AppCode Editor for Umbraco 4.0.3 is now available to download! Tested to work with usercontrols - pre-compilation wi...ElValWeb: ElValWeb 0.0.1.0: Version 0.0.1.0 contains client validation support forAndCompositeValidator ContainsCharactersValidator DomainValidator NotNullValidator Or...esatis yazilimi: magaza: magazanın yazılımları ve veri tabanının yazılımlarıGrunty OS: Grunty OS USB: Download Grunty OS for USBGrunty OS: Grunty OS.ISO: Grunty OS ISOKarbon VOS: Milestone 1 (Kaptua): Milestone 1...Live Meeting API Wrapper: LiveMeetingAPIWrapperV1.2: Added get meeting and update meeting.Multiuse Model View (MMV) Library: v0.3: first alpha release. Medium amount of functionality and some use cases tested.MVC Foolproof Validation: Beta 0.9.3774: Adds resource provided error messages, regular expression operators and a new RegularExpressionIf attribute.Process Affinity Control: Version 1.0.0: This is the first release. Planned features for the next release: No administrative privileges needed to run the manager Select the active scena...SharePoint 2010 Service Manager: SharePoint 2010 Service Manager 1.1: Added support to run under UAC with automatic security elevationSharePoint Event Handler Manager: Event Handler Manager 2.0: Please download the application here: http://www.ackermantech.com/registerevents.aspxSkyDrive Synchronizer: SkyDrive Sync Beta 0.1: Beta release includes: Upload and download Synchronize updated files Delete files on web/locally if not in source Split larger files into sma...Stratosphere: Stratosphere 1.0.0.0: Initial beta releaseSuggested Resources for .NET Developers: 0.8.0.0 VS2010 - focus on displaying content: This is the first release of Suggested Resources that can be downloaded from the internet. While there is still a lot of work to be done this rele...TRX Web-Viewer: TRX Web-Viewer V1.0: First working versionVCC: Latest build, v2.1.30502.0: Automatic drop of latest buildWatchersNET.TagCloud: WatchersNET.TagCloud 01.04.00: !Whats New New Tag Mode: Search Referrers (Shows Search Tags From Google, Ask, Bing, Yahoo and the Dnn Site Search) Taxonomy Tags now contains L...Web/Cloud Applications Development Framework | Visual WebGui: 6.4 Beta 2e: Fully featured beta version of Visual WebGui Web/Cloud Applicaiton Development FrameworkWPF Behavior Library: WPF Behavior Library 0.1 Release: First alpha release of the WPF Behavior Library. It should be stable but doesn't have all of the features it will have in the future and the API ma...xvanneste: Sharepoint Social Network Client: Client permettant d'avoir accés au social network de sharepoint a l'exterieur du navigateur.Most Popular ProjectsRawrWBFS ManagerAJAX Control Toolkitpatterns & practices – Enterprise LibraryMicrosoft SQL Server Product Samples: DatabaseSilverlight ToolkitWindows Presentation Foundation (WPF)iTuner - The iTunes CompanionASP.NETDotNetNuke® Community EditionMost Active ProjectsIonics Isapi Rewrite Filterpatterns & practices – Enterprise LibraryRawrHydroServer - CUAHSI Hydrologic Information System ServerAJAX Control Frameworkpatterns & practices: Azure Security GuidanceTinyProjectBlogEngine.NETNB_Store - Free DotNetNuke Ecommerce Catalog ModuleDambach Linear Algebra Framework

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• Setup and Use SpecFlow BDD with DevExpress XAF

  - by Patrick Liekhus

  Let’s get started with using the SpecFlow BDD syntax for writing tests with the DevExpress XAF EasyTest scripting syntax.  In order for this to work you will need to download and install the prerequisites listed below.  Once they are installed follow the steps outlined below and enjoy. Prerequisites Install the following items: DevExpress eXpress Application Framework (XAF) found here SpecFlow found here Liekhus BDD/XAF Testing library found here Assumptions I am going to assume at this point that you have created your XAF application and have your Module, Win.Module and Win ready for usage.  You should have also set any attributes and/or settings as you see fit. Setup So where to start. Create a new testing project within your solution. I typically call this with a similar naming convention as used by XAF, my project name .FunctionalTests (i.e. AlbumManager.FunctionalTests). Add the following references to your project.  It should look like the reference list below. DevExpress.Data.v11.x DevExpress.Persistent.Base.v11.x DevExpress.Persistent.BaseImpl.v11.x DevExpress.Xpo.v11.2 Liekhus.Testing.BDD.Core Liekhus.Testing.BDD.DevExpress TechTalk.SpecFlow TestExecutor.v11.x (found in %Program Files%\DevExpress 2011.x\eXpressApp Framework\Tools\EasyTest Right click the TestExecutor reference and set the “Copy Local” setting to True.  