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• SQL SERVER – Weekly Series – Memory Lane – #048

  - by Pinal Dave

  Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2007 Order of Result Set of SELECT Statement on Clustered Indexed Table When ORDER BY is Not Used Above theory is true in most of the cases. However SQL Server does not use that logic when returning the resultset. SQL Server always returns the resultset which it can return fastest.In most of the cases the resultset which can be returned fastest is the resultset which is returned using clustered index. Effect of TRANSACTION on Local Variable – After ROLLBACK and After COMMIT One of the Jr. Developer asked me this question (What will be the Effect of TRANSACTION on Local Variable – After ROLLBACK and After COMMIT?) while I was rushing to an important meeting. I was getting late so I asked him to talk with his Application Tech Lead. When I came back from meeting both of them were looking for me. They said they are confused. I quickly wrote down following example for them. 2008 SQL SERVER – Guidelines and Coding Standards Complete List Download Coding standards and guidelines are very important for any developer on the path of a successful career. A coding standard is a set of guidelines, rules and regulations on how to write code. Coding standards should be flexible enough or should take care of the situation where they should not prevent best practices for coding. They are basically the guidelines that one should follow for better understanding. Download Guidelines and Coding Standards complete List Download Get Answer in Float When Dividing of Two Integer Many times we have requirements of some calculations amongst different fields in Tables. One of the software developers here was trying to calculate some fields having integer values and divide it which gave incorrect results in integer where accurate results including decimals was expected. Puzzle – Computed Columns Datatype Explanation SQL Server automatically does a cast to the data type having the highest precedence. So the result of INT and INT will be INT, but INT and FLOAT will be FLOAT because FLOAT has a higher precedence. If you want a different data type, you need to do an EXPLICIT cast. Renaming SP is Not Good Idea – Renaming Stored Procedure Does Not Update sys.procedures I have written many articles about renaming a tables, columns and procedures SQL SERVER – How to Rename a Column Name or Table Name, here I found something interesting about renaming the stored procedures and felt like sharing it with you all. The interesting fact is that when we rename a stored procedure using SP_Rename command, the Stored Procedure is successfully renamed. But when we try to test the procedure using sp_helptext, the procedure will be having the old name instead of new names. 2009 Insert Values of Stored Procedure in Table – Use Table Valued Function It is clear from the result set that , where I have converted stored procedure logic into the table valued function, is much better in terms of logic as it saves a large number of operations. However, this option should be used carefully. The performance of the stored procedure is “usually” better than that of functions. Interesting Observation – Index on Index View Used in Similar Query Recently, I was working on an optimization project for one of the largest organizations. While working on one of the queries, we came across a very interesting observation. We found that there was a query on the base table and when the query was run, it used the index, which did not exist in the base table. On careful examination, we found that the query was using the index that was on another view. This was very interesting as I have personally never experienced a scenario like this. In simple words, “Query on the base table can use the index created on the indexed view of the same base table.” Interesting Observation – Execution Plan and Results of Aggregate Concatenation Queries Working with SQL Server has never seemed to be monotonous – no matter how long one has worked with it. Quite often, I come across some excellent comments that I feel like acknowledging them as blog posts. Recently, I wrote an article on SQL SERVER – Execution Plan and Results of Aggregate Concatenation Queries Depend Upon Expression Location, which is well received in the community. 2010 I encourage all of you to go through complete series and write your own on the subject. If you write an article and send it to me, I will publish it on this blog with due credit to you. If you write on your own blog, I will update this blog post pointing to your blog post. SQL SERVER – ORDER BY Does Not Work – Limitation of the View 1 SQL SERVER – Adding Column is Expensive by Joining Table Outside View – Limitation of the View 2 SQL SERVER – Index Created on View not Used Often – Limitation of the View 3 SQL SERVER – SELECT * and Adding Column Issue in View – Limitation of the View 4 SQL SERVER – COUNT(*) Not Allowed but COUNT_BIG(*) Allowed – Limitation of the View 5 SQL SERVER – UNION Not Allowed but OR Allowed in Index View – Limitation of the View 6 SQL SERVER – Cross Database Queries Not Allowed in Indexed View – Limitation of the View 7 SQL SERVER – Outer Join Not Allowed in Indexed Views – Limitation of the View 8 SQL SERVER – SELF JOIN Not Allowed in Indexed View – Limitation of the View 9 SQL SERVER – Keywords View Definition Must Not Contain for Indexed View – Limitation of the View 10 SQL SERVER – View Over the View Not Possible with Index View – Limitations of the View 11 2011 Startup Parameters Easy to Configure If you are a regular reader of this blog, you must be aware that I have written about SQL Server Denali recently. Here is the quickest way to reach into the screen where we can change the startup parameters. Go to SQL Server Configuration Manager >> SQL Server Services >> Right Click on the Server >> Properties >> Startup Parameters 2012 Validating Unique Columnname Across Whole Database I sometimes come across very strange requirements and often I do not receive a proper explanation of the same. Here is the one of those examples. For example “Our business requirement is when we add new column we want it unique across current database.” Read the solution to this strange request in this blog post. Excel Losing Decimal Values When Value Pasted from SSMS ResultSet It is very common when users are coping the resultset to Excel, the floating point or decimals are missed. The solution is very much simple and it requires a small adjustment in the Excel. By default Excel is very smart and when it detects the value which is getting pasted is numeric it changes the column format to accommodate that. Basic Calculation and PEMDAS Order of Operation Read this interesting blog post for fantastic conversation about the subject. Copy Column Headers from Resultset – SQL in Sixty Seconds #027 – Video http://www.youtube.com/watch?v=x_-3tLqTRv0 Delete From Multiple Table – Update Multiple Table in Single Statement There are two questions which I get every single day multiple times. In my gmail, I have created standard canned reply for them. Let us see the questions here. I want to delete from multiple table in a single statement how will I do it? I want to update multiple table in a single statement how will I do it? Read the answer in the blog post. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• The blocking nature of aggregates

  - by Rob Farley

  I wrote a post recently about how query tuning isn’t just about how quickly the query runs – that if you have something (such as SSIS) that is consuming your data (and probably introducing a bottleneck), then it might be more important to have a query which focuses on getting the first bit of data out. You can read that post here.  In particular, we looked at two operators that could be used to ensure that a query returns only Distinct rows. and The Sort operator pulls in all the data, sorts it (discarding duplicates), and then pushes out the remaining rows. The Hash Match operator performs a Hashing function on each row as it comes in, and then looks to see if it’s created a Hash it’s seen before. If not, it pushes the row out. The Sort method is quicker, but has to wait until it’s gathered all the data before it can do the sort, and therefore blocks the data flow. But that was my last post. This one’s a bit different. This post is going to look at how Aggregate functions work, which ties nicely into this month’s T-SQL Tuesday. I’ve frequently explained about the fact that DISTINCT and GROUP BY are essentially the same function, although DISTINCT is the poorer cousin because you have less control over it, and you can’t apply aggregate functions. Just like the operators used for Distinct, there are different flavours of Aggregate operators – coming in blocking and non-blocking varieties. The example I like to use to explain this is a pile of playing cards. If I’m handed a pile of cards and asked to count how many cards there are in each suit, it’s going to help if the cards are already ordered. Suppose I’m playing a game of Bridge, I can easily glance at my hand and count how many there are in each suit, because I keep the pile of cards in order. Moving from left to right, I could tell you I have four Hearts in my hand, even before I’ve got to the end. By telling you that I have four Hearts as soon as I know, I demonstrate the principle of a non-blocking operation. This is known as a Stream Aggregate operation. It requires input which is sorted by whichever columns the grouping is on, and it will release a row as soon as the group changes – when I encounter a Spade, I know I don’t have any more Hearts in my hand. Alternatively, if the pile of cards are not sorted, I won’t know how many Hearts I have until I’ve looked through all the cards. In fact, to count them, I basically need to put them into little piles, and when I’ve finished making all those piles, I can count how many there are in each. Because I don’t know any of the final numbers until I’ve seen all the cards, this is blocking. This performs the aggregate function using a Hash Match. Observant readers will remember this from my Distinct example. You might remember that my earlier Hash Match operation – used for Distinct Flow – wasn’t blocking. But this one is. They’re essentially doing a similar operation, applying a Hash function to some data and seeing if the set of values have been seen before, but before, it needs more information than the mere existence of a new set of values, it needs to consider how many of them there are. A lot is dependent here on whether the data coming out of the source is sorted or not, and this is largely determined by the indexes that are being used. If you look in the Properties of an Index Scan, you’ll be able to see whether the order of the data is required by the plan. A property called Ordered will demonstrate this. In this particular example, the second plan is significantly faster, but is dependent on having ordered data. In fact, if I force a Stream Aggregate on unordered data (which I’m doing by telling it to use a different index), a Sort operation is needed, which makes my plan a lot slower. This is all very straight-forward stuff, and information that most people are fully aware of. I’m sure you’ve all read my good friend Paul White (@sql_kiwi)’s post on how the Query Optimizer chooses which type of aggregate function to apply. But let’s take a look at SQL Server Integration Services. SSIS gives us a Aggregate transformation for use in Data Flow Tasks, but it’s described as Blocking. The definitive article on Performance Tuning SSIS uses Sort and Aggregate as examples of Blocking Transformations. I’ve just shown you that Aggregate operations used by the Query Optimizer are not always blocking, but that the SSIS Aggregate component is an example of a blocking transformation. But is it always the case? After all, there are plenty of SSIS Performance Tuning talks out there that describe the value of sorted data in Data Flow Tasks, describing the IsSorted property that can be set through the Advanced Editor of your Source component. And so I set about testing the Aggregate transformation in SSIS, to prove for sure whether providing Sorted data would let the Aggregate transform behave like a Stream Aggregate. (Of course, I knew the answer already, but it helps to be able to demonstrate these things). A query that will produce a million rows in order was in order. Let me rephrase. I used a query which produced the numbers from 1 to 1000000, in a single field, ordered. The IsSorted flag was set on the source output, with the only column as SortKey 1. Performing an Aggregate function over this (counting the number of rows per distinct number) should produce an additional column with 1 in it. If this were being done in T-SQL, the ordered data would allow a Stream Aggregate to be used. In fact, if the Query Optimizer saw that the field had a Unique Index on it, it would be able to skip the Aggregate function completely, and just insert the value 1. This is a shortcut I wouldn’t be expecting from SSIS, but certainly the Stream behaviour would be nice. Unfortunately, it’s not the case. As you can see from the screenshots above, the data is pouring into the Aggregate function, and not being released until all million rows have been seen. It’s not doing a Stream Aggregate at all. This is expected behaviour. (I put that in bold, because I want you to realise this.) An SSIS transformation is a piece of code that runs. It’s a physical operation. When you write T-SQL and ask for an aggregation to be done, it’s a logical operation. The physical operation is either a Stream Aggregate or a Hash Match. In SSIS, you’re telling the system that you want a generic Aggregation, that will have to work with whatever data is passed in. I’m not saying that it wouldn’t be possible to make a sometimes-blocking aggregation component in SSIS. A Custom Component could be created which could detect whether the SortKeys columns of the input matched the Grouping columns of the Aggregation, and either call the blocking code or the non-blocking code as appropriate. One day I’ll make one of those, and publish it on my blog. I’ve done it before with a Script Component, but as Script components are single-use, I was able to handle the data knowing everything about my data flow already. As per my previous post – there are a lot of aspects in which tuning SSIS and tuning execution plans use similar concepts. In both situations, it really helps to have a feel for what’s going on behind the scenes. Considering whether an operation is blocking or not is extremely relevant to performance, and that it’s not always obvious from the surface. In a future post, I’ll show the impact of blocking v non-blocking and synchronous v asynchronous components in SSIS, using some of LobsterPot’s Script Components and Custom Components as examples. When I get that sorted, I’ll make a Stream Aggregate component available for download.

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• Creating vCard action result

  - by DigiMortal

  I added support for vCards to one of my ASP.NET MVC applications. I worked vCard support out as very simple and intelligent solution that fits perfectly to ASP.NET MVC applications. In this posting I will show you how to send vCards out as response to ASP.NET MVC request. We need three things: some vCard class, vCard action result, controller method to test vCard action result. Everything is very simple, let’s get hands on. vCard class As first thing we need vCard class. Last year I introduced vCard class that supports also images. Let’s take this class because it is easy to use and some dirty work is already done for us. NB! Take a look at ASP.NET example in the blog posting referred above. We need it later when we close the topic. Now think about how useful blogging and information sharing with others can be. With this class available at public I saved pretty much time now. :) vCardResult As we have vCard it is now time to write action result that we can use in our controllers. Here’s the code. public class vCardResult : ActionResult {     private vCard _card;       protected vCardResult() { }       public vCardResult(vCard card)     {         _card = card;     }       public override void ExecuteResult(ControllerContext context)     {         var response = context.HttpContext.Response;         response.ContentType = "text/vcard";         response.AddHeader("Content-Disposition", "attachment; fileName=" + _card.FirstName + " " + _card.LastName + ".vcf");           var cardString = _card.ToString();         var inputEncoding = Encoding.Default;         var outputEncoding = Encoding.GetEncoding("windows-1257");         var cardBytes = inputEncoding.GetBytes(cardString);           var outputBytes = Encoding.Convert(inputEncoding,                                 outputEncoding, cardBytes);           response.OutputStream.Write(outputBytes, 0, outputBytes.Length);     } } And we are done. Some notes: vCard is sent to browser as downloadable file (user can save or open it with Outlook or any other e-mail client that supports vCards), File name is made of first and last name of contact. Encoding is important because Outlook may not understand vCards otherwise (don’t know if this problem is solved in Outlook 2010). Using vCardResult in controller Now let’s tale a look at simple controller method that accepts person ID and returns vCardResult. public class ContactsController : Controller {       // ... other controller methods ...       public vCardResult vCard(int id)     {         var person = _partyRepository.GetPersonById(id);         var card = new vCard                 {                     FirstName=person.FirstName,                     LastName = person.LastName,                     StreetAddress = person.StreetAddress,                     City = person.City,                     CountryName = person.Country.Name,                       Mobile = person.Mobile,                     Phone = person.Phone,                     Email = person.Email,                 };           return new vCardResult(card);     } } Now you can run Visual Studio and check out how your vCard is moving from your web application to your e-mail client. Conclusion We took old code that worked well with ASP.NET Forms and we divided it into action result and controller method that uses vCard as bridge between our controller and action result. All functionality is located where it should be and we did nothing complex. We wrote only couple of lines of very easy code to achieve our goal. Do you understand now why I love ASP.NET MVC? :)

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• The blocking nature of aggregates

