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  • SharePoint 2010 – Central Admin tooling to create host header site collections

    - by eJugnoo
    Just like SharePoint 2007, you can create host-header based site collections in SharePoint 2010 as well. It means, that you do not necessarily need to create a site-collection under a managed path like /sites/, you can create multiple root-level site collections on same web-application/port by using host-header site collections. All you need to do is point your domain or sub-domain to your web-application and create a matching site-collection that you want. But, just like in 2007, it is something that you do by using STSADM, and is not available on Central Admin UI in 2010 as well. Yeah, though you can now also use PowerShell to create one: C:\PS>$w = Get-SPWebApplication http://sitename   C:\PS>New-SPSite http://www.contoso.com -OwnerAlias "DOMAIN\jdoe" -HostHeaderWebApplication $w -Title "Contoso" -Template "STS#0"   This example creates a host header site collection. Because the template is provided, the root Web of this site collection will be created. .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } I’ve been playing with WCM in SharePoint 2010 more and more, and for that I preferred creating hosts file entries for desired domains and create site-collections by those headers – in my dev environment. I used PowerShell initially, but then got interested to build my own UI on Central Admin instead. Developed with Visual Studio 2010 So I used new Visual Studio 2010 tooling to create an empty SharePoint 2010 project. Added an application page (there is no option to add _Admin page item in VS 2010 RC), that got created in Layouts “mapped” folder. Created a new Admin mapped folder for 14-“hive”, and moved my new page there instead. Yes, I didn’t change the base class for page, its just that it runs under _admin, but it is indeed a LayoutsPageBase inherited page. To introduce a action-link in Central Admin console, I created following element: 1: <Elements xmlns="http://schemas.microsoft.com/sharepoint/"> 2: <CustomAction 3: Id="CreateSiteByHeader" 4: Location="Microsoft.SharePoint.Administration.Applications" 5: Title="Create site collections by host header" 6: GroupId="SiteCollections" 7: Sequence="15" 8: RequiredAdmin="Delegated" 9: Description="Create a new top-level web site, by host header" > 10: <UrlAction Url="/_admin/OfficeToolbox/CreateSiteByHeader.aspx" /> 11: </CustomAction> 12: </Elements> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Used Reflector to understand any special code behind createpage.aspx, and created a new for our purpose – CreateSiteByHeader.aspx. From there I quickly created a similar code behind, without all the fancy of Farm Config Wizard handling and dealt with alternate implementations of sealed classes! Goal was to create a professional looking and OOB-type experience. I also added Regex validation to ensure user types a valid domain name as header value. Below is the result…   Release @ Codeplex I’ve released to WSP on OfficeToolbox @ Codeplex, and you can download from here. Hope you find it useful… -- Sharad

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  • Upgrading from TFS 2010 RC to TFS 2010 RTM done

    - by Martin Hinshelwood
    Today is the big day, with the Launch of Visual Studio 2010 already done in Asia, and rolling around the world towards us, we are getting ready for the RTM (Released). We have had TFS 2010 in Production for nearly 6 months and have had only minimal problems. Update 12th April 2010  – Added Scott Hanselman’s tweet about the MSDN download release time. SSW was the first company in the world outside of Microsoft to deploy Visual Studio 2010 Team Foundation Server to production, not once, but twice. I am hoping to make it 3 in a row, but with all the hype around the new version, and with it being a production release and not just a go-live, I think there will be a lot of competition. Developers: MSDN will be updated with #vs2010 downloads and details at 10am PST *today*! @shanselman - Scott Hanselman Same as before, we need to Uninstall 2010 RC and install 2010 RTM. The installer will take care of all the complexity of actually upgrading any schema changes. If you are upgrading from TFS 2008 to TFS2010 you can follow our Rules To Better TFS 2010 Migration and read my post on our successes.   We run TFS 2010 in a Hyper-V virtual environment, so we have the advantage of running a snapshot as well as taking a DB backup. Done - Snapshot the hyper-v server Microsoft does not support taking a snapshot of a running server, for very good reason, and Brian Harry wrote a post after my last upgrade with the reason why you should never snapshot a running server. Done - Uninstall Visual Studio Team Explorer 2010 RC You will need to uninstall all of the Visual Studio 2010 RC client bits that you have on the server. Done - Uninstall TFS 2010 RC Done - Install TFS 2010 RTM Done - Configure TFS 2010 RTM Pick the Upgrade option and point it at your existing “tfs_Configuration” database to load all of the existing settings Done - Upgrade the SharePoint Extensions Upgrade Build Servers (Pending) Test the server The back out plan, and you should always have one, is to restore the snapshot. Upgrading to Team Foundation Server 2010 – Done The first thing you need to do is off the TFS server and then log into the Hyper-v server and create a snapshot. Figure: Make sure you turn the server off and delete all old snapshots before you take a new one I noticed that the snapshot that was taken before the Beta 2 to RC upgrade was still there. You should really delete old snapshots before you create a new one, but in this case the SysAdmin (who is currently tucked up in bed) asked me not to. I guess he is worried about a developer messing up his server Turn your server on and wait for it to boot in anticipation of all the nice shiny RTM’ness that is coming next. The upgrade procedure for TFS2010 is to uninstal the old version and install the new one. Figure: Remove Visual Studio 2010 Team Foundation Server RC from the system.   Figure: Most of the heavy lifting is done by the Uninstaller, but make sure you have removed any of the client bits first. Specifically Visual Studio 2010 or Team Explorer 2010.  Once the uninstall is complete, this took around 5 minutes for me, you can begin the install of the RTM. Running the 64 bit OS will allow the application to use more than 2GB RAM, which while not common may be of use in heavy load situations. Figure: It is always recommended to install the 64bit version of a server application where possible. I do not think it is likely, with SharePoint 2010 and Exchange 2010  and even Windows Server 2008 R2 being 64 bit only, I do not think there will be another release of a server app that is 32bit. You then need to choose what it is you want to install. This depends on how you are running TFS and on how many servers. In our case we run TFS and the Team Foundation Build Service (controller only) on out TFS server along with Analysis services and Reporting Services. But our SharePoint server lives elsewhere. Figure: This always confuses people, but in reality it makes sense. Don’t install what you do not need. Every extra you install has an impact of performance. If you are integrating with SharePoint you will need to run this install on every Front end server in your farm and don’t forget to upgrade your Build servers and proxy servers later. Figure: Selecting only Team Foundation Server (TFS) and Team Foundation Build Services (TFBS)   It is worth noting that if you have a lot of builds kicking off, and hence a lot of get operations against your TFS server, you can use a proxy server to cache the source control on another server in between your TFS server and your build servers. Figure: Installing Microsoft .NET Framework 4 takes the most time. Figure: Now run Windows Update, and SSW Diagnostic to make sure all your bits and bobs are up to date. Note: SSW Diagnostic will check your Power Tools, Add-on’s, Check in Policies and other bits as well. Configure Team Foundation Server 2010 – Done Now you can configure the server. If you have no key you will need to pick “Install a Trial Licence”, but it is only £500, or free with a MSDN subscription. Anyway, if you pick Trial you get 90 days to get your key. Figure: You can pick trial and add your key later using the TFS Server Admin. Here is where the real choices happen. We are doing an Upgrade from a previous version, so I will pick Upgrade the same as all you folks that are using the RC or TFS 2008. Figure: The upgrade wizard takes your existing 2010 or 2008 databases and upgraded them to the release.   Once you have entered your database server name you can click “List available databases” and it will show what it can upgrade. Figure: Select your database from the list and at this point, make sure you have a valid backup. At this point you have not made ANY changes to the databases. At this point the configuration wizard will load configuration from your existing database if you have one. If you are upgrading TFS 2008 refer to Rules To Better TFS 2010 Migration. Mostly during the wizard the default values will suffice, but depending on the configuration you want you can pick different options. Figure: Set the application tier account and Authentication method to use. We use NTLM to keep things simple as we host our TFS server externally for our remote developers.  Figure: Setting your TFS server URL’s to be the remote URL’s allows the reports to be accessed without using VPN. Very handy for those remote developers. Figure: Detected the existing Warehouse no problem. Figure: Again we love green ticks. It gives us a warm fuzzy feeling. Figure: The username for connecting to Reporting services should be a domain account (if you are on a domain that is). Figure: Setup the SharePoint integration to connect to your external SharePoint server. You can take the option to connect later.   You then need to run all of your readiness checks. These check can save your life! it will check all of the settings that you have entered as well as checking all the external services are configures and running properly. There are two reasons that TFS 2010 is so easy and painless to install where previous version were not. Microsoft changes the install to two steps, Install and configuration. The second reason is that they have pulled out all of the stops in making the install run all the checks necessary to make sure that once you start the install that it will complete. if you find any errors I recommend that you report them on http://connect.microsoft.com so everyone can benefit from your misery.   Figure: Now we have everything setup the configuration wizard can do its work.  Figure: Took a while on the “Web site” stage for some point, but zipped though after that.  Figure: last wee bit. TFS Needs to do a little tinkering with the data to complete the upgrade. Figure: All upgraded. I am not worried about the yellow triangle as SharePoint was being a little silly Exception Message: TF254021: The account name or password that you specified is not valid. (type TfsAdminException) Exception Stack Trace:    at Microsoft.TeamFoundation.Management.Controls.WizardCommon.AccountSelectionControl.TestLogon(String connectionString)    at System.ComponentModel.BackgroundWorker.WorkerThreadStart(Object argument) [Info   @16:10:16.307] Benign exception caught as part of verify: Exception Message: TF255329: The following site could not be accessed: http://projects.ssw.com.au/. The server that you specified did not return the expected response. Either you have not installed the Team Foundation Server Extensions for SharePoint Products on this server, or a firewall is blocking access to the specified site or the SharePoint Central Administration site. For more information, see the Microsoft Web site (http://go.microsoft.com/fwlink/?LinkId=161206). (type TeamFoundationServerException) Exception Stack Trace:    at Microsoft.TeamFoundation.Client.SharePoint.WssUtilities.VerifyTeamFoundationSharePointExtensions(ICredentials credentials, Uri url)    at Microsoft.TeamFoundation.Admin.VerifySharePointSitesUrl.Verify() Inner Exception Details: Exception Message: TF249064: The following Web service returned an response that is not valid: http://projects.ssw.com.au/_vti_bin/TeamFoundationIntegrationService.asmx. This Web service is used for the Team Foundation Server Extensions for SharePoint Products. Either the extensions are not installed, the request resulted in HTML being returned, or there is a problem with the URL. Verify that the following URL points to a valid SharePoint Web application and that the application is available: http://projects.ssw.com.au. If the URL is correct and the Web application is operating normally, verify that a firewall is not blocking access to the Web application. (type TeamFoundationServerInvalidResponseException) Exception Data Dictionary: ResponseStatusCode = InternalServerError I’ll look at SharePoint after, probably the SharePoint box just needs a restart or a kick If there is a problem with SharePoint it will come out in testing, But I will definatly be passing this on to Microsoft.   Upgrading the SharePoint connector to TFS 2010 You will need to upgrade the Extensions for SharePoint Products and Technologies on all of your SharePoint farm front end servers. To do this uninstall  the TFS 2010 RC from it in the same way as the server, and then install just the RTM Extensions. Figure: Only install the SharePoint Extensions on your SharePoint front end servers. TFS 2010 supports both SharePoint 2007 and SharePoint 2010.   Figure: When you configure SharePoint it uploads all of the solutions and templates. Figure: Everything is uploaded Successfully. Figure: TFS even remembered the settings from the previous installation, fantastic.   Upgrading the Team Foundation Build Servers to TFS 2010 Just like on the SharePoint servers you will need to upgrade the Build Server to the RTM. Just uninstall TFS 2010 RC and then install only the Team Foundation Build Services component. Unlike on the SharePoint server you will probably have some version of Visual Studio installed. You will need to remove this as well. (Coming Soon) Connecting Visual Studio 2010 / 2008 / 2005 and Eclipse to TFS2010 If you have developers still on Visual Studio 2005 or 2008 you will need do download the respective compatibility pack: Visual Studio Team System 2005 Service Pack 1 Forward Compatibility Update for Team Foundation Server 2010 Visual Studio Team System 2008 Service Pack 1 Forward Compatibility Update for Team Foundation Server 2010 If you are using Eclipse you can download the new Team Explorer Everywhere install for connecting to TFS. Get your developers to check that you have the latest version of your applications with SSW Diagnostic which will check for Service Packs and hot fixes to Visual Studio as well.   Technorati Tags: TFS,TFS2010,TFS 2010,Upgrade

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  • C#: System.Lazy&lt;T&gt; and the Singleton Design Pattern

    - by James Michael Hare
    So we've all coded a Singleton at one time or another.  It's a really simple pattern and can be a slightly more elegant alternative to global variables.  Make no mistake, Singletons can be abused and are often over-used -- but occasionally you find a Singleton is the most elegant solution. For those of you not familiar with a Singleton, the basic Design Pattern is that a Singleton class is one where there is only ever one instance of the class created.  This means that constructors must be private to avoid users creating their own instances, and a static property (or method in languages without properties) is defined that returns a single static instance. 1: public class Singleton 2: { 3: // the single instance is defined in a static field 4: private static readonly Singleton _instance = new Singleton(); 5:  6: // constructor private so users can't instantiate on their own 7: private Singleton() 8: { 9: } 10:  11: // read-only property that returns the static field 12: public static Singleton Instance 13: { 14: get 15: { 16: return _instance; 17: } 18: } 19: } This is the most basic singleton, notice the key features: Static readonly field that contains the one and only instance. Constructor is private so it can only be called by the class itself. Static property that returns the single instance. Looks like it satisfies, right?  There's just one (potential) problem.  C# gives you no guarantee of when the static field _instance will be created.  This is because the C# standard simply states that classes (which are marked in the IL as BeforeFieldInit) can have their static fields initialized any time before the field is accessed.  This means that they may be initialized on first use, they may be initialized at some other time before, you can't be sure when. So what if you want to guarantee your instance is truly lazy.  That is, that it is only created on first call to Instance?  Well, there's a few ways to do this.  First we'll show the old ways, and then talk about how .Net 4.0's new System.Lazy<T> type can help make the lazy-Singleton cleaner. Obviously, we could take on the lazy construction ourselves, but being that our Singleton may be accessed by many different threads, we'd need to lock it down. 1: public class LazySingleton1 2: { 3: // lock for thread-safety laziness 4: private static readonly object _mutex = new object(); 5:  6: // static field to hold single instance 7: private static LazySingleton1 _instance = null; 8:  9: // property that does some locking and then creates on first call 10: public static LazySingleton1 Instance 11: { 12: get 13: { 14: if (_instance == null) 15: { 16: lock (_mutex) 17: { 18: if (_instance == null) 19: { 20: _instance = new LazySingleton1(); 21: } 22: } 23: } 24:  25: return _instance; 26: } 27: } 28:  29: private LazySingleton1() 30: { 31: } 32: } This is a standard double-check algorithm so that you don't lock if the instance has already been created.  However, because it's possible two threads can go through the first if at the same time the first time back in, you need to check again after the lock is acquired to avoid creating two instances. Pretty straightforward, but ugly as all heck.  Well, you could also take advantage of the C# standard's BeforeFieldInit and define your class with a static constructor.  It need not have a body, just the presence of the static constructor will remove the BeforeFieldInit attribute on the class and guarantee that no fields are initialized until the first static field, property, or method is called.   1: public class LazySingleton2 2: { 3: // because of the static constructor, this won't get created until first use 4: private static readonly LazySingleton2 _instance = new LazySingleton2(); 5:  6: // Returns the singleton instance using lazy-instantiation 7: public static LazySingleton2 Instance 8: { 9: get { return _instance; } 10: } 11:  12: // private to prevent direct instantiation 13: private LazySingleton2() 14: { 15: } 16:  17: // removes BeforeFieldInit on class so static fields not 18: // initialized before they are used 19: static LazySingleton2() 20: { 21: } 22: } Now, while this works perfectly, I hate it.  Why?  Because it's relying on a non-obvious trick of the IL to guarantee laziness.  Just looking at this code, you'd have no idea that it's doing what it's doing.  Worse yet, you may decide that the empty static constructor serves no purpose and delete it (which removes your lazy guarantee).  Worse-worse yet, they may alter the rules around BeforeFieldInit in the future which could change this. So, what do I propose instead?  .Net 4.0 adds the System.Lazy type which guarantees thread-safe lazy-construction.  Using System.Lazy<T>, we get: 1: public class LazySingleton3 2: { 3: // static holder for instance, need to use lambda to construct since constructor private 4: private static readonly Lazy<LazySingleton3> _instance 5: = new Lazy<LazySingleton3>(() => new LazySingleton3()); 6:  7: // private to prevent direct instantiation. 8: private LazySingleton3() 9: { 10: } 11:  12: // accessor for instance 13: public static LazySingleton3 Instance 14: { 15: get 16: { 17: return _instance.Value; 18: } 19: } 20: } Note, you need your lambda to call the private constructor as Lazy's default constructor can only call public constructors of the type passed in (which we can't have by definition of a Singleton).  But, because the lambda is defined inside our type, it has access to the private members so it's perfect. Note how the Lazy<T> makes it obvious what you're doing (lazy construction), instead of relying on an IL generation side-effect.  This way, it's more maintainable.  Lazy<T> has many other uses as well, obviously, but I really love how elegant and readable it makes the lazy Singleton.