This forces the TestExecutor executable to be available in the bin directory which is where the EasyTest script will be executed further down in the process. Add an Application Configuration File (app.config) to your test application.  You will need to make a few modifications to have SpecFlow generate Microsoft style unit tests.  First add the section handler for SpecFlow and then set your choice of testing framework.  I prefer MS Tests for my projects. Add the EasyTest configuration file to your project.  Add a new XML file and call it Config.xml. Open the properties window for the Config.xml file and set the “Copy to Ouput Directory” to “Copy Always”. You will setup the Config file according to the specifications of the EasyTest library my mapping to your executable and other settings.  You can find the details for the configuration of EasyTest here.  My file looks like this Create a new folder in your test project called “StepDefinitions”.  Add a new SpecFlow Step Definition file item under the StepDefinitions folder.  I typically call this class StepDefinition.cs. Have your step definition inherit from the Liekhus.Testing.BDD.DevExpress.StepDefinition class.  This will give you the default behaviors for your test in the next section. OK.  Now that we have done this series of steps, we will work on simplifying this.  This is an early preview of this new project and is not fully ready for consumption.  If you would like to experiment with it, please feel free.  Our goals are to make this a installable project on it’s own with it’s own project templates and default settings.  This will be coming in later versions.  Currently this project is in Alpha release. Let’s write our first test Remove the basic test that is created for you. We will not use the default test but rather create our own SpecFlow “Feature” files. Add a new item to your project and select the SpecFlow Feature file under C#. Name your feature file as you do your class files after the test they are performing. Writing a feature file uses the Cucumber syntax of Given… When… Then.  Think of it in these terms.  Givens are the pre-conditions for the test.  The Whens are the actual steps for the test being performed.  The Thens are the verification steps that confirm your test either passed or failed.  All of these steps are generated into a an EasyTest format and executed against your XAF project.  You can find more on the Cucumber syntax by using the Secret Ninja Cucumber Scrolls.  This document has several good styles of tests, plus you can get your fill of Chuck Norris vs Ninjas.  Pretty humorous document but full of great content. My first test is going to test the entry of a new Album into the application and is outlined below. The Feature section at the top is more for your documentation purposes.  Try to be descriptive of the test so that it makes sense to the next person behind you.  The Scenario outline is described in the Ninja Scrolls, but think of it as test template.  You can write one test outline and have multiple datasets (Scenarios) executed against that test.  Here are the steps of my test and their descriptions Given I am starting a new test – tells our test to create a new EasyTest file And (Given) the application is open – tells EasyTest to open our application defined in the Config.xml When I am at the “Albums” screen – tells XAF to navigate to the Albums list view And (When) I click the “New:Album” button – tells XAF to click the New Album button on the ribbon And (When) I enter the following information – tells XAF to find the field on the screen and put the value in that field And (When) I click the “Save and Close” button – tells XAF to click the “Save and Close” button on the detail window Then I verify results as “user” – tells the testing framework to execute the EasyTest as your configured user Once you compile and prepare your tests you should see the following in your Test View.  For each of your CreateNewAlbum lines in your scenarios, you will see a new test ready to execute. From here you will use your testing framework of choice to execute the test.  This in turn will execute the EasyTest framework to call back into your XAF application and test your business application. Again, please remember that this is an early preview and we are still working out the details.  Please let us know if you have any comments/questions/concerns. Thanks and happy testing.

