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• You should NOT be writing jQuery in SharePoint if&hellip;

  - by Mark Rackley

  Yes… another one of these posts. What can I say? I’m a pot stirrer.. a rabble rouser *rabble rabble* jQuery in SharePoint seems to be a fairly polarizing issue with one side thinking it is the most awesome thing since Princess Leia as the slave girl in Return of the Jedi and the other half thinking it is the worst idea since Mannequin 2: On the Move. The correct answer is OF COURSE “it depends”. But what are those deciding factors that make jQuery an awesome fit or leave a bad taste in your mouth? Let’s see if I can drive the discussion here with some polarizing comments of my own… I know some of you are getting ready to leave your comments even now before reading the rest of the blog, which is great! Iron sharpens iron… These discussions hopefully open us up to understanding the entire process better and think about things in a different way. You should not be writing jQuery in SharePoint if you are not a developer… Let’s start off with my most polarizing and rant filled portion of the blog post. If you don’t know what you are doing or you don’t have a background that helps you understand the implications of what you are writing then you should not be writing jQuery in SharePoint! I truly believe that one of the biggest reasons for the jQuery haters is because of all the bad jQuery out there. If you don’t know what you are doing you can do some NASTY things! One of the best stories I’ve heard about this is from my good friend John Ferringer (@ferringer). John tells this story during our Mythbusters session we do together. One of his clients was undergoing a Denial of Service attack and they couldn’t figure out what was going on! After much searching they found that some genius jQuery developer wrote some code for an image rotator, but did not take into account what happens when there are no images to load! The code just kept hitting the servers over and over and over again which prevented anything else from getting done! Now, I’m NOT saying that I have not done the same sort of thing in the past or am immune from such mistakes. My point is that if you don’t know what you are doing, there are very REAL consequences that can have a major impact on your organization AND they will be hard to track down.  Think how happy your boss will be after you copy and pasted some jQuery from a blog without understanding what it does, it brings down the farm, AND it takes them 3 days to track it back to you.  :/ Good times will not be had. Like it or not JavaScript/jQuery is a programming language. While you .NET people sit on your high horses because your code is compiled and “runs faster” (also debatable), the rest of us will be actually getting work done and delivering solutions while you are trying to figure out why your widget won’t deploy. I can pick at that scab because I write .NET code too and speak from experience. I can do both, and do both well. So, I am not speaking from ignorance here. In JavaScript/jQuery you have variables, loops, conditionals, functions, arrays, events, and built in methods. If you are not a developer you just aren’t going to take advantage of all of that and use it correctly. Ahhh.. but there is hope! There is a lot of jQuery resources out there to help you learn and learn well! There are many experts on the subject that will gladly tell you when you are smoking crack. I just this minute saw a tweet from @cquick with a link to: “jQuery Fundamentals”. I just glanced through it and this may be a great primer for you aspiring jQuery devs. Take advantage of all the resources and become a developer! Hey, it will look awesome on your resume right? You should not be writing jQuery in SharePoint if it depends too much on client resources for a good user experience I’ve said it once and I’ll say it over and over until you understand. jQuery is executed on the client’s computer. Got it? If you are looping through hundreds of rows of data, searching through an enormous DOM, or performing many calculations it is going to take some time! AND if your user happens to be sitting on some old PC somewhere that they picked up at a garage sale their experience will be that much worse! If you can’t give the user a good experience they will not use the site. So, if jQuery is causing the user to have a bad experience, don’t use it. I sometimes go as far to say that you should NOT go to jQuery as a first option for external facing web sites because you have ZERO control over what the end user’s computer will be. You just can’t guarantee an awesome user experience all of the time. Ahhh… but you have no choice? (where have I heard that before?). Well… if you really have no choice, here are some tips to help improve the experience: Avoid screen scraping This is not 1999 and SharePoint is not an old green screen from a mainframe… so why are you treating it like it is? Screen scraping is time consuming and client intensive. Take advantage of tools like SPServices to do your data retrieval when possible. Fine tune your DOM searches A lot of time can be eaten up just searching the DOM and ignoring table rows that you don’t need. Write better jQuery to only loop through tables rows that you need, or only access specific elements you need. Take advantage of Element ID’s to return the one element you are looking for instead of looping through all the DOM over and over again. Write better jQuery Remember this is development. Think about how you can write cleaner, faster jQuery. This directly relates to the previous point of improving your DOM searches, but also when using arrays, variables and loops. Do you REALLY need to loop through that array 3 times? How can you knock it down to 2 times or even 1? When you have lots of calculations and data that you are manipulating every operation adds up. Think about how you can streamline it. Back in the old days before RAM was abundant, Cores were plentiful and dinosaurs roamed the earth, us developers had to take performance into account in everything we did. It’s a lost art that really needs to be used here. You should not be writing jQuery in SharePoint if you are sending a lot of data over the wire… Developer:  “Awesome… you can easily call SharePoint’s web services to retrieve and write data using SPServices!” Administrator: “Crap! you can easily call SharePoint’s web services to retrieve and write data using SPServices!” SPServices may indeed be the best thing that happened to SharePoint since the invention of SharePoint Saturdays by Godfather Lotter… BUT you HAVE to use it wisely! (I REFUSE to make the Spiderman reference). If you do not know what you are doing your code will bring back EVERY field and EVERY row from a list and push that over the internet with all that lovely XML wrapped around it. That can be a HUGE amount of data and will GREATLY impact performance! Calling several web service methods at the same time can cause the same problem and can negatively impact your SharePoint servers. These problems, thankfully, are not difficult to rectify if you are careful: Limit list data retrieved Use CAML to reduce the number of rows returned and limit the fields returned using ViewFields.  You should definitely be doing this regardless. If you aren’t I hope your admin thumps you upside the head. Batch large list updates You may or may not have noticed that if you try to do large updates (hundreds of rows) that the performance is either completely abysmal or it fails over half the time. You can greatly improve performance and avoid timeouts by breaking up your updates into several smaller updates. I don’t know if there is a magic number for best performance, it really depends on how much data you are sending back more than the number of rows. However, I have found that 200 rows generally works well.  Play around and find the right number for your situation. Delay Web Service calls when possible One of the cool things about jQuery and SPServices is that you can delay queries to the server until they are actually needed instead of doing them all at once. This can lead to performance improvements over DataViewWebParts and even .NET code in the right situations. So, don’t load the data until it’s needed. In some instances you may not need to retrieve the data at all, so why retrieve it ALL the time? You should not be writing jQuery in SharePoint if there is a better solution… jQuery is NOT the silver bullet in SharePoint, it is not the answer to every question, it is just another tool in the developers toolkit. I urge all developers to know what options exist out there and choose the right one! Sometimes it will be jQuery, sometimes it will be .NET,  sometimes it will be XSL, and sometimes it will be some other choice… So, when is there a better solution to jQuery? When you can’t get away from performance problems Sometimes jQuery will just give you horrible performance regardless of what you do because of unavoidable obstacles. In these situations you are going to have to figure out an alternative. Can I do it with a DVWP or do I have to crack open Visual Studio? When you need to do something that jQuery can’t do There are lots of things you can’t do in jQuery like elevate privileges, event handlers, workflows, or interact with back end systems that have no web service interface. It just can’t do everything. When it can be done faster and more efficiently another way Why are you spending time to write jQuery to do a DataViewWebPart that would take 5 minutes? Or why are you trying to implement complicated logic that would be simple to do in .NET? If your answer is that you don’t have the option, okay. BUT if you do have the option don’t reinvent the wheel! Take advantage of the other tools. The answer is not always jQuery… sorry… the kool-aid tastes good, but sweet tea is pretty awesome too. You should not be using jQuery in SharePoint if you are a moron… Let’s finish up the blog on a high note… Yes.. it’s true, I sometimes type things just to get a reaction… guess this section title might be a good example, but it feels good sometimes just to type the words that a lot of us think… So.. don’t be that guy! Another good buddy of mine that works for Microsoft told me. “I loved jQuery in SharePoint…. until I had to support it.”. He went on to explain that some user was making several web service calls on a page using jQuery and then was calling Microsoft and COMPLAINING because the page took so long to load… DUH! What do you expect to happen when you are pushing that much data over the wire and are making that many web service calls at once!! It’s one thing to write that kind of code and accept it’s just going to take a while, it’s COMPLETELY another issue to do that and then complain when it’s not lightning fast!  Someone’s gene pool needs some chlorine. So, I think this is a nice summary of the blog… DON’T be that guy… don’t be a moron. How can you stop yourself from being a moron? Ah.. glad you asked, here are some tips: Think Is jQuery the right solution to my problem? Is there a better approach? What are the implications and pitfalls of using jQuery in this situation? Search What are others doing? Does someone have a better solution? Is there a third party library that does the same thing I need? Plan Write good jQuery. Limit calculations and data sent over the wire and don’t reinvent the wheel when possible. Test Okay, it works well on your machine. Try it on others ESPECIALLY if this is for an external site. Test with empty data. Test with hundreds of rows of data. Test as many scenarios as possible. Monitor those server resources to see the impact there as well. Ask the experts As smart as you are, there are people smarter than you. Even the experts talk to each other to make sure they aren't doing something stupid. And for the MOST part they are pretty nice guys. Marc Anderson and Christophe Humbert are two guys who regularly keep me in line. Make sure you aren’t doing something stupid. Repeat So, when you think you have the best solution possible, repeat the steps above just to be safe.  Conclusion jQuery is an awesome tool and has come in handy on many occasions. I’m even teaching a 1/2 day SharePoint & jQuery workshop at the upcoming SPTechCon in Boston if you want to berate me in person. However, it’s only as awesome as the developer behind the keyboard. It IS development and has its pitfalls. Knowledge and experience are invaluable to giving the user the best experience possible.  Let’s face it, in the end, no matter our opinions, prejudices, or ego providing our clients, customers, and users with the best solution possible is what counts. Period… end of sentence…