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  • Developer Training – Various Options for Maximum Benefit – Part 4

    - by pinaldave
    Developer Training - Importance and Significance - Part 1 Developer Training – Employee Morals and Ethics – Part 2 Developer Training – Difficult Questions and Alternative Perspective - Part 3 Developer Training – Various Options for Developer Training – Part 4 Developer Training – A Conclusive Summary- Part 5 If you have been reading this series, by now you are aware of all the pros and cons that can come along with training.  We’ve asked and answered hard questions, and investigated them “whys” and “hows” of training.  Now it is time to talk about all the different kinds of training that are out there! On Job Training The most common type of training is on the job training.  Everyone receives this kind of education – even experts who come in to consult have to be taught where the printer, pens, and copy machines are.  If you are thinking about more concrete topics, though, on the job training can be some of the easiest to come across.  Picture this: someone in the company whom you really admire is hard at work on a project.  You come up to them and ask to help them out – if they are a busy developer, the odds are that they will say “yes, please!”   If you phrase your question as an offer of help, you can receive training without ever putting someone in the awkward position of acting as a mentor.  However, some people may want the task of being a mentor.  It can never hurt to ask.  Most people will be more than willing to pass their knowledge along. Extreme Programming If your company and coworkers are willing, you can even investigate Extreme Programming.  This is a type of programming that allows small teams to quickly develop code and products that are released with almost immediate user feedback.  You can find more information at http://www.extremeprogramming.org/.  If this is something your company could use, suggest it to your supervisor.  Even if they say no, it will make it clear that you are a go-getter who is interested in new and exciting projects.  If the answer is yes, then you have the opportunity to get some of the best on the job training around. In Person Training Click on Image to Enlarge When you say the word “training,” most people’s minds go back to the classroom, an image they are familiar with.  While training doesn’t always have to be in a traditional setting, because it is so familiar it can also be the most valuable type of training.  There are many ways to get training through a live instructor.  Some companies may be willing to send a representative to you, where employees will get training, sometimes food and coffee, and a live instructor who can answer questions immediately.  Sometimes these trainers are also able to do consultations at the same time, which can invaluable to a company.  If you are the one to asks your supervisor for a training session that can also be turned into a consultation, you may stick in their minds as an incredibly dedicated employee.  If you can’t find a representative, local colleges can also be a good resource for free or cheap classes – or they may have representatives coming who are willing to take on a few more students. Benefits of On Demand Developer Training Of course, you can often get the best of all these types of training with online or On Demand training.  You can get the benefit of a live instructor who is willing to answer questions (although in this case, usually through e-mail or other online venues), there are often real-world examples to follow along – like on the job training – and best of all you can learn whenever you have the time or need.  Did a problem with your server come up at midnight when all your supervisors are safe at home and probably in bed?  No problem!  On Demand training is especially useful if you need to slow down, pause, or rewind a training session.  Not even a real-life instructor can do that! When I was writing this blog post, I felt that each of the subject, which I have covered can be blog posts of itself. However, I wanted to keep the the blog post concise and so touch based on three major training aspects 1) On Job Training 2) In Person Training and 3) Online training. Here is the question for you – is there any other kind of training methods available, which are effective and one should consider it? If yes, what are those, I may write a follow up blog post on the same subject next week. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Developer Training, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Parallelism in .NET – Part 1, Decomposition

    - by Reed
    The first step in designing any parallelized system is Decomposition.  Decomposition is nothing more than taking a problem space and breaking it into discrete parts.  When we want to work in parallel, we need to have at least two separate things that we are trying to run.  We do this by taking our problem and decomposing it into parts. There are two common abstractions that are useful when discussing parallel decomposition: Data Decomposition and Task Decomposition.  These two abstractions allow us to think about our problem in a way that helps leads us to correct decision making in terms of the algorithms we’ll use to parallelize our routine. To start, I will make a couple of minor points. I’d like to stress that Decomposition has nothing to do with specific algorithms or techniques.  It’s about how you approach and think about the problem, not how you solve the problem using a specific tool, technique, or library.  Decomposing the problem is about constructing the appropriate mental model: once this is done, you can choose the appropriate design and tools, which is a subject for future posts. Decomposition, being unrelated to tools or specific techniques, is not specific to .NET in any way.  This should be the first step to parallelizing a problem, and is valid using any framework, language, or toolset.  However, this gives us a starting point – without a proper understanding of decomposition, it is difficult to understand the proper usage of specific classes and tools within the .NET framework. Data Decomposition is often the simpler abstraction to use when trying to parallelize a routine.  In order to decompose our problem domain by data, we take our entire set of data and break it into smaller, discrete portions, or chunks.  We then work on each chunk in the data set in parallel. This is particularly useful if we can process each element of data independently of the rest of the data.  In a situation like this, there are some wonderfully simple techniques we can use to take advantage of our data.  By decomposing our domain by data, we can very simply parallelize our routines.  In general, we, as developers, should be always searching for data that can be decomposed. Finding data to decompose if fairly simple, in many instances.  Data decomposition is typically used with collections of data.  Any time you have a collection of items, and you’re going to perform work on or with each of the items, you potentially have a situation where parallelism can be exploited.  This is fairly easy to do in practice: look for iteration statements in your code, such as for and foreach. Granted, every for loop is not a candidate to be parallelized.  If the collection is being modified as it’s iterated, or the processing of elements depends on other elements, the iteration block may need to be processed in serial.  However, if this is not the case, data decomposition may be possible. Let’s look at one example of how we might use data decomposition.  Suppose we were working with an image, and we were applying a simple contrast stretching filter.  When we go to apply the filter, once we know the minimum and maximum values, we can apply this to each pixel independently of the other pixels.  This means that we can easily decompose this problem based off data – we will do the same operation, in parallel, on individual chunks of data (each pixel). Task Decomposition, on the other hand, is focused on the individual tasks that need to be performed instead of focusing on the data.  In order to decompose our problem domain by tasks, we need to think about our algorithm in terms of discrete operations, or tasks, which can then later be parallelized. Task decomposition, in practice, can be a bit more tricky than data decomposition.  Here, we need to look at what our algorithm actually does, and how it performs its actions.  Once we have all of the basic steps taken into account, we can try to analyze them and determine whether there are any constraints in terms of shared data or ordering.  There are no simple things to look for in terms of finding tasks we can decompose for parallelism; every algorithm is unique in terms of its tasks, so every algorithm will have unique opportunities for task decomposition. For example, say we want our software to perform some customized actions on startup, prior to showing our main screen.  Perhaps we want to check for proper licensing, notify the user if the license is not valid, and also check for updates to the program.  Once we verify the license, and that there are no updates, we’ll start normally.  In this case, we can decompose this problem into tasks – we have a few tasks, but there are at least two discrete, independent tasks (check licensing, check for updates) which we can perform in parallel.  Once those are completed, we will continue on with our other tasks. One final note – Data Decomposition and Task Decomposition are not mutually exclusive.  Often, you’ll mix the two approaches while trying to parallelize a single routine.  It’s possible to decompose your problem based off data, then further decompose the processing of each element of data based on tasks.  This just provides a framework for thinking about our algorithms, and for discussing the problem.

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  • Windows Phone 7 development: Using isolated storage

    - by DigiMortal
    In my previous posting about Windows Phone 7 development I showed how to use WebBrowser control in Windows Phone 7. In this posting I make some other improvements to my blog reader application and I will show you how to use isolated storage to store information to phone. Why isolated storage? Isolated storage is place where your application can save its data and settings. The image on right (that I stole from MSDN library) shows you how application data store is organized. You have no other options to keep your files besides isolated storage because Windows Phone 7 does not allow you to save data directly to other file system locations. From MSDN: “Isolated storage enables managed applications to create and maintain local storage. The mobile architecture is similar to the Silverlight-based applications on Windows. All I/O operations are restricted to isolated storage and do not have direct access to the underlying operating system file system. Ultimately, this helps to provide security and prevents unauthorized access and data corruption.” Saving files from web to isolated storage I updated my RSS-reader so it reads RSS from web only if there in no local file with RSS. User can update RSS-file by clicking a button. Also file is created when application starts and there is no RSS-file. Why I am doing this? I want my application to be able to work also offline. As my code needs some more refactoring I provide it with some next postings about Windows Phone 7. If you want it sooner then please leave me a comment here. Here is the code for my RSS-downloader that downloads RSS-feed and saves it to isolated storage file calles rss.xml. public class RssDownloader {     private string _url;     private string _fileName;       public delegate void DownloadCompleteDelegate();     public event DownloadCompleteDelegate DownloadComplete;       public RssDownloader(string url, string fileName)     {         _url = url;         _fileName = fileName;     }       public void Download()     {         var request = (HttpWebRequest)WebRequest.Create(_url);         var result = (IAsyncResult)request.BeginGetResponse(ResponseCallback, request);            }       private void ResponseCallback(IAsyncResult result)     {         var request = (HttpWebRequest)result.AsyncState;         var response = request.EndGetResponse(result);           using(var stream = response.GetResponseStream())         using(var reader = new StreamReader(stream))         using(var appStorage = IsolatedStorageFile.GetUserStoreForApplication())         using(var file = appStorage.OpenFile("rss.xml", FileMode.OpenOrCreate))         using(var writer = new StreamWriter(file))         {             writer.Write(reader.ReadToEnd());         }           if (DownloadComplete != null)             DownloadComplete();     } } Of course I modified RSS-source for my application to use rss.xml file from isolated storage. As isolated storage files also base on streams we can use them everywhere where streams are expected. Reading isolated storage files As isolated storage files are opened as streams you can read them like usual files in your usual applications. The next code fragment shows you how to open file from isolated storage and how to read it using XmlReader. Previously I used response stream in same place. using(var appStorage = IsolatedStorageFile.GetUserStoreForApplication()) using(var file = appStorage.OpenFile("rss.xml", FileMode.Open)) {     var reader = XmlReader.Create(file);                      // more code } As you can see there is nothing complex. If you have worked with System.IO namespace objects then you will find isolated storage classes and methods to be very similar to these. Also mention that application storage and isolated storage files must be disposed after you are not using them anymore.

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  • Feedback on "market manipulation", a peripheral game mechanic for a satirical MMO

    - by BerndBrot
    This question asks for feedback on a specific game-mechanic. Since there is not one right feedback on a game mechanic, I tried to provide enough context and guidelines to still make it possible for users to rate answers and to accept an answer as the best answer (following these criteria from Writer.SE's meta website). Please comment if you have any suggestions on how I could improve the question in that regard. So, let's begin with the game itself and some of its elements which are relevant for this question. Context I'm working on a satirical, text-based multiplayer adventure and role-playing game set in modern-day London. The game resolves around the concept of sin and features a myriad of (venomous) allusions to all the things that go wrong in this world. Players can choose between character classes like bullshit artist (consultant), bankster, lawyer, mobster, celebrity, politician, etc. In order to complete the game, the player has to live so sinfully with regard to any of the seven deadly sins that a demon is willing to offer them a contract of sponsorship. On their quest to live a sinful live, characters explore more and more locations of modern-day London (on a GoogleMap), fight "monsters" like insurance sales agents or Jehovah's Witnesses, and complete quests, like building a PowerPoint presentation out of marketing buzz words or keeping up a number of substance abuse effects in order to progress on the gluttony path. Battles are turn based with both combatants having a deck of cards, with which they try to make their enemy give in to temptations of all sorts. Tempted enemies sometimes become contacts (an item drop mechanic), which can be exploited for various benefits, depending on their area of influence (finance, underworld, bureaucracy, etc.), level of influence, and kind of sway that the player has over them (bribed, seduced, threatened, etc.) Once a contract has been exploited, the player loses that contact. Most actions require turns. Turns are limited, but refill each day. Criteria A number of peripheral game mechanics are supposed to represent real world abuses and mischief in a humorous way integrate real world data and events to strengthen the feeling of relevance of the game's humor with regard to real world problems add fun ways of interacting with other players add ways for players to express themselves through game-play Market manipulation is one such peripheral game mechanic and should fulfill all of these goals. Market manipulation This is my initial design of the mechanic: Players can enter the London Stock Exchange (LSE) (without paying a turn) LSE displays the stock prices of a number of companies in industries like weapons or tobacco as well as some derivatives based on wheat and corn. The stock prices are calculated based on the actual stock prices of these companies and derivatives (in real time) any market manipulations that were conducted by the players any market corrections of the system Players can buy and sell shares with cash, a resource in the game, at current in-game market value (without paying a turn). Players can manipulate the market, i.e. let the price of a share either rise or fall, by some amount, over a certain period of time. Manipulating the market requires 1 turn A contact in the financial sector (see above). The higher the level of influence of the contact, the stronger the effect of the manipulation on the stock price, and/or the shorter it takes for the manipulation to manifest itself. Market manipulation also adds a crime to the player's record. (There are a multitude of ways to take care of that, but it is still another "cost" of market manipulations.) The system continuously corrects market manipulations by letting the in-game prices converge towards their real world counterparts at a rate of 2% of the difference between the two per hour. Because of this market correction mechanism, pushing up prices (and screwing down prices) becomes increasingly difficult the higher (lower) the price already is. Whenever food prices reach a certain level, in-game stories are posted about hunger catastrophes happening somewhere far, far away (maybe with links to real world news stories). Whenever a player sells a certain number of shares with a sufficiently high margin, they are mentioned in that day's in-game financial news. Since the number of stock options is very limited, players will inevitably collide in their efforts to manipulate the market in their favor. Hopefully, it will also be a fun side-arena for guilds and covenants to fight each other. Question(s) What do you think of this mechanism given the criteria for peripheral game mechanics that I specified for my game? Do you have any ideas how the mechanic could be improved with regard to these criteria (or otherwise)? Could it be improved to allow for more expressive game-play, or involve an allusion to some other real world madness (like short selling, leveraging, or some other banking magic)? Are there any game-theoretic problems with this mechanic, like maybe certain dominant individual strategies that, collectively, lead to every player profiting and thus eliminating the idea of market manipulation PVP? Also, if you like (or dislike) this question, feel free to participate in the discussion on GDSE meta: "Should we be more lax with regard to SE's question/answer format to make game design questions possible?"