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• CodePlex Daily Summary for Monday, July 01, 2013

  CodePlex Daily Summary for Monday, July 01, 2013Popular ReleasesQuickMon: Version 2.10.3: Mainly just a service release - no major changes. Toolbar buttons on main and config window can now be re-arrange (using ALT key) Added property to disable corrective scriptsDotNetNuke® IFrame: IFrame 04.05.00: New DNN6/7 Manifest file and Azure Compatibility.VidCoder: 1.5.2 Beta: Fixed crash on presets with an invalid bitrate.Roadkill - .NET Wiki engine: Roadkill v1.7: New features in 1.7: New file manager: Multiple file uploads Drag and drop uploads Delete folders (admins only) Delete files (admins only) (Experimental) Syntaxhighlighting custom variable (using https://github.com/alexgorbatchev/SyntaxHighlighter) - use [[[code lang=c#|your code here]]] (Experimental) MathJax custom variable - use [[[Mathjax]]] and $$your tex$$ on the page. Improved black bar theme Site speed improvements for Javascript/CSS files - now just two files files ea...Download Sharepoint Solution package: Release 4: version updated for SP2013WinRT XAML Toolkit: WinRT XAML Toolkit - 1.5: WinRT XAML Toolkit based on the Windows 8.0 and 8.1 Preview SDKs. Do not download the source code from here if you are looking for latest updates! You can download the latest source from the SOURCE CODE page. For compiled version use NuGet. You can add it to your project in Visual Studio by going to View/Other Windows/Package Manager Console and entering: PM> Install-Package winrtxamltoolkit Features Attachable Behaviors AwaitableUI extensions Composition library for visual tree rende...Gardens Point LEX: Gardens Point LEX version 1.2.1: The main distribution is a zip file. This contains the binary executable, documentation, source code and the examples. ChangesVersion 1.2.1 has new facilities for defining and manipulating character classes. These changes make the construction of large Unicode character classes more convenient. The runtime code for performing automaton backup has been re-implemented, and is now faster for scanners that need backup. Source CodeThe distribution contains a complete VS2010 project for the appli...ZXMAK2: Version 2.7.5.7: - fix TZX emulation (Bruce Lee, Zynaps) - fix ATM 16 colors for border - add memory module PROFI 512K; add PROFI V03 rom image; fix PROFI 3.XX configTwitter image Downloader: Twitter Image Downloader 2 with Installer: Application file with Install shield and Dot Net 4.0 redistributableUltimate Music Tagger: Ultimate Music Tagger 1.0.0.0: First release of Ultimate Music TaggerBlackJumboDog: Ver5.9.2: 2013.06.28 Ver5.9.2 (1) ??????????(????SMTP?????)?????????? (2) HTTPS???????????Outlook 2013 Add-In: Configuration Form: This new version includes the following changes: - Refactored code a bit. - Removing configuration from main form to gain more space to display items. - Moved configuration to separate form. You can click the little "gear" icon to access the configuration form (still very simple). - Added option to show past day appointments from the selected day (previous in time, that is). - Added some tooltips. You will have to uninstall the previous version (add/remove programs) if you had installed it ...Terminals: Version 3.0 - Release: Changes since version 2.0:Choose 100% portable or installed version Removed connection warning when running RDP 8 (Windows 8) client Fixed Active directory search Extended Active directory search by LDAP filters Fixed single instance mode when running on Windows Terminal server Merged usage of Tags and Groups Added columns sorting option in tables No UAC prompts on Windows 7 Completely new file persistence data layer New MS SQL persistence layer (Store data in SQL database)...NuGet: NuGet 2.6: Released June 26, 2013. Release notes: http://docs.nuget.org/docs/release-notes/nuget-2.6Python Tools for Visual Studio: 2.0 Beta: We’re pleased to announce the release of Python Tools for Visual Studio 2.0 Beta. Python Tools for Visual Studio (PTVS) is an open-source plug-in for Visual Studio which supports programming with the Python language. PTVS supports a broad range of features including CPython/IronPython, Edit/Intellisense/Debug/Profile, Cloud, HPC, IPython, and cross platform debugging support. For a quick overview of the general IDE experience, please watch this video: http://www.youtube.com/watch?v=TuewiStN...Player