  - by Rob Farley

  I wrote a post recently about how query tuning isn’t just about how quickly the query runs – that if you have something (such as SSIS) that is consuming your data (and probably introducing a bottleneck), then it might be more important to have a query which focuses on getting the first bit of data out. You can read that post here.  In particular, we looked at two operators that could be used to ensure that a query returns only Distinct rows. and The Sort operator pulls in all the data, sorts it (discarding duplicates), and then pushes out the remaining rows. The Hash Match operator performs a Hashing function on each row as it comes in, and then looks to see if it’s created a Hash it’s seen before. If not, it pushes the row out. The Sort method is quicker, but has to wait until it’s gathered all the data before it can do the sort, and therefore blocks the data flow. But that was my last post. This one’s a bit different. This post is going to look at how Aggregate functions work, which ties nicely into this month’s T-SQL Tuesday. I’ve frequently explained about the fact that DISTINCT and GROUP BY are essentially the same function, although DISTINCT is the poorer cousin because you have less control over it, and you can’t apply aggregate functions. Just like the operators used for Distinct, there are different flavours of Aggregate operators – coming in blocking and non-blocking varieties. The example I like to use to explain this is a pile of playing cards. If I’m handed a pile of cards and asked to count how many cards there are in each suit, it’s going to help if the cards are already ordered. Suppose I’m playing a game of Bridge, I can easily glance at my hand and count how many there are in each suit, because I keep the pile of cards in order. Moving from left to right, I could tell you I have four Hearts in my hand, even before I’ve got to the end. By telling you that I have four Hearts as soon as I know, I demonstrate the principle of a non-blocking operation. This is known as a Stream Aggregate operation. It requires input which is sorted by whichever columns the grouping is on, and it will release a row as soon as the group changes – when I encounter a Spade, I know I don’t have any more Hearts in my hand. Alternatively, if the pile of cards are not sorted, I won’t know how many Hearts I have until I’ve looked through all the cards. In fact, to count them, I basically need to put them into little piles, and when I’ve finished making all those piles, I can count how many there are in each. Because I don’t know any of the final numbers until I’ve seen all the cards, this is blocking. This performs the aggregate function using a Hash Match. Observant readers will remember this from my Distinct example. You might remember that my earlier Hash Match operation – used for Distinct Flow – wasn’t blocking. But this one is. They’re essentially doing a similar operation, applying a Hash function to some data and seeing if the set of values have been seen before, but before, it needs more information than the mere existence of a new set of values, it needs to consider how many of them there are. A lot is dependent here on whether the data coming out of the source is sorted or not, and this is largely determined by the indexes that are being used. If you look in the Properties of an Index Scan, you’ll be able to see whether the order of the data is required by the plan. A property called Ordered will demonstrate this. In this particular example, the second plan is significantly faster, but is dependent on having ordered data. In fact, if I force a Stream Aggregate on unordered data (which I’m doing by telling it to use a different index), a Sort operation is needed, which makes my plan a lot slower. This is all very straight-forward stuff, and information that most people are fully aware of. I’m sure you’ve all read my good friend Paul White (@sql_kiwi)’s post on how the Query Optimizer chooses which type of aggregate function to apply. But let’s take a look at SQL Server Integration Services. SSIS gives us a Aggregate transformation for use in Data Flow Tasks, but it’s described as Blocking. The definitive article on Performance Tuning SSIS uses Sort and Aggregate as examples of Blocking Transformations. I’ve just shown you that Aggregate operations used by the Query Optimizer are not always blocking, but that the SSIS Aggregate component is an example of a blocking transformation. But is it always the case? After all, there are plenty of SSIS Performance Tuning talks out there that describe the value of sorted data in Data Flow Tasks, describing the IsSorted property that can be set through the Advanced Editor of your Source component. And so I set about testing the Aggregate transformation in SSIS, to prove for sure whether providing Sorted data would let the Aggregate transform behave like a Stream Aggregate. (Of course, I knew the answer already, but it helps to be able to demonstrate these things). A query that will produce a million rows in order was in order. Let me rephrase. I used a query which produced the numbers from 1 to 1000000, in a single field, ordered. The IsSorted flag was set on the source output, with the only column as SortKey 1. Performing an Aggregate function over this (counting the number of rows per distinct number) should produce an additional column with 1 in it. If this were being done in T-SQL, the ordered data would allow a Stream Aggregate to be used. In fact, if the Query Optimizer saw that the field had a Unique Index on it, it would be able to skip the Aggregate function completely, and just insert the value 1. This is a shortcut I wouldn’t be expecting from SSIS, but certainly the Stream behaviour would be nice. Unfortunately, it’s not the case. As you can see from the screenshots above, the data is pouring into the Aggregate function, and not being released until all million rows have been seen. It’s not doing a Stream Aggregate at all. This is expected behaviour. (I put that in bold, because I want you to realise this.) An SSIS transformation is a piece of code that runs. It’s a physical operation. When you write T-SQL and ask for an aggregation to be done, it’s a logical operation. The physical operation is either a Stream Aggregate or a Hash Match. In SSIS, you’re telling the system that you want a generic Aggregation, that will have to work with whatever data is passed in. I’m not saying that it wouldn’t be possible to make a sometimes-blocking aggregation component in SSIS. A Custom Component could be created which could detect whether the SortKeys columns of the input matched the Grouping columns of the Aggregation, and either call the blocking code or the non-blocking code as appropriate. One day I’ll make one of those, and publish it on my blog. I’ve done it before with a Script Component, but as Script components are single-use, I was able to handle the data knowing everything about my data flow already. As per my previous post – there are a lot of aspects in which tuning SSIS and tuning execution plans use similar concepts. In both situations, it really helps to have a feel for what’s going on behind the scenes. Considering whether an operation is blocking or not is extremely relevant to performance, and that it’s not always obvious from the surface. In a future post, I’ll show the impact of blocking v non-blocking and synchronous v asynchronous components in SSIS, using some of LobsterPot’s Script Components and Custom Components as examples. When I get that sorted, I’ll make a Stream Aggregate component available for download.

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• CodePlex Daily Summary for Sunday, March 28, 2010

  CodePlex Daily Summary for Sunday, March 28, 2010New ProjectsFeed Tracker: Feed Tracker allows you to track your favorite feeds (RSS 2.0 and Atom 1.0) and open them up directly in your browser.FIM 2010 Resource Management Client: The Forefront Identity Management 2010 Resource Management Client is a library to communicate with the FIM 2010 web service. The development langu...Infection Protection: A game about controlling disease outbreak in a city. Developed for OGPC 2010, using Qt.OrthoLab: Homepage of Orthocone open-source laboratory.Paragliding ThermalMarker: Paragliding / Hanggliding Windows Application that receives waypoint files and returns only the thermals that get triggered more often in a place.RSSFalls: RssFalls makes it easier for developers to download RSS or Podcast enclosures.String Library for C++ Language: StrLib++ is a string library for C++ language. for now it support only ANSI strings, later Unicode support will added for UT8, UTF16 and UTF32 for...Sweeper: Sweeper is a Visual Studio 2008 add-in for C# that takes care of many of the trivial code-formatting issues that developers run into - particularly...System.Common: A .Net library that provides methods, properties and more that the .Net Framework doesn't provide.Tiveriad: The framework is designed to help you more easily build modular Windows applicationT-Shirts Online: Online shop build in Silverlight 4 using DIBS as payment module.New ReleasesArkSwitch: ArkSwitch v1.1.3: This release has some important changes. Thanks to MichyPrima for helping with some of the code. 1. Improved theming to more easily support multip...Catharsis: Catharsis 2.5 on catarsa.com: The Catharsis framework has finally its own portal http://catarsa.com The latest release version is 2.5 - string names of properties are not any ...EffiProz - A Pure C# Database: EffiProz CF 1.0: EffiProz for .Net compact framework.Encrypted Notes: Encrypted Notes 1.6: This is the latest version of Encrypted Notes (1.6). It has an installer - it will create a directory 'CPascoe' in My Documents. Once you have ext...Extend SmallBasic: Teaching Extensions v.009: Added Pentagon Crazy Recipe QuizGapi.NET - .NET (C#) wrapper for Google API: Gapi.NET 0.5.0.0: - Fixed some minor bugs. - Add minor features. - Performance improvement. See code check-ins for detailed informationHouseFly experimental controls: HouseFly experimental control: Alpha version of HouseFly experimental controlsiTuner - The iTunes Companion: iTuner 1.2.3738 Beta 2: V1.2 allows you to synchronize one or more iTunes playlists to a USB MP3 player. Beta 2 resolves all known issues. This continues the evolution ye...jQuery Library for SharePoint Web Services: SPServices 0.5.4: IMPORTANT NOTE: This release is in an alpha state. You should only download it if you know what you are getting and are interested in testing it f...JSINQ - LINQ to Objects for JavaScript: JSINQ 1.0: This is the first stable release of JSINQ. It is fully compatible with the 0.9 beta release. It contains the following new features: Now supports ...MSBuild Mercurial Tasks: 1.0.0 Beta: First release of the application. This version integrates all the basic functionalities of Mercurial as defined in the Use Case 1.Open Portal Foundation: Open Portal Foundation V1.4.2: What's news? noscript template was updated naming convention for layout autogenerated controls now use the "master" prefix. The documentation ce...Open Portal Foundation: Open Portal Foundation V1.4.4: What's news? ASP .NET Master page support for custom aspx integrated pages New usercontrols for ASCX, ASPX and Master page integration : Link: f...Paint.NET PSD Plugin: 1.5.0: RLE compression is now working fully on save. File sizes are now competitive with Photoshop's. Saving takes about twice as long with RLE compressi...Paragliding ThermalMarker: ThermalMarker_Alfa0.1: Release Alfa 1Simple Service Locator: Simple Service Locator v0.7: The Simple Service Locator is an easy-to-use Inversion of Control library that is a complete implementation of the Common Service Locator interface...String Library for C++ Language: Release 0.9: version 0.9 beta release DO NOT USE IN SERIOUS PROJECTS this release use default application heap, and because visual studio is using special debug...Sweeper: Sweeper Alpha 1: SweeperA Visual Studio Add-in for C# Code Formatting - Visual Studio 2008 Includes: A UI for options, Enable or disable any specific task you want ...T-Shirts Online: 1.0: First release of the online shop.Twilio Server Library for .NET (TSL.NET): v0.1.0 Beta: This is the first release of TSL.NET. This v0.1.0 release is a Beta. Subsequent builds will be posted as v0.1.x and release-candidate Betas will be...Vr30 OS: Facebook 1.0: Connect you to Facebook without your web browser.Vr30 OS: SkyBlog 1.0: SkyBlog without web browser.Vr30 OS: YouTube 1.0: Youtube without web browserWeb Image Resize Handler: Web Image Resize, Zoom, Rotate and Greyscale v.1.0: Efficient Web Image Resize, Zoom, Rotate and Greyscale cacheing handler for ASP.Net.WinXound: WinXound 3.3.0 Beta 1 for Mac OsX: This is the first Beta release for Apple Mac OsX (Universal Binary). DEBUG HELP NEEDED ! Please signal bugs, suggestions or feedback to: stefano_b...Most Popular ProjectsMetaSharpRawrWBFS ManagerASP.NET Ajax LibraryMicrosoft SQL Server Product Samples: DatabaseSilverlight ToolkitAJAX Control ToolkitLiveUpload to FacebookWindows Presentation Foundation (WPF)ASP.NETMost Active ProjectsRawrjQuery Library for SharePoint Web ServicesManaged Extensibility FrameworkBlogEngine.NETMicrosoft Biology Foundationpatterns & practices: Composite WPF and SilverlightLINQ to TwitterFarseer Physics EngineTable2ClassNB_Store - Free DotNetNuke Ecommerce Catalog Module

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• Applications: How to create a custom dialog box for Windows Mobile 6 (native)

  - by TechTwaddle

  Ashraf, on the MSDN forum, asks, “Is there a way to make a default choice for the messagebox that happens after a period of time if the user doesn't choose (Clicked ) Yes or No buttons.” To elaborate, the requirement is to show a message box to the user with certain options to select, and if the user does not respond within a predefined time limit (say 8 seconds) then the message box must dismiss itself and select a default option. Now such a functionality is not available with the MessageBox() api, you will have to write your own custom dialog box. Surely, creating a dialog box is quite a simple task using the DialogBox() api, and we have been creating full screen dialog boxes all the while. So how will this custom message box be any different? It’s not much different from a regular dialog box except for a few changes in its properties. First, it has a title bar but no buttons on the title bar (no ‘x’ or ‘ok’ button on the title bar), it doesn’t occupy full screen and it contains the controls that you put into it, thus justifying the title ‘custom’. So in this post we create a custom dialog box with two buttons, ‘Black’ and ‘White’. The user is given 8 seconds to select one of those colours, if the user doesn’t make a selection in 8 seconds, the default option ‘Black’ is selected. Before going into the implementation here is a video of how the dialog box works; Custom dialog box To start off, add a new dialog resource into your application, size it appropriately and add whatever controls you need to the dialog. In my case, I added two static text labels and two buttons, as below; Now we need to write up the window procedure for this dialog, here is the complete function; BOOL CALLBACK CustomDialogProc(HWND hDlg, UINT uMessage, WPARAM wParam, LPARAM lParam) {     int wmID, wmEvent;     PAINTSTRUCT ps;     HDC hdc;     static int timeCount = 0;     switch(uMessage)     {         case WM_INITDIALOG:             {                 SHINITDLGINFO shidi;                 memset(&shidi, 0, sizeof(shidi));                 shidi.dwMask = SHIDIM_FLAGS;                 //shidi.dwFlags = SHIDIF_DONEBUTTON | SHIDIF_SIPDOWN | SHIDIF_SIZEDLGFULLSCREEN | SHIDIF_EMPTYMENU;                 shidi.dwFlags = SHIDIF_SIPDOWN | SHIDIF_EMPTYMENU;                 shidi.hDlg = hDlg;                 SHInitDialog(&shidi);                 SHDoneButton(hDlg, SHDB_HIDE);                 timeCount = 0;                 SetWindowText(GetDlgItem(hDlg, IDC_STATIC_TIME_REMAINING), L"Time remaining: 8 second(s)");                 SetTimer(hDlg, MY_TIMER, 1000, NULL);             }             return TRUE;         case WM_COMMAND:             {                 wmID = LOWORD(wParam);                 wmEvent = HIWORD(wParam);                 switch(wmID)                 {                     case IDC_BUTTON_BLACK:                         KillTimer(hDlg, MY_TIMER);                         EndDialog(hDlg, IDC_BUTTON_BLACK);                         break;                     case IDC_BUTTON_WHITE:                         KillTimer(hDlg, MY_TIMER);                         EndDialog(hDlg, IDC_BUTTON_WHITE);                         break;                 }             }             break;         case WM_TIMER:             {                 if (wParam == MY_TIMER)                 {                     WCHAR wszText[128];                     memset(&wszText, 0, sizeof(wszText));                     timeCount++;                     //8 seconds are over, dismiss the dialog, select def value                     if (timeCount >= 8)                     {                         KillTimer(hDlg, MY_TIMER);                         EndDialog(hDlg, IDC_BUTTON_BLACK_DEF);                     }                     wsprintf(wszText, L"Time remaining: %d second(s)", 8-timeCount);                     SetWindowText(GetDlgItem(hDlg, IDC_STATIC_TIME_REMAINING), wszText);                     UpdateWindow(GetDlgItem(hDlg, IDC_STATIC_TIME_REMAINING));                 }             }             break;         case WM_PAINT:             {                 hdc = BeginPaint(hDlg, &ps);                 EndPaint(hDlg, &ps);             }             break;     }     return FALSE; } The MSDN documentation mentions that you need to specify the flag WS_NONAVDONEBUTTON, but I got an error saying that the value could not be found, so we can ignore this for now. Next up, while calling SHInitDialog() for your custom dialog, make sure that you don’t specify SHDIF_DONEBUTTON in the dwFlags member of the SHINITDIALOG structure, this member makes the ‘ok’ button appear on the dialog title bar. Finally, we need to call SHDoneButton() with SHDB_HIDE flag to, well, hide the Done button. The ‘Done’ button is the same as the ‘ok’ button, so this step might seem redundant, and the dialog works fine without calling SHDoneButton() too, but it’s better to stick with the documentation (; So you can see that we have followed all these steps above, under WM_INITDIALOG. We also setup a few things like a variable to keep track of the time, and setting off a one second timer. Every time the timer fires, we receive a WM_TIMER message. We then update the static label displaying the amount of time left to the user. If 8 seconds go by without the user selecting any option, we kill the timer and end the dialog with IDC_BUTTON_BLACK_DEF. This is just a #define’d integer value, make sure it’s unique. You’ll see why this is important. If the user makes a selection, either Black or White, we kill the timer and end the dialog with corresponding selection the user made, that is, either IDC_BUTTON_BLACK or IDC_BUTTON_WHITE. Ok, so now our custom dialog is ready to be used. I invoke the custom dialog from a menu entry in the main windows as below, case IDM_MENU_CUSTOMDLG:     {         int ret = DialogBox(g_hInst, MAKEINTRESOURCE(IDD_CUSTOM_DIALOG), hWnd, CustomDialogProc);         switch(ret)         {             case IDC_BUTTON_BLACK_DEF:                 SetWindowText(g_hStaticSelection, L"You Selected: Black (default)");                 break;             case IDC_BUTTON_BLACK:                 SetWindowText(g_hStaticSelection, L"You Selected: Black");                 break;             case IDC_BUTTON_WHITE:                 SetWindowText(g_hStaticSelection, L"You Selected: White");                 break;         }         UpdateWindow(g_hStaticSelection);     }     break; So you see why ending the dialog with the corresponding value was important, that’s what the DialogBox() api returns with. And in the main window I update a static text label to show which option was selected. I cranked this out in about an hour, and unfortunately don’t have time for a managed C# version. That will have to be another post, if I manage to get it working that is (;

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• Android - Create a custom multi-line ListView bound to an ArrayList