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• FAT Volume and CE

  - by Kate Moss' Open Space

  Whenever we format a disk volume, it is a good idea to name the label so it will be easier to categorize. To label a volume, we can use LABEL command or UI depends on your preference. Windows CE does provide FAT driver and support various format (FAT12, FAT16,FAT32, ExFAT and TFAT - transaction-safe FAT) and many feature to let you scan and even defrag the volume but not labeling. At any time you format a volume in CE and then mount it on PC, the label is always empty! Of course, you can always label the volume on PC, even it is formatted in CE. So looks like CE does not care about the volume label at all, neither report the label to OS nor changing the label on FAT.So how can we set the volume label in CE? To Answer this question, we need to know how does FAT stores the volume label. Here are some on-line resources are handy for parsing FAT. http://en.wikipedia.org/wiki/File_Allocation_Table http://www.pjrc.com/tech/8051/ide/fat32.html http://www.microsoft.com/whdc/system/platform/firmware/fatgen.mspx You can refer to PUBLIC\COMMON\OAK\DRIVERS\FSD\FATUTIL\MAIN\bootsec.h and dosbpb.h or the above links for the fields we discuss here. The first sector of a FAT Volume (it is not necessary to be the first sector of a disk.) is a FAT boot sector and BPB (BIOS Parameter Block). And at offset 43, bgbsVolumeLabel (or bsVolumeLabel on FAT16) is for storing the volume lable, but note in the spec also indicates "FAT file system drivers should make sure that they update this field when the volume label file in the root directory has its name changed or created.". So we can't just simply update the bgbsVolumeLabel but also need to create a volume lable file in root directory. The volume lable file is not a real file but just a file entry in root directory with zero file lenth and a very special file attribute, ATTR_VOLUME_ID. (defined in public\common\oak\drivers\fsd\fatutil\MAIN\fatutilp.h) Locating and accessing bootsector is quite straight forward, as long as we know the starting sector of a FAT volume, that's it. But where is the root directory? The layout of a typical FAT is like this Boot sector (Volume ID in the figure) followed by Reserved Sectors (1 on FAT12/16 and 32 on FAT32), then FAT chain table(s) (can be 1 or 2), after that is the root directory (FAT12/16 and not shows in the figure) then begining of the File and Directories. In FAT12/16, the root directory is placed right after FAT so it is not hard to caculate the offset in the volume. But in FAT32, this rule is no longer true: the first cluster of the root directory is determined by BGBPB_RootDirStrtClus (or offset 44 in boot sector). Although this field is usually 0x00000002 (it is how CE initial the root directory after formating a volume. Note we should never assume it is always true) which means the first cluster contains data but not like the root directory is contiguous in FAT12/16, it is just like a regular file can be fragmented. So we need to access the root directory (of FAT32) hopping one cluster to another by traversing FAT table. Let's trace the code now. Although the source of FAT driver is not available in CE Shared Source program, but the formatter, Fatutil.dll, is available in public\common\oak\drivers\fsd\fatutil\MAIN\formatdisk.cpp. Be aware the public code only provides formatter for FAT12/16/32 for ExFAT it is still not available. FormatVolumeInternal is the main worker function. With the knowledge here, you should be able the trace the code easily. But I would like to discuss the following code pieces     dwReservedSectors = (fo.dwFatVersion == 32) ? 32 : 1;     dwRootEntries = (fo.dwFatVersion == 32) ? 0 : fo.dwRootEntries; Note the dwReservedSectors is 32 in FAT32 and 1 in FAT12/16. Root Entries is another different mentioned in previous paragraph, 0 for FAT32 (dynamic allocated) and fixed size (usually 512, defined in DEFAULT_ROOT_ENTRIES in public\common\sdk\inc\fatutil.h) And then here   memset(pBootSec->bsVolumeLabel, 0x20, sizeof(pBootSec->bsVolumeLabel)); It sets the Volume Label as empty string. Now let's carry on to the next section - write the root directory.     if (fo.dwFatVersion == 32) {         if (!(fo.dwFlags & FATUTIL_FORMAT_TFAT)) {             dwRootSectors = dwSectorsPerCluster;         }         else {             DIRENTRY    dirEntry;             DWORD       offset;             int               iVolumeNo;             memset(pbBlock, 0, pdi->di_bytes_per_sect);             memset(&dirEntry, 0, sizeof(DIRENTRY));                         dirEntry.de_attr = ATTR_VOLUME_ID;             // the first one is volume label             memcpy(dirEntry.de_name, "TFAT       ", sizeof (dirEntry.de_name));             memcpy(pbBlock, &dirEntry, sizeof(dirEntry));              ...             // Skip the next step of zeroing out clusters             dwCurrentSec += dwSectorsPerCluster;             dwRootSectors = 0;         }     }     // Each new root directory sector needs to be zeroed.     memset(pbBlock, 0, cbSizeBlk);     iRootSec=0;     while ( iRootSec < dwRootSectors) { Basically, the code zero out the each entry in root directory depends on dwRootSectors. In FAT12/16, the dwRootSectors is calculated as the sectors we need for the root entries (512 for most of the case) and in FAT32 it just zero out the one cluster. Please note that, if it is a TFAT volume, it initialize the root directory with special volume label entries for some special purpose. Despite to its unusual initialization process for TFAT, it does provide a example for how to create a volume entry. With some minor modification, we can assign the volume label in FAT formatter and also remember to sync the volume label with bsVolumeLabel or bgbsVolumeLabel in boot sector.

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• Synchronize Data between a Silverlight ListBox and a User Control

  - by psheriff

  One of the great things about XAML is the powerful data-binding capabilities. If you load up a list box with a collection of objects, you can display detail data about each object without writing any C# or VB.NET code. Take a look at Figure 1 that shows a collection of Product objects in a list box. When you click on a list box you bind the current Product object selected in the list box to a set of controls in a user control with just a very simple Binding statement in XAML.  Figure 1: Synchronizing a ListBox to a User Control is easy with Data Binding Product and Products Classes To illustrate this data binding feature I am going to just create some local data instead of using a WCF service. The code below shows a Product class that has three properties, namely, ProductId, ProductName and Price. This class also has a constructor that takes 3 parameters and allows us to set the 3 properties in an instance of our Product class. C#public class Product{  public Product(int productId, string productName, decimal price)  {    ProductId = productId;    ProductName = productName;    Price = price;  }   public int ProductId { get; set; }  public string ProductName { get; set; }  public decimal Price { get; set; }} VBPublic Class Product  Public Sub New(ByVal _productId As Integer, _                 ByVal _productName As String, _                 ByVal _price As Decimal)    ProductId = _productId    ProductName = _productName    Price = _price  End Sub   Private mProductId As Integer  Private mProductName As String  Private mPrice As Decimal   Public Property ProductId() As Integer    Get      Return mProductId    End Get    Set(ByVal value As Integer)      mProductId = value    End Set  End Property   Public Property ProductName() As String    Get      Return mProductName    End Get    Set(ByVal value As String)      mProductName = value    End Set  End Property   Public Property Price() As Decimal    Get      Return mPrice    End Get    Set(ByVal value As Decimal)      mPrice = value    End Set  End PropertyEnd Class To fill up a list box you need a collection class of Product objects. The code below creates a generic collection class of Product objects. In the constructor of the Products class I have hard-coded five product objects and added them to the collection. In a real-world application you would get your data through a call to service to fill the list box, but for simplicity and just to illustrate the data binding, I am going to just hard code the data. C#public class Products : List<Product>{  public Products()  {    this.Add(new Product(1, "Microsoft VS.NET 2008", 1000));    this.Add(new Product(2, "Microsoft VS.NET 2010", 1000));    this.Add(new Product(3, "Microsoft Silverlight 4", 1000));    this.Add(new Product(4, "Fundamentals of N-Tier eBook", 20));    this.Add(new Product(5, "ASP.NET Security eBook", 20));  }} VBPublic Class Products  Inherits List(Of Product)   Public Sub New()    Me.Add(New Product(1, "Microsoft VS.NET 2008", 1000))    Me.Add(New Product(2, "Microsoft VS.NET 2010", 1000))    Me.Add(New Product(3, "Microsoft Silverlight 4", 1000))    Me.Add(New Product(4, "Fundamentals of N-Tier eBook", 20))    Me.Add(New Product(5, "ASP.NET Security eBook", 20))  End SubEnd Class The Product Detail User Control Below is a user control (named ucProduct) that is used to display the product detail information seen in the bottom portion of Figure 1. This is very basic XAML that just creates a text block and a text box control for each of the three properties in the Product class. Notice the {Binding Path=[PropertyName]} on each of the text box controls. This means that if the DataContext property of this user control is set to an instance of a Product class, then the data in the properties of that Product object will be displayed in each of the text boxes. <UserControl x:Class="SL_SyncListBoxAndUserControl_CS.ucProduct"  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  HorizontalAlignment="Left"  VerticalAlignment="Top">  <Grid Margin="4">    <Grid.RowDefinitions>      <RowDefinition Height="Auto" />      <RowDefinition Height="Auto" />      <RowDefinition Height="Auto" />    </Grid.RowDefinitions>    <Grid.ColumnDefinitions>      <ColumnDefinition MinWidth="120" />      <ColumnDefinition />    </Grid.ColumnDefinitions>    <TextBlock Grid.Row="0"               Grid.Column="0"               Text="Product Id" />    <TextBox Grid.Row="0"             Grid.Column="1"             Text="{Binding Path=ProductId}" />    <TextBlock Grid.Row="1"               Grid.Column="0"               Text="Product Name" />    <TextBox Grid.Row="1"             Grid.Column="1"             Text="{Binding Path=ProductName}" />    <TextBlock Grid.Row="2"               Grid.Column="0"               Text="Price" />    <TextBox Grid.Row="2"             Grid.Column="1"             Text="{Binding Path=Price}" />  </Grid></UserControl> Synchronize ListBox with User Control You are now ready to fill the list box with the collection class of Product objects and then bind the SelectedItem of the list box to the Product detail user control. The XAML below is the complete code for Figure 1. <UserControl x:Class="SL_SyncListBoxAndUserControl_CS.MainPage"  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  xmlns:src="clr-namespace:SL_SyncListBoxAndUserControl_CS"  VerticalAlignment="Top"  HorizontalAlignment="Left">  <UserControl.Resources>    <src:Products x:Key="productCollection" />  </UserControl.Resources>  <Grid x:Name="LayoutRoot"        Margin="4"        Background="White">    <Grid.RowDefinitions>      <RowDefinition Height="Auto" />      <RowDefinition Height="*" />    </Grid.RowDefinitions>    <ListBox x:Name="lstData"             Grid.Row="0"             BorderBrush="Black"             BorderThickness="1"             ItemsSource="{Binding                   Source={StaticResource productCollection}}"             DisplayMemberPath="ProductName" />    <src:ucProduct x:Name="prodDetail"                   Grid.Row="1"                   DataContext="{Binding ElementName=lstData,                                          Path=SelectedItem}" />  </Grid></UserControl> The first step to making this happen is to reference the Silverlight project (SL_SyncListBoxAndUserControl_CS) where the Product and Products classes are located. I added this namespace and assigned it a namespace prefix of “src” as shown in the line below: xmlns:src="clr-namespace:SL_SyncListBoxAndUserControl_CS" Next, to use the data from an instance of the Products collection, you create a UserControl.Resources section in the XAML and add a tag that creates an instance of the Products class and assigns it a key of “productCollection”.   <UserControl.Resources>    <src:Products x:Key="productCollection" />  </UserControl.Resources> Next, you bind the list box to this productCollection object using the ItemsSource property. You bind the ItemsSource of the list box to the static resource named productCollection. You can then set the DisplayMemberPath attribute of the list box to any property of the Product class that you want. In the XAML below I used the ProductName property. <ListBox x:Name="lstData"         ItemsSource="{Binding             Source={StaticResource productCollection}}"         DisplayMemberPath="ProductName" /> You now need to create an instance of the ucProduct user contol below the list box. You do this by once again referencing the “src” namespace and typing in the name of the user control. You then set the DataContext property on this user control to a binding. The binding uses the ElementName attribute to bind to the list box name, in this case “lstData”. The Path of the data is SelectedItem. These two attributes together tell Silverlight to bind the DataContext to the selected item of the list box. That selected item is a Product object. So, once this is bound, the bindings on each text box in the user control are updated and display the current product information. <src:ucProduct x:Name="prodDetail"               DataContext="{Binding ElementName=lstData,                                      Path=SelectedItem}" /> Summary Once you understand the basics of data binding in XAML, you eliminate a lot code that is otherwise needed to move data into controls and out of controls back into an object. Connecting two controls together is easy by just binding using the ElementName and Path properties of the Binding markup extension. Another good tip out of this blog is use user controls and set the DataContext of the user control to have all of the data on the user control update through the bindings. NOTE: You can download the complete sample code (in both VB and C#) at my website. http://www.pdsa.com/downloads. Choose Tips & Tricks, then "SL – Synchronize List Box Data with User Control" from the drop-down. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **Visit http://www.pdsa.com/Event/Blog for a free eBook on "Fundamentals of N-Tier".