Framework by Microsoft: Player Framework for Windows 8 and WP8 (v1.3 beta): Preview: New MPEG DASH adaptive streaming plugin for Windows Azure Media Services Preview: New Ultraviolet CFF plugin. Preview: New WP7 version with WP8 compatibility. (source code only) Source code is now available via CodePlex Git Misc bug fixes and improvements: WP8 only: Added optional fullscreen and mute buttons to default xaml JS only: protecting currentTime from returning infinity. Some videos would cause currentTime to be infinity which could cause errors in plugins expectin...AssaultCube Reloaded: 2.5.8: SERVER OWNERS: note that the default maprot has changed once again. Linux has Ubuntu 11.10 32-bit precompiled binaries and Ubuntu 10.10 64-bit precompiled binaries, but you can compile your own as it also contains the source. If you are using Mac or other operating systems, please wait while we continue to try to package for those OSes. Or better yet, try to compile it. If it fails, download a virtual machine. The server pack is ready for both Windows and Linux, but you might need to compi...Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.95: update parser to allow for CSS3 calc( function to nest. add recognition of -pponly (Preprocess-Only) switch in AjaxMinManifestTask build task. Fix crashing bug in EXE when processing a manifest file using the -xml switch and an error message needs to be displayed (like a missing input file). Create separate Clean and Bundle build tasks for working with manifest files (AjaxMinManifestCleanTask and AjaxMinBundleTask). Removed the IsCleanOperation from AjaxMinManifestTask -- use AjaxMinMan...VG-Ripper & PG-Ripper: VG-Ripper 2.9.44: changes NEW: Added Support for "ImgChili.net" links FIXED: Auto UpdaterDocument.Editor: 2013.25: What's new for Document.Editor 2013.25: Improved Spell Check support Improved User Interface Minor Bug Fix's, improvements and speed upsNew ProjectsAerCloud.net Client - Java, Linux & Windows: This project source code provides a step by step guide for using AerCloud.net Framework as a Service API. For more information please visit http://www.aercloudAmiClient – Asterisk Manager Interface (AMI) client based on the Rx Framework: Asterisk Manager Interface (AMI) client based on the Rx Frameworkbaidupan: cdcddddC#??????: C#??????ImageHelper: imagehelperIP switcher: IP switcher is a simple tool for switching settings, and store presets, on networkadapters.MastersProject: A MS project with a goal of creating a fully Code Contracts verified physics engine and a relatively simple game that uses it.Multiplatform card game: Example multipatform project.PhoneTools: A collection of tools designed to help developers create beautiful Windows Phone 8 apps.rodidexter: lllSharePoint 2013 List Item Encryption: This coding exercise project enables you to encrypt/decrypt list item text field in the browser using industry standard algorithms.tvaSoft: simulation, rotor dynamics, Finite Element Analisys, FEM, ODE, torsional vibration, flexural vibrationX3DML Project: X3DML is an xml-based markup language that defines rules for modeling 3D scenes from a tag-based document. It may be usefull in 3D web design and VR.zhuang-tfs: zhuang tfs

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• Writing the tests for FluentPath

  - by Bertrand Le Roy

  Writing the tests for FluentPath is a challenge. The library is a wrapper around a legacy API (System.IO) that wasn’t designed to be easily testable. If it were more testable, the sensible testing methodology would be to tell System.IO to act against a mock file system, which would enable me to verify that my code is doing the expected file system operations without having to manipulate the actual, physical file system: what we are testing here is FluentPath, not System.IO. Unfortunately, that is not an option as nothing in System.IO enables us to plug a mock file system in. As a consequence, we are left with few options. A few people have suggested me to abstract my calls to System.IO away so that I could tell FluentPath – not System.IO – to use a mock instead of the real thing. That in turn is getting a little silly: FluentPath already is a thin abstraction around System.IO, so layering another abstraction between them would double the test surface while bringing little or no value. I would have to test that new abstraction layer, and that would bring us back to square one. Unless I’m