  - by Bill Osuch

  The Android HelloListView tutorial shows how to bind a ListView to an array of string objects, but you'll probably outgrow that pretty quickly. This post will show you how to bind the ListView to an ArrayList of custom objects, as well as create a multi-line ListView. Let's say you have some sort of search functionality that returns a list of people, along with addresses and phone numbers. We're going to display that data in three formatted lines for each result, and make it clickable. First, create your new Android project, and create two layout files. Main.xml will probably already be created by default, so paste this in: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:orientation="vertical"  android:layout_width="fill_parent"   android:layout_height="fill_parent">  <TextView   android:layout_height="wrap_content"   android:text="Custom ListView Contents"   android:gravity="center_vertical|center_horizontal"   android:layout_width="fill_parent" />   <ListView    android:id="@+id/ListView01"    android:layout_height="wrap_content"    android:layout_width="fill_parent"/> </LinearLayout> Next, create a layout file called custom_row_view.xml. This layout will be the template for each individual row in the ListView. You can use pretty much any type of layout - Relative, Table, etc., but for this we'll just use Linear: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:orientation="vertical"  android:layout_width="fill_parent"   android:layout_height="fill_parent">   <TextView android:id="@+id/name"   android:textSize="14sp"   android:textStyle="bold"   android:textColor="#FFFF00"   android:layout_width="wrap_content"   android:layout_height="wrap_content"/>  <TextView android:id="@+id/cityState"   android:layout_width="wrap_content"   android:layout_height="wrap_content"/>  <TextView android:id="@+id/phone"   android:layout_width="wrap_content"   android:layout_height="wrap_content"/> </LinearLayout> Now, add an object called SearchResults. Paste this code in: public class SearchResults {  private String name = "";  private String cityState = "";  private String phone = "";  public void setName(String name) {   this.name = name;  }  public String getName() {   return name;  }  public void setCityState(String cityState) {   this.cityState = cityState;  }  public String getCityState() {   return cityState;  }  public void setPhone(String phone) {   this.phone = phone;  }  public String getPhone() {   return phone;  } } This is the class that we'll be filling with our data, and loading into an ArrayList. Next, you'll need a custom adapter. This one just extends the BaseAdapter, but you could extend the ArrayAdapter if you prefer. public class MyCustomBaseAdapter extends BaseAdapter {  private static ArrayList<SearchResults> searchArrayList;    private LayoutInflater mInflater;  public MyCustomBaseAdapter(Context context, ArrayList<SearchResults> results) {   searchArrayList = results;   mInflater = LayoutInflater.from(context);  }  public int getCount() {   return searchArrayList.size();  }  public Object getItem(int position) {   return searchArrayList.get(position);  }  public long getItemId(int position) {   return position;  }  public View getView(int position, View convertView, ViewGroup parent) {   ViewHolder holder;   if (convertView == null) {    convertView = mInflater.inflate(R.layout.custom_row_view, null);    holder = new ViewHolder();    holder.txtName = (TextView) convertView.findViewById(R.id.name);    holder.txtCityState = (TextView) convertView.findViewById(R.id.cityState);    holder.txtPhone = (TextView) convertView.findViewById(R.id.phone);    convertView.setTag(holder);   } else {    holder = (ViewHolder) convertView.getTag();   }      holder.txtName.setText(searchArrayList.get(position).getName());   holder.txtCityState.setText(searchArrayList.get(position).getCityState());   holder.txtPhone.setText(searchArrayList.get(position).getPhone());   return convertView;  }  static class ViewHolder {   TextView txtName;   TextView txtCityState;   TextView txtPhone;  } } (This is basically the same as the List14.java API demo) Finally, we'll wire it all up in the main class file: public class CustomListView extends Activity {     @Override     public void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.main);                 ArrayList<SearchResults> searchResults = GetSearchResults();                 final ListView lv1 = (ListView) findViewById(R.id.ListView01);         lv1.setAdapter(new MyCustomBaseAdapter(this, searchResults));                 lv1.setOnItemClickListener(new OnItemClickListener() {          @Override          public void onItemClick(AdapterView<?> a, View v, int position, long id) {           Object o = lv1.getItemAtPosition(position);           SearchResults fullObject = (SearchResults)o;           Toast.makeText(ListViewBlogPost.this, "You have chosen: " + " " + fullObject.getName(), Toast.LENGTH_LONG).show();          }          });     }         private ArrayList<SearchResults> GetSearchResults(){      ArrayList<SearchResults> results = new ArrayList<SearchResults>();            SearchResults sr1 = new SearchResults();      sr1.setName("John Smith");      sr1.setCityState("Dallas, TX");      sr1.setPhone("214-555-1234");      results.add(sr1);            sr1 = new SearchResults();      sr1.setName("Jane Doe");      sr1.setCityState("Atlanta, GA");      sr1.setPhone("469-555-2587");      results.add(sr1);            sr1 = new SearchResults();      sr1.setName("Steve Young");      sr1.setCityState("Miami, FL");      sr1.setPhone("305-555-7895");      results.add(sr1);            sr1 = new SearchResults();      sr1.setName("Fred Jones");      sr1.setCityState("Las Vegas, NV");      sr1.setPhone("612-555-8214");      results.add(sr1);            return results;     } } Notice that we first get an ArrayList of SearchResults objects (normally this would be from an external data source...), pass it to the custom adapter, then set up a click listener. The listener gets the item that was clicked, converts it back to a SearchResults object, and does whatever it needs to do. Fire it up in the emulator, and you should wind up with something like this:

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• Integration Patterns with Azure Service Bus Relay, Part 1: Exposing the on-premise service

  - by Elton Stoneman

  We're in the process of delivering an enabling project to expose on-premise WCF services securely to Internet consumers. The Azure Service Bus Relay is doing the clever stuff, we register our on-premise service with Azure, consumers call into our .servicebus.windows.net namespace, and their requests are relayed and serviced on-premise. In theory it's all wonderfully simple; by using the relay we get lots of protocol options, free HTTPS and load balancing, and by integrating to ACS we get plenty of security options. Part of our delivery is a suite of sample consumers for the service - .NET, jQuery, PHP - and this set of posts will cover setting up the service and the consumers. Part 1: Exposing the on-premise service In theory, this is ultra-straightforward. In practice, and on a dev laptop it is - but in a corporate network with firewalls and proxies, it isn't, so we'll walkthrough some of the pitfalls. Note that I'm using the "old" Azure portal which will soon be out of date, but the new shiny portal should have the same steps available and be easier to use. We start with a simple WCF service which takes a string as input, reverses the string and returns it. The Part 1 version of the code is on GitHub here: on GitHub here: IPASBR Part 1. Configuring Azure Service Bus Start by logging into the Azure portal and registering a Service Bus namespace which will be our endpoint in the cloud. Give it a globally unique name, set it up somewhere near you (if you’re in Europe, remember Europe (North) is Ireland, and Europe (West) is the Netherlands), and  enable ACS integration by ticking "Access Control" as a service: Authenticating and authorizing to ACS When we try to register our on-premise service as a listener for the Service Bus endpoint, we need to supply credentials, which means only trusted service providers can act as listeners. We can use the default "owner" credentials, but that has admin permissions so a dedicated service account is better (Neil Mackenzie has a good post On Not Using owner with the Azure AppFabric Service Bus with lots of permission details). Click on "Access Control Service" for the namespace, navigate to Service Identities and add a new one. Give the new account a sensible name and description: Let ACS generate a symmetric key for you (this will be the shared secret we use in the on-premise service to authenticate as a listener), but be sure to set the expiration date to something usable. The portal defaults to expiring new identities after 1 year - but when your year is up *your identity will expire without warning* and everything will stop working. In production, you'll need governance to manage identity expiration and a process to make sure you renew identities and roll new keys regularly. The new service identity needs to be authorized to listen on the service bus endpoint. This is done through claim mapping in ACS - we'll set up a rule that says if the nameidentifier in the input claims has the value serviceProvider, in the output we'll have an action claim with the value Listen. In the ACS portal you'll see that there is already a Relying Party Application set up for ServiceBus, which has a Default rule group. Edit the rule group and click Add to add this new rule: The values to use are: Issuer: Access Control Service Input claim type: http://schemas.xmlsoap.org/ws/2005/05/identity/claims/nameidentifier Input claim value: serviceProvider Output claim type: net.windows.servicebus.action Output claim value: Listen When your service namespace and identity are set up, open the Part 1 solution and put your own namespace, service identity name and secret key into the file AzureConnectionDetails.xml in Solution Items, e.g: <azure namespace="sixeyed-ipasbr">    <!-- ACS credentials for the listening service (Part1):-->   <service identityName="serviceProvider"            symmetricKey="nuR2tHhlrTCqf4YwjT2RA2BZ/+xa23euaRJNLh1a/V4="/>  </azure> Build the solution, and the T4 template will generate the Web.config for the service project with your Azure details in the transportClientEndpointBehavior:           <behavior name="SharedSecret">             <transportClientEndpointBehavior credentialType="SharedSecret">               <clientCredentials>                 <sharedSecret issuerName="serviceProvider"                               issuerSecret="nuR2tHhlrTCqf4YwjT2RA2BZ/+xa23euaRJNLh1a/V4="/>               </clientCredentials>             </transportClientEndpointBehavior>           </behavior> , and your service namespace in the Azure endpoint:         <!-- Azure Service Bus endpoints -->          <endpoint address="sb://sixeyed-ipasbr.servicebus.windows.net/net"                   binding="netTcpRelayBinding"                   contract="Sixeyed.Ipasbr.Services.IFormatService"                   behaviorConfiguration="SharedSecret">         </endpoint> The sample project is hosted in IIS, but it won't register with Azure until the service is activated. Typically you'd install AppFabric 1.1 for Widnows Server and set the service to auto-start in IIS, but for dev just navigate to the local REST URL, which will activate the service and register it with Azure. Testing the service locally As well as an Azure endpoint, the service has a WebHttpBinding for local REST access:         <!-- local REST endpoint for internal use -->         <endpoint address="rest"                   binding="webHttpBinding"                   behaviorConfiguration="RESTBehavior"                   contract="Sixeyed.Ipasbr.Services.IFormatService" /> Build the service, then navigate to: http://localhost/Sixeyed.Ipasbr.Services/FormatService.svc/rest/reverse?string=abc123 - and you should see the reversed string response: If your network allows it, you'll get the expected response as before, but in the background your service will also be listening in the cloud. Good stuff! Who needs network security? Onto the next post for consuming the service with the netTcpRelayBinding.  Setting up network access to Azure But, if you get an error, it's because your network is secured and it's doing something to stop the relay working. The Service Bus relay bindings try to use direct TCP connections to Azure, so if ports 9350-9354 are available *outbound*, then the relay will run through them. If not, the binding steps down to standard HTTP, and issues a CONNECT across port 443 or 80 to set up a tunnel for the relay. If your network security guys are doing their job, the first option will be blocked by the firewall, and the second option will be blocked by the proxy, so you'll get this error: System.ServiceModel.CommunicationException: Unable to reach sixeyed-ipasbr.servicebus.windows.net via TCP (9351, 9352) or HTTP (80, 443) - and that will probably be the start of lots of discussions. Network guys don't really like giving servers special permissions for the web proxy, and they really don't like opening ports, so they'll need to be convinced about this. The resolution in our case was to put up a dedicated box in a DMZ, tinker with the firewall and the proxy until we got a relay connection working, then run some traffic which the the network guys monitored to do a security assessment afterwards. Along the way we hit a few more issues, diagnosed mainly with Fiddler and Wireshark: System.Net.ProtocolViolationException: Chunked encoding upload is not supported on the HTTP/1.0 protocol - this means the TCP ports are not available, so Azure tries to relay messaging traffic across HTTP. The service can access the endpoint, but the proxy is downgrading traffic to HTTP 1.0, which does not support tunneling, so Azure can’t make its connection. We were using the Squid proxy, version 2.6. The Squid project is incrementally adding HTTP 1.1 support, but there's no definitive list of what's supported in what version (here are some hints). System.ServiceModel.Security.SecurityNegotiationException: The X.509 certificate CN=servicebus.windows.net chain building failed. The certificate that was used has a trust chain that cannot be verified. Replace the certificate or change the certificateValidationMode. The evocation function was unable to check revocation because the revocation server was offline. - by this point we'd given up on the HTTP proxy and opened the TCP ports. We got this error when the relay binding does it's authentication hop to ACS. The messaging traffic is TCP, but the control traffic still goes over HTTP, and as part of the ACS authentication the process checks with a revocation server to see if Microsoft’s ACS cert is still valid, so the proxy still needs some clearance. The service account (the IIS app pool identity) needs access to: www.public-trust.com mscrl.microsoft.com We still got this error periodically with different accounts running the app pool. We fixed that by ensuring the machine-wide proxy settings are set up, so every account uses the correct proxy: netsh winhttp set proxy proxy-server="http://proxy.x.y.z" - and you might need to run this to clear out your credential cache: certutil -urlcache * delete If your network guys end up grudgingly opening ports, they can restrict connections to the IP address range for your chosen Azure datacentre, which might make them happier - see Windows Azure Datacenter IP Ranges. After all that you've hopefully got an on-premise service listening in the cloud, which you can consume from pretty much any technology.

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• SortedDictionary and SortedList

  - by Simon Cooper

  Apart from Dictionary<TKey, TValue>, there's two other dictionaries in the BCL - SortedDictionary<TKey, TValue> and SortedList<TKey, TValue>. On the face of it, these two classes do the same thing - provide an IDictionary<TKey, TValue> interface where the iterator returns the items sorted by the key. So what's the difference between them, and when should you use one rather than the other? (as in my previous post, I'll assume you have some basic algorithm & datastructure knowledge) SortedDictionary We'll first cover SortedDictionary. This is implemented as a special sort of binary tree called a red-black tree. Essentially, it's a binary tree that uses various constraints on how the nodes of the tree can be arranged to ensure the tree is always roughly balanced (for more gory algorithmical details, see the wikipedia link above). What I'm concerned about in this post is how the .NET SortedDictionary is actually implemented. In .NET 4, behind the scenes, the actual implementation of the tree is delegated to a SortedSet<KeyValuePair<TKey, TValue>>. One example tree might look like this: Each node in the above tree is stored as a separate SortedSet<T>.Node object (remember, in a SortedDictionary, T is instantiated to KeyValuePair<TKey, TValue>): class Node { public bool IsRed; public T Item; public SortedSet<T>.Node Left; public SortedSet<T>.Node Right; } The SortedSet only stores a reference to the root node; all the data in the tree is accessed by traversing the Left and Right node references until you reach the node you're looking for. Each individual node can be physically stored anywhere in memory; what's important is the relationship between the nodes. This is also why there is no constructor to SortedDictionary or SortedSet that takes an integer representing the capacity; there are no internal arrays that need to be created and resized. This may seen trivial, but it's an important distinction between SortedDictionary and SortedList that I'll cover later on. And that's pretty much it; it's a standard red-black tree. Plenty of webpages and datastructure books cover the algorithms behind the tree itself far better than I could. What's interesting is the comparions between SortedDictionary and SortedList, which I'll cover at the end. As a side point, SortedDictionary has existed in the BCL ever since .NET 2. That means that, all through .NET 2, 3, and 3.5, there has been a bona-fide sorted set class in the BCL (called TreeSet). However, it was internal, so it couldn't be used outside System.dll. Only in .NET 4 was this class exposed as SortedSet. SortedList Whereas SortedDictionary didn't use any backing arrays, SortedList does. It is implemented just as the name suggests; two arrays, one containing the keys, and one the values (I've just used random letters for the values): The items in the keys array are always guarenteed to be stored in sorted order, and the value corresponding to each key is stored in the same index as the key in the values array. In this example, the value for key item 5 is 'z', and for key item 8 is 'm'. Whenever an item is inserted or removed from the SortedList, a binary search is run on the keys array to find the correct index, then all the items in the arrays are shifted to accomodate the new or removed item. For example, if the key 3 was removed, a binary search would be run to find the array index the item was at, then everything above that index would be moved down by one: and then if the key/value pair {7, 'f'} was added, a binary search would be run on the keys to find the index to insert the new item, and everything above that index would be moved up to accomodate the new item: If another item was then added, both arrays would be resized (to a length of 10) before the new item was added to the arrays. As you can see, any insertions or removals in the middle of the list require a proportion of the array contents to be moved; an O(n) operation. However, if the insertion or removal is at the end of the array (ie the largest key), then it's only O(log n); the cost of the binary search to determine it does actually need to be added to the end (excluding the occasional O(n) cost of resizing the arrays to fit more items). As a side effect of using backing arrays, SortedList offers IList Keys and Values views that simply use the backing keys or values arrays, as well as various methods utilising the array index of stored items, which SortedDictionary does not (and cannot) offer. The Comparison So, when should you use one and not the other? Well, here's the important differences: Memory usage SortedDictionary and SortedList have got very different memory profiles. SortedDictionary... has a memory overhead of one object instance, a bool, and two references per item. On 64-bit systems, this adds up to ~40 bytes, not including the stored item and the reference to it from the Node object. stores the items in separate objects that can be spread all over the heap. This helps to keep memory fragmentation low, as the individual node objects can be allocated wherever there's a spare 60 bytes. In contrast, SortedList... has no additional overhead per item (only the reference to it in the array entries), however the backing arrays can be significantly larger than you need; every time the arrays are resized they double in size. That means that if you add 513 items to a SortedList, the backing arrays will each have a length of 1024. To conteract this, the TrimExcess method resizes the arrays back down to the actual size needed, or you can simply assign list.Capacity = list.Count. stores its items in a continuous block in memory. If the list stores thousands of items, this can cause significant problems with Large Object Heap memory fragmentation as the array resizes, which SortedDictionary doesn't have. Performance Operations on a SortedDictionary always have O(log n) performance, regardless of where in the collection you're adding or removing items. In contrast, SortedList has O(n) performance when you're altering the middle of the collection. If you're adding or removing from the end (ie the largest item), then performance is O(log n), same as SortedDictionary (in practice, it will likely be slightly faster, due to the array items all being in the same area in memory, also called locality of reference). So, when should you use one and not the other? As always with these sort of things, there are no hard-and-fast rules. But generally, if you: need to access items using their index within the collection are populating the dictionary all at once from sorted data aren't adding or removing keys once it's populated then use a SortedList. But if you: don't know how many items are going to be in the dictionary are populating the dictionary from random, unsorted data are adding & removing items randomly then use a SortedDictionary. The default (again, there's no definite rules on these sort of things!) should be to use SortedDictionary, unless there's a good reason to use SortedList, due to the bad performance of SortedList when altering the middle of the collection.