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  • Faceted search with Solr on Windows

    - by Dr.NETjes
    With over 10 million hits a day, funda.nl is probably the largest ASP.NET website which uses Solr on a Windows platform. While all our data (i.e. real estate properties) is stored in SQL Server, we're using Solr 1.4.1 to return the faceted search results as fast as we can.And yes, Solr is very fast. We did do some heavy stress testing on our Solr service, which allowed us to do over 1,000 req/sec on a single 64-bits Solr instance; and that's including converting search-url's to Solr http-queries and deserializing Solr's result-XML back to .NET objects! Let me tell you about faceted search and how to integrate Solr in a .NET/Windows environment. I'll bet it's easier than you think :-) What is faceted search? Faceted search is the clustering of search results into categories, allowing users to drill into search results. By showing the number of hits for each facet category, users can easily see how many results match that category. If you're still a bit confused, this example from CNET explains it all: The SQL solution for faceted search Our ("pre-Solr") solution for faceted search was done by adding a lot of redundant columns to our SQL tables and doing a COUNT(...) for each of those columns:   So if a user was searching for real estate properties in the city 'Amsterdam', our facet-query would be something like: SELECT COUNT(hasGarden), COUNT(has2Bathrooms), COUNT(has3Bathrooms), COUNT(etc...) FROM Houses WHERE city = 'Amsterdam' While this solution worked fine for a couple of years, it wasn't very easy for developers to add new facets. And also, performing COUNT's on all matched rows only performs well if you have a limited amount of rows in a table (i.e. less than a million). Enter Solr "Solr is an open source enterprise search server based on the Lucene Java search library, with XML/HTTP and JSON APIs, hit highlighting, faceted search, caching, replication, and a web administration interface." (quoted from Wikipedia's page on Solr) Solr isn't a database, it's more like a big index. Every time you upload data to Solr, it will analyze the data and create an inverted index from it (like the index-pages of a book). This way Solr can lookup data very quickly. To explain the inner workings of Solr is beyond the scope of this post, but if you want to learn more, please visit the Solr Wiki pages. Getting faceted search results from Solr is very easy; first let me show you how to send a http-query to Solr:    http://localhost:8983/solr/select?q=city:Amsterdam This will return an XML document containing the search results (in this example only three houses in the city of Amsterdam):    <response>     <result name="response" numFound="3" start="0">         <doc>            <long name="id">3203</long>            <str name="city">Amsterdam</str>            <str name="steet">Keizersgracht</str>            <int name="numberOfBathrooms">2</int>        </doc>         <doc>             <long name="id">3205</long>             <str name="city">Amsterdam</str>             <str name="steet">Vondelstraat</str>             <int name="numberOfBathrooms">3</int>          </doc>          <doc>             <long name="id">4293</long>             <str name="city">Amsterdam</str>             <str name="steet">Wibautstraat</str>             <int name="numberOfBathrooms">2</int>          </doc>       </result>   </response> By adding a facet-querypart for the field "numberOfBathrooms", Solr will return the facets for this particular field. We will see that there's one house in Amsterdam with three bathrooms and two houses with two bathrooms.    http://localhost:8983/solr/select?q=city:Amsterdam&facet=true&facet.field=numberOfBathrooms The complete XML response from Solr now looks like:    <response>      <result name="response" numFound="3" start="0">         <doc>            <long name="id">3203</long>            <str name="city">Amsterdam</str>            <str name="steet">Keizersgracht</str>            <int name="numberOfBathrooms">2</int>         </doc>         <doc>            <long name="id">3205</long>            <str name="city">Amsterdam</str>            <str name="steet">Vondelstraat</str>            <int name="numberOfBathrooms">3</int>         </doc>         <doc>            <long name="id">4293</long>            <str name="city">Amsterdam</str>            <str name="steet">Wibautstraat</str>            <int name="numberOfBathrooms">2</int>         </doc>      </result>      <lst name="facet_fields">         <lst name="numberOfBathrooms">            <int name="2">2</int>            <int name="3">1</int>         </lst>      </lst>   </response> Trying Solr for yourself To run Solr on your local machine and experiment with it, you should read the Solr tutorial. This tutorial really only takes 1 hour, in which you install Solr, upload sample data and get some query results. And yes, it works on Windows without a problem. Note that in the Solr tutorial, you're using Jetty as a Java Servlet Container (that's why you must start it using "java -jar start.jar"). In our environment we prefer to use Apache Tomcat to host Solr, which installs like a Windows service and works more like .NET developers expect. See the SolrTomcat page.Some best practices for running Solr on Windows: Use the 64-bits version of Tomcat. In our tests, this doubled the req/sec we were able to handle!Use a .NET XmlReader to convert Solr's XML output-stream to .NET objects. Don't use XPath; it won't scale well.Use filter queries ("fq" parameter) instead of the normal "q" parameter where possible. Filter queries are cached by Solr and will speed up Solr's response time (see FilterQueryGuidance)In my next post I’ll talk about how to keep Solr's indexed data in sync with the data in your SQL tables. Timestamps / rowversions will help you out here!

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  • Form, function and complexity in rule processing

    - by Charles Young
    Tim Bass posted on ‘Orwellian Event Processing’. I was involved in a heated exchange in the comments, and he has more recently published a post entitled ‘Disadvantages of Rule-Based Systems (Part 1)’. Whatever the rights and wrongs of our exchange, it clearly failed to generate any agreement or understanding of our different positions. I don't particularly want to promote further argument of that kind, but I do want to take the opportunity of offering a different perspective on rule-processing and an explanation of my comments. For me, the ‘red rag’ lay in Tim’s claim that “...rules alone are highly inefficient for most classes of (not simple) problems” and a later paragraph that appears to equate the simplicity of form (‘IF-THEN-ELSE’) with simplicity of function.   It is not the first time Tim has expressed these views and not the first time I have responded to his assertions.   Indeed, Tim has a long history of commenting on the subject of complex event processing (CEP) and, less often, rule processing in ‘robust’ terms, often asserting that very many other people’s opinions on this subject are mistaken.   In turn, I am of the opinion that, certainly in terms of rule processing, which is an area in which I have a specific interest and knowledge, he is often mistaken. There is no simple answer to the fundamental question ‘what is a rule?’ We use the word in a very fluid fashion in English. Likewise, the term ‘rule processing’, as used widely in IT, is equally difficult to define simplistically. The best way to envisage the term is as a ‘centre of gravity’ within a wider domain. That domain contains many other ‘centres of gravity’, including CEP, statistical analytics, neural networks, natural language processing and so much more. Whole communities tend to gravitate towards and build themselves around some of these centres. The term 'rule processing' is associated with many different technology types, various software products, different architectural patterns, the functional capability of many applications and services, etc. There is considerable variation amongst these different technologies, techniques and products. Very broadly, a common theme is their ability to manage certain types of processing and problem solving through declarative, or semi-declarative, statements of propositional logic bound to action-based consequences. It is generally important to be able to decouple these statements from other parts of an overall system or architecture so that they can be managed and deployed independently.  As a centre of gravity, ‘rule processing’ is no island. It exists in the context of a domain of discourse that is, itself, highly interconnected and continuous.   Rule processing does not, for example, exist in splendid isolation to natural language processing.   On the contrary, an on-going theme of rule processing is to find better ways to express rules in natural language and map these to executable forms.   Rule processing does not exist in splendid isolation to CEP.   On the contrary, an event processing agent can reasonably be considered as a rule engine (a theme in ‘Power of Events’ by David Luckham).   Rule processing does not live in splendid isolation to statistical approaches such as Bayesian analytics. On the contrary, rule processing and statistical analytics are highly synergistic.   Rule processing does not even live in splendid isolation to neural networks. For example, significant research has centred on finding ways to translate trained nets into explicit rule sets in order to support forms of validation and facilitate insight into the knowledge stored in those nets. What about simplicity of form?   Many rule processing technologies do indeed use a very simple form (‘If...Then’, ‘When...Do’, etc.)   However, it is a fundamental mistake to equate simplicity of form with simplicity of function.   It is absolutely mistaken to suggest that simplicity of form is a barrier to the efficient handling of complexity.   There are countless real-world examples which serve to disprove that notion.   Indeed, simplicity of form is often the key to handling complexity. Does rule processing offer a ‘one size fits all’. No, of course not.   No serious commentator suggests it does.   Does the design and management of large knowledge bases, expressed as rules, become difficult?   Yes, it can do, but that is true of any large knowledge base, regardless of the form in which knowledge is expressed.   The measure of complexity is not a function of rule set size or rule form.  It tends to be correlated more strongly with the size of the ‘problem space’ (‘search space’) which is something quite different.   Analysis of the problem space and the algorithms we use to search through that space are, of course, the very things we use to derive objective measures of the complexity of a given problem. This is basic computer science and common practice. Sailing a Dreadnaught through the sea of information technology and lobbing shells at some of the islands we encounter along the way does no one any good.   Building bridges and causeways between islands so that the inhabitants can collaborate in open discourse offers hope of real progress.

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  • WebLogic Server Performance and Tuning: Part I - Tuning JVM

    - by Gokhan Gungor
    Each WebLogic Server instance runs in its own dedicated Java Virtual Machine (JVM) which is their runtime environment. Every Admin Server in any domain executes within a JVM. The same also applies for Managed Servers. WebLogic Server can be used for a wide variety of applications and services which uses the same runtime environment and resources. Oracle WebLogic ships with 2 different JVM, HotSpot and JRocket but you can choose which JVM you want to use. JVM is designed to optimize itself however it also provides some startup options to make small changes. There are default values for its memory and garbage collection. In real world, you will not want to stick with the default values provided by the JVM rather want to customize these values based on your applications which can produce large gains in performance by making small changes with the JVM parameters. We can tell the garbage collector how to delete garbage and we can also tell JVM how much space to allocate for each generation (of java Objects) or for heap. Remember during the garbage collection no other process is executed within the JVM or runtime, which is called STOP THE WORLD which can affect the overall throughput. Each JVM has its own memory segment called Heap Memory which is the storage for java Objects. These objects can be grouped based on their age like young generation (recently created objects) or old generation (surviving objects that have lived to some extent), etc. A java object is considered garbage when it can no longer be reached from anywhere in the running program. Each generation has its own memory segment within the heap. When this segment gets full, garbage collector deletes all the objects that are marked as garbage to create space. When the old generation space gets full, the JVM performs a major collection to remove the unused objects and reclaim their space. A major garbage collect takes a significant amount of time and can affect system performance. When we create a managed server either on the same machine or on remote machine it gets its initial startup parameters from $DOMAIN_HOME/bin/setDomainEnv.sh/cmd file. By default two parameters are set:     Xms: The initial heapsize     Xmx: The max heapsize Try to set equal initial and max heapsize. The startup time can be a little longer but for long running applications it will provide a better performance. When we set -Xms512m -Xmx1024m, the physical heap size will be 512m. This means that there are pages of memory (in the state of the 512m) that the JVM does not explicitly control. It will be controlled by OS which could be reserve for the other tasks. In this case, it is an advantage if the JVM claims the entire memory at once and try not to spend time to extend when more memory is needed. Also you can use -XX:MaxPermSize (Maximum size of the permanent generation) option for Sun JVM. You should adjust the size accordingly if your application dynamically load and unload a lot of classes in order to optimize the performance. You can set the JVM options/heap size from the following places:     Through the Admin console, in the Server start tab     In the startManagedWeblogic script for the managed servers     $DOMAIN_HOME/bin/startManagedWebLogic.sh/cmd     JAVA_OPTIONS="-Xms1024m -Xmx1024m" ${JAVA_OPTIONS}     In the setDomainEnv script for the managed servers and admin server (domain wide)     USER_MEM_ARGS="-Xms1024m -Xmx1024m" When there is free memory available in the heap but it is too fragmented and not contiguously located to store the object or when there is actually insufficient memory we can get java.lang.OutOfMemoryError. We should create Thread Dump and analyze if that is possible in case of such error. The second option we can use to produce higher throughput is to garbage collection. We can roughly divide GC algorithms into 2 categories: parallel and concurrent. Parallel GC stops the execution of all the application and performs the full GC, this generally provides better throughput but also high latency using all the CPU resources during GC. Concurrent GC on the other hand, produces low latency but also low throughput since it performs GC while application executes. The JRockit JVM provides some useful command-line parameters that to control of its GC scheme like -XgcPrio command-line parameter which takes the following options; XgcPrio:pausetime (To minimize latency, parallel GC) XgcPrio:throughput (To minimize throughput, concurrent GC ) XgcPrio:deterministic (To guarantee maximum pause time, for real time systems) Sun JVM has similar parameters (like  -XX:UseParallelGC or -XX:+UseConcMarkSweepGC) to control its GC scheme. We can add -verbosegc -XX:+PrintGCDetails to monitor indications of a problem with garbage collection. Try configuring JVM’s of all managed servers to execute in -server mode to ensure that it is optimized for a server-side production environment.

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  • Back to Basics: When does a .NET Assembly Dependency get loaded