missing something, the only option I have here is to bite the bullet and test against the real file system. Of course, the tests that do that can hardly be called unit tests. They are more integration tests as they don’t only test bits of my code. They really test the successful integration of my code with the underlying System.IO. In order to write such tests, the techniques of BDD work particularly well as they enable you to express scenarios in natural language, from which test code is generated. Integration tests are being better expressed as scenarios orchestrating a few basic behaviors, so this is a nice fit. The Orchard team has been successfully using SpecFlow for integration tests for a while and I thought it was pretty cool so that’s what I decided to use. Consider for example the following scenario: Scenario: Change extension Given a clean test directory When I change the extension of bar\notes.txt to foo Then bar\notes.txt should not exist And bar\notes.foo should exist This is human readable and tells you everything you need to know about what you’re testing, but it is also executable code. What happens when SpecFlow compiles this scenario is that it executes a bunch of regular expressions that identify the known Given (set-up phases), When (actions) and Then (result assertions) to identify the code to run, which is then translated into calls into the appropriate methods. Nothing magical. Here is the code generated by SpecFlow: [NUnit.Framework.TestAttribute()] [NUnit.Framework.DescriptionAttribute("Change extension")] public virtual void ChangeExtension() { TechTalk.SpecFlow.ScenarioInfo scenarioInfo = new TechTalk.SpecFlow.ScenarioInfo("Change extension", ((string[])(null))); #line 6 this.ScenarioSetup(scenarioInfo); #line 7 testRunner.Given("a clean test directory"); #line 8 testRunner.When("I change the extension of " + "bar\\notes.txt to foo"); #line 9 testRunner.Then("bar\\notes.txt should not exist"); #line 10 testRunner.And("bar\\notes.foo should exist"); #line hidden testRunner.CollectScenarioErrors();} The #line directives are there to give clues to the debugger, because yes, you can put breakpoints into a scenario: The way you usually write tests with SpecFlow is that you write the scenario first, let it fail, then write the translation of your Given, When and Then into code if they don’t already exist, which results in running but failing tests, and then you write the code to make your tests pass (you implement the scenario). In the case of FluentPath, I built a simple Given method that builds a simple file hierarchy in a temporary directory that all scenarios are going to work with: [Given("a clean test directory")] public void GivenACleanDirectory() { _path = new Path(SystemIO.Path.GetTempPath()) .CreateSubDirectory("FluentPathSpecs") .MakeCurrent(); _path.GetFileSystemEntries() .Delete(true); _path.CreateFile("foo.txt", "This is a text file named foo."); var bar = _path.CreateSubDirectory("bar"); bar.CreateFile("baz.txt", "bar baz") .SetLastWriteTime(DateTime.Now.AddSeconds(-2)); bar.CreateFile("notes.txt", "This is a text file containing notes."); var barbar = bar.CreateSubDirectory("bar"); barbar.CreateFile("deep.txt", "Deep thoughts"); var sub = _path.CreateSubDirectory("sub"); sub.CreateSubDirectory("subsub"); sub.CreateFile("baz.txt", "sub baz") .SetLastWriteTime(DateTime.Now); sub.CreateFile("binary.bin", new byte[] {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0xFF}); } Then, to implement the scenario that you can read above, I had to write the following When: [When("I change the extension of (.*) to (.*)")] public void WhenIChangeTheExtension( string path, string newExtension) { var oldPath = Path.Current.Combine(path.Split('\\')); oldPath.Move(p => p.ChangeExtension(newExtension)); } As you can see, the When attribute is specifying the regular expression that will enable the SpecFlow engine to recognize what When method to call and also how to map its parameters. For our scenario, “bar\notes.txt” will get mapped to the path parameter, and “foo” to the newExtension parameter. And of course, the code that verifies the assumptions of the scenario: [Then("(.*) should exist")] public void ThenEntryShouldExist(string path) { Assert.IsTrue(_path.Combine(path.Split('\\')).Exists); } [Then("(.