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• Monitoring Html Element CSS Changes in JavaScript

  - by Rick Strahl

  [ updated Feb 15, 2011: Added event unbinding to avoid unintended recursion ] Here's a scenario I've run into on a few occasions: I need to be able to monitor certain CSS properties on an HTML element and know when that CSS element changes. For example, I have a some HTML element behavior plugins like a drop shadow that attaches to any HTML element, but I then need to be able to automatically keep the shadow in sync with the window if the  element dragged around the window or moved via code. Unfortunately there's no move event for HTML elements so you can't tell when it's location changes. So I've been looking around for some way to keep track of the element and a specific CSS property, but no luck. I suspect there's nothing native to do this so the only way I could think of is to use a timer and poll rather frequently for the property. I ended up with a generic jQuery plugin that looks like this: (function($){ $.fn.watch = function (props, func, interval, id) { /// <summary> /// Allows you to monitor changes in a specific /// CSS property of an element by polling the value. /// when the value changes a function is called. /// The function called is called in the context /// of the selected element (ie. this) /// </summary> /// <param name="prop" type="String">CSS Properties to watch sep. by commas</param> /// <param name="func" type="Function"> /// Function called when the value has changed. /// </param> /// <param name="interval" type="Number"> /// Optional interval for browsers that don't support DOMAttrModified or propertychange events. /// Determines the interval used for setInterval calls. /// </param> /// <param name="id" type="String">A unique ID that identifies this watch instance on this element</param> /// <returns type="jQuery" /> if (!interval) interval = 200; if (!id) id = "_watcher"; return this.each(function () { var _t = this; var el$ = $(this); var fnc = function () { __watcher.call(_t, id) }; var itId = null; var data = { id: id, props: props.split(","), func: func, vals: [props.split(",").length], fnc: fnc, origProps: props, interval: interval }; $.each(data.props, function (i) { data.vals[i] = el$.css(data.props[i]); }); el$.data(id, data); hookChange(el$, id, data.fnc); }); function hookChange(el$, id, fnc) { el$.each(function () { var el = $(this); if (typeof (el.get(0).onpropertychange) == "object") el.bind("propertychange." + id, fnc); else if ($.browser.mozilla) el.bind("DOMAttrModified." + id, fnc); else itId = setInterval(fnc, interval); }); } function __watcher(id) { var el$ = $(this); var w = el$.data(id); if (!w) return; var _t = this; if (!w.func) return; // must unbind or else unwanted recursion may occur el$.unwatch(id); var changed = false; var i = 0; for (i; i < w.props.length; i++) { var newVal = el$.css(w.props[i]); if (w.vals[i] != newVal) { w.vals[i] = newVal; changed = true; break; } } if (changed) w.func.call(_t, w, i); // rebind event hookChange(el$, id, w.fnc); } } $.fn.unwatch = function (id) { this.each(function () { var el = $(this); var fnc = el.data(id).fnc; try { if (typeof (this.onpropertychange) == "object") el.unbind("propertychange." + id, fnc); else if ($.browser.mozilla) el.unbind("DOMAttrModified." + id, fnc); else clearInterval(id); } // ignore if element was already unbound catch (e) { } }); return this; } })(jQuery); With this I can now monitor movement by monitoring say the top CSS property of the element. The following code creates a box and uses the draggable (jquery.ui) plugin and a couple of custom plugins that center and create a shadow. Here's how I can set this up with the watcher: $("#box") .draggable() .centerInClient() .shadow() .watch("top", function() { $(this).shadow(); },70,"_shadow"); ... $("#box") .unwatch("_shadow") .shadow("remove"); This code basically sets up the window to be draggable and initially centered and then a shadow is added. The .watch() call then assigns a CSS property to monitor (top in this case) and a function to call in response. The component now sets up a setInterval call and keeps on pinging this property every time. When the top value changes the supplied function is called. While this works and I can now drag my window around with the shadow following suit it's not perfect by a long shot. The shadow move is delayed and so drags behind the window, but using a higher timer value is not appropriate either as the UI starts getting jumpy if the timer's set with too small of an increment. This sort of monitor can be useful for other things as well where operations are maybe not quite as time critical as a UI operation taking place. Can anybody see a better a better way of capturing movement of an element on the page?© Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  JavaScript  jQuery  

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• Unable to enable wireless on a Vostro 2520

  - by Joe

  I have a Vostro 2520 and not sure how to enable wireless on my machine. The details are given below, would appreciate any pointers to resolving this issue. lsmod returns Module Size Used by ath9k 132390 0 ath9k_common 14053 1 ath9k ath9k_hw 411151 2 ath9k,ath9k_common ath 24067 3 ath9k,ath9k_common,ath9k_hw b43 365785 0 mac80211 506816 2 ath9k,b43 cfg80211 205544 4 ath9k,ath,b43,mac80211 bcma 26696 1 b43 ssb 52752 1 b43 ndiswrapper 282628 0 ums_realtek 18248 0 usb_storage 49198 1 ums_realtek uas 18180 0 snd_hda_codec_hdmi 32474 1 snd_hda_codec_cirrus 24002 1 joydev 17693 0 parport_pc 32866 0 ppdev 17113 0 rfcomm 47604 0 bnep 18281 2 bluetooth 180104 10 rfcomm,bnep psmouse 97362 0 dell_wmi 12681 0 sparse_keymap 13890 1 dell_wmi snd_hda_intel 33773 3 snd_hda_codec 127706 3 snd_hda_codec_hdmi,snd_hda_codec_cirrus,snd_hda_intel snd_hwdep 13668 1 snd_hda_codec snd_pcm 97188 3 snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec snd_seq_midi 13324 0 snd_rawmidi 30748 1 snd_seq_midi snd_seq_midi_event 14899 1 snd_seq_midi snd_seq 61896 2 snd_seq_midi,snd_seq_midi_event snd_timer 29990 2 snd_pcm,snd_seq snd_seq_device 14540 3 snd_seq_midi,snd_rawmidi,snd_seq wmi 19256 1 dell_wmi snd 78855 16 snd_hda_codec_hdmi,snd_hda_codec_cirrus,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm,snd_rawmidi,snd_seq,snd_timer,snd_seq_device mac_hid 13253 0 i915 473240 3 drm_kms_helper 46978 1 i915 uvcvideo 72627 0 drm 242038 4 i915,drm_kms_helper videodev 98259 1 uvcvideo soundcore 15091 1 snd dell_laptop 18119 0 dcdbas 14490 1 dell_laptop i2c_algo_bit 13423 1 i915 v4l2_compat_ioctl32 17128 1 videodev snd_page_alloc 18529 2 snd_hda_intel,snd_pcm video 19596 1 i915 serio_raw 13211 0 mei 41616 0 lp 17799 0 parport 46562 3 parport_pc,ppdev,lp r8169 62099 0 sudo lshw -class network *-network UNCLAIMED description: Network controller product: Broadcom Corporation vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:07:00.0 version: 01 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: latency=0 resources: memory:f7c00000-f7c07fff *-network description: Ethernet interface product: RTL8111/8168B PCI Express Gigabit Ethernet controller vendor: Realtek Semiconductor Co., Ltd. physical id: 0 bus info: pci@0000:09:00.0 logical name: eth0 version: 07 serial: 78:45:c4:a3:aa:65 size: 100Mbit/s capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl8168e-3_0.0.4 03/27/12 ip=192.168.1.5 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s resources: irq:41 ioport:e000(size=256) memory:f0004000-f0004fff memory:f0000000-f0003fff rfkill list all 0: dell-wifi: Wireless LAN Soft blocked: yes Hard blocked: yes 1: dell-bluetooth: Bluetooth Soft blocked: yes Hard blocked: yes Output of lspci > 00:00.0 Host bridge: Intel Corporation Ivy Bridge DRAM Controller (rev > 09) 00:02.0 VGA compatible controller: Intel Corporation Ivy Bridge > Graphics Controller (rev 09) 00:16.0 Communication controller: Intel > Corporation Panther Point MEI Controller #1 (rev 04) 00:1a.0 USB > controller: Intel Corporation Panther Point USB Enhanced Host > Controller #2 (rev 04) 00:1b.0 Audio device: Intel Corporation Panther > Point High Definition Audio Controller (rev 04) 00:1c.0 PCI bridge: > Intel Corporation Panther Point PCI Express Root Port 1 (rev c4) > 00:1c.3 PCI bridge: Intel Corporation Panther Point PCI Express Root > Port 4 (rev c4) 00:1c.5 PCI bridge: Intel Corporation Panther Point > PCI Express Root Port 6 (rev c4) 00:1d.0 USB controller: Intel > Corporation Panther Point USB Enhanced Host Controller #1 (rev 04) > 00:1f.0 ISA bridge: Intel Corporation Panther Point LPC Controller > (rev 04) 00:1f.2 SATA controller: Intel Corporation Panther Point 6 > port SATA Controller [AHCI mode] (rev 04) 00:1f.3 SMBus: Intel > Corporation Panther Point SMBus Controller (rev 04) 07:00.0 Network > controller: Broadcom Corporation Device 4365 (rev 01) 09:00.0 Ethernet > controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express > Gigabit Ethernet controller (rev 07) Output of lspci -v 0:00.0 Host bridge: Intel Corporation Ivy Bridge DRAM Controller (rev 09) Subsystem: Dell Device 0558 Flags: bus master, fast devsel, latency 0 Capabilities: <access denied> Kernel driver in use: agpgart-intel 00:02.0 VGA compatible controller: Intel Corporation Ivy Bridge Graphics Controller (rev 09) (prog-if 00 [VGA controller]) Subsystem: Dell Device 0558 Flags: bus master, fast devsel, latency 0, IRQ 43 Memory at f7800000 (64-bit, non-prefetchable) [size=4M] Memory at e0000000 (64-bit, prefetchable) [size=256M] I/O ports at f000 [size=64] Expansion ROM at <unassigned> [disabled] Capabilities: <access denied> Kernel driver in use: i915 Kernel modules: i915 00:16.0 Communication controller: Intel Corporation Panther Point MEI Controller #1 (rev 04) Subsystem: Dell Device 0558 Flags: bus master, fast devsel, latency 0, IRQ 42 Memory at f7d0a000 (64-bit, non-prefetchable) [size=16] Capabilities: <access denied> Kernel driver in use: mei Kernel modules: mei 00:1a.0 USB controller: Intel Corporation Panther Point USB Enhanced Host Controller #2 (rev 04) (prog-if 20 [EHCI]) Subsystem: Dell Device 0558 Flags: bus master, medium devsel, latency 0, IRQ 16 Memory at f7d08000 (32-bit, non-prefetchable) [size=1K] Capabilities: <access denied> Kernel driver in use: ehci_hcd 00:1b.0 Audio device: Intel Corporation Panther Point High Definition Audio Controller (rev 04) Subsystem: Dell Device 0558 Flags: bus master, fast devsel, latency 0, IRQ 44 Memory at f7d00000 (64-bit, non-prefetchable) [size=16K] Capabilities: <access denied> Kernel driver in use: snd_hda_intel Kernel modules: snd-hda-intel 00:1c.0 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 1 (rev c4) (prog-if 00 [Normal decode]) Flags: bus master, fast devsel, latency 0 Bus: primary=00, secondary=04, subordinate=04, sec-latency=0 Capabilities: <access denied> Kernel driver in use: pcieport Kernel modules: shpchp 00:1c.3 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 4 (rev c4) (prog-if 00 [Normal decode]) Flags: bus master, fast devsel, latency 0 Bus: primary=00, secondary=07, subordinate=07, sec-latency=0 Memory behind bridge: f7c00000-f7cfffff Capabilities: <access denied> Kernel driver in use: pcieport Kernel modules: shpchp 00:1c.5 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 6 (rev c4) (prog-if 00 [Normal decode]) Flags: bus master, fast devsel, latency 0 Bus: primary=00, secondary=09, subordinate=09, sec-latency=0 I/O behind bridge: 0000e000-0000efff Prefetchable memory behind bridge: 00000000f0000000-00000000f00fffff Capabilities: <access denied> Kernel driver in use: pcieport Kernel modules: shpchp 00:1d.0 USB controller: Intel Corporation Panther Point USB Enhanced Host Controller #1 (rev 04) (prog-if 20 [EHCI]) Subsystem: Dell Device 0558 Flags: bus master, medium devsel, latency 0, IRQ 23 Memory at f7d07000 (32-bit, non-prefetchable) [size=1K] Capabilities: <access denied> Kernel driver in use: ehci_hcd 00:1f.0 ISA bridge: Intel Corporation Panther Point LPC Controller (rev 04) Subsystem: Dell Device 0558 Flags: bus master, medium devsel, latency 0 Capabilities: <access denied> Kernel modules: iTCO_wdt 00:1f.2 SATA controller: Intel Corporation Panther Point 6 port SATA Controller [AHCI mode] (rev 04) (prog-if 01 [AHCI 1.0]) Subsystem: Dell Device 0558 Flags: bus master, 66MHz, medium devsel, latency 0, IRQ 40 I/O ports at f0b0 [size=8] I/O ports at f0a0 [size=4] I/O ports at f090 [size=8] I/O ports at f080 [size=4] I/O ports at f060 [size=32] Memory at f7d06000 (32-bit, non-prefetchable) [size=2K] Capabilities: <access denied> Kernel driver in use: ahci 00:1f.3 SMBus: Intel Corporation Panther Point SMBus Controller (rev 04) Subsystem: Dell Device 0558 Flags: medium devsel, IRQ 11 Memory at f7d05000 (64-bit, non-prefetchable) [size=256] I/O ports at f040 [size=32] Kernel modules: i2c-i801 07:00.0 Network controller: Broadcom Corporation Device 4365 (rev 01) Subsystem: Dell Device 0016 Flags: bus master, fast devsel, latency 0, IRQ 10 Memory at f7c00000 (64-bit, non-prefetchable) [size=32K] Capabilities: <access denied> 09:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 07) Subsystem: Dell Device 0558 Flags: bus master, fast devsel, latency 0, IRQ 41 I/O ports at e000 [size=256] Memory at f0004000 (64-bit, prefetchable) [size=4K] Memory at f0000000 (64-bit, prefetchable) [size=16K] Capabilities: <access denied> Kernel driver in use: r8169 Kernel modules: r8169

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• Changing CSS with jQuery syntax in Silverlight using jLight

  - by Timmy Kokke

  Lately I’ve ran into situations where I had to change elements or had to request a value in the DOM from Silverlight. jLight, which was introduced in an earlier article, can help with that. jQuery offers great ways to change CSS during runtime. Silverlight can access the DOM, but it isn’t as easy as jQuery. All examples shown in this article can be looked at in this online demo. The code can be downloaded here.   Part 1: The easy stuff Selecting and changing properties is pretty straight forward. Setting the text color in all <B> </B> elements can be done using the following code:   jQuery.Select("b").Css("color", "red");   The Css() method is an extension method on jQueryObject which is return by the jQuery.Select() method. The Css() method takes to parameters. The first is the Css style property. All properties used in Css can be entered in this string. The second parameter is the value you want to give the property. In this case the property is “color” and it is changed to “red”. To specify which element you want to select you can add a :selector parameter to the Select() method as shown in the next example.   jQuery.Select("b:first").Css("font-family", "sans-serif");   The “:first” pseudo-class selector selects only the first element. This example changes the “font-family” property of the first <B></B> element to “sans-serif”. To make use of intellisense in Visual Studio I’ve added a extension methods to help with the pseudo-classes. In the example below the “font-weight” of every “Even” <LI></LI> is set to “bold”.   jQuery.Select("li".Even()).Css("font-weight", "bold");   Because the Css() extension method returns a jQueryObject it is possible to chain calls to Css(). The following example show setting the “color”, “background-color” and the “font-size” of all headers in one go.   jQuery.Select(":header").Css("color", "#12FF70") .Css("background-color", "yellow") .Css("font-size", "25px");   Part 2: More complex stuff In only a few cases you need to change only one style property. More often you want to change an entire set op style properties all in one go.  You could chain a lot of Css() methods together. A better way is to add a class to a stylesheet and define all properties in there. With the AddClass() method you can set a style class to a set of elements. This example shows how to add the “demostyle” class to all <B></B> in the document.   jQuery.Select("b").AddClass("demostyle");   Removing the class works in the same way:   jQuery.Select("b").RemoveClass("demostyle");   jLight is build for interacting with to the DOM from Silverlight using jQuery. A jQueryObjectCss object can be used to define different sets of style properties in Silverlight. The over 60 most common Css style properties are defined in the jQueryObjectCss class. A string indexer can be used to access all style properties ( CssObject1[“background-color”] equals CssObject1.BackgroundColor). In the code below, two jQueryObjectCss objects are defined and instantiated.   private jQueryObjectCss CssObject1; private jQueryObjectCss CssObject2;   public Demo2() { CssObject1 = new jQueryObjectCss { BackgroundColor = "Lime", Color="Black", FontSize = "12pt", FontFamily = "sans-serif", FontWeight = "bold", MarginLeft = 150, LineHeight = "28px", Border = "Solid 1px #880000" }; CssObject2 = new jQueryObjectCss { FontStyle = "Italic", FontSize = "48", Color = "#225522" }; InitializeComponent(); }   Now instead of chaining to set all different properties you can just pass one of the jQueryObjectCss objects to the Css() method. In this case all <LI></LI> elements are set to match this object.   jQuery.Select("li").Css(CssObject1); When using the jQueryObjectCss objects chaining is still possible. In the following example all headers are given a blue backgroundcolor and the last is set to match CssObject2.   jQuery.Select(":header").Css(new jQueryObjectCss{BackgroundColor = "Blue"}) .Eq(-1).Css(CssObject2);   Part 3: The fun stuff Having Silverlight call JavaScript and than having JavaScript to call Silverlight requires a lot of plumbing code. Everything has to be registered and strings are passed back and forth to execute the JavaScript. jLight makes this kind of stuff so easy, it becomes fun to use. In a lot of situations jQuery can call a function to decide what to do, setting a style class based on complex expressions for example. jLight can do the same, but the callback methods are defined in Silverlight. This example calls the function() method for each <LI></LI> element. The callback method has to take a jQueryObject, an integer and a string as parameters. In this case jLight differs a bit from the actual jQuery implementation. jQuery uses only the index and the className parameters. A jQueryObject is added to make it simpler to access the attributes and properties of the element. If the text of the listitem starts with a ‘D’ or an ‘M’ the class is set. Otherwise null is returned and nothing happens.   private void button1_Click(object sender, RoutedEventArgs e) { jQuery.Select("li").AddClass(function); }   private string function(jQueryObject obj, int index, string className) { if (obj.Text[0] == 'D' || obj.Text[0] == 'M') return "demostyle"; return null; }   The last thing I would like to demonstrate uses even more Silverlight and less jLight, but demonstrates the power of the combination. Animating a style property using a Storyboard with easing functions. First a dependency property is defined. In this case it is a double named Intensity. By handling the changed event the color is set using jQuery.   public double Intensity { get { return (double)GetValue(IntensityProperty); } set { SetValue(IntensityProperty, value); } }   public static readonly DependencyProperty IntensityProperty = DependencyProperty.Register("Intensity", typeof(double), typeof(Demo3), new PropertyMetadata(0.0, IntensityChanged));   private static void IntensityChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { var i = (byte)(double)e.NewValue; jQuery.Select("span").Css("color", string.Format("#{0:X2}{0:X2}{0:X2}", i)); }   An animation has to be created. This code defines a Storyboard with one keyframe that uses a bounce ease as an easing function. The animation is set to target the Intensity dependency property defined earlier.   private Storyboard CreateAnimation(double value) { Storyboard storyboard = new Storyboard(); var da = new DoubleAnimationUsingKeyFrames(); var d = new EasingDoubleKeyFrame { EasingFunction = new BounceEase(), KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromSeconds(1.0)), Value = value }; da.KeyFrames.Add(d); Storyboard.SetTarget(da, this); Storyboard.SetTargetProperty(da, new PropertyPath(Demo3.IntensityProperty)); storyboard.Children.Add(da); return storyboard; }   Initially the Intensity is set to 128 which results in a gray color. When one of the buttons is pressed, a new animation is created an played. One to animate to black, and one to animate to white.   public Demo3() { InitializeComponent(); Intensity = 128; }   private void button2_Click(object sender, RoutedEventArgs e) { CreateAnimation(255).Begin(); }   private void button3_Click(object sender, RoutedEventArgs e) { CreateAnimation(0).Begin(); }   Conclusion As you can see jLight can make the life of a Silverlight developer a lot easier when accessing the DOM. Almost all jQuery functions that are defined in jLight use the same constructions as described above. I’ve tried to stay as close as possible to the real jQuery. Having JavaScript perform callbacks to Silverlight using jLight will be described in more detail in a future tutorial about AJAX or eventing.