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• ASP.NET MVC: Converting business objects to select list items

  - by DigiMortal

  Some of our business classes are used to fill dropdown boxes or select lists. And often you have some base class for all your business classes. In this posting I will show you how to use base business class to write extension method that converts collection of business objects to ASP.NET MVC select list items without writing a lot of code. BusinessBase, BaseEntity and other base classes I prefer to have some base class for all my business classes so I can easily use them regardless of their type in contexts I need. NB! Some guys say that it is good idea to have base class for all your business classes and they also suggest you to have mappings done same way in database. Other guys say that it is good to have base class but you don’t have to have one master table in database that contains identities of all your business objects. It is up to you how and what you prefer to do but whatever you do – think and analyze first, please. :) To keep things maximally simple I will use very primitive base class in this example. This class has only Id property and that’s it. public class BaseEntity {     public virtual long Id { get; set; } } Now we have Id in base class and we have one more question to solve – how to better visualize our business objects? To users ID is not enough, they want something more informative. We can define some abstract property that all classes must implement. But there is also another option we can use – overriding ToString() method in our business classes. public class Product : BaseEntity {     public virtual string SKU { get; set; }     public virtual string Name { get; set; }       public override string ToString()     {         if (string.IsNullOrEmpty(Name))             return base.ToString();           return Name;     } } Although you can add more functionality and properties to your base class we are at point where we have what we needed: identity and human readable presentation of business objects. Writing list items converter Now we can write method that creates list items for us. public static class BaseEntityExtensions {            public static IEnumerable<SelectListItem> ToSelectListItems<T>         (this IList<T> baseEntities) where T : BaseEntity     {         return ToSelectListItems((IEnumerator<BaseEntity>)                    baseEntities.GetEnumerator());     }       public static IEnumerable<SelectListItem> ToSelectListItems         (this IEnumerator<BaseEntity> baseEntities)     {         var items = new HashSet<SelectListItem>();           while (baseEntities.MoveNext())         {             var item = new SelectListItem();             var entity = baseEntities.Current;               item.Value = entity.Id.ToString();             item.Text = entity.ToString();               items.Add(item);         }           return items;     } } You can see here to overloads of same method. One works with List<T> and the other with IEnumerator<BaseEntity>. Although mostly my repositories return IList<T> when querying data there are always situations where I can use more abstract types and interfaces. Using extension methods in code In your code you can use ToSelectListItems() extension methods like shown on following code fragment. ... var model = new MyFormModel(); model.Statuses = _myRepository.ListStatuses().ToSelectListItems(); ... You can call this method on all your business classes that extend your base entity. Wanna have some fun with this code? Write overload for extension method that accepts selected item ID.

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• Talking JavaOne with Rock Star Martijn Verburg

  - by Janice J. Heiss

  JavaOne Rock Stars, conceived in 2005, are the top-rated speakers at each JavaOne Conference. They are awarded by their peers, who, through conference surveys, recognize them for their outstanding sessions and speaking ability. Over the years many of the world’s leading Java developers have been so recognized. Martijn Verburg has, in recent years, established himself as an important mover and shaker in the Java community. His “Diabolical Developer” session at the JavaOne 2011 Conference got people’s attention by identifying some of the worst practices Java developers are prone to engage in. Among other things, he is co-leader and organizer of the thriving London Java User Group (JUG) which has more than 2,500 members, co-represents the London JUG on the Executive Committee of the Java Community Process, and leads the global effort for the Java User Group “Adopt a JSR” and “Adopt OpenJDK” programs. Career highlights include overhauling technology stacks and SDLC practices at Mizuho International, mentoring Oracle on technical community management, and running off shore development teams for AIG. He is currently CTO at jClarity, a start-up focusing on automating optimization for Java/JVM related technologies, and Product Advisor at ZeroTurnaround. He co-authored, with Ben Evans, "The Well-Grounded Java Developer" published by Manning and, as a leading authority on technical team optimization, he is in high demand at major software conferences.Verburg is participating in five sessions, a busy man indeed. Here they are: CON6152 - Modern Software Development Antipatterns (with Ben Evans) UGF10434 - JCP and OpenJDK: Using the JUGs’ “Adopt” Programs in Your Group (with Csaba Toth) BOF4047 - OpenJDK Building and Testing: Case Study—Java User Group OpenJDK Bugathon (with Ben Evans and Cecilia Borg) BOF6283 - 101 Ways to Improve Java: Why Developer Participation Matters (with Bruno Souza and Heather Vancura-Chilson) HOL6500 - Finding and Solving Java Deadlocks (with Heinz Kabutz, Kirk Pepperdine, Ellen Kraffmiller and Henri Tremblay) When I asked Verburg about the biggest mistakes Java developers tend to make, he listed three: A lack of communication -- Software development is far more a social activity than a technical one; most projects fail because of communication issues and social dynamics, not because of a bad technical decision. Sadly, many developers never learn this lesson. No source control -- Developers simply storing code in local filesystems and emailing code in order to integrate Design-driven Design -- The need for some developers to cram every design pattern from the Gang of Four (GoF) book into their source code All of which raises the question: If these practices are so bad, why do developers engage in them? “I've seen a wide gamut of reasons,” said Verburg, who lists them as: * They were never taught at high school/university that their bad habits were harmful.* They weren't mentored in their first professional roles.* They've lost passion for their craft.* They're being deliberately malicious!* They think software development is a technical activity and not a social one.* They think that they'll be able to tidy it up later.A couple of key confusions and misconceptions beset Java developers, according to Verburg. “With Java and the JVM in particular I've seen a couple of trends,” he remarked. “One is that developers think that the JVM is a magic box that will clean up their memory, make their code run fast, as well as make them cups of coffee. The JVM does help in a lot of cases, but bad code can and will still lead to terrible results! The other trend is to try and force Java (the language) to do something it's not very good at, such as rapid web development. So you get a proliferation of overly complex frameworks, libraries and techniques trying to get around the fact that Java is a monolithic, statically typed, compiled, OO environment. It's not a Golden Hammer!”I asked him about the keys to running a good Java User Group. “You need to have a ‘Why,’” he observed. “Many user groups know what they do (typically, events) and how they do it (the logistics), but what really drives users to join your group and to stay is to give them a purpose. For example, within the LJC we constantly talk about the ‘Why,’ which in our case is several whys:* Re-ignite the passion that developers have for their craft* Raise the bar of Java developers in London* We want developers to have a voice in deciding the future of Java* We want to inspire the next generation of tech leaders* To bring the disparate tech groups in London together* So we could learn from each other* We believe that the Java ecosystem forms a cornerstone of our society today -- we want to protect that for the futureLooking ahead to Java 8 Verburg expressed excitement about Lambdas. “I cannot wait for Lambdas,” he enthused. “Brian Goetz and his group are doing a great job, especially given some of the backwards compatibility that they have to maintain. It's going to remove a lot of boiler plate and yet maintain readability, plus enable massive scaling.”Check out Martijn Verburg at JavaOne if you get a chance, and, stay tuned for a longer interview yours truly did with Martijn to be publish on otn/java some time after JavaOne. Originally published on blogs.oracle.com/javaone.

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• Talking JavaOne with Rock Star Martijn Verburg