    - by Rick Strahl
    When we work on typical day to day applications, it's easy to forget some of the core features of the .NET framework. For me personally it's been a long time since I've learned about some of the underlying CLR system level services even though I rely on them on a daily basis. I often think only about high level application constructs and/or high level framework functionality, but the low level stuff is often just taken for granted. Over the last week at DevConnections I had all sorts of low level discussions with other developers about the inner workings of this or that technology (especially in light of my Low Level ASP.NET Architecture talk and the Razor Hosting talk). One topic that came up a couple of times and ended up a point of confusion even amongst some seasoned developers (including some folks from Microsoft <snicker>) is when assemblies actually load into a .NET process. There are a number of different ways that assemblies are loaded in .NET. When you create a typical project assemblies usually come from: The Assembly reference list of the top level 'executable' project The Assembly references of referenced projects Dynamically loaded at runtime via AppDomain/Reflection loading In addition .NET automatically loads mscorlib (most of the System namespace) the boot process that hosts the .NET runtime in EXE apps, or some other kind of runtime hosting environment (runtime hosting in servers like IIS, SQL Server or COM Interop). In hosting environments the runtime host may also pre-load a bunch of assemblies on its own (for example the ASP.NET host requires all sorts of assemblies just to run itself, before ever routing into your user specific code). Assembly Loading The most obvious source of loaded assemblies is the top level application's assembly reference list. You can add assembly references to a top level application and those assembly references are then available to the application. In a nutshell, referenced assemblies are not immediately loaded - they are loaded on the fly as needed. So regardless of whether you have an assembly reference in a top level project, or a dependent assembly assemblies typically load on an as needed basis, unless explicitly loaded by user code. The same is true of dependent assemblies. To check this out I ran a simple test: I have a utility assembly Westwind.Utilities which is a general purpose library that can work in any type of project. Due to a couple of small requirements for encoding and a logging piece that allows logging Web content (dependency on HttpContext.Current) this utility library has a dependency on System.Web. Now System.Web is a pretty large assembly and generally you'd want to avoid adding it to a non-Web project if it can be helped. So I created a Console Application that loads my utility library: You can see that the top level Console app a reference to Westwind.Utilities and System.Data (beyond the core .NET libs). The Westwind.Utilities project on the other hand has quite a few dependencies including System.Web. I then add a main program that accesses only a simple utillity method in the Westwind.Utilities library that doesn't require any of the classes that access System.Web: static void Main(string[] args) { Console.WriteLine(StringUtils.NewStringId()); Console.ReadLine(); } StringUtils.NewStringId() calls into Westwind.Utilities, but it doesn't rely on System.Web. Any guesses what the assembly list looks like when I stop the code on the ReadLine() command? I'll wait here while you think about it… … … So, when I stop on ReadLine() and then fire up Process Explorer and check the assembly list I get: We can see here that .NET has not actually loaded any of the dependencies of the Westwind.Utilities assembly. Also not loaded is the top level System.Data reference even though it's in the dependent assembly list of the top level project. Since this particular function I called only uses core System functionality (contained in mscorlib) there's in fact nothing else loaded beyond the main application and my Westwind.Utilities assembly that contains the method accessed. None of the dependencies of Westwind.Utilities loaded. If you were to open the assembly in a disassembler like Reflector or ILSpy, you would however see all the compiled in dependencies. The referenced assemblies are in the dependency list and they are loadable, but they are not immediately loaded by the application. In other words the C# compiler and .NET linker are smart enough to figure out the dependencies based on the code that actually is referenced from your application and any dependencies cascading down into the dependencies from your top level application into the referenced assemblies. In the example above the usage requirement is pretty obvious since I'm only calling a single static method and then exiting the app, but in more complex applications these dependency relationships become very complicated - however it's all taken care of by the compiler and linker figuring out what types and members are actually referenced and including only those assemblies that are in fact referenced in your code or required by any of your dependencies. The good news here is: That if you are referencing an assembly that has a dependency on something like System.Web in a few places that are not actually accessed by any of your code or any dependent assembly code that you are calling, that assembly is never loaded into memory! Some Hosting Environments pre-load Assemblies The load behavior can vary however. In Console and desktop applications we have full control over assembly loading so we see the core CLR behavior. However other environments like ASP.NET for example will preload referenced assemblies explicitly as part of the startup process - primarily to minimize load conflicts. Specifically ASP.NET pre-loads all assemblies referenced in the assembly list and the /bin folder. So in Web applications it definitely pays to minimize your top level assemblies if they are not used. Understanding when Assemblies Load To clarify and see it actually happen what I described in the first example , let's look at a couple of other scenarios. To see assemblies loading at runtime in real time lets create a utility function to print out loaded assemblies to the console: public static void PrintAssemblies() { var assemblies = AppDomain.CurrentDomain.GetAssemblies(); foreach (var assembly in assemblies) { Console.WriteLine(assembly.GetName()); } } Now let's look at the first scenario where I have class method that references internally uses System.Web. In the first scenario lets add a method to my main program like this: static void Main(string[] args) { Console.WriteLine(StringUtils.NewStringId()); Console.ReadLine(); PrintAssemblies(); } public static void WebLogEntry() { var entry = new WebLogEntry(); entry.UpdateFromRequest(); Console.WriteLine(entry.QueryString); } UpdateFromWebRequest() internally accesses HttpContext.Current to read some information of the ASP.NET Request object so it clearly needs a reference System.Web to work. In this first example, the method that holds the calling code is never called, but exists as a static method that can potentially be called externally at some point. What do you think will happen here with the assembly loading? Will System.Web load in this example? No - it doesn't. Because the WebLogEntry() method is never called by the mainline application (or anywhere else) System.Web is not loaded. .NET dynamically loads assemblies as code that needs it is called. No code references the WebLogEntry() method and so System.Web is never loaded. Next, let's add the call to this method, which should trigger System.Web to be loaded because a dependency exists. Let's change the code to: static void Main(string[] args) { Console.WriteLine(StringUtils.NewStringId()); Console.WriteLine("--- Before:"); PrintAssemblies(); WebLogEntry(); Console.WriteLine("--- After:"); PrintAssemblies(); Console.ReadLine(); } public static void WebLogEntry() { var entry = new WebLogEntry(); entry.UpdateFromRequest(); Console.WriteLine(entry.QueryString); } Looking at the code now, when do you think System.Web will be loaded? Will the before list include it? Yup System.Web gets loaded, but only after it's actually referenced. In fact, just until before the call to UpdateFromRequest() System.Web is not loaded - it only loads when the method is actually called and requires the reference in the executing code. Moral of the Story So what have we learned - or maybe remembered again? Dependent Assembly References are not pre-loaded when an application starts (by default) Dependent Assemblies that are not referenced by executing code are never loaded Dependent Assemblies are just in time loaded when first referenced in code All of this is nothing new - .NET has always worked like this. But it's good to have a refresher now and then and go through the exercise of seeing it work in action. It's not one of those things we think about everyday, and as I found out last week, I couldn't remember exactly how it worked since it's been so long since I've learned about this. And apparently I'm not the only one as several other people I had discussions with in relation to loaded assemblies also didn't recall exactly what should happen or assumed incorrectly that just having a reference automatically loads the assembly. The moral of the story for me is: Trying at all costs to eliminate an assembly reference from a component is not quite as important as it's often made out to be. For example, the Westwind.Utilities module described above has a logging component, including a Web specific logging entry that supports pulling information from the active HTTP Context. Adding that feature requires a reference to System.Web. Should I worry about this in the scope of this library? Probably not, because if I don't use that one class of nearly a hundred, System.Web never gets pulled into the parent process. IOW, System.Web only loads when I use that specific feature and if I am, well I clearly have to be running in a Web environment anyway to use it realistically. The alternative would be considerably uglier: Pulling out the WebLogEntry class and sticking it into another assembly and breaking up the logging code. In this case - definitely not worth it. So, .NET definitely goes through some pretty nifty optimizations to ensure that it loads only what it needs and in most cases you can just rely on .NET to do the right thing. Sometimes though assembly loading can go wrong (especially when signed and versioned local assemblies are involved), but that's subject for a whole other post…© Rick Strahl, West Wind Technologies, 2005-2012Posted in .NET  CSharp   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Trace File Source Adapter

    The Trace File Source adapter is a useful addition to your SSIS toolbox.  It allows you to read 2005 and 2008 profiler traces stored as .trc files and read them into the Data Flow.  From there you can perform filtering and analysis using the power of SSIS. There is no need for a SQL Server connection this just uses the trace file. Example Usages Cache warming for SQL Server Analysis Services Reading the flight recorder Find out the longest running queries on a server Analyze statements for CPU, memory by user or some other criteria you choose Properties The Trace File Source adapter has two properties, both of which combine to control the source trace file that is read at runtime. SQL Server 2005 and SQL Server 2008 trace files are supported for both the Database Engine (SQL Server) and Analysis Services. The properties are managed by the Editor form or can be set directly from the Properties Grid in Visual Studio. Property Type Description AccessMode Enumeration This property determines how the Filename property is interpreted. The values available are: DirectInput Variable Filename String This property holds the path for trace file to load (*.trc). The value is either a full path, or the name of a variable which contains the full path to the trace file, depending on the AccessMode property. Trace Column Definition Hopefully the majority of you can skip this section entirely, but if you encounter some problems processing a trace file this may explain it and allow you to fix the problem. The component is built upon the trace management API provided by Microsoft. Unfortunately API methods that expose the schema of a trace file have known issues and are unreliable, put simply the data often differs from what was specified. To overcome these limitations the component uses  some simple XML files. These files enable the trace column data types and sizing attributes to be overridden. For example SQL Server Profiler or TMO generated structures define EventClass as an integer, but the real value is a string. TraceDataColumnsSQL.xml  - SQL Server Database Engine Trace Columns TraceDataColumnsAS.xml    - SQL Server Analysis Services Trace Columns The files can be found in the %ProgramFiles%\Microsoft SQL Server\100\DTS\PipelineComponents folder, e.g. "C:\Program Files\Microsoft SQL Server\100\DTS\PipelineComponents\TraceDataColumnsSQL.xml" "C:\Program Files\Microsoft SQL Server\100\DTS\PipelineComponents\TraceDataColumnsAS.xml" If at runtime the component encounters a type conversion or sizing error it is most likely due to a discrepancy between the column definition as reported by the API and the actual value encountered. Whilst most common issues have already been fixed through these files we have implemented specific exception traps to direct you to the files to enable you to fix any further issues due to different usage or data scenarios that we have not tested. An example error that you can fix through these files is shown below. Buffer exception writing value to column 'Column Name'. The string value is 999 characters in length, the column is only 111. Columns can be overridden by the TraceDataColumns XML files in "C:\Program Files\Microsoft SQL Server\100\DTS\PipelineComponents\TraceDataColumnsAS.xml". Installation The component is provided as an MSI file which you can download and run to install it. This simply places the files on disk in the correct locations and also installs the assemblies in the Global Assembly Cache as per Microsoft’s recommendations. You may need to restart the SQL Server Integration Services service, as this caches information about what components are installed, as well as restarting any open instances of Business Intelligence Development Studio (BIDS) / Visual Studio that you may be using to build your SSIS packages. Finally you will have to add the transformation to the Visual Studio toolbox manually. Right-click the toolbox, and select Choose Items.... Select the SSIS Data Flow Items tab, and then check the Trace File Source transformation in the Choose Toolbox Items window. This process has been described in detail in the related FAQ entry for How do I install a task or transform component? We recommend you follow best practice and apply the current Microsoft SQL Server Service pack to your SQL Server servers and workstations. Please note that the Microsoft Trace classes used in the component are not supported on 64-bit platforms. To use the Trace File Source on a 64-bit host you need to ensure you have the 32-bit (x86) tools available, and the way you execute your package is setup to use them, please see the help topic 64-bit Considerations for Integration Services for more details. Downloads Trace Sources for SQL Server 2005 -- Trace Sources for SQL Server 2008 Version History SQL Server 2008 Version 2.0.0.382 - SQL Sever 2008 public release. (9 Apr 2009) SQL Server 2005 Version 1.0.0.321 - SQL Server 2005 public release. (18 Nov 2008) -- Screenshots

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  • CodePlex Daily Summary for Saturday, March 10, 2012

    CodePlex Daily Summary for Saturday, March 10, 2012Popular ReleasesPlayer Framework by Microsoft: Player Framework for Windows 8 Metro (BETA): Player Framework for HTML/JavaScript and XAML/C# Metro Style Applications.WPF Application Framework (WAF): WAF for .NET 4.5 (Experimental): Version: 2.5.0.440 (Experimental): This is an experimental release! It can be used to investigate the new .NET Framework 4.5 features. The ideas shown in this release might come in a future release (after 2.5) of the WPF Application Framework (WAF). More information can be found in this dicussion post. Requirements .NET Framework 4.5 (The package contains a solution file for Visual Studio 11) The unit test projects require Visual Studio 11 Professional Changelog All: Upgrade all proje...SSH.NET Library: 2012.3.9: There are still few outstanding issues I wanted to include in this release but since its been a while and there are few new features already I decided to create a new release now. New Features Add SOCKS4, SOCKS5 and HTTP Proxy support when connecting to remote server. For silverlight only IP address can be used for server address when using proxy. Add dynamic port forwarding support using ForwardedPortDynamic class. Add new ShellStream class to work with SSH Shell. Add supports for mu...Test Case Import Utilities for Visual Studio 2010 and Visual Studio 11 Beta: V1.2 RTM: This release (V1.2 RTM) includes: Support for connecting to Hosted Team Foundation Server Preview. Support for connecting to Team Foundation Server 11 Beta. Fix to issue with read-only attribute being set for LinksMapping-ReportFile which may have led to problems when saving the report file. Fix to issue with “related links” not being set properly in certain conditions. Fix to ensure that tool works fine when the Excel file contained rich text data. Note: Data is still imported in pl...Audio Pitch & Shift: Audio Pitch And Shift 3.5.0: Modules (mod, xm, it, etc..) supportcallisto: callisto 2.0.19: BUG FIX: Autorun.load() function in scripting now has sandboxed path (Thanks Mikey!) BUG FIX: UserObject.Name property now allows full 20 byte string replacements. FEATURE REQUEST: File.* script functions now allow file extensions.EntitiesToDTOs - Entity Framework DTO Generator: EntitiesToDTOs.v2.1: Changelog Fixed template file access issue on Win7. Fix on configuration load when target project was not found and "Use project default namespace" was checked. Minor fix on loading latest configuration at startup. Minor fix in VisualStudioHelper class. DTO's properties accessors are now in one line. Improvements in PropertyHelper to get a cleaner and more performant code. Added Website project type as a not supported project type. Using Error List pane from VS IDE to show Enti...DotNetNuke® Community Edition CMS: 06.01.04: Major Highlights Fixed issue with loading the splash page skin in the login, privacy and terms of use pages Fixed issue when searching for words with special characters in them Fixed redirection issue when the user does not have permissions to access a resource Fixed issue when clearing the cache using the ClearHostCache() function Fixed issue when displaying the site structure in the link to page feature Fixed issue when inline editing the title of modules Fixed issue with ...Mayhem: Mayhem Developer Preview: This is the developer preview of Mayhem. Enjoy!Team Foundation Server Process Template Customization Guidance: v1 - For Visual Studio 11: Welcome to the BETA release of the Team Foundation Server Process Template Customization preview. As this is a BETA release and the quality bar for the final Release has not been achieved, we value your candid feedback and recommend that you do not use or deploy these BETA artifacts in a production environment. Quality-Bar Details Documentation has been reviewed by Visual Studio ALM Rangers Documentation has not been through an independent technical review Documentation has not been rev...Magelia WebStore Open-source Ecommerce software: Magelia WebStore 1.2: Medium trust compliant lot of small change for medium trust compliance full refactoring of user management refactoring of Client Refactoring of user management Magelia.WebStore.Client no longer reference Magelia.WebStore.Services.Contract Refactoring page category multi parent category added copy category feature added Refactoring page catalog copy catalog feature added variant management improvement ability to define a default variant for a variable product ability to ord...PDFsharp - A .NET library for processing PDF: PDFsharp and MigraDoc Foundation 1.32: PDFsharp and MigraDoc Foundation 1.32 is a stable version that fixes a few bugs that were found with version 1.31. Version 1.32 includes solutions for Visual Studio 2010 only (but it should be possible to add the project files to existing solutions for VS 2005 or VS 2008). Users of VS 2005 or VS 2008 can still download version 1.31 with the solutions for those versions that allow them to easily try the samples that are included. While it may create smaller PDF files than version 1.30 because...Terminals: Version 2.0 - Release: Changes since version 1.9a:New art works New usability in Organize favorites window Improved usability of imports/exports and scans Large number of fixes Improvements in single instance mode Comparing November beta 4, this corrects: New application icons Doesn't show Logon error codes Fixed command line arguments exception for single instance mode Fixed detaching of tabs improved usability in detached window Fixed option settings for Capture manager Fixed system tray noti...MFCMAPI: March 2012 Release: Build: 15.0.0.1032 Full release notes at SGriffin's blog. If you just want to run the MFCMAPI or MrMAPI, get the executables. If you want to debug them, get the symbol files and the source. The 64 bit builds will only work on a machine with Outlook 2010 64 bit installed. All other machines should use the 32 bit builds, regardless of the operating system. Facebook BadgeTortoiseHg: TortoiseHg 2.3.1: bugfix releaseSimple Injector: Simple Injector v1.4.1: This release adds two small improvements to the SimpleInjector.Extensions.dll. No changes have been made to the core library. New features and improvements in this release for the SimpleInjector.Extensions.dll The RegisterManyForOpenGeneric extension methods now accept non-generic decorator, as long as they implement the given open generic service type. GetTypesToRegister methods added to the OpenGenericBatchRegistrationExtensions class which allows to customize the behavior. Note that the...CommonLibrary: Code: CodeVidCoder: 1.3.1: Updated HandBrake core to 0.9.6 release (svn 4472). Removed erroneous "None" container choice. Change some logic and help text to stop assuming you have to pick the VIDEO_TS folder for a DVD scan. This should make previewing DVD titles on the Queue Multiple Titles window possible when you've picked the root DVD directory.Google Books Downloader for Windows: Google Books Downloader: Google Books Downloader 1.8ExtAspNet: ExtAspNet v3.1.0: ExtAspNet - ?? ExtJS ??? ASP.NET 2.0 ???,????? AJAX ?????????? ExtAspNet ????? ExtJS ??? ASP.NET 2.0 ???,????? AJAX ??????????。 ExtAspNet ??????? JavaScript,?? CSS,?? UpdatePanel,?? ViewState,?? WebServices ???????。 ??????: IE 7.0, Firefox 3.6, Chrome 3.0, Opera 10.5, Safari 3.0+ ????:Apache License 2.0 (Apache) ??:http://extasp.net/ ??:http://bbs.extasp.net/ ??:http://extaspnet.codeplex.com/ ??:http://sanshi.cnblogs.com/ ????: +2012-03-04 v3.1.0 -??Hidden???????(〓?〓)。 -?PageManager??...New ProjectsAres Backup: Ares Backup is a Backup software which can save bytediffs and provides several storage plugins.BackItUp: Backup-Tool für Visual Studio Projektebinbin domain: binbin domain Blexus Service Plattform: Some cool stuff about Wcf Services. - can communicate files - can communicate xaml objects (generate dynamically Gui) CardPlay - a Solitaire Framework for .Net: CardPlay is a C# framework for developing Solitaire card games. The solution includes a sample WPF client along with over 100 games.Cloud Files Upload: Windows application to script cloud file uploads.Code First API Library, Scaffolding & Guidance for Coded UI Tests: Code first Coded UI Tests for web apps. Library, Scaffolding and Guidance.CPEBook by FMUG & TPAY: CPEBook by MUG & TPAY Projet dot NET CPEBookDot Net Application String Resources Viewer: Dot Net Application String Resources ViewerFilter for SharePoint Web Settings Page: This solution show a simple way to integrate a filter box by using jquery, a global farm feature and a simple delegate control for AdditionalPageHead.Google Books Downloader for Windows: Save Google books in PDF, JPEG or PNG format.GUIToolkit: C++ Windowless GUI,DirectUIHarvest Sports: Harvest SportsInfoPath Analyzer: InfoPath Analyzer makes InfoPath form development and troubleshooting much easier. You're easy to find the relationship between controls and data fields, search data fields or controls by name, edit InfoPath inner html directly.Kinectsignlanguage project: This project will help kinect be used for sign language to speech so that sign language people can be understood while talking to important people. LotteryVote: ????manager123: Trying out CodePlexMcRegister: McRegister is an asp.net mvc 3 razor website that enables you to register users on your minecraft server it works in conjunction with a minecraft mod called EasyAuth.MetroTipi: HelloTipi Sous l'interface Metro de Windows 8Microsoft AppFactory: AppFactory is a powerful data-driven build system for Windows Phone (and soon Windows 8) projects. Its purpose is to help developers start with template projects and turn them into suites of applications.MiniStock: MiniStock is an experimental reference architecture for scalable cloud-based architectures. Implemented in .net.online book shopping: online book shoppingScopa: Carousel Team Scopa per WP7 XNA testtom03092012tfs01: testtom03092012tfs01UsingLib: A library of automatically removed utilities: 1.Changing cursor to hourglass in Windows Forms 2.Logging It's developed in C#WHMCS Library: WHMCS is an all-in-one client management, billing & support solution for online businesses. Handling everything from signup to termination, WHMCS is a powerful business automation tool that puts you firmly in control. The WHMCS Library is a .NET wrapper for the WHMCS API. Written entirely in C# but really easy to port over to VB.NET. Coming from a VB.NET background we tried hard to make sure porting would be simple for VB.NET community members. ZoneEditService: Windows service to update ZoneEdit for dynamic dns.