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• tile_static, tile_barrier, and tiled matrix multiplication with C++ AMP

  - by Daniel Moth

  We ended the previous post with a mechanical transformation of the C++ AMP matrix multiplication example to the tiled model and in the process introduced tiled_index and tiled_grid. This is part 2. tile_static memory You all know that in regular CPU code, static variables have the same value regardless of which thread accesses the static variable. This is in contrast with non-static local variables, where each thread has its own copy. Back to C++ AMP, the same rules apply and each thread has its own value for local variables in your lambda, whereas all threads see the same global memory, which is the data they have access to via the array and array_view. In addition, on an accelerator like the GPU, there is a programmable cache, a third kind of memory type if you'd like to think of it that way (some call it shared memory, others call it scratchpad memory). Variables stored in that memory share the same value for every thread in the same tile. So, when you use the tiled model, you can have variables where each thread in the same tile sees the same value for that variable, that threads from other tiles do not. The new storage class for local variables introduced for this purpose is called tile_static. You can only use tile_static in restrict(direct3d) functions, and only when explicitly using the tiled model. What this looks like in code should be no surprise, but here is a snippet to confirm your mental image, using a good old regular C array // each tile of threads has its own copy of locA, // shared among the threads of the tile tile_static float locA[16][16]; Note that tile_static variables are scoped and have the lifetime of the tile, and they cannot have constructors or destructors. tile_barrier In amp.h one of the types introduced is tile_barrier. You cannot construct this object yourself (although if you had one, you could use a copy constructor to create another one). So how do you get one of these? You get it, from a tiled_index object. Beyond the 4 properties returning index objects, tiled_index has another property, barrier, that returns a tile_barrier object. The tile_barrier class exposes a single member, the method wait. 15: // Given a tiled_index object named t_idx 16: t_idx.barrier.wait(); 17: // more code …in the code above, all threads in the tile will reach line 16 before a single one progresses to line 17. Note that all threads must be able to reach the barrier, i.e. if you had branchy code in such a way which meant that there is a chance that not all threads could reach line 16, then the code above would be illegal. Tiled Matrix Multiplication Example – part 2 So now that we added to our understanding the concepts of tile_static and tile_barrier, let me obfuscate rewrite the matrix multiplication code so that it takes advantage of tiling. Before you start reading this, I suggest you get a cup of your favorite non-alcoholic beverage to enjoy while you try to fully understand the code. 01: void MatrixMultiplyTiled(vector<float>& vC, const vector<float>& vA, const vector<float>& vB, int M, int N, int W) 02: { 03: static const int TS = 16; 04: array_view<const float,2> a(M, W, vA); 05: array_view<const float,2> b(W, N, vB); 06: array_view<writeonly<float>,2> c(M,N,vC); 07: parallel_for_each(c.grid.tile< TS, TS >(), 08: [=] (tiled_index< TS, TS> t_idx) restrict(direct3d) 09: { 10: int row = t_idx.local[0]; int col = t_idx.local[1]; 11: float sum = 0.0f; 12: for (int i = 0; i < W; i += TS) { 13: tile_static float locA[TS][TS], locB[TS][TS]; 14: locA[row][col] = a(t_idx.global[0], col + i); 15: locB[row][col] = b(row + i, t_idx.global[1]); 16: t_idx.barrier.wait(); 17: for (int k = 0; k < TS; k++) 18: sum += locA[row][k] * locB[k][col]; 19: t_idx.barrier.wait(); 20: } 21: c[t_idx.global] = sum; 22: }); 23: } Notice that all the code up to line 9 is the same as per the changes we made in part 1 of tiling introduction. If you squint, the body of the lambda itself preserves the original algorithm on lines 10, 11, and 17, 18, and 21. The difference being that those lines use new indexing and the tile_static arrays; the tile_static arrays are declared and initialized on the brand new lines 13-15. On those lines we copy from the global memory represented by the array_view objects (a and b), to the tile_static vanilla arrays (locA and locB) – we are copying enough to fit a tile. Because in the code that follows on line 18 we expect the data for this tile to be in the tile_static storage, we need to synchronize the threads within each tile with a barrier, which we do on line 16 (to avoid accessing uninitialized memory on line 18). We also need to synchronize the threads within a tile on line 19, again to avoid the race between lines 14, 15 (retrieving the next set of data for each tile and overwriting the previous set) and line 18 (not being done processing the previous set of data). Luckily, as part of the awesome C++ AMP debugger in Visual Studio there is an option that helps you find such races, but that is a story for another blog post another time. May I suggest reading the next section, and then coming back to re-read and walk through this code with pen and paper to really grok what is going on, if you haven't already? Cool. Why would I introduce this tiling complexity into my code? Funny you should ask that, I was just about to tell you. There is only one reason we tiled our extent, had to deal with finding a good tile size, ensure the number of threads we schedule are correctly divisible with the tile size, had to use a tiled_index instead of a normal index, and had to understand tile_barrier and to figure out where we need to use it, and double the size of our lambda in terms of lines of code: the reason is to be able to use tile_static memory. Why do we want to use tile_static memory? Because accessing tile_static memory is around 10 times faster than accessing the global memory on an accelerator like the GPU, e.g. in the code above, if you can get 150GB/second accessing data from the array_view a, you can get 1500GB/second accessing the tile_static array locA. And since by definition you are dealing with really large data sets, the savings really pay off. We have seen tiled implementations being twice as fast as their non-tiled counterparts. Now, some algorithms will not have performance benefits from tiling (and in fact may deteriorate), e.g. algorithms that require you to go only once to global memory will not benefit from tiling, since with tiling you already have to fetch the data once from global memory! Other algorithms may benefit, but you may decide that you are happy with your code being 150 times faster than the serial-version you had, and you do not need to invest to make it 250 times faster. Also algorithms with more than 3 dimensions, which C++ AMP supports in the non-tiled model, cannot be tiled. Also note that in future releases, we may invest in making the non-tiled model, which already uses tiling under the covers, go the extra step and use tile_static memory on your behalf, but it is obviously way to early to commit to anything like that, and we certainly don't do any of that today. Comments about this post by Daniel Moth welcome at the original blog.

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• Java collision detection and player movement: tips

  - by Loris

  I have read a short guide for game develompent (java, without external libraries). I'm facing with collision detection and player (and bullets) movements. Now i put the code. Most of it is taken from the guide (should i link this guide?). I'm just trying to expand and complete it. This is the class that take care of updates movements and firing mechanism (and collision detection): public class ArenaController { private Arena arena; /** selected cell for movement */ private float targetX, targetY; /** true if droid is moving */ private boolean moving = false; /** true if droid is shooting to enemy */ private boolean shooting = false; private DroidController droidController; public ArenaController(Arena arena) { this.arena = arena; this.droidController = new DroidController(arena); } public void update(float delta) { Droid droid = arena.getDroid(); //droid movements if (moving) { droidController.moveDroid(delta, targetX, targetY); //check if arrived if (droid.getX() == targetX && droid.getY() == targetY) moving = false; } //firing mechanism if(shooting) { //stop shot if there aren't bullets if(arena.getBullets().isEmpty()) { shooting = false; } for(int i = 0; i < arena.getBullets().size(); i++) { //current bullet Bullet bullet = arena.getBullets().get(i); System.out.println(bullet.getBounds()); //angle calculation double angle = Math.atan2(bullet.getEnemyY() - bullet.getY(), bullet.getEnemyX() - bullet.getX()); //increments x and y bullet.setX((float) (bullet.getX() + (Math.cos(angle) * bullet.getSpeed() * delta))); bullet.setY((float) (bullet.getY() + (Math.sin(angle) * bullet.getSpeed() * delta))); //collision with obstacles for(int j = 0; j < arena.getObstacles().size(); j++) { Obstacle obs = arena.getObstacles().get(j); if(bullet.getBounds().intersects(obs.getBounds())) { System.out.println("Collision detect!"); arena.removeBullet(bullet); } } //collisions with enemies for(int j = 0; j < arena.getEnemies().size(); j++) { Enemy ene = arena.getEnemies().get(j); if(bullet.getBounds().intersects(ene.getBounds())) { System.out.println("Collision detect!"); arena.removeBullet(bullet); } } } } } public boolean onClick(int x, int y) { //click on empty cell if(arena.getGrid()[(int)(y / Arena.TILE)][(int)(x / Arena.TILE)] == null) { //coordinates targetX = x / Arena.TILE; targetY = y / Arena.TILE; //enables movement moving = true; return true; } //click on enemy: fire if(arena.getGrid()[(int)(y / Arena.TILE)][(int)(x / Arena.TILE)] instanceof Enemy) { //coordinates float enemyX = x / Arena.TILE; float enemyY = y / Arena.TILE; //new bullet Bullet bullet = new Bullet(); //start coordinates bullet.setX(arena.getDroid().getX()); bullet.setY(arena.getDroid().getY()); //end coordinates (enemie) bullet.setEnemyX(enemyX); bullet.setEnemyY(enemyY); //adds bullet to arena arena.addBullet(bullet); //enables shooting shooting = true; return true; } return false; } As you can see for collision detection i'm trying to use Rectangle object. Droid example: import java.awt.geom.Rectangle2D; public class Droid { private float x; private float y; private float speed = 20f; private float rotation = 0f; private float damage = 2f; public static final int DIAMETER = 32; private Rectangle2D rectangle; public Droid() { rectangle = new Rectangle2D.Float(x, y, DIAMETER, DIAMETER); } public float getX() { return x; } public void setX(float x) { this.x = x; //rectangle update rectangle.setRect(x, y, DIAMETER, DIAMETER); } public float getY() { return y; } public void setY(float y) { this.y = y; //rectangle update rectangle.setRect(x, y, DIAMETER, DIAMETER); } public float getSpeed() { return speed; } public void setSpeed(float speed) { this.speed = speed; } public float getRotation() { return rotation; } public void setRotation(float rotation) { this.rotation = rotation; } public float getDamage() { return damage; } public void setDamage(float damage) { this.damage = damage; } public Rectangle2D getRectangle() { return rectangle; } } For now, if i start the application and i try to shot to an enemy, is immediately detected a collision and the bullet is removed! Can you help me with this? If the bullet hit an enemy or an obstacle in his way, it must disappear. Ps: i know that the movements of the bullets should be managed in another class. This code is temporary. update I realized what happens, but not why. With those for loops (which checks collisions) the movements of the bullets are instantaneous instead of gradual. In addition to this, if i add the collision detection to the Droid, the method intersects returns true ALWAYS while the droid is moving! public void moveDroid(float delta, float x, float y) { Droid droid = arena.getDroid(); int bearing = 1; if (droid.getX() > x) { bearing = -1; } if (droid.getX() != x) { droid.setX(droid.getX() + bearing * droid.getSpeed() * delta); //obstacles collision detection for(Obstacle obs : arena.getObstacles()) { if(obs.getRectangle().intersects(droid.getRectangle())) { System.out.println("Collision detected"); //ALWAYS HERE } } //controlla se è arrivato if ((droid.getX() < x && bearing == -1) || (droid.getX() > x && bearing == 1)) droid.setX(x); } bearing = 1; if (droid.getY() > y) { bearing = -1; } if (droid.getY() != y) { droid.setY(droid.getY() + bearing * droid.getSpeed() * delta); if ((droid.getY() < y && bearing == -1) || (droid.getY() > y && bearing == 1)) droid.setY(y); } }

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• ASP.NET MVC: Using ProfileRequiredAttribute to restrict access to pages

  - by DigiMortal

  If you are using AppFabric Access Control Services to authenticate users when they log in to your community site using Live ID, Google or some other popular identity provider, you need more than AuthorizeAttribute to make sure that users can access the content that is there for authenticated users only. In this posting I will show you hot to extend the AuthorizeAttribute so users must also have user profile filled. Semi-authorized users When user is authenticated through external identity provider then not all identity providers give us user name or other information we ask users when they join with our site. What all identity providers have in common is unique ID that helps you identify the user. Example. Users authenticated through Windows Live ID by AppFabric ACS have no name specified. Google’s identity provider is able to provide you with user name and e-mail address if user agrees to publish this information to you. They both give you unique ID of user when user is successfully authenticated in their service. There is logical shift between ASP.NET and my site when considering user as authorized. For ASP.NET MVC user is authorized when user has identity. For my site user is authorized when user has profile and row in my users table. Having profile means that user has unique username in my system and he or she is always identified by this username by other users. My solution is simple: I created my own action filter attribute that makes sure if user has profile to access given method and if user has no profile then browser is redirected to join page. Illustrating the problem Usually we restrict access to page using AuthorizeAttribute. Code is something like this. [Authorize] public ActionResult Details(string id) {     var profile = _userRepository.GetUserByUserName(id);     return View(profile); } If this page is only for site users and we have user profiles then all users – the ones that have profile and all the others that are just authenticated – can access the information. It is okay because all these users have successfully logged in in some service that is supported by AppFabric ACS. In my site the users with no profile are in grey spot. They are on half way to be users because they have no username and profile on my site yet. So looking at the image above again we need something that adds profile existence condition to user-only content. [ProfileRequired] public ActionResult Details(string id) {     var profile = _userRepository.GetUserByUserName(id);     return View(profile); } Now, this attribute will solve our problem as soon as we implement it. ProfileRequiredAttribute: Profiles are required to be fully authorized Here is my implementation of ProfileRequiredAttribute. It is pretty new and right now it is more like working draft but you can already play with it. public class ProfileRequiredAttribute : AuthorizeAttribute {     private readonly string _redirectUrl;       public ProfileRequiredAttribute()     {         _redirectUrl = ConfigurationManager.AppSettings["JoinUrl"];         if (string.IsNullOrWhiteSpace(_redirectUrl))             _redirectUrl = "~/";     }              public override void OnAuthorization(AuthorizationContext filterContext)     {         base.OnAuthorization(filterContext);           var httpContext = filterContext.HttpContext;         var identity = httpContext.User.Identity;           if (!identity.IsAuthenticated || identity.GetProfile() == null)             if(filterContext.Result == null)                 httpContext.Response.Redirect(_redirectUrl);          } } All methods with this attribute work as follows: if user is not authenticated then he or she is redirected to AppFabric ACS identity provider selection page, if user is authenticated but has no profile then user is by default redirected to main page of site but if you have application setting with name JoinUrl then user is redirected to this URL. First case is handled by AuthorizeAttribute and the second one is handled by custom logic in ProfileRequiredAttribute class. GetProfile() extension method To get user profile using less code in places where profiles are needed I wrote GetProfile() extension method for IIdentity interface. There are some more extension methods that read out user and identity provider identifier from claims and based on this information user profile is read from database. If you take this code with copy and paste I am sure it doesn’t work for you but you get the idea. public static User GetProfile(this IIdentity identity) {     if (identity == null)         return null;       var context = HttpContext.Current;     if (context.Items["UserProfile"] != null)         return context.Items["UserProfile"] as User;       var provider = identity.GetIdentityProvider();     var nameId = identity.GetNameIdentifier();       var rep = ObjectFactory.GetInstance<IUserRepository>();     var profile = rep.GetUserByProviderAndNameId(provider, nameId);       context.Items["UserProfile"] = profile;       return profile; } To avoid round trips to database I cache user profile to current request because the chance that profile gets changed meanwhile is very minimal. The other reason is maybe more tricky – profile objects are coming from Entity Framework context and context has also HTTP request as lifecycle. Conclusion This posting gave you some ideas how to finish user profiles stuff when you use AppFabric ACS as external authentication provider. Although there was little shift between us and ASP.NET MVC with interpretation of “authorized” we were easily able to solve the problem by extending AuthorizeAttribute to get all our requirements fulfilled. We also write extension method for IIdentity that returns as user profile based on username and caches the profile in HTTP request scope.