  - by Janice J. Heiss

  JavaOne Rock Stars, conceived in 2005, are the top-rated speakers at each JavaOne Conference. They are awarded by their peers, who, through conference surveys, recognize them for their outstanding sessions and speaking ability. Over the years many of the world’s leading Java developers have been so recognized. Martijn Verburg has, in recent years, established himself as an important mover and shaker in the Java community. His “Diabolical Developer” session at the JavaOne 2011 Conference got people’s attention by identifying some of the worst practices Java developers are prone to engage in. Among other things, he is co-leader and organizer of the thriving London Java User Group (JUG) which has more than 2,500 members, co-represents the London JUG on the Executive Committee of the Java Community Process, and leads the global effort for the Java User Group “Adopt a JSR” and “Adopt OpenJDK” programs. Career highlights include overhauling technology stacks and SDLC practices at Mizuho International, mentoring Oracle on technical community management, and running off shore development teams for AIG. He is currently CTO at jClarity, a start-up focusing on automating optimization for Java/JVM related technologies, and Product Advisor at ZeroTurnaround. He co-authored, with Ben Evans, "The Well-Grounded Java Developer" published by Manning and, as a leading authority on technical team optimization, he is in high demand at major software conferences.Verburg is participating in five sessions, a busy man indeed. Here they are: CON6152 - Modern Software Development Antipatterns (with Ben Evans) UGF10434 - JCP and OpenJDK: Using the JUGs’ “Adopt” Programs in Your Group (with Csaba Toth) BOF4047 - OpenJDK Building and Testing: Case Study—Java User Group OpenJDK Bugathon (with Ben Evans and Cecilia Borg) BOF6283 - 101 Ways to Improve Java: Why Developer Participation Matters (with Bruno Souza and Heather Vancura-Chilson) HOL6500 - Finding and Solving Java Deadlocks (with Heinz Kabutz, Kirk Pepperdine, Ellen Kraffmiller and Henri Tremblay) When I asked Verburg about the biggest mistakes Java developers tend to make, he listed three: A lack of communication -- Software development is far more a social activity than a technical one; most projects fail because of communication issues and social dynamics, not because of a bad technical decision. Sadly, many developers never learn this lesson. No source control -- Developers simply storing code in local filesystems and emailing code in order to integrate Design-driven Design -- The need for some developers to cram every design pattern from the Gang of Four (GoF) book into their source code All of which raises the question: If these practices are so bad, why do developers engage in them? “I've seen a wide gamut of reasons,” said Verburg, who lists them as: * They were never taught at high school/university that their bad habits were harmful.* They weren't mentored in their first professional roles.* They've lost passion for their craft.* They're being deliberately malicious!* They think software development is a technical activity and not a social one.* They think that they'll be able to tidy it up later.A couple of key confusions and misconceptions beset Java developers, according to Verburg. “With Java and the JVM in particular I've seen a couple of trends,” he remarked. “One is that developers think that the JVM is a magic box that will clean up their memory, make their code run fast, as well as make them cups of coffee. The JVM does help in a lot of cases, but bad code can and will still lead to terrible results! The other trend is to try and force Java (the language) to do something it's not very good at, such as rapid web development. So you get a proliferation of overly complex frameworks, libraries and techniques trying to get around the fact that Java is a monolithic, statically typed, compiled, OO environment. It's not a Golden Hammer!”I asked him about the keys to running a good Java User Group. “You need to have a ‘Why,’” he observed. “Many user groups know what they do (typically, events) and how they do it (the logistics), but what really drives users to join your group and to stay is to give them a purpose. For example, within the LJC we constantly talk about the ‘Why,’ which in our case is several whys:* Re-ignite the passion that developers have for their craft* Raise the bar of Java developers in London* We want developers to have a voice in deciding the future of Java* We want to inspire the next generation of tech leaders* To bring the disparate tech groups in London together* So we could learn from each other* We believe that the Java ecosystem forms a cornerstone of our society today -- we want to protect that for the futureLooking ahead to Java 8 Verburg expressed excitement about Lambdas. “I cannot wait for Lambdas,” he enthused. “Brian Goetz and his group are doing a great job, especially given some of the backwards compatibility that they have to maintain. It's going to remove a lot of boiler plate and yet maintain readability, plus enable massive scaling.”Check out Martijn Verburg at JavaOne if you get a chance, and, stay tuned for a longer interview yours truly did with Martijn to be publish on otn/java some time after JavaOne.

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• Unit testing is… well, flawed.

  - by Dewald Galjaard

  Hey someone had to say it. I clearly recall my first IT job. I was appointed Systems Co-coordinator for a leading South African retailer at store level. Don’t get me wrong, there is absolutely nothing wrong with an honest day’s labor and in fact I highly recommend it, however I’m obliged to refer to the designation cautiously; in reality all I had to do was monitor in-store prices and two UNIX front line controllers. If anything went wrong – I only had to phone it in… Luckily that wasn’t all I did. My duties extended to some other interesting annual occurrence – stock take. Despite a bit more curious affair, it was still a tedious process that took weeks of preparation and several nights to complete.  Then also I remember that no matter how elaborate our planning was, the entire exercise would be rendered useless if we couldn’t get the basics right – that being the act of counting. Sounds simple right? We’ll with a store which could potentially carry over tens of thousands of different items… we’ll let’s just say I believe that’s when I first became a coffee addict. In those days the act of counting stock was a very humble process. Nothing like we have today. A staff member would be assigned a bin or shelve filled with items he or she had to sort then count. Thereafter they had to record their findings on a complementary piece of paper. Every night I would manage several teams. Each team was divided into two groups - counters and auditors. Both groups had the same task, only auditors followed shortly on the heels of the counters, recounting stock levels, making sure the original count correspond to their findings. It was a simple yet hugely responsible orchestration of people and thankfully there was one fundamental and golden rule I could always abide by to ensure things run smoothly – No-one was allowed to audit their own work. Nope, not even on nights when I didn’t have enough staff available. This meant I too at times had to get up there and get counting, or have the audit stand over until the next evening. The reason for this was obvious - late at night and with so much to do we were prone to make some mistakes, then on the recount, without a fresh set of eyes, you were likely to repeat the offence. Now years later this rule or guideline still holds true as we develop software (as far removed as software development from counting stock may be). For some reason it is a fundamental guideline we’re simply ignorant of. We write our code, we write our tests and thus commit the same horrendous offence. Yes, the procedure of writing unit tests as practiced in most development houses today – is flawed. Most if not all of the tests we write today exercise application logic – our logic. They are based on the way we believe an application or method should/may/will behave or function. As we write our tests, our unit tests mirror our best understanding of the inner workings of our application code. Unfortunately these tests will therefore also include (or be unaware of) any imperfections and errors on our part. If your logic is flawed as you write your initial code, chances are, without a fresh set of eyes, you will commit the same error second time around too. Not even experience seems to be a suitable solution. It certainly helps to have deeper insight, but is that really the answer we should be looking for? Is that really failsafe? What about code review? Code review is certainly an answer. You could have one developer coding away and another (or team) making sure the logic is sound. The practice however has its obvious drawbacks. Firstly and mainly it is resource intensive and from what I’ve seen in most development houses, given heavy deadlines, this guideline is seldom adhered to. Hardly ever do we have the resources, money or time readily available. So what other options are out there? A quest to find some solution revealed a project by Microsoft Research called PEX. PEX is a framework which creates several test scenarios for each method or class you write, automatically. Think of it as your own personal auditor. Within a few clicks the framework will auto generate several unit tests for a given class or method and save them to a single project. PEX help to audit your work. It lends a fresh set of eyes to any project you’re working on and best of all; it is cost effective and fast. Check them out at http://research.microsoft.com/en-us/projects/pex/ In upcoming posts we’ll dive deeper into how it works and how it can help you.   Certainly there are more similar frameworks out there and I would love to hear from you. Please share your experiences and insights.

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• Chart Control in ASP.Net 4 – Second Part

  - by sreejukg

    Couple of weeks before, I have written an introduction about the chart control available in .Net framework. In that article, I explained the basic usage of the chart control with a simple example. You can read that article from the url http://weblogs.asp.net/sreejukg/archive/2010/12/31/getting-started-with-chart-control-in-asp-net-4-0.aspx. In this article I am going to demonstrate how one can generate various types of charts that can be generated easily using the ASP.Net chart control. Let us recollect the data sample we were working in the previous sample. The following is the data I used in the previous article. id SaleAmount SalesPerson SaleType SaleDate CompletionStatus (%) 1 1000 Jack Development 2010-01-01 100 2 300 Mills Consultancy 2010-04-14 90 3 4000 Mills Development 2010-05-15 80 4 2500 Mike eMarketting 2010-06-15 40 5 1080 Jack Development 2010-07-15 30 6 6500 Mills Consultancy 2010-08-24 65 In this article I am going to demonstrate various graphical reports generated from this data with the help of chart control. The following are the reports I am going to generate 1. Representation of share of Sales by each Sales person. 2. Representation of share of sales data according to sale type 3. Representation of sales progress over time period I am going to demonstrate how to bind the chart control programmatically. In order to facilitate this, I created an aspx page named “SalesAnalysis.Aspx” to my project. In the page I added the following controls 1. Dropdownlist control – with id ddlAnalysisType, user will use this to choose the type of chart they want to see. 2. A Button control – with id btnSubmit , by clicking this button, the chart based on the dropdownlist selection will be shown to the user 3. A label Control – with id lblMessage, to display the message to the user, initially this will ask the user to select an option and click on the button. 4. Chart control – with id chrtAnalysis, by default, I set visible = false so that during the page load the chart will be hidden to the users. The following is the initial output of the page. Generating chart for salesperson share Now from Visual Studio, I have double clicked on the button; it created the event handler btnSubmit_Click. In the button Submit event handler, I am using a switch case to execute the corresponding SQL statement and bind it to the chart control. The below is the code for generating the sales person share chart using a pie chart. The above code produces the following output The steps for creating the above chart can be summarized as follows. You specify a chart area, then a series and bind the chart to some x and y values. That is it. If you want to control the chart size and position, you can set the properties for the ChartArea.Position element. For e.g. in the previous code, after instantiating the chart area, setting the below code will give you a bigger pie chart. c.Position.Width = 100; c.Position.Height = 100; The width and height values are in percentage. In this case the chart will be generated by utilizing all the width and height of the chart object. See the output updated with the width and height set to 100% each. Generate Chart for sales type share Now for generating the chart according to the sales type, you just need to change the SQL query and x and y values of the chart. The Sql query used is “SELECT SUM(saleAmount) amount, SaleType from SalesData group by SaleType” and the X-Value is amount and Y-Values is SaleType. s.XValueMember = "SaleType"; s.YValueMembers = "amount"; After modifying the above code with these, the following output is generated. Generate Chart for sales progress over time period For generating the progress of sale chart against sales amount / period, line chart is the ideal tool. In order to facilitate the line chart, you can use Chart Type as System.Web.UI.DataVisualization.Charting.SeriesChartType.Line. Also we need to retrieve the amount and sales date from the data source. I have used the following query to facilitate this. “SELECT SaleAmount, SaleDate FROM SalesData” The output for the line chart is as follows Now you have seen how easily you can build various types of charts. Chart control is an excellent one that helps you to bring business intelligence to your applications. What I demonstrated in only a small part of what you can do with the chart control. Refer http://msdn.microsoft.com/en-us/library/dd456632.aspx for further reading. If you want to get the project files in zip format, post your email below. Hope you enjoyed reading this article.