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  • SSAS Compare: an intern’s journey

    - by Red Gate Software BI Tools Team
    About a month ago, David mentioned an intern working in the BI Tools Team. That intern happens to be me! In five weeks’ time, I’ll start my second year of Computer Science at the University of Cambridge and be a full-time student again, but for the past eight weeks, I’ve been living a completely different life. As Jon mentioned before, the teams here at Red Gate are small and everyone (including the interns!) is responsible for the product as a whole. I’ve attended planning sessions, UX tests, daily meetings, and everything else a full-time member of the team would; I had as much say in where we would go next with the product as anyone; I was able to see that what I was doing was an important part of the product from the feedback we got in the UX tests. All these things almost made me forget that this is just an internship and not my full-time job. First steps at Red Gate Being based in Cambridge, Red Gate has many Cambridge university graduates working for them. They also hire some Cambridge undergraduates for internships each summer. With its popularity with university graduates and its great working environment, Red Gate has managed to build up a great reputation. When I thought of doing an internship here in Cambridge, Red Gate just seemed to be the obvious choice for my first real work experience. On my first day at Red Gate, David, the lead developer for SSAS Compare, helped me settle in and explained what I’d be doing. My task was to improve the user experience of displaying differences between MDX scripts by syntax highlighting, script formatting, and improving the difference identification in the first place. David suggested how I should approach the problem, but left all the details and design decisions to me. That was when I realised how much independence and responsibility I’d have. What I’ve done If you launch the latest version of SSAS Compare and drill down to an MDX script difference, you can see the changes that have been made. In earlier versions, you could only see the scripts in plain text on both sides — either in black or grey, depending on whether they were the same or not. However, you couldn’t see exactly where the scripts were different, which was especially annoying when the two scripts were large – as they often are. Furthermore, if parts of the two scripts were formatted differently, they seemed to be different but were actually the same, which caused even more confusion and made it difficult to see where the differences were. All these issues have been fixed now. The two scripts are automatically formatted by the tool so that if two things are syntactically equivalent, they look the same – including case differences in keywords! The actual difference is highlighted in grey, which makes them easy to spot. The difference identification has been improved as well, so two scripts aren’t identified as different if there’s just a difference in meaningless whitespace characters, or when you have “select” on one side and “SELECT” on the other. We also have syntax highlighting, which makes it easier to read the scripts. How I did it In order to do the formatting properly, we decided to parse the MDX scripts. After some investigation into parser builders, I decided to go with the GOLD Parser builder and the bsn-goldparser .NET engine. GOLD Parser builder provides a fairly nice GUI to write, build, and test grammar in. We also liked the idea of separating the grammar building from parsing a text. The bsn-goldparser is one of many .NET engines for GOLD, and although it doesn’t support the newest features of GOLD Parser, it has “the ability to map semantic action classes to terminals or reduction rules, so that a completely functional semantic AST can be created directly without intermediate token AST representation, and without the need for glue code.” That makes it much easier for us to change the implementation in our program when we change the grammar. As bsn-goldparser is open source, and I wanted some more features in it, I contributed two new features which have now been merged to the project. Unfortunately, there wasn’t an MDX grammar written for GOLD already, so I had to write it myself. I was referencing MSDN to get the formal grammar specification, but the specification was all over the place, so it wasn’t that easy to implement and find. We’re aware that we don’t yet fully support all valid MDX, so sometimes you’ll just see the MDX script difference displayed the old way. In that case, there is some grammar construct we don’t yet recognise. If you come across something SSAS Compare doesn’t recognise, we’d love to hear about it so we can add it to our grammar. When some MDX script gets parsed, a tree is produced. That tree can then be processed into a list of inlines which deal with the correct formatting and can be outputted to the screen. Doing all this has led me to many new technologies and projects I haven’t worked with before. This was my first experience with C# and Visual Studio, although I have done things in Java before. I have learnt how to unit test with NUnit, how to do dependency injection with Ninject, how to source-control code with SVN and Mercurial, how to build with TeamCity, how to use GOLD, and many other things. What’s coming next Sadly, my internship comes to an end this week, so there will be less development on MDX difference view for a while. But the team is going to work on marking the differences better and making it consistent with difference indication in the top part of comparison window, and will keep adding support for more MDX grammar so you can see the differences easily in every comparison you make. So long! And maybe I’ll see you next summer!

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  • Auto-Suggest via &lsquo;Trie&rsquo; (Pre-fix Tree)

    - by Strenium
    Auto-Suggest (Auto-Complete) “thing” has been around for a few years. Here’s my little snippet on the subject. For one of my projects, I had to deal with a non-trivial set of items to be pulled via auto-suggest used by multiple concurrent users. Simple, dumb iteration through a list in local cache or back-end access didn’t quite cut it. Enter a nifty little structure, perfectly suited for storing and matching verbal data: “Trie” (http://tinyurl.com/db56g) also known as a Pre-fix Tree: “Unlike a binary search tree, no node in the tree stores the key associated with that node; instead, its position in the tree defines the key with which it is associated. All the descendants of a node have a common prefix of the string associated with that node, and the root is associated with the empty string. Values are normally not associated with every node, only with leaves and some inner nodes that correspond to keys of interest.” This is a very scalable, performing structure. Though, as usual, something ‘fast’ comes at a cost of ‘size’; fortunately RAM is more plentiful today so I can live with that. I won’t bore you with the detailed algorithmic performance here - Google can do a better job of such. So, here’s C# implementation of all this. Let’s start with individual node: Trie Node /// <summary> /// Contains datum of a single trie node. /// </summary> public class AutoSuggestTrieNode {     public char Value { get; set; }       /// <summary>     /// Gets a value indicating whether this instance is leaf node.     /// </summary>     /// <value>     ///     <c>true</c> if this instance is leaf node; otherwise, a prefix node <c>false</c>.     /// </value>     public bool IsLeafNode { get; private set; }       public List<AutoSuggestTrieNode> DescendantNodes { get; private set; }         /// <summary>     /// Initializes a new instance of the <see cref="AutoSuggestTrieNode"/> class.     /// </summary>     /// <param name="value">The phonetic value.</param>     /// <param name="isLeafNode">if set to <c>true</c> [is leaf node].</param>     public AutoSuggestTrieNode(char value = ' ', bool isLeafNode = false)     {         Value = value;         IsLeafNode = isLeafNode;           DescendantNodes = new List<AutoSuggestTrieNode>();     }       /// <summary>     /// Gets the descendants of the pre-fix node, if any.     /// </summary>     /// <param name="descendantValue">The descendant value.</param>     /// <returns></returns>     public AutoSuggestTrieNode GetDescendant(char descendantValue)     {         return DescendantNodes.FirstOrDefault(descendant => descendant.Value == descendantValue);     } }   Quite self-explanatory, imho. A node is either a “Pre-fix” or a “Leaf” node. “Leaf” contains the full “word”, while the “Pre-fix” nodes act as indices used for matching the results.   Ok, now the Trie: Trie Structure /// <summary> /// Contains structure and functionality of an AutoSuggest Trie (Pre-fix Tree) /// </summary> public class AutoSuggestTrie {     private readonly AutoSuggestTrieNode _root = new AutoSuggestTrieNode();       /// <summary>     /// Adds the word to the trie by breaking it up to pre-fix nodes + leaf node.     /// </summary>     /// <param name="word">Phonetic value.</param>     public void AddWord(string word)     {         var currentNode = _root;         word = word.Trim().ToLower();           for (int i = 0; i < word.Length; i++)         {             var child = currentNode.GetDescendant(word[i]);               if (child == null) /* this character hasn't yet been indexed in the trie */             {                 var newNode = new AutoSuggestTrieNode(word[i], word.Count() - 1 == i);                   currentNode.DescendantNodes.Add(newNode);                 currentNode = newNode;             }             else                 currentNode = child; /* this character is already indexed, move down the trie */         }     }         /// <summary>     /// Gets the suggested matches.     /// </summary>     /// <param name="word">The phonetic search value.</param>     /// <returns></returns>     public List<string> GetSuggestedMatches(string word)     {         var currentNode = _root;         word = word.Trim().ToLower();           var indexedNodesValues = new StringBuilder();         var resultBag = new ConcurrentBag<string>();           for (int i = 0; i < word.Trim().Length; i++)  /* traverse the trie collecting closest indexed parent (parent can't be leaf, obviously) */         {             var child = currentNode.GetDescendant(word[i]);               if (child == null || word.Count() - 1 == i)                 break; /* done looking, the rest of the characters aren't indexed in the trie */               indexedNodesValues.Append(word[i]);             currentNode = child;         }           Action<AutoSuggestTrieNode, string> collectAllMatches = null;         collectAllMatches = (node, aggregatedValue) => /* traverse the trie collecting matching leafNodes (i.e. "full words") */             {                 if (node.IsLeafNode) /* full word */                     resultBag.Add(aggregatedValue); /* thread-safe write */                   Parallel.ForEach(node.DescendantNodes, descendandNode => /* asynchronous recursive traversal */                 {                     collectAllMatches(descendandNode, String.Format("{0}{1}", aggregatedValue, descendandNode.Value));                 });             };           collectAllMatches(currentNode, indexedNodesValues.ToString());           return resultBag.OrderBy(o => o).ToList();     }         /// <summary>     /// Gets the total words (leafs) in the trie. Recursive traversal.     /// </summary>     public int TotalWords     {         get         {             int runningCount = 0;               Action<AutoSuggestTrieNode> traverseAllDecendants = null;             traverseAllDecendants = n => { runningCount += n.DescendantNodes.Count(o => o.IsLeafNode); n.DescendantNodes.ForEach(traverseAllDecendants); };             traverseAllDecendants(this._root);               return runningCount;         }     } }   Matching operations and Inserts involve traversing the nodes before the right “spot” is found. Inserts need be synchronous since ordering of data matters here. However, matching can be done in parallel traversal using recursion (line 64). Here’s sample usage:   [TestMethod] public void AutoSuggestTest() {     var autoSuggestCache = new AutoSuggestTrie();       var testInput = @"Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer nec odio. Praesent libero.                 Sed cursus ante dapibus diam. Sed nisi. Nulla quis sem at nibh elementum imperdiet. Duis sagittis ipsum. Praesent mauris.                 Fusce nec tellus sed augue semper porta. Mauris massa. Vestibulum lacinia arcu eget nulla. Class aptent taciti sociosqu ad                 litora torquent per conubia nostra, per inceptos himenaeos. Curabitur sodales ligula in libero. Sed dignissim lacinia nunc.                 Curabitur tortor. Pellentesque nibh. Aenean quam. In scelerisque sem at dolor. Maecenas mattis. Sed convallis tristique sem.                 Proin ut ligula vel nunc egestas porttitor. Morbi lectus risus, iaculis vel, suscipit quis, luctus non, massa. Fusce ac                 turpis quis ligula lacinia aliquet. Mauris ipsum. Nulla metus metus, ullamcorper vel, tincidunt sed, euismod in, nibh. Quisque                 volutpat condimentum velit. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Nam                 nec ante. Sed lacinia, urna non tincidunt mattis, tortor neque adipiscing diam, a cursus ipsum ante quis turpis. Nulla                 facilisi. Ut fringilla. Suspendisse potenti. Nunc feugiat mi a tellus consequat imperdiet. Vestibulum sapien. Proin quam. Etiam                 ultrices. Suspendisse in justo eu magna luctus suscipit. Sed lectus. Integer euismod lacus luctus magna. Quisque cursus, metus                 vitae pharetra auctor, sem massa mattis sem, at interdum magna augue eget diam. Vestibulum ante ipsum primis in faucibus orci                 luctus et ultrices posuere cubilia Curae; Morbi lacinia molestie dui. Praesent blandit dolor. Sed non quam. In vel mi sit amet                 augue congue elementum. Morbi in ipsum sit amet pede facilisis laoreet. Donec lacus nunc, viverra nec.";       testInput.Split(' ').ToList().ForEach(word => autoSuggestCache.AddWord(word));       var testMatches = autoSuggestCache.GetSuggestedMatches("le"); }   ..and the result: That’s it!