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• Deterministic/Consistent Unique Masking

  - by Dinesh Rajasekharan-Oracle

  One of the key requirements while masking data in large databases or multi database environment is to consistently mask some columns, i.e. for a given input the output should always be the same. At the same time the masked output should not be predictable. Deterministic masking also eliminates the need to spend enormous amount of time spent in identifying data relationships, i.e. parent and child relationships among columns defined in the application tables. In this blog post I will explain different ways of consistently masking the data across databases using Oracle Data Masking and Subsetting The readers of post should have minimal knowledge on Oracle Enterprise Manager 12c, Application Data Modeling, Data Masking concepts. For more information on these concepts, please refer to Oracle Data Masking and Subsetting document Oracle Data Masking and Subsetting 12c provides four methods using which users can consistently yet irreversibly mask their inputs. 1. Substitute 2. SQL Expression 3. Encrypt 4. User Defined Function SUBSTITUTE The substitute masking format replaces the original value with a value from a pre-created database table. As the method uses a hash based algorithm in the back end the mappings are consistent. For example consider DEPARTMENT_ID in EMPLOYEES table is replaced with FAKE_DEPARTMENT_ID from FAKE_TABLE. The substitute masking transformation that all occurrences of DEPARTMENT_ID say ‘101’ will be replaced with ‘502’ provided same substitution table and column is used , i.e. FAKE_TABLE.FAKE_DEPARTMENT_ID. The following screen shot shows the usage of the Substitute masking format with in a masking definition: Note that the uniqueness of the masked value depends on the number of columns being used in the substitution table i.e. if the original table contains 50000 unique values, then for the masked output to be unique and deterministic the substitution column should also contain 50000 unique values without which only consistency is maintained but not uniqueness. SQL EXPRESSION SQL Expression replaces an existing value with the output of a specified SQL Expression. For example while masking an EMPLOYEES table the EMAIL_ID of an employee has to be in the format EMPLOYEE’s [email protected] while FIRST_NAME and LAST_NAME are the actual column names of the EMPLOYEES table then the corresponding SQL Expression will look like %FIRST_NAME%||’.’||%LAST_NAME%||’@COMPANY.COM’. The advantage of this technique is that if you are masking FIRST_NAME and LAST_NAME of the EMPLOYEES table than the corresponding EMAIL ID will be replaced accordingly by the masking scripts. One of the interesting aspect’s of a SQL Expressions is that you can use sub SQL expressions, which means that you can write a nested SQL and use it as SQL Expression to address a complex masking business use cases. SQL Expression can also be used to consistently replace value with hashed value using Oracle’s PL/SQL function ORA_HASH. The following SQL Expression will help in the previous example for replacing the DEPARTMENT_IDs with a hashed number ORA_HASH (%DEPARTMENT_ID%, 1000) The following screen shot shows the usage of encrypt masking format with in the masking definition: ORA_HASH takes three arguments: 1. Expression which can be of any data type except LONG, LOB, User Defined Type [nested table type is allowed]. In the above example I used the Original value as expression. 2. Number of hash buckets which can be number between 0 and 4294967295. The default value is 4294967295. You can also co-relate the number of hash buckets to a range of numbers. In the above example above the bucket value is specified as 1000, so the end result will be a hashed number in between 0 and 1000. 3. Seed, can be any number which decides the consistency, i.e. for a given seed value the output will always be same. The default seed is 0. In the above SQL Expression a seed in not specified, so it to 0. If you have to use a non default seed then the function will look like. ORA_HASH (%DEPARTMENT_ID%, 1000, 1234 The uniqueness depends on the input and the number of hash buckets used. However as ORA_HASH uses a 32 bit algorithm, considering birthday paradox or pigeonhole principle there is a 0.5 probability of collision after 232-1 unique values. ENCRYPT Encrypt masking format uses a blend of 3DES encryption algorithm, hashing, and regular expression to produce a deterministic and unique masked output. The format of the masked output corresponds to the specified regular expression. As this technique uses a key [string] to encrypt the data, the same string can be used to decrypt the data. The key also acts as seed to maintain consistent outputs for a given input. The following screen shot shows the usage of encrypt masking format with in the masking definition: Regular Expressions may look complex for the first time users but you will soon realize that it’s a simple language. There are many resources in internet, oracle documentation, oracle learning library, my oracle support on writing a Regular Expressions, out of all the following My Oracle Support document helped me to get started with Regular Expressions: Oracle SQL Support for Regular Expressions[Video](Doc ID 1369668.1) USER DEFINED FUNCTION [UDF] User Defined Function or UDF provides flexibility for the users to code their own masking logic in PL/SQL, which can be called from masking Defintion. The standard format of an UDF in Oracle Data Masking and Subsetting is: Function udf_func (rowid varchar2, column_name varchar2, original_value varchar2) returns varchar2; Where • rowid is the row identifier of the column that needs to be masked • column_name is the name of the column that needs to be masked • original_value is the column value that needs to be masked You can achieve deterministic masking by using Oracle’s built in hash functions like, ORA_HASH, DBMS_CRYPTO.MD4, DBMS_CRYPTO.MD5, DBMS_UTILITY. GET_HASH_VALUE.Please refers to the Oracle Database Documentation for more information on the Oracle Hash functions. For example the following masking UDF generate deterministic unique hexadecimal values for a given string input: CREATE OR REPLACE FUNCTION RD_DUX (rid varchar2, column_name varchar2, orig_val VARCHAR2) RETURN VARCHAR2 DETERMINISTIC PARALLEL_ENABLE IS stext varchar2 (26); no_of_characters number(2); BEGIN no_of_characters:=6; stext:=substr(RAWTOHEX(DBMS_CRYPTO.HASH(UTL_RAW.CAST_TO_RAW(text),1)),0,no_of_characters); RETURN stext; END; The uniqueness depends on the input and length of the string and number of bits used by hash algorithm. In the above function MD4 hash is used [denoted by argument 1 in the DBMS_CRYPTO.HASH function which is a 128 bit algorithm which produces 2^128-1 unique hashed values , however this is limited by the length of the input string which is 6, so only 6^6 unique values will be generated. Also do not forget about the birthday paradox/pigeonhole principle mentioned earlier in this post. An another example is to consistently replace characters or numbers preserving the length and special characters as shown below: CREATE OR REPLACE FUNCTION RD_DUS(rid varchar2,column_name varchar2,orig_val VARCHAR2) RETURN VARCHAR2 DETERMINISTIC PARALLEL_ENABLE IS stext varchar2(26); BEGIN DBMS_RANDOM.SEED(orig_val); stext:=TRANSLATE(orig_val,'ABCDEFGHILKLMNOPQRSTUVWXYZ',DBMS_RANDOM.STRING('U',26)); stext:=TRANSLATE(stext,'abcdefghijklmnopqrstuvwxyz',DBMS_RANDOM.STRING('L',26)); stext:=TRANSLATE(stext,'0123456789',to_char(DBMS_RANDOM.VALUE(1,9))); stext:=REPLACE(stext,'.','0'); RETURN stext; END; The following screen shot shows the usage of an UDF with in a masking definition: To summarize, Oracle Data Masking and Subsetting helps you to consistently mask data across databases using one or all of the methods described in this post. It saves the hassle of identifying the parent-child relationships defined in the application table. Happy Masking

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• Inheritance Mapping Strategies with Entity Framework Code First CTP5: Part 2 – Table per Type (TPT)

  - by mortezam

  In the previous blog post you saw that there are three different approaches to representing an inheritance hierarchy and I explained Table per Hierarchy (TPH) as the default mapping strategy in EF Code First. We argued that the disadvantages of TPH may be too serious for our design since it results in denormalized schemas that can become a major burden in the long run. In today’s blog post we are going to learn about Table per Type (TPT) as another inheritance mapping strategy and we'll see that TPT doesn’t expose us to this problem. Table per Type (TPT)Table per Type is about representing inheritance relationships as relational foreign key associations. Every class/subclass that declares persistent properties—including abstract classes—has its own table. The table for subclasses contains columns only for each noninherited property (each property declared by the subclass itself) along with a primary key that is also a foreign key of the base class table. This approach is shown in the following figure: For example, if an instance of the CreditCard subclass is made persistent, the values of properties declared by the BillingDetail base class are persisted to a new row of the BillingDetails table. Only the values of properties declared by the subclass (i.e. CreditCard) are persisted to a new row of the CreditCards table. The two rows are linked together by their shared primary key value. Later, the subclass instance may be retrieved from the database by joining the subclass table with the base class table. TPT Advantages The primary advantage of this strategy is that the SQL schema is normalized. In addition, schema evolution is straightforward (modifying the base class or adding a new subclass is just a matter of modify/add one table). Integrity constraint definition are also straightforward (note how CardType in CreditCards table is now a non-nullable column). Another much more important advantage is the ability to handle polymorphic associations (a polymorphic association is an association to a base class, hence to all classes in the hierarchy with dynamic resolution of the concrete class at runtime). A polymorphic association to a particular subclass may be represented as a foreign key referencing the table of that particular subclass. Implement TPT in EF Code First We can create a TPT mapping simply by placing Table attribute on the subclasses to specify the mapped table name (Table attribute is a new data annotation and has been added to System.ComponentModel.DataAnnotations namespace in CTP5): public abstract class BillingDetail {     public int BillingDetailId { get; set; }     public string Owner { get; set; }     public string Number { get; set; } } [Table("BankAccounts")] public class BankAccount : BillingDetail {     public string BankName { get; set; }     public string Swift { get; set; } } [Table("CreditCards")] public class CreditCard : BillingDetail {     public int CardType { get; set; }     public string ExpiryMonth { get; set; }     public string ExpiryYear { get; set; } } public class InheritanceMappingContext : DbContext {     public DbSet<BillingDetail> BillingDetails { get; set; } } If you prefer fluent API, then you can create a TPT mapping by using ToTable() method: protected override void OnModelCreating(ModelBuilder modelBuilder) {     modelBuilder.Entity<BankAccount>().ToTable("BankAccounts");     modelBuilder.Entity<CreditCard>().ToTable("CreditCards"); } Generated SQL For QueriesLet’s take an example of a simple non-polymorphic query that returns a list of all the BankAccounts: var query = from b in context.BillingDetails.OfType<BankAccount>() select b; Executing this query (by invoking ToList() method) results in the following SQL statements being sent to the database (on the bottom, you can also see the result of executing the generated query in SQL Server Management Studio): Now, let’s take an example of a very simple polymorphic query that requests all the BillingDetails which includes both BankAccount and CreditCard types: projects some properties out of the base class BillingDetail, without querying for anything from any of the subclasses: var query = from b in context.BillingDetails             select new { b.BillingDetailId, b.Number, b.Owner }; -- var query = from b in context.BillingDetails select b; This LINQ query seems even more simple than the previous one but the resulting SQL query is not as simple as you might expect: -- As you can see, EF Code First relies on an INNER JOIN to detect the existence (or absence) of rows in the subclass tables CreditCards and BankAccounts so it can determine the concrete subclass for a particular row of the BillingDetails table. Also the SQL CASE statements that you see in the beginning of the query is just to ensure columns that are irrelevant for a particular row have NULL values in the returning flattened table. (e.g. BankName for a row that represents a CreditCard type) TPT ConsiderationsEven though this mapping strategy is deceptively simple, the experience shows that performance can be unacceptable for complex class hierarchies because queries always require a join across many tables. In addition, this mapping strategy is more difficult to implement by hand— even ad-hoc reporting is more complex. This is an important consideration if you plan to use handwritten SQL in your application (For ad hoc reporting, database views provide a way to offset the complexity of the TPT strategy. A view may be used to transform the table-per-type model into the much simpler table-per-hierarchy model.) SummaryIn this post we learned about Table per Type as the second inheritance mapping in our series. So far, the strategies we’ve discussed require extra consideration with regard to the SQL schema (e.g. in TPT, foreign keys are needed). This situation changes with the Table per Concrete Type (TPC) that we will discuss in the next post. References ADO.NET team blog Java Persistence with Hibernate book a { text-decoration: none; } a:visited { color: Blue; } .title { padding-bottom: 5px; font-family: Segoe UI; font-size: 11pt; font-weight: bold; padding-top: 15px; } .code, .typeName { font-family: consolas; } .typeName { color: #2b91af; } .padTop5 { padding-top: 5px; } .padTop10 { padding-top: 10px; } p.MsoNormal { margin-top: 0in; margin-right: 0in; margin-bottom: 10.0pt; margin-left: 0in; line-height: 115%; font-size: 11.0pt; font-family: "Calibri" , "sans-serif"; }

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• Use a Fake Http Channel to Unit Test with HttpClient

  - by Steve Michelotti

  Applications get data from lots of different sources. The most common is to get data from a database or a web service. Typically, we encapsulate calls to a database in a Repository object and we create some sort of IRepository interface as an abstraction to decouple between layers and enable easier unit testing by leveraging faking and mocking. This works great for database interaction. However, when consuming a RESTful web service, this is is not always the best approach. The WCF Web APIs that are available on CodePlex (current drop is Preview 3) provide a variety of features to make building HTTP REST services more robust. When you download the latest bits, you’ll also find a new HttpClient which has been updated for .NET 4.0 as compared to the one that shipped for 3.5 in the original REST Starter Kit. The HttpClient currently provides the best API for consuming REST services on the .NET platform and the WCF Web APIs provide a number of extension methods which extend HttpClient and make it even easier to use. Let’s say you have a client application that is consuming an HTTP service – this could be Silverlight, WPF, or any UI technology but for my example I’ll use an MVC application: 1: using System; 2: using System.Net.Http; 3: using System.Web.Mvc; 4: using FakeChannelExample.Models; 5: using Microsoft.Runtime.Serialization; 6:   7: namespace FakeChannelExample.Controllers 8: { 9: public class HomeController : Controller 10: { 11: private readonly HttpClient httpClient; 12:   13: public HomeController(HttpClient httpClient) 14: { 15: this.httpClient = httpClient; 16: } 17:   18: public ActionResult Index() 19: { 20: var response = httpClient.Get("Person(1)"); 21: var person = response.Content.ReadAsDataContract<Person>(); 22:   23: this.ViewBag.Message = person.FirstName + " " + person.LastName; 24: 25: return View(); 26: } 27: } 28: } On line #20 of the code above you can see I’m performing an HTTP GET request to a Person resource exposed by an HTTP service. On line #21, I use the ReadAsDataContract() extension method provided by the WCF Web APIs to serialize to a Person object. In this example, the HttpClient is being passed into the constructor by MVC’s dependency resolver – in this case, I’m using StructureMap as an IoC and my StructureMap initialization code looks like this: 1: using StructureMap; 2: using System.Net.Http; 3:   4: namespace FakeChannelExample 5: { 6: public static class IoC 7: { 8: public static IContainer Initialize() 9: { 10: ObjectFactory.Initialize(x => 11: { 12: x.For<HttpClient>().Use(() => new HttpClient("http://localhost:31614/")); 13: }); 14: return ObjectFactory.Container; 15: } 16: } 17: } My controller code currently depends on a concrete instance of the HttpClient. Now I *could* create some sort of interface and wrap the HttpClient in this interface and use that object inside my controller instead – however, there are a few why reasons that is not desirable: For one thing, the API provided by the HttpClient provides nice features for dealing with HTTP services. I don’t really *want* these to look like C# RPC method calls – when HTTP services have REST features, I may want to inspect HTTP response headers and hypermedia contained within the message so that I can make intelligent decisions as to what to do next in my workflow (although I don’t happen to be doing these things in my example above) – this type of workflow is common in hypermedia REST scenarios. If I just encapsulate HttpClient behind some IRepository interface and make it look like a C# RPC method call, it will become difficult to take advantage of these types of things. Second, it could get pretty mind-numbing to have to create interfaces all over the place just to wrap the HttpClient. Then you’re probably going to have to hard-code HTTP knowledge into your code to formulate requests rather than just “following the links” that the hypermedia in a message might provide. Third, at first glance it might appear that we need to create an interface to facilitate unit testing, but actually it’s unnecessary. Even though the code above is dependent on a concrete type, it’s actually very easy to fake the data in a unit test. The HttpClient provides a Channel property (of type HttpMessageChannel) which allows you to create a fake message channel which can be leveraged in unit testing. In this case, what I want is to be able to write a unit test that just returns fake data. I also want this to be as re-usable as possible for my unit testing. I want to be able to write a unit test that looks like this: 1: [TestClass] 2: public class HomeControllerTest 3: { 4: [TestMethod] 5: public void Index() 6: { 7: // Arrange 8: var httpClient = new HttpClient("http://foo.com"); 9: httpClient.Channel = new FakeHttpChannel<Person>(new Person { FirstName = "Joe", LastName = "Blow" }); 10:   11: HomeController controller = new HomeController(httpClient); 12:   13: // Act 14: ViewResult result = controller.Index() as ViewResult; 15:   16: // Assert 17: Assert.AreEqual("Joe Blow", result.ViewBag.Message); 18: } 19: } Notice on line #9, I’m setting the Channel property of the HttpClient to be a fake channel. I’m also specifying the fake object that I want to be in the response on my “fake” Http request. I don’t need to rely on any mocking frameworks to do this. All I need is my FakeHttpChannel. The code to do this is not complex: 1: using System; 2: using System.IO; 3: using System.Net.Http; 4: using System.Runtime.Serialization; 5: using System.Threading; 6: using FakeChannelExample.Models; 7:   8: namespace FakeChannelExample.Tests 9: { 10: public class FakeHttpChannel<T> : HttpClientChannel 11: { 12: private T responseObject; 13:   14: public FakeHttpChannel(T responseObject) 15: { 16: this.responseObject = responseObject; 17: } 18:   19: protected override HttpResponseMessage Send(HttpRequestMessage request, CancellationToken cancellationToken) 20: { 21: return new HttpResponseMessage() 22: { 23: RequestMessage = request, 24: Content = new StreamContent(this.GetContentStream()) 25: }; 26: } 27:   28: private Stream GetContentStream() 29: { 30: var serializer = new DataContractSerializer(typeof(T)); 31: Stream stream = new MemoryStream(); 32: serializer.WriteObject(stream, this.responseObject); 33: stream.Position = 0; 34: return stream; 35: } 36: } 37: } The HttpClientChannel provides a Send() method which you can override to return any HttpResponseMessage that you want. You can see I’m using the DataContractSerializer to serialize the object and write it to a stream. That’s all you need to do. In the example above, the only thing I’ve chosen to do is to provide a way to return different response objects. But there are many more features you could add to your own re-usable FakeHttpChannel. For example, you might want to provide the ability to add HTTP headers to the message. You might want to use a different serializer other than the DataContractSerializer. You might want to provide custom hypermedia in the response as well as just an object or set HTTP response codes. This list goes on. This is the just one example of the really cool features being added to the next version of WCF to enable various HTTP scenarios. The code sample for this post can be downloaded here.