*) should not exist")] public void ThenEntryShouldNotExist(string path) { Assert.IsFalse(_path.Combine(path.Split('\\')).Exists); } These steps should be written with reusability in mind. They are building blocks for your scenarios, not implementation of a specific scenario. Think small and fine-grained. In the case of the above steps, I could reuse each of those steps in other scenarios. Those tests are easy to write and easier to read, which means that they also constitute a form of documentation. Oh, and SpecFlow is just one way to do this. Rob wrote a long time ago about this sort of thing (but using a different framework) and I highly recommend this post if I somehow managed to pique your interest: http://blog.wekeroad.com/blog/make-bdd-your-bff-2/ And this screencast (Rob always makes excellent screencasts): http://blog.wekeroad.com/mvc-storefront/kona-3/ (click the “Download it here” link)

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• Sliding collision response

  - by dbostream

  I have been reading plenty of tutorials about sliding collision responses yet I am not able to implement it properly in my project. What I want to do is make a puck slide along the rounded corner boards of a hockey rink. In my latest attempt the puck does slide along the boards but there are some strange velocity behaviors. First of all the puck slows down a lot pretty much right away and then it slides for awhile and stops before exiting the corner. Even if I double the speed I get a similar behavior and the puck does not make it out of the corner. I used some ideas from this document http://www.peroxide.dk/papers/collision/collision.pdf. This is what I have: Update method called from the game loop when it is time to update the puck (I removed some irrelevant parts). I use two states (current, previous) which are used to interpolate the position during rendering. public override void Update(double fixedTimeStep) { /* Acceleration is set to 0 for now. */ Acceleration.Zero(); PreviousState = CurrentState; _collisionRecursionDepth = 0; CurrentState.Position = SlidingCollision(CurrentState.Position, CurrentState.Velocity * fixedTimeStep + 0.5 * Acceleration * fixedTimeStep * fixedTimeStep); /* Should not this be affected by a sliding collision? and not only the position. */ CurrentState.Velocity = CurrentState.Velocity + Acceleration * fixedTimeStep; Heading = Vector2.NormalizeRet(CurrentState.Velocity); } private Vector2 SlidingCollision(Vector2 position, Vector2 velocity) { if(_collisionRecursionDepth > 5) return position; bool collisionFound = false; Vector2 futurePosition = position + velocity; Vector2 intersectionPoint = new Vector2(); Vector2 intersectionPointNormal = new Vector2(); /* I did not include the collision detection code, if a collision is detected the intersection point and normal in that point is returned. */ if(!collisionFound) return futurePosition; /* If no collision was detected it is safe to move to the future position. */ /* It is not exactly the intersection point, but slightly before. */ Vector2 newPosition = intersectionPoint; /* oldVelocity is set to the distance from the newPosition(intersection point) to the position it had moved to had it not collided. */ Vector2 oldVelocity = futurePosition - newPosition; /* Project the distance left to move along the intersection normal. */ Vector2 newVelocity = oldVelocity - intersectionPointNormal * oldVelocity.DotProduct(intersectionPointNormal); if(newVelocity.LengthSq() < 0.001) return newPosition; /* If almost no speed, no need to continue. */ _collisionRecursionDepth++; return SlidingCollision(newPosition, newVelocity); } What am I doing wrong with the velocity? I have been staring at this for very long so I have gone blind. I have tried different values of recursion depth but it does not seem to make it better. Let me know if you need more information. I appreciate any help. EDIT: A combination of Patrick Hughes' and teodron's answers solved the velocity problem (I think), thanks a lot! This is the new code: I decided to use a separate recursion method now too since I don't want to recalculate the acceleration in each recursion. public override void Update(double fixedTimeStep) { Acceleration.Zero();// = CalculateAcceleration(fixedTimeStep); PreviousState = new MovingEntityState(CurrentState.Position, CurrentState.Velocity); CurrentState = SlidingCollision(CurrentState, fixedTimeStep); Heading = Vector2.NormalizeRet(CurrentState.Velocity); } private MovingEntityState SlidingCollision(MovingEntityState state, double