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• A Communication System for XAML Applications

  - by psheriff

  In any application, you want to keep the coupling between any two or more objects as loose as possible. Coupling happens when one class contains a property that is used in another class, or uses another class in one of its methods. If you have this situation, then this is called strong or tight coupling. One popular design pattern to help with keeping objects loosely coupled is called the Mediator design pattern. The basics of this pattern are very simple; avoid one object directly talking to another object, and instead use another class to mediate between the two. As with most of my blog posts, the purpose is to introduce you to a simple approach to using a message broker, not all of the fine details. IPDSAMessageBroker Interface As with most implementations of a design pattern, you typically start with an interface or an abstract base class. In this particular instance, an Interface will work just fine. The interface for our Message Broker class just contains a single method “SendMessage” and one event “MessageReceived”. public delegate void MessageReceivedEventHandler( object sender, PDSAMessageBrokerEventArgs e); public interface IPDSAMessageBroker{  void SendMessage(PDSAMessageBrokerMessage msg);   event MessageReceivedEventHandler MessageReceived;} PDSAMessageBrokerMessage Class As you can see in the interface, the SendMessage method requires a type of PDSAMessageBrokerMessage to be passed to it. This class simply has a MessageName which is a ‘string’ type and a MessageBody property which is of the type ‘object’ so you can pass whatever you want in the body. You might pass a string in the body, or a complete Customer object. The MessageName property will help the receiver of the message know what is in the MessageBody property. public class PDSAMessageBrokerMessage{  public PDSAMessageBrokerMessage()  {  }   public PDSAMessageBrokerMessage(string name, object body)  {    MessageName = name;    MessageBody = body;  }   public string MessageName { get; set; }   public object MessageBody { get; set; }} PDSAMessageBrokerEventArgs Class As our message broker class will be raising an event that others can respond to, it is a good idea to create your own event argument class. This class will inherit from the System.EventArgs class and add a couple of additional properties. The properties are the MessageName and Message. The MessageName property is simply a string value. The Message property is a type of a PDSAMessageBrokerMessage class. public class PDSAMessageBrokerEventArgs : EventArgs{  public PDSAMessageBrokerEventArgs()  {  }   public PDSAMessageBrokerEventArgs(string name,     PDSAMessageBrokerMessage msg)  {    MessageName = name;    Message = msg;  }   public string MessageName { get; set; }   public PDSAMessageBrokerMessage Message { get; set; }} PDSAMessageBroker Class Now that you have an interface class and a class to pass a message through an event, it is time to create your actual PDSAMessageBroker class. This class implements the SendMessage method and will also create the event handler for the delegate created in your Interface. public class PDSAMessageBroker : IPDSAMessageBroker{  public void SendMessage(PDSAMessageBrokerMessage msg)  {    PDSAMessageBrokerEventArgs args;     args = new PDSAMessageBrokerEventArgs(      msg.MessageName, msg);     RaiseMessageReceived(args);  }   public event MessageReceivedEventHandler MessageReceived;   protected void RaiseMessageReceived(    PDSAMessageBrokerEventArgs e)  {    if (null != MessageReceived)      MessageReceived(this, e);  }} The SendMessage method will take a PDSAMessageBrokerMessage object as an argument. It then creates an instance of a PDSAMessageBrokerEventArgs class, passing to the constructor two items: the MessageName from the PDSAMessageBrokerMessage object and also the object itself. It may seem a little redundant to pass in the message name when that same message name is part of the message, but it does make consuming the event and checking for the message name a little cleaner – as you will see in the next section. Create a Global Message Broker In your WPF application, create an instance of this message broker class in the App class located in the App.xaml file. Create a public property in the App class and create a new instance of that class in the OnStartUp event procedure as shown in the following code: public partial class App : Application{  public PDSAMessageBroker MessageBroker { get; set; }   protected override void OnStartup(StartupEventArgs e)  {    base.OnStartup(e);     MessageBroker = new PDSAMessageBroker();  }} Sending and Receiving Messages Let’s assume you have a user control that you load into a control on your main window and you want to send a message from that user control to the main window. You might have the main window display a message box, or put a string into a status bar as shown in Figure 1. Figure 1: The main window can receive and send messages The first thing you do in the main window is to hook up an event procedure to the MessageReceived event of the global message broker. This is done in the constructor of the main window: public MainWindow(){  InitializeComponent();   (Application.Current as App).MessageBroker.     MessageReceived += new MessageReceivedEventHandler(       MessageBroker_MessageReceived);} One piece of code you might not be familiar with is accessing a property defined in the App class of your XAML application. Within the App.Xaml file is a class named App that inherits from the Application object. You access the global instance of this App class by using Application.Current. You cast Application.Current to ‘App’ prior to accessing any of the public properties or methods you defined in the App class. Thus, the code (Application.Current as App).MessageBroker, allows you to get at the MessageBroker property defined in the App class. In the MessageReceived event procedure in the main window (shown below) you can now check to see if the MessageName property of the PDSAMessageBrokerEventArgs is equal to “StatusBar” and if it is, then display the message body into the status bar text block control. void MessageBroker_MessageReceived(object sender,   PDSAMessageBrokerEventArgs e){  switch (e.MessageName)  {    case "StatusBar":      tbStatus.Text = e.Message.MessageBody.ToString();      break;  }} In the Page 1 user control’s Loaded event procedure you will send the message “StatusBar” through the global message broker to any listener using the following code: private void UserControl_Loaded(object sender,  RoutedEventArgs e){  // Send Status Message  (Application.Current as App).MessageBroker.    SendMessage(new PDSAMessageBrokerMessage("StatusBar",      "This is Page 1"));} Since the main window is listening for the message ‘StatusBar’, it will display the value “This is Page 1” in the status bar at the bottom of the main window. Sending a Message to a User Control The previous example sent a message from the user control to the main window. You can also send messages from the main window to any listener as well. Remember that the global message broker is really just a broadcaster to anyone who has hooked into the MessageReceived event. In the constructor of the user control named ucPage1 you can hook into the global message broker’s MessageReceived event. You can then listen for any messages that are sent to this control by using a similar switch-case structure like that in the main window. public ucPage1(){  InitializeComponent();   // Hook to the Global Message Broker  (Application.Current as App).MessageBroker.    MessageReceived += new MessageReceivedEventHandler(      MessageBroker_MessageReceived);} void MessageBroker_MessageReceived(object sender,  PDSAMessageBrokerEventArgs e){  // Look for messages intended for Page 1  switch (e.MessageName)  {    case "ForPage1":      MessageBox.Show(e.Message.MessageBody.ToString());      break;  }} Once the ucPage1 user control has been loaded into the main window you can then send a message using the following code: private void btnSendToPage1_Click(object sender,  RoutedEventArgs e){  PDSAMessageBrokerMessage arg =     new PDSAMessageBrokerMessage();   arg.MessageName = "ForPage1";  arg.MessageBody = "Message For Page 1";   // Send a message to Page 1  (Application.Current as App).MessageBroker.SendMessage(arg);} Since the MessageName matches what is in the ucPage1 MessageReceived event procedure, ucPage1 can do anything in response to that event. It is important to note that when the message gets sent it is sent to all MessageReceived event procedures, not just the one that is looking for a message called “ForPage1”. If the user control ucPage1 is not loaded and this message is broadcast, but no other code is listening for it, then it is simply ignored. Remove Event Handler In each class where you add an event handler to the MessageReceived event you need to make sure to remove those event handlers when you are done. Failure to do so can cause a strong reference to the class and thus not allow that object to be garbage collected. In each of your user control’s make sure in the Unloaded event to remove the event handler. private void UserControl_Unloaded(object sender, RoutedEventArgs e){  if (_MessageBroker != null)    _MessageBroker.MessageReceived -=         _MessageBroker_MessageReceived;} Problems with Message Brokering As with most “global” classes or classes that hook up events to other classes, garbage collection is something you need to consider. Just the simple act of hooking up an event procedure to a global event handler creates a reference between your user control and the message broker in the App class. This means that even when your user control is removed from your UI, the class will still be in memory because of the reference to the message broker. This can cause messages to still being handled even though the UI is not being displayed. It is up to you to make sure you remove those event handlers as discussed in the previous section. If you don’t, then the garbage collector cannot release those objects. Instead of using events to send messages from one object to another you might consider registering your objects with a central message broker. This message broker now becomes a collection class into which you pass an object and what messages that object wishes to receive. You do end up with the same problem however. You have to un-register your objects; otherwise they still stay in memory. To alleviate this problem you can look into using the WeakReference class as a method to store your objects so they can be garbage collected if need be. Discussing Weak References is beyond the scope of this post, but you can look this up on the web. Summary In this blog post you learned how to create a simple message broker system that will allow you to send messages from one object to another without having to reference objects directly. This does reduce the coupling between objects in your application. You do need to remember to get rid of any event handlers prior to your objects going out of scope or you run the risk of having memory leaks and events being called even though you can no longer access the object that is responding to that event. NOTE: You can download the sample code for this article by visiting my website at http://www.pdsa.com/downloads. Select “Tips & Tricks”, then select “A Communication System for XAML Applications” from the drop down list.

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• XNA Level Select Menu

  - by user29901

  I'll try to explain this the best I can. I'm trying to create a level select menu for a game I'm making. The menu is basically a group of blocks numbered 1-16, similar to something like the Angry Birds menu. What I've done is created a cursor, basically just an outline to surround a block, that the user can move to select what level they want to play. What I want it do is move from block to block instead of simply moving around on the X and Y axes as it does now. So my question is, how can I get the cursor (highLight in the below code) to move from block to block(destinationRectangle1 etc. in the code)? /// Field for the "cursor" Vector2 highLightPos = new Vector2(400, 200); ///This is the Update code KeyboardState keyBoardState = Keyboard.GetState(); if (keyBoardState.IsKeyDown(Keys.Up)) highLightPos.Y--; if (keyBoardState.IsKeyDown(Keys.Down)) highLightPos.Y++; if (keyBoardState.IsKeyDown(Keys.Right)) highLightPos.X++; if (keyBoardState.IsKeyDown(Keys.Left)) highLightPos.X--; /// This is the draw code SpriteBatch spriteBatch = ScreenManager.SpriteBatch; Rectangle screenRectangle = new Rectangle(0, 0, 1280, 720); Rectangle destinationRectangle1 = new Rectangle(400, 200, 64, 64); Rectangle frameRectangle1 = new Rectangle(0, 0, 64, 64); Rectangle destinationRectangle2 = new Rectangle(500, 200, 64, 64); Rectangle frameRectangle2 = new Rectangle(64, 0, 64, 64); Rectangle destinationRectangle3 = new Rectangle(600, 200, 64, 64); Rectangle frameRectangle3 = new Rectangle(128, 0, 64, 64); Rectangle destinationRectangle4 = new Rectangle(700, 200, 64, 64); Rectangle frameRectangle4 = new Rectangle(192, 0, 64, 64); Rectangle destinationRectangle5 = new Rectangle(800, 200, 64, 64); Rectangle frameRectangle5 = new Rectangle(256, 0, 64, 64); Rectangle destinationRectangle6 = new Rectangle(400, 300, 64, 64); Rectangle frameRectangle6 = new Rectangle(320, 0, 64, 64); Rectangle destinationRectangle7 = new Rectangle(500, 300, 64, 64); Rectangle frameRectangle7 = new Rectangle(384, 0, 64, 64); Rectangle destinationRectangle8 = new Rectangle(600, 300, 64, 64); Rectangle frameRectangle8 = new Rectangle(448, 0, 64, 64); Rectangle destinationRectangle9 = new Rectangle(700, 300, 64, 64); Rectangle frameRectangle9 = new Rectangle(0, 64, 64, 64); Rectangle destinationRectangle10 = new Rectangle(800, 300, 64, 64); Rectangle frameRectangle10 = new Rectangle(64, 64, 64, 64); Rectangle destinationRectangle11 = new Rectangle(400, 400, 64, 64); Rectangle frameRectangle11 = new Rectangle(128, 64, 64, 64); Rectangle destinationRectangle12 = new Rectangle(500, 400, 64, 64); Rectangle frameRectangle12 = new Rectangle(192, 64, 64, 64); Rectangle destinationRectangle13 = new Rectangle(600, 400, 64, 64); Rectangle frameRectangle13 = new Rectangle(256, 64, 64, 64); Rectangle destinationRectangle14 = new Rectangle(700, 400, 64, 64); Rectangle frameRectangle14 = new Rectangle(320, 64, 64, 64); Rectangle destinationRectangle15 = new Rectangle(800, 400, 64, 64); Rectangle frameRectangle15 = new Rectangle(384, 64, 64, 64); Rectangle destinationRectangle16 = new Rectangle(600, 500, 64, 64); Rectangle frameRectangle16 = new Rectangle(448, 64, 64, 64); spriteBatch.Begin(); spriteBatch.Draw(forestBG, screenRectangle, Color.White); spriteBatch.Draw(highLight, highLightPos, Color.White); spriteBatch.Draw(levelSelectTiles, destinationRectangle1, frameRectangle1, Color.White); spriteBatch.Draw(levelSelectTiles, destinationRectangle2, frameRectangle2, Color.White); spriteBatch.Draw(levelSelectTiles, destinationRectangle3, frameRectangle3, Color.White); spriteBatch.Draw(levelSelectTiles, destinationRectangle4, frameRectangle4, Color.White); spriteBatch.Draw(levelSelectTiles, destinationRectangle5, frameRectangle5, Color.White); spriteBatch.Draw(levelSelectTiles, destinationRectangle6, frameRectangle6, Color.White); spriteBatch.Draw(levelSelectTiles, destinationRectangle7, frameRectangle7, Color.White); spriteBatch.Draw(levelSelectTiles, destinationRectangle8, frameRectangle8, Color.White); spriteBatch.Draw(levelSelectTiles, destinationRectangle9, frameRectangle9, Color.White); spriteBatch.Draw(levelSelectTiles, destinationRectangle10, frameRectangle10, Color.White); spriteBatch.Draw(levelSelectTiles, destinationRectangle11, frameRectangle11, Color.White); spriteBatch.Draw(levelSelectTiles, destinationRectangle12, frameRectangle12, Color.White); spriteBatch.Draw(levelSelectTiles, destinationRectangle13, frameRectangle13, Color.White); spriteBatch.Draw(levelSelectTiles, destinationRectangle14, frameRectangle14, Color.White); spriteBatch.Draw(levelSelectTiles, destinationRectangle15, frameRectangle15, Color.White); spriteBatch.Draw(levelSelectTiles, destinationRectangle16, frameRectangle16, Color.White); spriteBatch.End(); PS, I'm aware that this code is probably inefficient, cumbersome or that there's a better way to draw parts of a tile sheet. Any suggestions would be appreciated.