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• SQL Server Table Polling by Multiple Subscribers

  - by Daniel Hester

  Background Designing Stored Procedures that are safe for multiple subscribers (to call simultaneously) can be challenging.  For example let’s say that you want multiple worker processes to poll a shared work queue that’s encapsulated as a SQL Table. This is a common scenario and through experience you’ll find that you want to use Table Hints to prevent unwanted locking when performing simultaneous queries on the same table. There are three table hints to consider: NOLOCK, READPAST and UPDLOCK. Both NOLOCK and READPAST table hints allow you to SELECT from a table without placing a LOCK on that table. However, SELECTs with the READPAST hint will ignore any records that are locked due to being updated/inserted (or otherwise “dirty”), whereas a SELECT with NOLOCK ignores all locks including dirty reads. For the initial update of the flag (that marks the record as available for subscription) I don’t use the NOLOCK Table Hint because I want to be sensitive to the “active” records in the table and I want to exclude them.  I use an Update Lock (UPDLOCK) in conjunction with a WHERE clause that uses a sub-select with a READPAST Table Hint in order to explicitly lock the records I’m updating (UPDLOCK) but not place a lock on the table when selecting the records that I’m going to update (READPAST). UPDATES should be allowed to lock the rows affected because we’re probably changing a flag on a record so that it is not included in a SELECT from another subscriber. On the UPDATE statement we should explicitly use the UPDLOCK to guard against lock escalation. A SELECT to check for the next record(s) to process can result in a shared read lock being held by more than one subscriber polling the shared work queue (SQL table). It is expected that more than one worker process (or server) might try to process the same new record(s) at the same time. When each process then tries to obtain the update lock, none of them can because another process has a shared read lock in place. Thus without the UPDLOCK hint the result would be a lock escalation deadlock; however with the UPDLOCK hint this condition is mitigated against. Note that using the READPAST table hint requires that you also set the ISOLATION LEVEL of the transaction to be READ COMMITTED (rather than the default of SERIALIZABLE). Guidance In the Stored Procedure that returns records to the multiple subscribers: Perform the UPDATE first. Change the flag that makes the record available to subscribers.  Additionally, you may want to update a LastUpdated datetime field in order to be able to check for records that “got stuck” in an intermediate state or for other auditing purposes. In the UPDATE statement use the (UPDLOCK) Table Hint on the UPDATE statement to prevent lock escalation. In the UPDATE statement also use a WHERE Clause that uses a sub-select with a (READPAST) Table Hint to select the records that you’re going to update. In the UPDATE statement use the OUTPUT clause in conjunction with a Temporary Table to isolate the record(s) that you’ve just updated and intend to return to the subscriber. This is the fastest way to update the record(s) and to get the records’ identifiers within the same operation. Finally do a set-based SELECT on the main Table (using the Temporary Table to identify the records in the set) with either a READPAST or NOLOCK table hint.  Use NOLOCK if there are other processes (besides the multiple subscribers) that might be changing the data that you want to return to the multiple subscribers; or use READPAST if you're sure there are no other processes (besides the multiple subscribers) that might be updating column data in the table for other purposes (e.g. changes to a person’s last name).  NOLOCK is generally the better fit in this part of the scenario. See the following as an example: CREATE PROCEDURE [dbo].[usp_NewCustomersSelect] AS BEGIN -- OVERRIDE THE DEFAULT ISOLATION LEVEL SET TRANSACTION ISOLATION LEVEL READ COMMITTED -- SET NOCOUNT ON SET NOCOUNT ON -- DECLARE TEMP TABLE -- Note that this example uses CustomerId as an identifier; -- you could just use the Identity column Id if that’s all you need. DECLARE @CustomersTempTable TABLE ( CustomerId NVARCHAR(255) ) -- PERFORM UPDATE FIRST -- [Customers] is the name of the table -- [Id] is the Identity Column on the table -- [CustomerId] is the business document key used to identify the -- record globally, i.e. in other systems or across SQL tables -- [Status] is INT or BIT field (if the status is a binary state) -- [LastUpdated] is a datetime field used to record the time of the -- last update UPDATE [Customers] WITH (UPDLOCK) SET [Status] = 1, [LastUpdated] = GETDATE() OUTPUT [INSERTED].[CustomerId] INTO @CustomersTempTable WHERE ([Id] = (SELECT TOP 100 [Id] FROM [Customers] WITH (READPAST) WHERE ([Status] = 0) ORDER BY [Id] ASC)) -- PERFORM SELECT FROM ENTITY TABLE SELECT [C].[CustomerId], [C].[FirstName], [C].[LastName], [C].[Address1], [C].[Address2], [C].[City], [C].[State], [C].[Zip], [C].[ShippingMethod], [C].[Id] FROM [Customers] AS [C] WITH (NOLOCK), @CustomersTempTable AS [TEMP] WHERE ([C].[CustomerId] = [TEMP].[CustomerId]) END In a system that has been designed to have multiple status values for records that need to be processed in the Work Queue it is necessary to have a “Watch Dog” process by which “stale” records in intermediate states (such as “In Progress”) are detected, i.e. a [Status] of 0 = New or Unprocessed; a [Status] of 1 = In Progress; a [Status] of 2 = Processed; etc.. Thus, if you have a business rule that states that the application should only process new records if all of the old records have been processed successfully (or marked as an error), then it will be necessary to build a monitoring process to detect stalled or stale records in the Work Queue, hence the use of the LastUpdated column in the example above. The Status field along with the LastUpdated field can be used as the criteria to detect stalled / stale records. It is possible to put this watchdog logic into the stored procedure above, but I would recommend making it a separate monitoring function. In writing the stored procedure that checks for stale records I would recommend using the same kind of lock semantics as suggested above. The example below looks for records that have been in the “In Progress” state ([Status] = 1) for greater than 60 seconds: CREATE PROCEDURE [dbo].[usp_NewCustomersWatchDog] AS BEGIN -- TO OVERRIDE THE DEFAULT ISOLATION LEVEL SET TRANSACTION ISOLATION LEVEL READ COMMITTED -- SET NOCOUNT ON SET NOCOUNT ON DECLARE @MaxWait int; SET @MaxWait = 60 IF EXISTS (SELECT 1 FROM [dbo].[Customers] WITH (READPAST) WHERE ([Status] = 1) AND (DATEDIFF(s, [LastUpdated], GETDATE()) > @MaxWait)) BEGIN SELECT 1 AS [IsWatchDogError] END ELSE BEGIN SELECT 0 AS [IsWatchDogError] END END Downloads The zip file below contains two SQL scripts: one to create a sample database with the above stored procedures and one to populate the sample database with 10,000 sample records.  I am very grateful to Red-Gate software for their excellent SQL Data Generator tool which enabled me to create these sample records in no time at all. References http://msdn.microsoft.com/en-us/library/ms187373.aspx http://www.techrepublic.com/article/using-nolock-and-readpast-table-hints-in-sql-server/6185492 http://geekswithblogs.net/gwiele/archive/2004/11/25/15974.aspx http://grounding.co.za/blogs/romiko/archive/2009/03/09/biztalk-sql-receive-location-deadlocks-dirty-reads-and-isolation-levels.aspx

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• Retrieving a list of eBay categories using the .NET SDK and GetCategoriesCall

  - by Bill Osuch

  eBay offers a .Net SDK for its Trading API - this post will show you the basics of making an API call and retrieving a list of current categories. You'll need the category ID(s) for any apps that post or search eBay. To start, download the latest SDK from https://www.x.com/developers/ebay/documentation-tools/sdks/dotnet and create a new console app project. Add a reference to the eBay.Service DLL, and a few using statements: using eBay.Service.Call; using eBay.Service.Core.Sdk; using eBay.Service.Core.Soap; I'm assuming at this point you've already joined the eBay Developer Network and gotten your app IDs and user tokens. If not: Join the developer program Generate tokens Next, add an app.config file that looks like this: <?xml version="1.0"?> <configuration>   <appSettings>     <add key="Environment.ApiServerUrl" value="https://api.ebay.com/wsapi"/>     <add key="UserAccount.ApiToken" value="YourBigLongToken"/>   </appSettings> </configuration> And then add the code to get the xml list of categories: ApiContext apiContext = GetApiContext(); GetCategoriesCall apiCall = new GetCategoriesCall(apiContext); apiCall.CategorySiteID = "0"; //Leave this commented out to retrieve all category levels (all the way down): //apiCall.LevelLimit = 4; //Uncomment this to begin at a specific parent category: //StringCollection parentCategories = new StringCollection(); //parentCategories.Add("63"); //apiCall.CategoryParent = parentCategories; apiCall.DetailLevelList.Add(DetailLevelCodeType.ReturnAll); CategoryTypeCollection cats = apiCall.GetCategories(); using (StreamWriter outfile = new StreamWriter(@"C:\Temp\EbayCategories.xml")) {    outfile.Write(apiCall.SoapResponse); } GetApiContext() (provided in the sample apps in the SDK) is required for any call:         static ApiContext GetApiContext()         {             //apiContext is a singleton,             //to avoid duplicate configuration reading             if (apiContext != null)             {                 return apiContext;             }             else             {                 apiContext = new ApiContext();                 //set Api Server Url                 apiContext.SoapApiServerUrl = ConfigurationManager.AppSettings["Environment.ApiServerUrl"];                 //set Api Token to access eBay Api Server                 ApiCredential apiCredential = new ApiCredential();                 apiCredential.eBayToken = ConfigurationManager.AppSettings["UserAccount.ApiToken"];                 apiContext.ApiCredential = apiCredential;                 //set eBay Site target to US                 apiContext.Site = SiteCodeType.US;                 return apiContext;             }         } Running this will give you a large (4 or 5 megs) XML file that looks something like this: <soapenv:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">    <soapenv:Body>       <GetCategoriesResponse >          <Timestamp>2012-06-06T16:03:46.158Z</Timestamp>          <Ack>Success</Ack>          <CorrelationID>d02dd9e3-295a-4268-9ea5-554eeb2e0e18</CorrelationID>          <Version>775</Version>          <Build>E775_CORE_BUNDLED_14891042_R1</Build> -          <CategoryArray>             <Category>                <BestOfferEnabled>true</BestOfferEnabled>                <AutoPayEnabled>true</AutoPayEnabled>                <CategoryID>20081</CategoryID>                <CategoryLevel>1</CategoryLevel>                <CategoryName>Antiques</CategoryName>                <CategoryParentID>20081</CategoryParentID>             </Category>             <Category>                <BestOfferEnabled>true</BestOfferEnabled>                <AutoPayEnabled>true</AutoPayEnabled>                <CategoryID>37903</CategoryID>                <CategoryLevel>2</CategoryLevel>                <CategoryName>Antiquities</CategoryName>                <CategoryParentID>20081</CategoryParentID>             </Category> (etc.) You could work with this, but I wanted a nicely nested view, like this: <CategoryArray>    <Category Name='Antiques' ID='20081' Level='1'>       <Category Name='Antiquities' ID='37903' Level='2'/> </CategoryArray> ...so I transformed the xml: private void TransformXML(CategoryTypeCollection cats)         {             XmlElement topLevelElement = null;             XmlElement childLevelElement = null;             XmlNode parentNode = null;             string categoryString = "";             XmlDocument returnDoc = new XmlDocument();             XmlElement root = returnDoc.CreateElement("CategoryArray");             returnDoc.AppendChild(root);             XmlNode rootNode = returnDoc.SelectSingleNode("/CategoryArray");             //Loop through CategoryTypeCollection             foreach (CategoryType category in cats)             {                 if (category.CategoryLevel == 1)                 {                     //Top-level category, so we know we can just add it                     topLevelElement = returnDoc.CreateElement("Category");                     topLevelElement.SetAttribute("Name", category.CategoryName);                     topLevelElement.SetAttribute("ID", category.CategoryID);                     rootNode.AppendChild(topLevelElement);                 }                 else                 {                     // Level number will determine how many Category nodes we are deep                     categoryString = "";                     for (int x = 1; x < category.CategoryLevel; x++)                     {                         categoryString += "/Category";                     }                     parentNode = returnDoc.SelectSingleNode("/CategoryArray" + categoryString + "[@ID='" + category.CategoryParentID[0] + "']");                     childLevelElement = returnDoc.CreateElement("Category");                     childLevelElement.SetAttribute("Name", category.CategoryName);                     childLevelElement.SetAttribute("ID", category.CategoryID);                     parentNode.AppendChild(childLevelElement);                 }             }             returnDoc.Save(@"C:\Temp\EbayCategories-Modified.xml");         } Yes, there are probably much cleaner ways of dealing with it, but I'm not an xml expert… Keep in mind, eBay categories do not change on a regular basis, so you should be able to cache this data (either in a file or database) for some time. The xml returns a CategoryVersion node that you can use to determine if the category list has changed. Technorati Tags: Csharp, eBay

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• How to Identify Which Hardware Component is Failing in Your Computer

  - by Chris Hoffman

  Concluding that your computer has a hardware problem is just the first step. If you’re dealing with a hardware issue and not a software issue, the next step is determining what hardware problem you’re actually dealing with. If you purchased a laptop or pre-built desktop PC and it’s still under warranty, you don’t need to care about this. Have the manufacturer fix the PC for you — figuring it out is their problem. If you’ve built your own PC or you want to fix a computer that’s out of warranty, this is something you’ll need to do on your own. Blue Screen 101: Search for the Error Message This may seem like obvious advice, but searching for information about a blue screen’s error message can help immensely. Most blue screens of death you’ll encounter on modern versions of Windows will likely be caused by hardware failures. The blue screen of death often displays information about the driver that crashed or the type of error it encountered. For example, let’s say you encounter a blue screen that identified “NV4_disp.dll” as the driver that caused the blue screen. A quick Google search will reveal that this is the driver for NVIDIA graphics cards, so you now have somewhere to start. It’s possible that your graphics card is failing if you encounter such an error message. Check Hard Drive SMART Status Hard drives have a built in S.M.A.R.T. (Self-Monitoring, Analysis, and Reporting Technology) feature. The idea is that the hard drive monitors itself and will notice if it starts to fail, providing you with some advance notice before the drive fails completely. This isn’t perfect, so your hard drive may fail even if SMART says everything is okay. If you see any sort of “SMART error” message, your hard drive is failing. You can use SMART analysis tools to view the SMART health status information your hard drives are reporting. Test Your RAM RAM failure can result in a variety of problems. If the computer writes data to RAM and the RAM returns different data because it’s malfunctioning, you may see application crashes, blue screens, and file system corruption. To test your memory and see if it’s working properly, use Windows’ built-in Memory Diagnostic tool. The Memory Diagnostic tool will write data to every sector of your RAM and read it back afterwards, ensuring that all your RAM is working properly. Check Heat Levels How hot is is inside your computer? Overheating can rsult in blue screens, crashes, and abrupt shut downs. Your computer may be overheating because you’re in a very hot location, it’s ventilated poorly, a fan has stopped inside your computer, or it’s full of dust. Your computer monitors its own internal temperatures and you can access this information. It’s generally available in your computer’s BIOS, but you can also view it with system information utilities such as SpeedFan or Speccy. Check your computer’s recommended temperature level and ensure it’s within the appropriate range. If your computer is overheating, you may see problems only when you’re doing something demanding, such as playing a game that stresses your CPU and graphics card. Be sure to keep an eye on how hot your computer gets when it performs these demanding tasks, not only when it’s idle. Stress Test Your CPU You can use a utility like Prime95 to stress test your CPU. Such a utility will fore your computer’s CPU to perform calculations without allowing it to rest, working it hard and generating heat. If your CPU is becoming too hot, you’ll start to see errors or system crashes. Overclockers use Prime95 to stress test their overclock settings — if Prime95 experiences errors, they throttle back on their overclocks to ensure the CPU runs cooler and more stable. It’s a good way to check if your CPU is stable under load. Stress Test Your Graphics Card Your graphics card can also be stress tested. For example, if your graphics driver crashes while playing games, the games themselves crash, or you see odd graphical corruption, you can run a graphics benchmark utility like 3DMark. The benchmark will stress your graphics card and, if it’s overheating or failing under load, you’ll see graphical problems, crashes, or blue screens while running the benchmark. If the benchmark seems to work fine but you have issues playing a certain game, it may just be a problem with that game. Swap it Out Not every hardware problem is easy to diagnose. If you have a bad motherboard or power supply, their problems may only manifest through occasional odd issues with other components. It’s hard to tell if these components are causing problems unless you replace them completely. Ultimately, the best way to determine whether a component is faulty is to swap it out. For example, if you think your graphics card may be causing your computer to blue screen, pull the graphics card out of your computer and swap in a new graphics card. If everything is working well, it’s likely that your previous graphics card was bad. This isn’t easy for people who don’t have boxes of components sitting around, but it’s the ideal way to troubleshoot. Troubleshooting is all about trial and error, and swapping components out allows you to pin down which component is actually causing the problem through a process of elimination. This isn’t a complete guide to everything that could likely go wrong and how to identify it — someone could write a full textbook on identifying failing components and still not cover everything. But the tips above should give you some places to start dealing with the more common problems. Image Credit: Justin Marty on Flickr     