timeStep) { bool collisionFound = false; /* Calculate the next position given no detected collision. */ Vector2 futurePosition = state.Position + state.Velocity * timeStep; Vector2 intersectionPoint = new Vector2(); Vector2 intersectionPointNormal = new Vector2(); /* I did not include the collision detection code, if a collision is detected the intersection point and normal in that point is returned. */ /* If no collision was detected it is safe to move to the future position. */ if (!collisionFound) return new MovingEntityState(futurePosition, state.Velocity); /* Set new position to the intersection point (slightly before). */ Vector2 newPosition = intersectionPoint; /* Project the new velocity along the intersection normal. */ Vector2 newVelocity = state.Velocity - 1.90 * intersectionPointNormal * state.Velocity.DotProduct(intersectionPointNormal); /* Calculate the time of collision. */ double timeOfCollision = Math.Sqrt((newPosition - state.Position).LengthSq() / (futurePosition - state.Position).LengthSq()); /* Calculate new time step, remaining time of full step after the collision * current time step. */ double newTimeStep = timeStep * (1 - timeOfCollision); return SlidingCollision(new MovingEntityState(newPosition, newVelocity), newTimeStep); } Even though the code above seems to slide the puck correctly please have a look at it. I have a few questions, if I don't multiply by 1.90 in the newVelocity calculation it doesn't work (I get a stack overflow when the puck enters the corner because the timeStep decreases very slowly - a collision is found early in every recursion), why is that? what does 1.90 really do and why 1.90? Also I have a new problem, the puck does not move parallell to the short side after exiting the curve; to be more exact it moves outside the rink (I am not checking for any collisions with the short side at the moment). When I perform the collision detection I first check that the puck is in the correct quadrant. For example bottom-right corner is quadrant four i.e. circleCenter.X < puck.X && circleCenter.Y puck.Y is this a problem? or should the short side of the rink be the one to make the puck go parallell to it and not the last collision in the corner? EDIT2: This is the code I use for collision detection, maybe it has something to do with the fact that I can't make the puck slide (-1.0) but only reflect (-2.0): /* Point is the current position (not the predicted one) and quadrant is 4 for the bottom-right corner for example. */ if (GeometryHelper.PointInCircleQuadrant(circleCenter, circleRadius, state.Position, quadrant)) { /* The line is: from = state.Position, to = futurePosition. So a collision is detected when from is inside the circle and to is outside. */ if (GeometryHelper.LineCircleIntersection2d(state.Position, futurePosition, circleCenter, circleRadius, intersectionPoint, quadrant)) { collisionFound = true; /* Set the intersection point to slightly before the real intersection point (I read somewhere this was good to do because of floting point precision, not sure exactly how much though). */ intersectionPoint = intersectionPoint - Vector2.NormalizeRet(state.Velocity) * 0.001; /* Normal at the intersection point. */ intersectionPointNormal = Vector2.NormalizeRet(circleCenter - intersectionPoint) } } When I set the intersection point, if I for example use 0.1 instead of 0.001 the puck travels further before it gets stuck, but for all values I have tried (including 0 - the real intersection point) it gets stuck somewhere (but I necessarily not get a stack overflow). Can something in this part be the cause of my problem? I can see why I get the stack overflow when using -1.0 when calculating the new velocity vector; but not how to solve it. I traced the time steps used in the recursion (initial time step is always 1/60 ~ 0.01666): Recursion depth Time step next recursive call [Start recursion, time step ~ 0.016666] 0 0,000985806527246773 [No collision, stop recursion] [Start recursion, time step ~ 0.016666] 0 0,0149596704364629 1 0,0144883449376379 2 0,0143155612984837 3 0,014224925727213 4 0,0141673917461608 5 0,0141265435314026 6 0,0140953966184117 7 0,0140704653746625 ...and so on. As you can see the collision is detected early in every recursive call which means the next time step decreases very slowly thus the recursion depth gets very big - stack overflow.

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