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• CLR via C# 3rd Edition is out

  - by Abhijeet Patel

  Time for some book news update. CLR via C#, 3rd Edition seems to have been out for a little while now. The book was released in early Feb this year, and needless to say my copy is on it’s way. I can barely wait to dig in and chew on the goodies that one of the best technical authors and software professionals I respect has in store. The 2nd edition of the book was an absolute treat and this edition promises to be no less. Here is a brief description of what’s new and updated from the 2nd edition. Part I – CLR Basics Chapter 1-The CLR’s Execution Model Added about discussion about C#’s /optimize and /debug switches and how they relate to each other. Chapter 2-Building, Packaging, Deploying, and Administering Applications and Types Improved discussion about Win32 manifest information and version resource information. Chapter 3-Shared Assemblies and Strongly Named Assemblies Added discussion of TypeForwardedToAttribute and TypeForwardedFromAttribute. Part II – Designing Types Chapter 4-Type Fundamentals No new topics. Chapter 5-Primitive, Reference, and Value Types Enhanced discussion of checked and unchecked code and added discussion of new BigInteger type. Also added discussion of C# 4.0’s dynamic primitive type. Chapter 6-Type and Member Basics No new topics. Chapter 7-Constants and Fields No new topics. Chapter 8-Methods Added discussion of extension methods and partial methods. Chapter 9-Parameters Added discussion of optional/named parameters and implicitly-typed local variables. Chapter 10-Properties Added discussion of automatically-implemented properties, properties and the Visual Studio debugger, object and collection initializers, anonymous types, the System.Tuple type and the ExpandoObject type. Chapter 11-Events Added discussion of events and thread-safety as well as showing a cool extension method to simplify the raising of an event. Chapter 12-Generics Added discussion of delegate and interface generic type argument variance. Chapter 13-Interfaces No new topics. Part III – Essential Types Chapter 14-Chars, Strings, and Working with Text No new topics. Chapter 15-Enums Added coverage of new Enum and Type methods to access enumerated type instances. Chapter 16-Arrays Added new section on initializing array elements. Chapter 17-Delegates Added discussion of using generic delegates to avoid defining new delegate types. Also added discussion of lambda expressions. Chapter 18-Attributes No new topics. Chapter 19-Nullable Value Types Added discussion on performance. Part IV – CLR Facilities Chapter 20-Exception Handling and State Management This chapter has been completely rewritten. It is now about exception handling and state management. It includes discussions of code contracts and constrained execution regions (CERs). It also includes a new section on trade-offs between writing productive code and reliable code. Chapter 21-Automatic Memory Management Added discussion of C#’s fixed state and how it works to pin objects in the heap. Rewrote the code for weak delegates so you can use them with any class that exposes an event (the class doesn’t have to support weak delegates itself). Added discussion on the new ConditionalWeakTable class, GC Collection modes, Full GC notifications, garbage collection modes and latency modes. I also include a new sample showing how your application can receive notifications whenever Generation 0 or 2 collections occur. Chapter 22-CLR Hosting and AppDomains Added discussion of side-by-side support allowing multiple CLRs to be loaded in a single process. Added section on the performance of using MarshalByRefObject-derived types. Substantially rewrote the section on cross-AppDomain communication. Added section on AppDomain Monitoring and first chance exception notifications. Updated the section on the AppDomainManager class. Chapter 23-Assembly Loading and Reflection Added section on how to deploy a single file with dependent assemblies embedded inside it. Added section comparing reflection invoke vs bind/invoke vs bind/create delegate/invoke vs C#’s dynamic type. Chapter 24-Runtime Serialization This is a whole new chapter that was not in the 2nd Edition. Part V – Threading Chapter 25-Threading Basics Whole new chapter motivating why Windows supports threads, thread overhead, CPU trends, NUMA Architectures, the relationship between CLR threads and Windows threads, the Thread class, reasons to use threads, thread scheduling and priorities, foreground thread vs background threads. Chapter 26-Performing Compute-Bound Asynchronous Operations Whole new chapter explaining the CLR’s thread pool. This chapter covers all the new .NET 4.0 constructs including cooperative cancelation, Tasks, the aralle class, parallel language integrated query, timers, how the thread pool manages its threads, cache lines and false sharing. Chapter 27-Performing I/O-Bound Asynchronous Operations Whole new chapter explaining how Windows performs synchronous and asynchronous I/O operations. Then, I go into the CLR’s Asynchronous Programming Model, my AsyncEnumerator class, the APM and exceptions, Applications and their threading models, implementing a service asynchronously, the APM and Compute-bound operations, APM considerations, I/O request priorities, converting the APM to a Task, the event-based Asynchronous Pattern, programming model soup. Chapter 28-Primitive Thread Synchronization Constructs Whole new chapter discusses class libraries and thread safety, primitive user-mode, kernel-mode constructs, and data alignment. Chapter 29-Hybrid Thread Synchronization Constructs Whole new chapter discussion various hybrid constructs such as ManualResetEventSlim, SemaphoreSlim, CountdownEvent, Barrier, ReaderWriterLock(Slim), OneManyResourceLock, Monitor, 3 ways to solve the double-check locking technique, .NET 4.0’s Lazy and LazyInitializer classes, the condition variable pattern, .NET 4.0’s concurrent collection classes, the ReaderWriterGate and SyncGate classes.

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• Oracle SQL Developer v3.2.1 Now Available

  - by thatjeffsmith

  Oracle SQL Developer version 3.2.1 is now available. I recommend that everyone now upgrade to this release. It features more than 200 bug fixes, tweaks, and polish applied to the 3.2 edition. The high profile bug fixes submitted by customers and users on our forums are listed in all their glory for your review. I want to highlight a few of the changes though, as I recognize many of you lack the time and/or patience to ‘read the docs.’ That would include me, which is why I enjoy writing these kinds of blog posts. I’m lazy – just like you! No more artificial line breaks between CREATE OR REPLACE and your PL/SQL In versions 3.2 and older, when you pull up your stored procedural objects in our editor, you would see a line break inserted between the CREATE OR REPLACE and then the body of your code. In version 3.2.1, we have removed the line break. 3.1 3.2.1 Trivia Did You Know? The database doesn’t store the ‘CREATE’ or ‘CREATE OR REPLACE’ bit of your PL/SQL code in the database. If we look at the USER_SOURCE view, we can see that the code begins with the object name. So the CREATE OR REPLACE bit is ‘artificial’ The intent is to give you the code necessary to recreate your object – and have it ‘compile’ into the database. We pretty much HAVE to add the ‘CREATE OR REPLACE.’ From now on it will appear inline with the first line of your code. Exporting Tables & Views When exporting data from your tables or views, previous versions of SQL Developer presented a 3 step wizard. It allows you to choose your columns and apply data filters for what is exported. This was kind of redundant. The grids already allowed you to select your columns and apply filters. Wouldn’t it be more intuitive AND efficient to just make the grids behave in a What You See Is What You Get (WYSIWYG) fashion? In version 3.2.1, that is exactly what will happen. The wizard now only has two steps and the grid will export the data and columns as defined in the visible grid. Let the grid properties define what is actually exported! And here is what is pasted into my worksheet: "BREWERY"|"CITY" "3 Brewers Restaurant Micro-Brewery"|"Toronto" "Amsterdam Brewing Co."|"Toronto" "Ball Brewing Company Ltd."|"Toronto" "Big Ram Brewing Company"|"Toronto" "Black Creek Historic Brewery"|"Toronto" "Black Oak Brewing"|"Toronto" "C'est What?"|"Toronto" "Cool Beer Brewing Company"|"Toronto" "Denison's Brewing"|"Toronto" "Duggan's Brewery"|"Toronto" "Feathers"|"Toronto" "Fermentations! - Danforth"|"Toronto" "Fermentations! - Mount Pleasant"|"Toronto" "Granite Brewery & Restaurant"|"Toronto" "Labatt's Breweries of Canada"|"Toronto" "Mill Street Brew Pub"|"Toronto" "Mill Street Brewery"|"Toronto" "Molson Breweries of Canada"|"Toronto" "Molson Brewery at Air Canada Centre"|"Toronto" "Pioneer Brewery Ltd."|"Toronto" "Post-Production Bistro"|"Toronto" "Rotterdam Brewing"|"Toronto" "Steam Whistle Brewing"|"Toronto" "Strand Brasserie"|"Toronto" "Upper Canada Brewing"|"Toronto" JUST what I wanted And One Last Thing Speaking of export, sometimes I want to send data to Excel. And sometimes I want to send multiple objects to Excel – to a single Excel file that is. In version 3.2.1 you can now do that. Let’s export the bulk of the HR schema to Excel, with each table going to it’s own workbook in the same worksheet. Select many tables, put them in in a single Excel worksheet If you try this in previous versions of SQL Developer it will just write the first table to the Excel file. This is one of the bugs we addressed in v3.2.1. Here is what the output Excel file looks like now: Many tables - Many workbooks in an Excel Worksheet I have a sneaky suspicion that this will be a frequently used feature going forward. Excel seems to be the cornerstone of many of our popular features. Imagine that!