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• Pathfinding results in false path costs that are too high

  - by user2144536

  I'm trying to implement pathfinding in a game I'm programming using this method. I'm implementing it with recursion but some of the values after the immediate circle of tiles around the player are way off. For some reason I cannot find the problem with it. This is a screen cap of the problem: The pathfinding values are displayed in the center of every tile. Clipped blocks are displayed with the value of 'c' because the values were too high and were covering up the next value. The red circle is the first value that is incorrect. The code below is the recursive method. //tileX is the coordinates of the current tile, val is the current pathfinding value, used[][] is a boolean //array to keep track of which tiles' values have already been assigned public void pathFind(int tileX, int tileY, int val, boolean[][] used) { //increment pathfinding value int curVal = val + 1; //set current tile to true if it hasn't been already used[tileX][tileY] = true; //booleans to know which tiles the recursive call needs to be used on boolean topLeftUsed = false, topUsed = false, topRightUsed = false, leftUsed = false, rightUsed = false, botomLeftUsed = false, botomUsed = false, botomRightUsed = false; //set value of top left tile if necessary if(tileX - 1 >= 0 && tileY - 1 >= 0) { //isClipped(int x, int y) returns true if the coordinates givin are in a tile that can't be walked through (IE walls) //occupied[][] is an array that keeps track of which tiles have an enemy in them // //if the tile is not clipped and not occupied set the pathfinding value if(isClipped((tileX - 1) * 50 + 25, (tileY - 1) * 50 + 25) == false && occupied[tileX - 1][tileY - 1] == false && !(used[tileX - 1][tileY - 1])) { pathFindingValues[tileX - 1][tileY - 1] = curVal; topLeftUsed = true; used[tileX - 1][tileY - 1] = true; } //if it is occupied set it to an arbitrary high number so enemies find alternate routes if the best is clogged if(occupied[tileX - 1][tileY - 1] == true) pathFindingValues[tileX - 1][tileY - 1] = 1000000000; //if it is clipped set it to an arbitrary higher number so enemies don't travel through walls if(isClipped((tileX - 1) * 50 + 25, (tileY - 1) * 50 + 25) == true) pathFindingValues[tileX - 1][tileY - 1] = 2000000000; } //top middle if(tileY - 1 >= 0 ) { if(isClipped(tileX * 50 + 25, (tileY - 1) * 50 + 25) == false && occupied[tileX][tileY - 1] == false && !(used[tileX][tileY - 1])) { pathFindingValues[tileX][tileY - 1] = curVal; topUsed = true; used[tileX][tileY - 1] = true; } if(occupied[tileX][tileY - 1] == true) pathFindingValues[tileX][tileY - 1] = 1000000000; if(isClipped(tileX * 50 + 25, (tileY - 1) * 50 + 25) == true) pathFindingValues[tileX][tileY - 1] = 2000000000; } //top right if(tileX + 1 <= used.length && tileY - 1 >= 0) { if(isClipped((tileX + 1) * 50 + 25, (tileY - 1) * 50 + 25) == false && occupied[tileX + 1][tileY - 1] == false && !(used[tileX + 1][tileY - 1])) { pathFindingValues[tileX + 1][tileY - 1] = curVal; topRightUsed = true; used[tileX + 1][tileY - 1] = true; } if(occupied[tileX + 1][tileY - 1] == true) pathFindingValues[tileX + 1][tileY - 1] = 1000000000; if(isClipped((tileX + 1) * 50 + 25, (tileY - 1) * 50 + 25) == true) pathFindingValues[tileX + 1][tileY - 1] = 2000000000; } //left if(tileX - 1 >= 0) { if(isClipped((tileX - 1) * 50 + 25, (tileY) * 50 + 25) == false && occupied[tileX - 1][tileY] == false && !(used[tileX - 1][tileY])) { pathFindingValues[tileX - 1][tileY] = curVal; leftUsed = true; used[tileX - 1][tileY] = true; } if(occupied[tileX - 1][tileY] == true) pathFindingValues[tileX - 1][tileY] = 1000000000; if(isClipped((tileX - 1) * 50 + 25, (tileY) * 50 + 25) == true) pathFindingValues[tileX - 1][tileY] = 2000000000; } //right if(tileX + 1 <= used.length) { if(isClipped((tileX + 1) * 50 + 25, (tileY) * 50 + 25) == false && occupied[tileX + 1][tileY] == false && !(used[tileX + 1][tileY])) { pathFindingValues[tileX + 1][tileY] = curVal; rightUsed = true; used[tileX + 1][tileY] = true; } if(occupied[tileX + 1][tileY] == true) pathFindingValues[tileX + 1][tileY] = 1000000000; if(isClipped((tileX + 1) * 50 + 25, (tileY) * 50 + 25) == true) pathFindingValues[tileX + 1][tileY] = 2000000000; } //botom left if(tileX - 1 >= 0 && tileY + 1 <= used[0].length) { if(isClipped((tileX - 1) * 50 + 25, (tileY + 1) * 50 + 25) == false && occupied[tileX - 1][tileY + 1] == false && !(used[tileX - 1][tileY + 1])) { pathFindingValues[tileX - 1][tileY + 1] = curVal; botomLeftUsed = true; used[tileX - 1][tileY + 1] = true; } if(occupied[tileX - 1][tileY + 1] == true) pathFindingValues[tileX - 1][tileY + 1] = 1000000000; if(isClipped((tileX - 1) * 50 + 25, (tileY + 1) * 50 + 25) == true) pathFindingValues[tileX - 1][tileY + 1] = 2000000000; } //botom middle if(tileY + 1 <= used[0].length) { if(isClipped((tileX) * 50 + 25, (tileY + 1) * 50 + 25) == false && occupied[tileX][tileY + 1] == false && !(used[tileX][tileY + 1])) { pathFindingValues[tileX][tileY + 1] = curVal; botomUsed = true; used[tileX][tileY + 1] = true; } if(occupied[tileX][tileY + 1] == true) pathFindingValues[tileX][tileY + 1] = 1000000000; if(isClipped((tileX) * 50 + 25, (tileY + 1) * 50 + 25) == true) pathFindingValues[tileX][tileY + 1] = 2000000000; } //botom right if(tileX + 1 <= used.length && tileY + 1 <= used[0].length) { if(isClipped((tileX + 1) * 50 + 25, (tileY + 1) * 50 + 25) == false && occupied[tileX + 1][tileY + 1] == false && !(used[tileX + 1][tileY + 1])) { pathFindingValues[tileX + 1][tileY + 1] = curVal; botomRightUsed = true; used[tileX + 1][tileY + 1] = true; } if(occupied[tileX + 1][tileY + 1] == true) pathFindingValues[tileX + 1][tileY + 1] = 1000000000; if(isClipped((tileX + 1) * 50 + 25, (tileY + 1) * 50 + 25) == true) pathFindingValues[tileX + 1][tileY + 1] = 2000000000; } //call the method on the tiles that need it if(tileX - 1 >= 0 && tileY - 1 >= 0 && topLeftUsed) pathFind(tileX - 1, tileY - 1, curVal, used); if(tileY - 1 >= 0 && topUsed) pathFind(tileX , tileY - 1, curVal, used); if(tileX + 1 <= used.length && tileY - 1 >= 0 && topRightUsed) pathFind(tileX + 1, tileY - 1, curVal, used); if(tileX - 1 >= 0 && leftUsed) pathFind(tileX - 1, tileY, curVal, used); if(tileX + 1 <= used.length && rightUsed) pathFind(tileX + 1, tileY, curVal, used); if(tileX - 1 >= 0 && tileY + 1 <= used[0].length && botomLeftUsed) pathFind(tileX - 1, tileY + 1, curVal, used); if(tileY + 1 <= used[0].length && botomUsed) pathFind(tileX, tileY + 1, curVal, used); if(tileX + 1 <= used.length && tileY + 1 <= used[0].length && botomRightUsed) pathFind(tileX + 1, tileY + 1, curVal, used); }

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• Control-Break Style ADF Table - Comparing Values with Previous Row

  - by Steven Davelaar

  Sometimes you need to display data in an ADF Faces table in a control-break layout style, where rows should be "indented" when the break column has the same value as in the previous row. In the screen shot below, you see how the table breaks on both the RegionId column as well as the CountryId column. To implement this I didn't use fancy SQL statements. The table is based on a straightforward Locations ViewObject that is based on the Locations entity object and the Countries reference entity object, and the join query was automatically created by adding the reference EO. To get the indentation in the ADF Faces table, we simple use two rendered properties on the RegionId and CountryId outputText items:  <af:column sortProperty="RegionId" sortable="false"            headerText="#{bindings.LocationsView1.hints.RegionId.label}"            id="c5">   <af:outputText value="#{row.RegionId}" id="ot2"                  rendered="#{!CompareWithPreviousRowBean['RegionId']}">     <af:convertNumber groupingUsed="false"                       pattern="#{bindings.LocationsView1.hints.RegionId.format}"/>   </af:outputText> </af:column> <af:column sortProperty="CountryId" sortable="false"            headerText="#{bindings.LocationsView1.hints.CountryId.label}"            id="c1">   <af:outputText value="#{row.CountryId}" id="ot5"                  rendered="#{!CompareWithPreviousRowBean['CountryId']}"/> </af:column> The CompareWithPreviousRowBean managed bean is defined in request scope and is a generic bean that can be used for all the tables in your application that needs this layout style. As you can see the bean is a Map-style bean where we pass in the name of the attribute that should be compared with the previous row. The get method in the bean that is called returns boolean false when the attribute has the same value in the same row. Here is the code of the get method:  public Object get(Object key) {   String attrName = (String) key;   boolean isSame = false;   // get the currently processed row, using row expression #{row}   JUCtrlHierNodeBinding row = (JUCtrlHierNodeBinding) resolveExpression(getRowExpression());   JUCtrlHierBinding tableBinding = row.getHierBinding();   int rowRangeIndex = row.getViewObject().getRangeIndexOf(row.getRow());   Object currentAttrValue = row.getRow().getAttribute(attrName);   if (rowRangeIndex > 0)   {     Object previousAttrValue = tableBinding.getAttributeFromRow(rowRangeIndex - 1, attrName);     isSame = currentAttrValue != null && currentAttrValue.equals(previousAttrValue);   }   else if (tableBinding.getRangeStart() > 0)   {     // previous row is in previous range, we create separate rowset iterator,     // so we can change the range start without messing up the table rendering which uses     // the default rowset iterator     int absoluteIndexPreviousRow = tableBinding.getRangeStart() - 1;     RowSetIterator rsi = null;     try     {       rsi = tableBinding.getViewObject().getRowSet().createRowSetIterator(null);       rsi.setRangeStart(absoluteIndexPreviousRow);       Row previousRow = rsi.getRowAtRangeIndex(0);       Object previousAttrValue = previousRow.getAttribute(attrName);       isSame = currentAttrValue != null && currentAttrValue.equals(previousAttrValue);     }     finally     {       rsi.closeRowSetIterator();     }   }   return isSame; } The row expression defaults to #{row} but this can be changed through the rowExpression  managed property of the bean.  You can download the sample application here.

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• Single Key Multiple Values Data Structure for one to many mapping

  - by nijhawan.saurabh

  Dictionaries are good, they are great to store Key / Value pairs but what if you want to store multiple values for a single key? Dictionaries would not allow duplicate keys. I came across a nice way to represent such a Data Structure using one of the Extension Method (ToLookup) present in System.Linq Namespace which converts an IEnumerable<T> to an ILookup<TKey, TElement>.   Now, there are two parameters this method expects (The other overload expects 3 parameters): IEnumerable<TSource> - This list would contain the actual data. Func<TSource, TKey> keySelector - The Delegate which which computes the keys   The method returns the following: ILookup<TKey, TElement>   This DS would store Keys and multiple values along those keys.   Let's see a small example:        12  using System;    13     using System.Collections.Generic;    14     using System.Linq;    15     16     /// <summary>    17     /// </summary>    18     internal class Program    19     {    20         #region Methods    21     22         /// <summary>    23         /// </summary>    24         /// <param name="args">    25         /// The args.    26         /// </param>    27         private static void Main(string[] args)    28         {    29             // Create an array of strings.    30             var list = new List<string> { "IceCream1", "Chocolate Moose", "IceCream2" };    31     32             // Generate a lookup Data Structure    33             ILookup<int, string> lookupDs = list.ToLookup(item => item.Length);    34     35           // Enumerate groupings.    36             foreach (var group in lookupDs)    37             {    38                 foreach (string element in group)    39                 {    40                     Console.WriteLine(element);    41                 }    42             }    43         } Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

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• Mscorlib mocking minus the attribute

  - by mehfuzh

  Mocking .net framework members (a.k.a. mscorlib) is always a daunting task. It’s the breed of static and final methods and full of surprises. Technically intercepting mscorlib members is completely different from other class libraries. This is the reason it is dealt differently. Generally, I prefer writing a wrapper around an mscorlib member (Ex. File.Delete(“abc.txt”)) and expose it via interface but that is not always an easy task if you already have years old codebase. While mocking mscorlib members first thing that comes to people’s mind is DateTime.Now. If you Google through, you will find tons of example dealing with just that. May be it’s the most important class that we can’t ignore and I will create an example using JustMock Q2 with the same. In Q2 2012, we just get rid of the MockClassAtrribute for mocking mscorlib members. JustMock is already attribute free for mocking class libraries. We radically think that vendor specific attributes only makes your code smelly and therefore decided the same for mscorlib. Now, I want to fake DateTime.Now for the following class: public class NestedDateTime { public DateTime GetDateTime() { return DateTime.Now; } } It is the simplest one that can be. The first thing here is that I tell JustMock “hey we have a DateTime.Now in NestedDateTime class that we want to mock”. To do so, during the test initialization I write this: .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; } Mock.Replace(() => DateTime.Now).In<NestedDateTime>(x => x.GetDateTime());.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 can also define it for all the members in the class, but that’s just a waste of extra watts. Mock.Replace(() => DateTime.Now).In<NestedDateTime>(); Now question, why should I bother doing it? The answer is that I am not using attribute and with this approach, I can mock any framework members not just File, FileInfo or DateTime. Here to note that we already mock beyond the three but when nested around a complex class, JustMock was not intercepting it correctly. Therefore, we decided to get rid of the attribute altogether fixing the issue. Finally, I write my test as usual. [TestMethod] public void ShouldAssertMockingDateTimeFromNestedClass() { var expected = new DateTime(2000, 1, 1); Mock.Arrange(() => DateTime.Now).Returns(expected); Assert.Equal(new NestedDateTime().GetDateTime(), expected); } .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; } That’s it, we are good. Now let me do the same for a random one, let’s say I want mock a member from DriveInfo: Mock.Replace<DriveInfo[]>(() => DriveInfo.GetDrives()).In<MsCorlibFixture>(x => x.ShouldReturnExpectedDriveWhenMocked()); Moving forward, I write my test: [TestMethod] public void ShouldReturnExpectedDriveWhenMocked() { Mock.Arrange(() => DriveInfo.GetDrives()).MustBeCalled(); DriveInfo.GetDrives(); Mock.Assert(()=> DriveInfo.GetDrives()); } .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; } Here is one convention; you have to replace the mscorlib member before executing the target method that contains it. Here the call to DriveInfo is within the MsCorlibFixture therefore it should be defined during test initialization or before executing the test method. Hope this gives you the idea.

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