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  • ViewBag dynamic in ASP.NET MVC 3 - RC 2

    - by hajan
    Earlier today Scott Guthrie announced the ASP.NET MVC 3 - Release Candidate 2. I installed the new version right after the announcement since I was eager to see the new features. Among other cool features included in this release candidate, there is a new ViewBag dynamic which can be used to pass data from Controllers to Views same as you use ViewData[] dictionary. What is great and nice about ViewBag (despite the name) is that its a dynamic type which means you can dynamically get/set values and add any number of additional fields without need of strongly-typed classes. In order to see the difference, please take a look at the following examples. Example - Using ViewData Controller public ActionResult Index() {     List<string> colors = new List<string>();     colors.Add("red");     colors.Add("green");     colors.Add("blue");                 ViewData["listColors"] = colors;     ViewData["dateNow"] = DateTime.Now;     ViewData["name"] = "Hajan";     ViewData["age"] = 25;     return View(); } View (ASPX View Engine) <p>     My name is     <b><%: ViewData["name"] %></b>,     <b><%: ViewData["age"] %></b> years old.     <br />         I like the following colors: </p> <ul id="colors"> <% foreach (var color in ViewData["listColors"] as List<string>){ %>     <li>        <font color="<%: color %>"><%: color %></font>    </li> <% } %> </ul> <p>     <%: ViewData["dateNow"] %> </p> (I know the code might look cleaner with Razor View engine, but it doesn’t matter right? ;) ) Example - Using ViewBag Controller public ActionResult Index() {     List<string> colors = new List<string>();     colors.Add("red");     colors.Add("green");     colors.Add("blue");     ViewBag.ListColors = colors; //colors is List     ViewBag.DateNow = DateTime.Now;     ViewBag.Name = "Hajan";     ViewBag.Age = 25;     return View(); } You see the difference? View (ASPX View Engine) <p>     My name is     <b><%: ViewBag.Name %></b>,     <b><%: ViewBag.Age %></b> years old.     <br />         I like the following colors: </p> <ul id="colors"> <% foreach (var color in ViewBag.ListColors) { %>     <li>         <font color="<%: color %>"><%: color %></font>     </li> <% } %> </ul> <p>     <%: ViewBag.DateNow %> </p> In my example now I don’t need to cast ViewBag.ListColors as List<string> since ViewBag is dynamic type! On the other hand the ViewData[“key”] is object.I would like to note that if you use ViewData["ListColors"] = colors; in your Controller, you can retrieve it in the View by using ViewBag.ListColors. And the result in both cases is Hope you like it! Regards, Hajan

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  • New .NET Library for Accessing the Survey Monkey API

    - by Ben Emmett
    I’ve used Survey Monkey’s API for a while, and though it’s pretty powerful, there’s a lot of boilerplate each time it’s used in a new project, and the json it returns needs a bunch of processing to be able to use the raw information. So I’ve finally got around to releasing a .NET library you can use to consume the API more easily. The main advantages are: Only ever deal with strongly-typed .NET objects, making everything much more robust and a lot faster to get going Automatically handles things like rate-limiting and paging through results Uses combinations of endpoints to get all relevant data for you, and processes raw response data to map responses to questions To start, either install it using NuGet with PM> Install-Package SurveyMonkeyApi (easier option), or grab the source from https://github.com/bcemmett/SurveyMonkeyApi if you prefer to build it yourself. You’ll also need to have signed up for a developer account with Survey Monkey, and have both your API key and an OAuth token. A simple usage would be something like: string apiKey = "KEY"; string token = "TOKEN"; var sm = new SurveyMonkeyApi(apiKey, token); List<Survey> surveys = sm.GetSurveyList(); The surveys object is now a list of surveys with all the information available from the /surveys/get_survey_list API endpoint, including the title, id, date it was created and last modified, language, number of questions / responses, and relevant urls. If there are more than 1000 surveys in your account, the library pages through the results for you, making multiple requests to get a complete list of surveys. All the filtering available in the API can be controlled using .NET objects. For example you might only want surveys created in the last year and containing “pineapple” in the title: var settings = new GetSurveyListSettings { Title = "pineapple", StartDate = DateTime.Now.AddYears(-1) }; List<Survey> surveys = sm.GetSurveyList(settings); By default, whenever optional fields can be requested with a response, they will all be fetched for you. You can change this behaviour if for some reason you explicitly don’t want the information, using var settings = new GetSurveyListSettings { OptionalData = new GetSurveyListSettingsOptionalData { DateCreated = false, AnalysisUrl = false } }; Survey Monkey’s 7 read-only endpoints are supported, and the other 4 which make modifications to data might be supported in the future. The endpoints are: Endpoint Method Object returned /surveys/get_survey_list GetSurveyList() List<Survey> /surveys/get_survey_details GetSurveyDetails() Survey /surveys/get_collector_list GetCollectorList() List<Collector> /surveys/get_respondent_list GetRespondentList() List<Respondent> /surveys/get_responses GetResponses() List<Response> /surveys/get_response_counts GetResponseCounts() Collector /user/get_user_details GetUserDetails() UserDetails /batch/create_flow Not supported Not supported /batch/send_flow Not supported Not supported /templates/get_template_list Not supported Not supported /collectors/create_collector Not supported Not supported The hierarchy of objects the library can return is Survey List<Page> List<Question> QuestionType List<Answer> List<Item> List<Collector> List<Response> Respondent List<ResponseQuestion> List<ResponseAnswer> Each of these classes has properties which map directly to the names of properties returned by the API itself (though using PascalCasing which is more natural for .NET, rather than the snake_casing used by SurveyMonkey). For most users, Survey Monkey imposes a rate limit of 2 requests per second, so by default the library leaves at least 500ms between requests. You can request higher limits from them, so if you want to change the delay between requests just use a different constructor: var sm = new SurveyMonkeyApi(apiKey, token, 200); //200ms delay = 5 reqs per sec There’s a separate cap of 1000 requests per day for each API key, which the library doesn’t currently enforce, so if you think you’ll be in danger of exceeding that you’ll need to handle it yourself for now.  To help, you can see how many requests the current instance of the SurveyMonkeyApi object has made by reading its RequestsMade property. If the library encounters any errors, including communicating with the API, it will throw a SurveyMonkeyException, so be sure to handle that sensibly any time you use it to make calls. Finally, if you have a survey (or list of surveys) obtained using GetSurveyList(), the library can automatically fill in all available information using sm.FillMissingSurveyInformation(surveys); For each survey in the list, it uses the other endpoints to fill in the missing information about the survey’s question structure, respondents, and responses. This results in at least 5 API calls being made per survey, so be careful before passing it a large list. It also joins up the raw response information to the survey’s question structure, so that for each question in a respondent’s set of replies, you can access a ProcessedAnswer object. For example, a response to a dropdown question (from the /surveys/get_responses endpoint) might be represented in json as { "answers": [ { "row": "9384627365", } ], "question_id": "615487516" } Separately, the question’s structure (from the /surveys/get_survey_details endpoint) might have several possible answers, one of which might look like { "text": "Fourth item in dropdown list", "visible": true, "position": 4, "type": "row", "answer_id": "9384627365" } The library understands how this mapping works, and uses that to give you the following ProcessedAnswer object, which first describes the family and type of question, and secondly gives you the respondent’s answers as they relate to the question. Survey Monkey has many different question types, with 11 distinct data structures, each of which are supported by the library. If you have suggestions or spot any bugs, let me know in the comments, or even better submit a pull request .

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  • LLBLGen Pro v3.5 has been released!

    - by FransBouma
    Last weekend we released LLBLGen Pro v3.5! Below the list of what's new in this release. Of course, not everything is on this list, like the large amount of work we put in refactoring the runtime framework. The refactoring was necessary because our framework has two paradigms which are added to the framework at a different time, and from a design perspective in the wrong order (the paradigm we added first, SelfServicing, should have been built on top of Adapter, the other paradigm, which was added more than a year after the first released version). The refactoring made sure the framework re-uses more code across the two paradigms (they already shared a lot of code) and is better prepared for the future. We're not done yet, but refactoring a massive framework like ours without breaking interfaces and existing applications is ... a bit of a challenge ;) To celebrate the release of v3.5, we give every customer a 30% discount! Use the coupon code NR1ORM with your order :) The full list of what's new: Designer Rule based .NET Attribute definitions. It's now possible to specify a rule using fine-grained expressions with an attribute definition to define which elements of a given type will receive the attribute definition. Rules can be assigned to attribute definitions on the project level, to make it even easier to define attribute definitions in bulk for many elements in the project. More information... Revamped Project Settings dialog. Multiple project related properties and settings dialogs have been merged into a single dialog called Project Settings, which makes it easier to configure the various settings related to project elements. It also makes it easier to find features previously not used  by many (e.g. type conversions) More information... Home tab with Quick Start Guides. To make new users feel right at home, we added a home tab with quick start guides which guide you through four main use cases of the designer. System Type Converters. Many common conversions have been implemented by default in system type converters so users don't have to develop their own type converters anymore for these type conversions. Bulk Element Setting Manipulator. To change setting values for multiple project elements, it was a little cumbersome to do that without a lot of clicking and opening various editors. This dialog makes changing settings for multiple elements very easy. EDMX Importer. It's now possible to import entity model data information from an existing Entity Framework EDMX file. Other changes and fixes See for the full list of changes and fixes the online documentation. LLBLGen Pro Runtime Framework WCF Data Services (OData) support has been added. It's now possible to use your LLBLGen Pro runtime framework powered domain layer in a WCF Data Services application using the VS.NET tools for WCF Data Services. WCF Data Services is a Microsoft technology for .NET 4 to expose your domain model using OData. More information... New query specification and execution API: QuerySpec. QuerySpec is our new query specification and execution API as an alternative to Linq and our more low-level API. It's build, like our Linq provider, on top of our lower-level API. More information... SQL Server 2012 support. The SQL Server DQE allows paging using the new SQL Server 2012 style. More information... System Type converters. For a common set of types the LLBLGen Pro runtime framework contains built-in type conversions so you don't need to write your own type converters anymore. Public/NonPublic property support. It's now possible to mark a field / navigator as non-public which is reflected in the runtime framework as an internal/friend property instead of a public property. This way you can hide properties from the public interface of a generated class and still access it through code added to the generated code base. FULL JOIN support. It's now possible to perform FULL JOIN joins using the native query api and QuerySpec. It's left to the developer to check whether the used target database supports FULL (OUTER) JOINs. Using a FULL JOIN with entity fetches is not recommended, and should only be used when both participants in the join aren't the target of the fetch. Dependency Injection Tracing. It's now possible to enable tracing on dependency injection. Enable tracing at level '4' on the traceswitch 'ORMGeneral'. This will emit trace information about which instance of which type got an instance of type T injected into property P. Entity Instances in projections in Linq. It's now possible to return an entity instance in a custom Linq projection. It's now also possible to pass this instance to a method inside the query projection. Inheritance fully supported in this construct. Entity Framework support The Entity Framework has been updated in the recent year with code-first support and a new simpler context api: DbContext (with DbSet). The amount of code to generate is smaller and the context simpler. LLBLGen Pro v3.5 comes with support for DbContext and DbSet and generates code which utilizes these new classes. NHibernate support NHibernate v3.2+ built-in proxy factory factory support. By default the built-in ProxyFactoryFactory is selected. FluentNHibernate Session Manager uses 1.2 syntax. Fluent NHibernate mappings generate a SessionManager which uses the v1.2 syntax for the ProxyFactoryFactory location Optionally emit schema / catalog name in mappings Two settings have been added which allow the user to control whether the catalog name and/or schema name as known in the project in the designer is emitted into the mappings.

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  • Book Review: Oracle ADF Real World Developer’s Guide

    - by Frank Nimphius
    Recently PACKT Publishing published "Oracle ADF Real World Developer’s Guide" by Jobinesh Purushothaman, a product manager in our team. Though already the sixth book dedicated to Oracle ADF, it has a lot of great information in it that none of the previous books covered, making it a safe buy even for those who own the other books published by Oracle Press (McGrwHill) and PACKT Publishing. More than the half of the "Oracle ADF Real World Developer’s Guide" book is dedicated to Oracle ADF Business Components in a depth and clarity that allows you to feel the expertise that Jobinesh gained in this area. If you enjoy Jobinesh blog (http://jobinesh.blogspot.co.uk/) about Oracle ADF, then, no matter what expert you are in Oracle ADF, this book makes you happy as it provides you with detail information you always wished to have. If you are new to Oracle ADF, then this book alone doesn't get you flying, but, if you have some Java background, accelerates your learning big, big, big times. Chapter 1 is an introduction to Oracle ADF and not only explains the layers but also how it compares to plain Java EE solutions (page 13). If you are new to Oracle JDeveloper and ADF, then at the end of this chapter you know how to start JDeveloper and begin your ADF development Chapter 2 starts with what Jobinesh really is good at: ADF Business Components. In this chapter you learn about the architecture ingredients of ADF Business Components: View Objects, View Links, Associations, Entities, Row Sets, Query Collections and Application Modules. This chapter also provides a introduction to ADFBC SDO services, as well as sequence diagrams for what happens when you execute queries or commit updates. Chapter 3 is dedicated to entity objects and  is one of many chapters in this book you will enjoy and never want to miss. Jobinesh explains the artifacts that make up an entity object, how to work with entities and resource bundles, and many advanced topics, including inheritance, change history tracking, custom properties, validation and cursor handling.  Chapter 4 - you guessed it - is all about View objects. Comparable to entities, you learn about the XM files and classes that make a view object, as well as how to define and work with queries. List-of-values, inheritance, polymorphism, bind variables and data filtering are interesting - and important topics that follow. Again the chapter provides helpful sequence diagrams for you to understand what happens internally within a view object. Chapter 5 focuses on advanced view object and entity object topics, like lifecycle callback methods and when you want to override them. This chapter is a good digest of Jobinesh's blog entries (which most ADF developers have in their bookmark list). Really worth reading ! Chapter 6 then is bout Application Modules. Beside of what application modules are, this chapter covers important topics like properties, passivation, activation, application module pooling, how and where to write custom logic. In addition you learn about the AM lifecycle and request sequence. Chapter 7 is about the ADF binding layer. If you are new to Oracle ADF and got lost in the more advanced ADF Business Components chapters, then this chapter is where you get back into the game. In very easy terms, Jobinesh explains what the ADF binding is, how it fits into the JSF request lifecycle and what are the metadata file involved. Chapter 8 then goes into building data bound web user interfaces. In this chapter you get the basics of JavaServer Faces (e.g. managed beans) and learn about the interaction between the JSF UI and the ADF binding layer. Later this chapter provides advanced solutions for working with tree components and list of values. Chapter 9 introduces bounded task flows and ADF controller. This is a chapter you want to read if you are new to ADF of have started. Experts don't find anything new here, which doesn't mean that it is not worth reading it (I for example, enjoyed the controller talk very much) Chapter 10 is an advanced coverage of bounded task flow and talks about contextual events  Chapter 11 is another highlight and explains error handling, trains, transactions and more. I can only recommend you read this chapter. I am aware of many documents that cover exception handling in Oracle ADF (and my Oracle Magazine article for January/February 2013 does the same), but none that covers it in such a great depth. Chapter 12 covers ADF best practices, which is a great round-up of all the tips provided in this book (without Jobinesh to repeat himself). Its all cool stuff that helps you with your ADF projects. In summary, "Oracle ADF Real World Developer’s Guide" by Jobinesh Purushothaman is a great book and addition for all Oracle ADF developers and those who want to become one. Frank