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• F# for the C# Programmer

  - by mbcrump

  Are you a C# Programmer and can’t make it past a day without seeing or hearing someone mention F#?  Today, I’m going to walk you through your first F# application and give you a brief introduction to the language. Sit back this will only take about 20 minutes. Introduction Microsoft's F# programming language is a functional language for the .NET framework that was originally developed at Microsoft Research Cambridge by Don Syme. In October 2007, the senior vice president of the developer division at Microsoft announced that F# was being officially productized to become a fully supported .NET language and professional developers were hired to create a team of around ten people to build the product version. In September 2008, Microsoft released the first Community Technology Preview (CTP), an official beta release, of the F# distribution . In December 2008, Microsoft announced that the success of this CTP had encouraged them to escalate F# and it is now will now be shipped as one of the core languages in Visual Studio 2010 , alongside C++, C# 4.0 and VB. The F# programming language incorporates many state-of-the-art features from programming language research and ossifies them in an industrial strength implementation that promises to revolutionize interactive, parallel and concurrent programming. Advantages of F# F# is the world's first language to combine all of the following features: Type inference: types are inferred by the compiler and generic definitions are created automatically. Algebraic data types: a succinct way to represent trees. Pattern matching: a comprehensible and efficient way to dissect data structures. Active patterns: pattern matching over foreign data structures. Interactive sessions: as easy to use as Python and Mathematica. High performance JIT compilation to native code: as fast as C#. Rich data structures: lists and arrays built into the language with syntactic support. Functional programming: first-class functions and tail calls. Expressive static type system: finds bugs during compilation and provides machine-verified documentation. Sequence expressions: interrogate huge data sets efficiently. Asynchronous workflows: syntactic support for monadic style concurrent programming with cancellations. Industrial-strength IDE support: multithreaded debugging, and graphical throwback of inferred types and documentation. Commerce friendly design and a viable commercial market. Lets try a short program in C# then F# to understand the differences. Using C#: Create a variable and output the value to the console window: Sample Program. using System;   namespace ConsoleApplication9 {     class Program     {         static void Main(string[] args)         {             var a = 2;             Console.WriteLine(a);             Console.ReadLine();         }     } } A breeze right? 14 Lines of code. We could have condensed it a bit by removing the “using” statment and tossing the namespace. But this is the typical C# program. Using F#: Create a variable and output the value to the console window: To start, open Visual Studio 2010 or Visual Studio 2008. Note: If using VS2008, then please download the SDK first before getting started. If you are using VS2010 then you are already setup and ready to go. So, click File-> New Project –> Other Languages –> Visual F# –> Windows –> F# Application. You will get the screen below. Go ahead and enter a name and click OK. Now, you will notice that the Solution Explorer contains the following: Double click the Program.fs and enter the following information. Hit F5 and it should run successfully. Sample Program. open System let a = 2        Console.WriteLine a As Shown below: Hmm, what? F# did the same thing in 3 lines of code. Show me the interactive evaluation that I keep hearing about. The F# development environment for Visual Studio 2010 provides two different modes of execution for F# code: Batch compilation to a .NET executable or DLL. (This was accomplished above). Interactive evaluation. (Demo is below) The interactive session provides a > prompt, requires a double semicolon ;; identifier at the end of a code snippet to force evaluation, and returns the names (if any) and types of resulting definitions and values. To access the F# prompt, in VS2010 Goto View –> Other Window then F# Interactive. Once you have the interactive window type in the following expression: 2+3;; as shown in the screenshot below: I hope this guide helps you get started with the language, please check out the following books for further information. F# Books for further reading   Foundations of F# Author: Robert Pickering An introduction to functional programming with F#. Including many samples, this book walks through the features of the F# language and libraries, and covers many of the .NET Framework features which can be leveraged with F#.       Functional Programming for the Real World: With Examples in F# and C# Authors: Tomas Petricek and Jon Skeet An introduction to functional programming for existing C# developers written by Tomas Petricek and Jon Skeet. This book explains the core principles using both C# and F#, shows how to use functional ideas when designing .NET applications and presents practical examples such as design of domain specific language, development of multi-core applications and programming of reactive applications.

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• LWJGL Voxel game, glDrawArrays

  - by user22015

  I've been learning about 3D for a couple days now. I managed to create a chunk (8x8x8). Add optimization so it only renders the active and visible blocks. Then I added so it only draws the faces which don't have a neighbor. Next what I found from online research was that it is better to use glDrawArrays to increase performance. So I restarted my little project. Render an entire chunck, add optimization so it only renders active and visible blocks. But now I want to add so it only draws the visible faces while using glDrawArrays. This is giving me some trouble with calling glDrawArrays because I'm passing a wrong count parameter. > # A fatal error has been detected by the Java Runtime Environment: > # > # EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x0000000006e31a03, pid=1032, tid=3184 > # Stack: [0x00000000023a0000,0x00000000024a0000], sp=0x000000000249ef70, free space=1019k Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code) C [ig4icd64.dll+0xa1a03] Java frames: (J=compiled Java code, j=interpreted, Vv=VM code) j org.lwjgl.opengl.GL11.nglDrawArrays(IIIJ)V+0 j org.lwjgl.opengl.GL11.glDrawArrays(III)V+20 j com.vox.block.Chunk.render()V+410 j com.vox.ChunkManager.render()V+30 j com.vox.Game.render()V+11 j com.vox.GameHandler.render()V+12 j com.vox.GameHandler.gameLoop()V+15 j com.vox.Main.main([Ljava/lang/StringV+13 v ~StubRoutines::call_stub public class Chunk { public final static int[] DIM = { 8, 8, 8}; public final static int CHUNK_SIZE = (DIM[0] * DIM[1] * DIM[2]); Block[][][] blocks; private int index; private int vBOVertexHandle; private int vBOColorHandle; public Chunk(int index) { this.index = index; vBOColorHandle = GL15.glGenBuffers(); vBOVertexHandle = GL15.glGenBuffers(); blocks = new Block[DIM[0]][DIM[1]][DIM[2]]; for(int x = 0; x < DIM[0]; x++){ for(int y = 0; y < DIM[1]; y++){ for(int z = 0; z < DIM[2]; z++){ blocks[x][y][z] = new Block(); } } } } public void render(){ Block curr; FloatBuffer vertexPositionData2 = BufferUtils.createFloatBuffer(CHUNK_SIZE * 6 * 12); FloatBuffer vertexColorData2 = BufferUtils.createFloatBuffer(CHUNK_SIZE * 6 * 12); int counter = 0; for(int x = 0; x < DIM[0]; x++){ for(int y = 0; y < DIM[1]; y++){ for(int z = 0; z < DIM[2]; z++){ curr = blocks[x][y][z]; boolean[] neightbours = validateNeightbours(x, y, z); if(curr.isActive() && !neightbours[6]) { float[] arr = curr.createCube((index*DIM[0]*Block.BLOCK_SIZE*2) + x*2, y*2, z*2, neightbours); counter += arr.length; vertexPositionData2.put(arr); vertexColorData2.put(createCubeVertexCol(curr.getCubeColor())); } } } } vertexPositionData2.flip(); vertexPositionData2.flip(); FloatBuffer vertexPositionData = BufferUtils.createFloatBuffer(vertexColorData2.position()); FloatBuffer vertexColorData = BufferUtils.createFloatBuffer(vertexColorData2.position()); for(int i = 0; i < vertexPositionData2.position(); i++) vertexPositionData.put(vertexPositionData2.get(i)); for(int i = 0; i < vertexColorData2.position(); i++) vertexColorData.put(vertexColorData2.get(i)); vertexColorData.flip(); vertexPositionData.flip(); GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, vBOVertexHandle); GL15.glBufferData(GL15.GL_ARRAY_BUFFER, vertexPositionData, GL15.GL_STATIC_DRAW); GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, 0); GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, vBOColorHandle); GL15.glBufferData(GL15.GL_ARRAY_BUFFER, vertexColorData, GL15.GL_STATIC_DRAW); GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, 0); GL11.glPushMatrix(); GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, vBOVertexHandle); GL11.glVertexPointer(3, GL11.GL_FLOAT, 0, 0L); GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, vBOColorHandle); GL11.glColorPointer(3, GL11.GL_FLOAT, 0, 0L); System.out.println("Counter " + counter); GL11.glDrawArrays(GL11.GL_LINE_LOOP, 0, counter); GL11.glPopMatrix(); //blocks[r.nextInt(DIM[0])][2][r.nextInt(DIM[2])].setActive(false); } //Random r = new Random(); private float[] createCubeVertexCol(float[] CubeColorArray) { float[] cubeColors = new float[CubeColorArray.length * 4 * 6]; for (int i = 0; i < cubeColors.length; i++) { cubeColors[i] = CubeColorArray[i % CubeColorArray.length]; } return cubeColors; } private boolean[] validateNeightbours(int x, int y, int z) { boolean[] bools = new boolean[7]; bools[6] = true; bools[6] = bools[6] && (bools[0] = y > 0 && y < DIM[1]-1 && blocks[x][y+1][z].isActive());//top bools[6] = bools[6] && (bools[1] = y > 0 && y < DIM[1]-1 && blocks[x][y-1][z].isActive());//bottom bools[6] = bools[6] && (bools[2] = z > 0 && z < DIM[2]-1 && blocks[x][y][z+1].isActive());//front bools[6] = bools[6] && (bools[3] = z > 0 && z < DIM[2]-1 && blocks[x][y][z-1].isActive());//back bools[6] = bools[6] && (bools[4] = x > 0 && x < DIM[0]-1 && blocks[x+1][y][z].isActive());//left bools[6] = bools[6] && (bools[5] = x > 0 && x < DIM[0]-1 && blocks[x-1][y][z].isActive());//right return bools; } } public class Block { public static final float BLOCK_SIZE = 1f; public enum BlockType { Default(0), Grass(1), Dirt(2), Water(3), Stone(4), Wood(5), Sand(6), LAVA(7); int BlockID; BlockType(int i) { BlockID=i; } } private boolean active; private BlockType type; public Block() { this(BlockType.Default); } public Block(BlockType type){ active = true; this.type = type; } public float[] getCubeColor() { switch (type.BlockID) { case 1: return new float[] { 1, 1, 0 }; case 2: return new float[] { 1, 0.5f, 0 }; case 3: return new float[] { 0, 0f, 1f }; default: return new float[] {0.5f, 0.5f, 1f}; } } public float[] createCube(float x, float y, float z, boolean[] neightbours){ int counter = 0; for(boolean b : neightbours) if(!b) counter++; float[] array = new float[counter*12]; int offset = 0; if(!neightbours[0]){//top array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; } if(!neightbours[1]){//bottom array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; } if(!neightbours[2]){//front array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; } if(!neightbours[3]){//back array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; } if(!neightbours[4]){//left array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; } if(!neightbours[5]){//right array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; } return Arrays.copyOf(array, offset); } public boolean isActive() { return active; } public void setActive(boolean active) { this.active = active; } public BlockType getType() { return type; } public void setType(BlockType type) { this.type = type; } } I highlighted the code I'm concerned about in this following screenshot: - http://imageshack.us/a/img820/7606/18626782.png - (Not allowed to upload images yet) I know the code is a mess but I'm just testing stuff so I wasn't really thinking about it.