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  • Testing Mobile Websites with Adobe Shadow

    - by dwahlin
    It’s no surprise that mobile development is all the rage these days. With all of the new mobile devices being released nearly every day the ability for developers to deliver mobile solutions is more important than ever. Nearly every developer or company I’ve talked to recently about mobile development in training classes, at conferences, and on consulting projects says that they need to find a solution to get existing websites into the mobile space. Although there are several different frameworks out there that can be used such as jQuery Mobile, Sencha Touch, jQTouch, and others, how do you test how your site renders on iOS, Android, Blackberry, Windows Phone, and the variety of mobile form factors out there? Although there are different virtual solutions that can be used including Electric Plum for iOS, emulators, browser plugins for resizing the laptop/desktop browser, and more, at some point you need to test on as many physical devices as possible. This can be extremely challenging and quite time consuming though especially when you consider that you have to manually enter URLs into devices and click links on each one to drill-down into sites. Adobe Labs just released a product called Adobe Shadow (thanks to Kurt Sprinzl for letting me know about it) that significantly simplifies testing sites on physical devices, debugging problems you find, and even making live modifications to HTML and CSS content while viewing a site on the device to see how rendering changes. You can view a page in your laptop/desktop browser and have it automatically pushed to all of your devices without actually touching the device (a huge time saver). See a problem with a device? Locate it using the free Chrome extension, pull up inspection tools (based on the Chrome Developer tools) and make live changes through Chrome that appear on the respective device so that it’s easy to identify how problems can be resolved. I’ve been using Adobe Shadow and am very impressed with the amount of time saved and the different features that it offers. In the rest of the post I’ll walk through how to get it installed, get it started, and use it to view and debug pages.   Getting Adobe Shadow Installed The following steps can be used to get Adobe Shadow installed: 1. Download and install Adobe Shadow on your laptop/desktop 2. Install the Adobe Shadow extension for Chrome 3. Install the Adobe Shadow app on all of your devices (you can find it in various app stores) 4. Connect your devices to Wifi. Make sure they’re on the same network that your laptop/desktop machine is on   Getting Adobe Shadow Started Once Adobe Shadow is installed, you’ll need to get it running on your laptop/desktop and on all your mobile devices. The following steps walk through that process: 1. Start the Adobe Shadow application on your laptop/desktop 2. Start the Adobe Shadow app on each of your mobile devices 3. Locate the laptop/desktop name in the list that’s shown on each mobile device: 4. Select the laptop/desktop name and a passcode will be shown: 5. Open the Adobe Shadow Chrome extension on the laptop/desktop and enter the passcode for the given device: Using Adobe Shadow to View and Modify Pages Once Adobe Shadow is up and running on your laptop/desktop and on all of your mobile devices you can navigate to a page in Chrome on the laptop/desktop and it will automatically be pushed out to all connected mobile devices. If you have 5 mobile devices setup they’ll all navigate to the page displayed in Chrome (pretty awesome!). This makes it super easy to see how a given page looks on your iPad, Android device, etc. without having to touch the device itself. If you find a problem with a page on a device you can select the device in the Chrome Adobe Shadow extension on your laptop/desktop and select the remote inspector icon (it’s the < > icon): This will pull up the Adobe Shadow remote debugging window which contains the standard Chrome Developer tool tabs such as Elements, Resources, Network, etc. Click on the Elements tab to see the HTML rendered for the target device and then drill into the respective HTML content, CSS styles, etc. As HTML elements are selected in the Adobe Shadow debugging tool they’ll be highlighted on the device itself just like they would if you were debugging a page directly in Chrome with the developer tools. Here’s an example from my Android device that shows how the page looks on the device as I select different HTML elements on the laptop/desktop: Conclusion I’m really impressed with what I’ve to this point from Adobe Shadow. Controlling pages that display on devices directly from my laptop/desktop is a big time saver and the ability to remotely see changes made through the Chrome Developer Tools (on my laptop/desktop) really pushes the tool over the top. If you’re developing mobile applications it’s definitely something to check out. It’s currently free to download and use. For additional details check out the video below:  

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  • Invariant code contracts – using class-wide contracts

    - by DigiMortal
    It is possible to define invariant code contracts for classes. Invariant contracts should always hold true whatever member of class is called. In this posting I will show you how to use invariant code contracts so you understand how they work and how they should be tested. This is my randomizer class I am using to demonstrate code contracts. I added one method for invariant code contracts. Currently there is one contract that makes sure that random number generator is not null. public class Randomizer {     private IRandomGenerator _generator;       private Randomizer() { }       public Randomizer(IRandomGenerator generator)     {         _generator = generator;     }       public int GetRandomFromRangeContracted(int min, int max)     {         Contract.Requires<ArgumentOutOfRangeException>(             min < max,             "Min must be less than max"         );           Contract.Ensures(             Contract.Result<int>() >= min &&             Contract.Result<int>() <= max,             "Return value is out of range"         );           return _generator.Next(min, max);     }       [ContractInvariantMethod]     private void ObjectInvariant()     {         Contract.Invariant(_generator != null);     } } Invariant code contracts are define in methods that have ContractInvariantMethod attribute. Some notes: It is good idea to define invariant methods as private. Don’t call invariant methods from your code because code contracts system does not allow it. Invariant methods are defined only as place where you can keep invariant contracts. Invariant methods are called only when call to some class member is made! The last note means that having invariant method and creating Randomizer object with null as argument does not automatically generate exception. We have to call at least one method from Randomizer class. Here is the test for generator. You can find more about contracted code testing from my posting Code Contracts: Unit testing contracted code. There is also explained why the exception handling in test is like it is. [TestMethod] [ExpectedException(typeof(Exception))] public void Should_fail_if_generator_is_null() {     try     {         var randomizer = new Randomizer(null);         randomizer.GetRandomFromRangeContracted(1, 4);     }     catch (Exception ex)     {         throw new Exception(ex.Message, ex);     } } Try out this code – with unit tests or with test application to see that invariant contracts are checked as soon as you call some member of Randomizer class.

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  • CodePlex Daily Summary for Friday, July 19, 2013

    CodePlex Daily Summary for Friday, July 19, 2013Popular ReleasesuComponents: uComponents v5.5.0: Following on from our 101355 release, we bring you... v5.5.0! Resolved issues The following issues have been resolved in 5.5.0: 14634 14848 DataType Grid 14840 14842 14845 UpgradingThe best way to upgrade uComponents is to re-install via Umbraco's back-office package installer, (either from the package repository or a local package upload). Do not uninstall an existing uComponents package, as this may lead to data loss! Umbraco compatibilityThis release is compatible with Umbraco 4...51Degrees.mobi - Mobile Device Detection and Redirection: 2.1.19.4: One Click Install from NuGet This release introduces the 51Degrees.mobi IIS Vary Header Fix. When Compression and Caching is used in IIS, the Vary header is overwritten, making intelligent caching with dynamic content impossible. Find out more about installing the Vary Header fix. Changes to Version 2.1.19.4Handlers now have a ‘Count’ property. This is an integer value that shows how many devices in the dataset that use that handler. Provider.cs -> GetDeviceInfoByID to address a problem w...SalarDbCodeGenerator: SalarDbCodeGenerator v2.1.2013.0719: Version 2.1.2013.0719 2013/7/19 Pattern Changes: * DapperContext pattern is added. * All patterns are updated to work with one-to-one relations. Changes: * One-to-one relation is supported. * Minor bug fixes.Scryber PDF Generation: Scryber.Installer.v0.8.3: This one has tables! A significant update to the scryber library, with the inclusion of tables. There is no column span, or row span, and nested tables are not fully supported. But - they overflow nicely and are well styled. And they can be data bound. Other updates The Link element has inner components directly as a child, rather than in a Content element. The existing files will still continue to work, but are invalid wrt the schema. Databinding is now supported at the document level, r...Player Framework by Microsoft: Player Framework for Windows and WP (v1.3 beta 2): Includes all changes in v1.3 beta 1 Additional support for Windows 8.1 Preview New API (JS): addTextTrack New API (JS): msKeys New API (JS): msPlayToPreferredSourceUri New API (JS): msSetMediaKeys New API (JS): onmsneedkey New API (Xaml): SetMediaStreamSource method New API (Xaml): Stretch property New API (Xaml): StretchChanged event New API (Xaml): AreTransportControlsEnabled property New API (Xaml): IsFullWindow property New API (Xaml): PlayToPreferredSourceUri proper...Outlook 2013 Add-In: Multiple Calendars: As per popular request, this new version includes: - Support for multiple calendars. This can be enabled in the configuration by choosing which ones to show/hide appointments from. In some cases (public folders) it may time out and crash, and so far it only supports "My Calendars", so not shared ones yet. Also they're currently shown in the same font/color so there are no confusions with color categories, but please drop me a line on any suggestions you'd like to see implemented. - Added fri...GoAgent GUI: GoAgent GUI 1.2.0 ???: *???????,??????????????,?????????????? ????????* ????????(Beta) Beta????:https://goagent.codeplex.com/workitem/list/basic ??????:uygw@outlook.com ????:https://goagent.codeplex.com/documentation ?????????????????。Circuit Diagram: Circuit Diagram 2.0 Beta 2: New in this release: Show grid in editor Cut/copy/paste support Bug fixesAscend 3D: Ascend (2013-07-17): Ascend 2.1 Animation bugfixes and speed/robustness improvements Added compatibility for multiple top-level bones on armatures Ascend Blender Exporter 2.1 Removed need to create parent-child relationship between armature and skinning mesh Added support for exporting multiple top-level bones on armatures AscendViewer 1.0.4 Updated to use latest version of Ascend libraryCommunity TFS Build Extensions: July 2013: The July 2013 release contains VS2010 Activities(target .NET 4.0) VS2012 Activities (target .NET 4.5) VS2013 Activities (target .NET 4.5.1) Community TFS Build Manager VS2012 The Community TFS Build Manager can also be found in the Visual Studio Gallery here where updates will first become available. A version supporting VS2010 is also available in the Gallery here.smoketestgit1: new release: Wiki Markup Guide bold italics underline Heading 1 Heading 2 Bullet List Bullet List 2 Number List Number List 2 http://www.example.com Do not apply formattingsmoketesthg: new release: Wiki Markup Guide bold italics underline Heading 1 Heading 2 Bullet List Bullet List 2 Number List Number List 2 http://www.example.com Do not apply formattingsmoketesttfs: new release: Wiki Markup Guide bold italics underline Heading 1 Heading 2 Bullet List Bullet List 2 Number List Number List 2 http://www.example.com Do not apply formattingdatajs - JavaScript Library for data-centric web applications: datajs version 1.1.1: datajs is a cross-browser and UI agnostic JavaScript library that enables data-centric web applications with the following features: OData client that enables CRUD operations including batching and metadata support using both ATOM and JSON payloads. Single store abstraction that provides a common API on top of HTML5 local storage technologies. Data cache component that allows reading data ranges from a collection and storing them locally to reduce the number of network requests. Changes ...Orchard Project: Orchard 1.7 RC: Planning releasedTerminals: Version 3.1 - Release: Changes since version 3.0:15992 Unified usage of icons in user interface Added context menu in Organize favorites grid Fixed:34219 34210 34223 33981 34209 Install notes:No changes in database (use database from release 3.0) No upgrade of configuration, passwords, credentials or favorites See also upgrade notes for release 3.0Media Companion: Media Companion MC3.573b: XBMC Link - Let MC update your XBMC Library Fixes in place, Enjoy the XBMC Link function Well, Phil's been busy in the background, and come up with a Great new feature for Media Companion. Currently only implemented for movies. Once we're happy that's working with no issues, we'll extend the functionality to include TV shows. All the help for this is build into the application. Go to General Preferences - XBMC Link for details. Help us make it better* Currently only tested on local and ...Wsus Package Publisher: Release v1.2.1307.15: Fix a bug where WPP crash if 'ShowPendingUpdates' is start with wrong credentials. Fix a bug where WPP crash if ArrivalDateAfter and ArrivalDateBefore is equal in the ComputerView. Add a filter in the ComputerView. (Thanks to NorbertFe for this feature request) Add an option, when right-clicking on a computer, you can ask for display the current logon user of the remote computer. Add an option in settings to choose if WPP ping remote computers using IPv4, IPv6 or IPv6 and, if fail, IP...Lab Of Things: vBeta1: Initial release of LoTVidCoder: 1.4.23: New in 1.4.23 Added French translation. Fixed non-x264 video encoders not sticking in video tab. New in 1.4 Updated HandBrake core to 0.9.9 Blu-ray subtitle (PGS) support Additional framerates: 30, 50, 59.94, 60 Additional sample rates: 8, 11.025, 12 and 16 kHz Additional higher bitrates for audio Same as Source Constant Framerate 24-bit FLAC encoding Added Windows Phone 8 and Apple TV 3 presets Introduced process isolation for encodes. Now if HandBrake crashes, VidCoder will ...New Projects[C#]A Complete MySQL Manager Project: An open-source MySQL database manager oriented to multi-threading environments, supporting to create an entire database from scratch and edit it.bCal Javascript Calendar Generator: Using this simple javascript library, you can create simple navigable calendars in your website with just one line of user code.Better Network: Tools to delete network profile and network lists in Windows 8.C# Intellisense for Notepad++: 'CS-Script Intellisense' is a real C# intellisense solution based on CS-Script and ICSharpCode.NRefactory/Mono.Cecil.DARF: Dynamic Application Runtime Framework: A set of tools and libraries which help software developers create fully distributed and component-based applications. FeiXinV5: Just TestFollower Catcher: Game made for the 2012 Windows 8 Megathon. Second place in Madrid's local competition.MeeOS .NET: El primer sistema operativo GNU GPL en español.Music Vault: Music Vault is program to store your favorite music in one place, you can in any time move all your music library by moving only one file.MVC uTorrent: This is an ASP.NET MVC uTorrent front end, that utilises the uTorrent API. The main features: - Single page application - Can be hosted in IISMyTaskManager: This project Related to distribute the task to log in users OO2RDF: OO2RDF is a framework for data triplification. P(y)rotein Subcellular Location Image Database: A library that allows communication with an OMERO database, an open-source software for storage and manipulation of biological images.PE Toolbox: PE Toolbox ? ????? ?? ???????????, ????? ??????? ??? ??????????? ?? ?????. ???? ????? ??????????? ???????: - PE IFE (Importing from Excel) PeGscan: *PeGscan*ScriptZilla: ScriptZilla is an Free Editor for Windows with more Than 23 Languages.Sharepoint : Reconciliate SSRS Reports and Datasets with datasources Powershell: Powershell to link datasources to SSRS reports and datasetsSync-Moped: The idea behind the "Sync-Moped" is to synchronize two directories with backup functionality.System.Time: System.Time provides a type for .NET that allows the managing of a time in System.String, System.DateTime and System.TimeSpan form at the same time.Text Analytics: Project summary will be added later.Tibia Universal MC .NET: This tool was written as an attempt to port the [url:http://code.google.com/p/xenomc/] to the .NET Framework.VRFramework: VR Framework is a system for creating a virtual reality games using your PC, and Android smart phone, and Unity 3D.

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  • How to build Open JavaFX for Android.

    - by PictureCo
    Here's a short recipe for baking JavaFX for Android dalvik. We will need just a few ingredients but each one requires special care. So let's get down to the business.  SourcesThe first ingredient is an open JavaFX repository. This should be piece of cake. As always there's a catch. You probably know that dalvik is jdk6 compatible  and also that certain APIs are missing comparing to good old java vm from Oracle.  Fortunately there is a repository which is a backport of regular OpenJFX to jdk7 and going from jdk7 to jdk6 is possible. The first thing to do is to clone or download the repository from https://bitbucket.org/narya/jfx78. Main page of the project says "It works in some cases" so we will presume that it will work in most cases As I've said dalvik vm misses some APIs which would lead to a build failures. To get them use another compatibility repository which is available on GitHub https://github.com/robovm/robovm-jfx78-compat. Download the zip and unzip sources into jfx78/modules/base.We need also a javafx binary stubs. Use jfxrt.jar from jdk8.The last thing to download are freetype sources from http://freetype.org. These will be necessary for native font rendering. Toolchain setup I have to point out that these instructions were tested only on linux. I suppose they will work with minimal changes also on Mac OS. I also presume that you were able to build open JavaFX. That means all tools like ant, gradle, gcc and jdk8 have been installed and are working all right. In addition to this you will need to download and install jdk7, Android SDK and Android NDK for native code compilation.  Installing all of them will take some time. Don't forget to put them in your path. export ANDROID_SDK=/opt/android-sdk-linux export ANDROID_NDK=/opt/android-ndk-r9b export JAVA_HOME=/opt/jdk1.7.0 export PATH=$JAVA_HOME/bin:$ANDROID_SDK/tools:$ANDROID_SDK/platform-tools:$ANDROID_NDK FreetypeUnzip freetype release sources first. We will have to cross compile them for arm. Firstly we will create a standalone toolchain for cross compiling installed in ~/work/ndk-standalone-19. $ANDROID_NDK/build/tools/make-standalone-toolchain.sh  --platform=android-19 --install-dir=~/work/ndk-standalone-19 After the standalone toolchain has been created cross compile freetype with following script: export TOOLCHAIN=~/work/freetype/ndk-standalone-19 export PATH=$TOOLCHAIN/bin:$PATH export FREETYPE=`pwd` ./configure --host=arm-linux-androideabi --prefix=$FREETYPE/install --without-png --without-zlib --enable-shared sed -i 's/\-version\-info \$(version_info)/-avoid-version/' builds/unix/unix-cc.mk make make install It will compile and install freetype library into $FREETYPE/install. We will link to this install dir later on. It would be possible also to link openjfx font support dynamically against skia library available on Android which already contains freetype. It creates smaller result but can have compatibility problems. Patching Download patches javafx-android-compat.patch + android-tools.patch and patch jfx78 repository. I recommend to have look at patches. First one android-compat.patch updates openjfx build script, removes dependency on SharedSecret classes and updates LensLogger to remove dependency on jdk specific PlatformLogger. Second one android-tools.patch creates helper script in android-tools. The script helps to setup javaFX Android projects. Building Now is time to try the build. Run following script: JAVA_HOME=/opt/jdk1.7.0 JDK_HOME=/opt/jdk1.7.0 ANDROID_SDK=/opt/android-sdk-linux ANDROID_NDK=/opt/android-ndk-r9b PATH=$JAVA_HOME/bin:$ANDROID_SDK/tools:$ANDROID_SDK/platform-tools:$ANDROID_NDK:$PATH gradle -PDEBUG -PDALVIK_VM=true -PBINARY_STUB=~/work/binary_stub/linux/rt/lib/ext/jfxrt.jar \ -PFREETYPE_DIR=~/work/freetype/install -PCOMPILE_TARGETS=android If everything went all right the output is in build/android-sdk Create first JavaFX Android project Use gradle script int android-tools. The script sets the project structure for you.   Following command creates Android HelloWorld project which links to a freshly built javafx runtime and to a HelloWorld application. NAME is a name of Android project. DIR where to create our first project. PACKAGE is package name required by Android. It has nothing to do with a packaging of javafx application. JFX_SDK points to our recently built runtime. JFX_APP points to dist directory of javafx application. (where all application jars sit) JFX_MAIN is fully qualified name of a main class. gradle -PDEBUG -PDIR=/home/user/work -PNAME=HelloWorld -PPACKAGE=com.helloworld \ -PJFX_SDK=/home/user/work/jfx78/build/android-sdk -PJFX_APP=/home/user/NetBeansProjects/HelloWorld/dist \ -PJFX_MAIN=com.helloworld.HelloWorld createProject Now cd to the created project and use it like any other android project. ant clean, debug, uninstall, installd will work. I haven't tried it from any IDE Eclipse nor Netbeans. Special thanks to Stefan Fuchs and Daniel Zwolenski for the repositories used in this blog post.

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  • What is the most efficient way to convert to binary and back in C#?

    - by Saad Imran.
    I'm trying to write a general purpose socket server for a game I'm working on. I know I could very well use already built servers like SmartFox and Photon, but I wan't to go through the pain of creating one myself for learning purposes. I've come up with a BSON inspired protocol to convert the the basic data types, their arrays, and a special GSObject to binary and arrange them in a way so that it can be put back together into object form on the client end. At the core, the conversion methods utilize the .Net BitConverter class to convert the basic data types to binary. Anyways, the problem is performance, if I loop 50,000 times and convert my GSObject to binary each time it takes about 5500ms (the resulting byte[] is just 192 bytes per conversion). I think think this would be way too slow for an MMO that sends 5-10 position updates per second with a 1000 concurrent users. Yes, I know it's unlikely that a game will have a 1000 users on at the same time, but like I said earlier this is supposed to be a learning process for me, I want to go out of my way and build something that scales well and can handle at least a few thousand users. So yea, if anyone's aware of other conversion techniques or sees where I'm loosing performance I would appreciate the help. GSBitConverter.cs This is the main conversion class, it adds extension methods to main datatypes to convert to the binary format. It uses the BitConverter class to convert the base types. I've shown only the code to convert integer and integer arrays, but the rest of the method are pretty much replicas of those two, they just overload the type. public static class GSBitConverter { public static byte[] ToGSBinary(this short value) { return BitConverter.GetBytes(value); } public static byte[] ToGSBinary(this IEnumerable<short> value) { List<byte> bytes = new List<byte>(); short length = (short)value.Count(); bytes.AddRange(length.ToGSBinary()); for (int i = 0; i < length; i++) bytes.AddRange(value.ElementAt(i).ToGSBinary()); return bytes.ToArray(); } public static byte[] ToGSBinary(this bool value); public static byte[] ToGSBinary(this IEnumerable<bool> value); public static byte[] ToGSBinary(this IEnumerable<byte> value); public static byte[] ToGSBinary(this int value); public static byte[] ToGSBinary(this IEnumerable<int> value); public static byte[] ToGSBinary(this long value); public static byte[] ToGSBinary(this IEnumerable<long> value); public static byte[] ToGSBinary(this float value); public static byte[] ToGSBinary(this IEnumerable<float> value); public static byte[] ToGSBinary(this double value); public static byte[] ToGSBinary(this IEnumerable<double> value); public static byte[] ToGSBinary(this string value); public static byte[] ToGSBinary(this IEnumerable<string> value); public static string GetHexDump(this IEnumerable<byte> value); } Program.cs Here's the the object that I'm converting to binary in a loop. class Program { static void Main(string[] args) { GSObject obj = new GSObject(); obj.AttachShort("smallInt", 15); obj.AttachInt("medInt", 120700); obj.AttachLong("bigInt", 10900800700); obj.AttachDouble("doubleVal", Math.PI); obj.AttachStringArray("muppetNames", new string[] { "Kermit", "Fozzy", "Piggy", "Animal", "Gonzo" }); GSObject apple = new GSObject(); apple.AttachString("name", "Apple"); apple.AttachString("color", "red"); apple.AttachBool("inStock", true); apple.AttachFloat("price", (float)1.5); GSObject lemon = new GSObject(); apple.AttachString("name", "Lemon"); apple.AttachString("color", "yellow"); apple.AttachBool("inStock", false); apple.AttachFloat("price", (float)0.8); GSObject apricoat = new GSObject(); apple.AttachString("name", "Apricoat"); apple.AttachString("color", "orange"); apple.AttachBool("inStock", true); apple.AttachFloat("price", (float)1.9); GSObject kiwi = new GSObject(); apple.AttachString("name", "Kiwi"); apple.AttachString("color", "green"); apple.AttachBool("inStock", true); apple.AttachFloat("price", (float)2.3); GSArray fruits = new GSArray(); fruits.AddGSObject(apple); fruits.AddGSObject(lemon); fruits.AddGSObject(apricoat); fruits.AddGSObject(kiwi); obj.AttachGSArray("fruits", fruits); Stopwatch w1 = Stopwatch.StartNew(); for (int i = 0; i < 50000; i++) { byte[] b = obj.ToGSBinary(); } w1.Stop(); Console.WriteLine(BitConverter.IsLittleEndian ? "Little Endian" : "Big Endian"); Console.WriteLine(w1.ElapsedMilliseconds + "ms"); } Here's the code for some of my other classes that are used in the code above. Most of it is repetitive. GSObject GSArray GSWrappedObject

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  • Inside the Concurrent Collections: ConcurrentBag

    - by Simon Cooper
    Unlike the other concurrent collections, ConcurrentBag does not really have a non-concurrent analogy. As stated in the MSDN documentation, ConcurrentBag is optimised for the situation where the same thread is both producing and consuming items from the collection. We'll see how this is the case as we take a closer look. Again, I recommend you have ConcurrentBag open in a decompiler for reference. Thread Statics ConcurrentBag makes heavy use of thread statics - static variables marked with ThreadStaticAttribute. This is a special attribute that instructs the CLR to scope any values assigned to or read from the variable to the executing thread, not globally within the AppDomain. This means that if two different threads assign two different values to the same thread static variable, one value will not overwrite the other, and each thread will see the value they assigned to the variable, separately to any other thread. This is a very useful function that allows for ConcurrentBag's concurrency properties. You can think of a thread static variable: [ThreadStatic] private static int m_Value; as doing the same as: private static Dictionary<Thread, int> m_Values; where the executing thread's identity is used to automatically set and retrieve the corresponding value in the dictionary. In .NET 4, this usage of ThreadStaticAttribute is encapsulated in the ThreadLocal class. Lists of lists ConcurrentBag, at its core, operates as a linked list of linked lists: Each outer list node is an instance of ThreadLocalList, and each inner list node is an instance of Node. Each outer ThreadLocalList is owned by a particular thread, accessible through the thread local m_locals variable: private ThreadLocal<ThreadLocalList<T>> m_locals It is important to note that, although the m_locals variable is thread-local, that only applies to accesses through that variable. The objects referenced by the thread (each instance of the ThreadLocalList object) are normal heap objects that are not specific to any thread. Thinking back to the Dictionary analogy above, if each value stored in the dictionary could be accessed by other means, then any thread could access the value belonging to other threads using that mechanism. Only reads and writes to the variable defined as thread-local are re-routed by the CLR according to the executing thread's identity. So, although m_locals is defined as thread-local, the m_headList, m_nextList and m_tailList variables aren't. This means that any thread can access all the thread local lists in the collection by doing a linear search through the outer linked list defined by these variables. Adding items So, onto the collection operations. First, adding items. This one's pretty simple. If the current thread doesn't already own an instance of ThreadLocalList, then one is created (or, if there are lists owned by threads that have stopped, it takes control of one of those). Then the item is added to the head of that thread's list. That's it. Don't worry, it'll get more complicated when we account for the other operations on the list! Taking & Peeking items This is where it gets tricky. If the current thread's list has items in it, then it peeks or removes the head item (not the tail item) from the local list and returns that. However, if the local list is empty, it has to go and steal another item from another list, belonging to a different thread. It iterates through all the thread local lists in the collection using the m_headList and m_nextList variables until it finds one that has items in it, and it steals one item from that list. Up to this point, the two threads had been operating completely independently. To steal an item from another thread's list, the stealing thread has to do it in such a way as to not step on the owning thread's toes. Recall how adding and removing items both operate on the head of the thread's linked list? That gives us an easy way out - a thread trying to steal items from another thread can pop in round the back of another thread's list using the m_tail variable, and steal an item from the back without the owning thread knowing anything about it. The owning thread can carry on completely independently, unaware that one of its items has been nicked. However, this only works when there are at least 3 items in the list, as that guarantees there will be at least one node between the owning thread performing operations on the list head and the thread stealing items from the tail - there's no chance of the two threads operating on the same node at the same time and causing a race condition. If there's less than three items in the list, then there does need to be some synchronization between the two threads. In this case, the lock on the ThreadLocalList object is used to mediate access to a thread's list when there's the possibility of contention. Thread synchronization In ConcurrentBag, this is done using several mechanisms: Operations performed by the owner thread only take out the lock when there are less than three items in the collection. With three or greater items, there won't be any conflict with a stealing thread operating on the tail of the list. If a lock isn't taken out, the owning thread sets the list's m_currentOp variable to a non-zero value for the duration of the operation. This indicates to all other threads that there is a non-locked operation currently occuring on that list. The stealing thread always takes out the lock, to prevent two threads trying to steal from the same list at the same time. After taking out the lock, the stealing thread spinwaits until m_currentOp has been set to zero before actually performing the steal. This ensures there won't be a conflict with the owning thread when the number of items in the list is on the 2-3 item borderline. If any add or remove operations are started in the meantime, and the list is below 3 items, those operations try to take out the list's lock and are blocked until the stealing thread has finished. This allows a thread to steal an item from another thread's list without corrupting it. What about synchronization in the collection as a whole? Collection synchronization Any thread that operates on the collection's global structure (accessing anything outside the thread local lists) has to take out the collection's global lock - m_globalListsLock. This single lock is sufficient when adding a new thread local list, as the items inside each thread's list are unaffected. However, what about operations (such as Count or ToArray) that need to access every item in the collection? In order to ensure a consistent view, all operations on the collection are stopped while the count or ToArray is performed. This is done by freezing the bag at the start, performing the global operation, and unfreezing at the end: The global lock is taken out, to prevent structural alterations to the collection. m_needSync is set to true. This notifies all the threads that they need to take out their list's lock irregardless of what operation they're doing. All the list locks are taken out in order. This blocks all locking operations on the lists. The freezing thread waits for all current lockless operations to finish by spinwaiting on each m_currentOp field. The global operation can then be performed while the bag is frozen, but no other operations can take place at the same time, as all other threads are blocked on a list's lock. Then, once the global operation has finished, the locks are released, m_needSync is unset, and normal concurrent operation resumes. Concurrent principles That's the essence of how ConcurrentBag operates. Each thread operates independently on its own local list, except when they have to steal items from another list. When stealing, only the stealing thread is forced to take out the lock; the owning thread only has to when there is the possibility of contention. And a global lock controls accesses to the structure of the collection outside the thread lists. Operations affecting the entire collection take out all locks in the collection to freeze the contents at a single point in time. So, what principles can we extract here? Threads operate independently Thread-static variables and ThreadLocal makes this easy. Threads operate entirely concurrently on their own structures; only when they need to grab data from another thread is there any thread contention. Minimised lock-taking Even when two threads need to operate on the same data structures (one thread stealing from another), they do so in such a way such that the probability of actually blocking on a lock is minimised; the owning thread always operates on the head of the list, and the stealing thread always operates on the tail. Management of lockless operations Any operations that don't take out a lock still have a 'hook' to force them to lock when necessary. This allows all operations on the collection to be stopped temporarily while a global snapshot is taken. Hopefully, such operations will be short-lived and infrequent. That's all the concurrent collections covered. I hope you've found it as informative and interesting as I have. Next, I'll be taking a closer look at ThreadLocal, which I came across while analyzing ConcurrentBag. As you'll see, the operation of this class deserves a much closer look.

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