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• ASP.NET WebAPI Security 2: Identity Architecture

  - by Your DisplayName here!

  Pedro has beaten me to the punch with a detailed post (and diagram) about the WebAPI hosting architecture. So go read his post first, then come back so we can have a closer look at what that means for security. The first important takeaway is that WebAPI is hosting independent-  currently it ships with two host integration implementations – one for ASP.NET (aka web host) and WCF (aka self host). Pedro nicely shows the integration into the web host. Self hosting is not done yet so we will mainly focus on the web hosting case and I will point out security related differences when they exist. The interesting part for security (amongst other things of course) is the HttpControllerHandler (see Pedro’s diagram) – this is where the host specific representation of an HTTP request gets converted to the WebAPI abstraction (called HttpRequestMessage). The ConvertRequest method does the following: Create a new HttpRequestMessage. Copy URI, method and headers from the HttpContext. Copies HttpContext.User to the Properties<string, object> dictionary on the HttpRequestMessage. The key used for that can be found on HttpPropertyKeys.UserPrincipalKey (which resolves to “MS_UserPrincipal”). So the consequence is that WebAPI receives whatever IPrincipal has been set by the ASP.NET pipeline (in the web hosting case). Common questions are: Are there situations where is property does not get set? Not in ASP.NET – the DefaultAuthenticationModule in the HTTP pipeline makes sure HttpContext.User (and Thread.CurrentPrincipal – more on that later) are always set. Either to some authenticated user – or to an anonymous principal. This may be different in other hosting environments (again more on that later). Why so generic? Keep in mind that WebAPI is hosting independent and may run on a host that materializes identity completely different compared to ASP.NET (or .NET in general). This gives them a way to evolve the system in the future. How does WebAPI code retrieve the current client identity? HttpRequestMessage has an extension method called GetUserPrincipal() which returns the property as an IPrincipal. A quick look at self hosting shows that the moral equivalent of HttpControllerHandler.ConvertRequest() is HttpSelfHostServer.ProcessRequestContext(). Here the principal property gets only set when the host is configured for Windows authentication (inconsisteny). Do I like that? Well – yes and no. Here are my thoughts: I like that it is very straightforward to let WebAPI inherit the client identity context of the host. This might not always be what you want – think of an ASP.NET app that consists of UI and APIs – the UI might use Forms authentication, the APIs token based authentication. So it would be good if the two parts would live in a separate security world. It makes total sense to have this generic hand off point for identity between the host and WebAPI. It also makes total sense for WebAPI plumbing code (especially handlers) to use the WebAPI specific identity abstraction. But – c’mon we are running on .NET. And the way .NET represents identity is via IPrincipal/IIdentity. That’s what every .NET developer on this planet is used to. So I would like to see a User property of type IPrincipal on ApiController. I don’t like the fact that Thread.CurrentPrincipal is not populated. T.CP is a well established pattern as a one stop shop to retrieve client identity on .NET.  That makes a lot of sense – even if the name is misleading at best. There might be existing library code you want to call from WebAPI that makes use of T.CP (e.g. PrincipalPermission, or a simple .Name or .IsInRole()). Having the client identity as an ambient property is useful for code that does not have access to the current HTTP request (for calling GetUserPrincipal()). I don’t like the fact that that the client identity conversion from host to WebAPI is inconsistent. This makes writing security plumbing code harder. I think the logic should always be: If the host has a client identity representation, copy it. If not, set an anonymous principal on the request message. Btw – please don’t annoy me with the “but T.CP is static, and static is bad for testing” chant. T.CP is a getter/setter and, in fact I find it beneficial to be able to set different security contexts in unit tests before calling in some logic. And, in case you have wondered – T.CP is indeed thread static (and the name comes from a time where a logical operation was bound to a thread – which is not true anymore). But all thread creation APIs in .NET actually copy T.CP to the new thread they create. This is the case since .NET 2.0 and is certainly an improvement compared to how Win32 does things. So to sum it up: The host plumbing copies the host client identity to WebAPI (this is not perfect yet, but will surely be improved). or in other words: The current WebAPI bits don’t ship with any authentication plumbing, but solely use whatever authentication (and thus client identity) is set up by the host. WebAPI developers can retrieve the client identity from the HttpRequestMessage. Hopefully my proposed changes around T.CP and the User property on ApiController will be added. In the next post, I will detail how to add WebAPI specific authentication support, e.g. for Basic Authentication and tokens. This includes integrating the notion of claims based identity. After that we will look at the built-in authorization bits and how to improve them as well. Stay tuned.

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• Developing custom MBeans to manage J2EE Applications (Part III)

  - by philippe Le Mouel

  This is the third and final part in a series of blogs, that demonstrate how to add management capability to your own application using JMX MBeans. In Part I we saw: How to implement a custom MBean to manage configuration associated with an application. How to package the resulting code and configuration as part of the application's ear file. How to register MBeans upon application startup, and unregistered them upon application stop (or undeployment). How to use generic JMX clients such as JConsole to browse and edit our application's MBean. In Part II we saw: How to add localized descriptions to our MBean, MBean attributes, MBean operations and MBean operation parameters. How to specify meaningful name to our MBean operation parameters. We also touched on future enhancements that will simplify how we can implement localized MBeans. In this third and last part, we will re-write our MBean to simplify how we added localized descriptions. To do so we will take advantage of the functionality we already described in part II and that is now part of WebLogic 10.3.3.0. We will show how to take advantage of WebLogic's localization support to localize our MBeans based on the client's Locale independently of the server's Locale. Each client will see MBean descriptions localized based on his/her own Locale. We will show how to achieve this using JConsole, and also using a sample programmatic JMX Java client. The complete code sample and associated build files for part III are available as a zip file. The code has been tested against WebLogic Server 10.3.3.0 and JDK6. To build and deploy our sample application, please follow the instruction provided in Part I, as they also apply to part III's code and associated zip file. Providing custom descriptions take II In part II we localized our MBean descriptions by extending the StandardMBean class and overriding its many getDescription methods. WebLogic 10.3.3.0 similarly to JDK 7 can automatically localize MBean descriptions as long as those are specified according to the following conventions: Descriptions resource bundle keys are named according to: MBean description: <MBeanInterfaceClass>.mbean MBean attribute description: <MBeanInterfaceClass>.attribute.<AttributeName> MBean operation description: <MBeanInterfaceClass>.operation.<OperationName> MBean operation parameter description: <MBeanInterfaceClass>.operation.<OperationName>.<ParameterName> MBean constructor description: <MBeanInterfaceClass>.constructor.<ConstructorName> MBean constructor parameter description: <MBeanInterfaceClass>.constructor.<ConstructorName>.<ParameterName> We also purposely named our resource bundle class MBeanDescriptions and included it as part of the same package as our MBean. We already followed the above conventions when creating our resource bundle in part II, and our default resource bundle class with English descriptions looks like: package blog.wls.jmx.appmbean; import java.util.ListResourceBundle; public class MBeanDescriptions extends ListResourceBundle { protected Object[][] getContents() { return new Object[][] { {"PropertyConfigMXBean.mbean", "MBean used to manage persistent application properties"}, {"PropertyConfigMXBean.attribute.Properties", "Properties associated with the running application"}, {"PropertyConfigMXBean.operation.setProperty", "Create a new property, or change the value of an existing property"}, {"PropertyConfigMXBean.operation.setProperty.key", "Name that identify the property to set."}, {"PropertyConfigMXBean.operation.setProperty.value", "Value for the property being set"}, {"PropertyConfigMXBean.operation.getProperty", "Get the value for an existing property"}, {"PropertyConfigMXBean.operation.getProperty.key", "Name that identify the property to be retrieved"} }; } } We have now also added a resource bundle with French localized descriptions: package blog.wls.jmx.appmbean; import java.util.ListResourceBundle; public class MBeanDescriptions_fr extends ListResourceBundle { protected Object[][] getContents() { return new Object[][] { {"PropertyConfigMXBean.mbean", "Manage proprietes sauvegarde dans un fichier disque."}, {"PropertyConfigMXBean.attribute.Properties", "Proprietes associee avec l'application en cour d'execution"}, {"PropertyConfigMXBean.operation.setProperty", "Construit une nouvelle proprietee, ou change la valeur d'une proprietee existante."}, {"PropertyConfigMXBean.operation.setProperty.key", "Nom de la propriete dont la valeur est change."}, {"PropertyConfigMXBean.operation.setProperty.value", "Nouvelle valeur"}, {"PropertyConfigMXBean.operation.getProperty", "Retourne la valeur d'une propriete existante."}, {"PropertyConfigMXBean.operation.getProperty.key", "Nom de la propriete a retrouver."} }; } } So now we can just remove the many getDescriptions methods from our MBean code, and have a much cleaner: package blog.wls.jmx.appmbean; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.File; import java.net.URL; import java.util.Map; import java.util.HashMap; import java.util.Properties; import javax.management.MBeanServer; import javax.management.ObjectName; import javax.management.MBeanRegistration; import javax.management.StandardMBean; import javax.management.MBeanOperationInfo; import javax.management.MBeanParameterInfo; public class PropertyConfig extends StandardMBean implements PropertyConfigMXBean, MBeanRegistration { private String relativePath_ = null; private Properties props_ = null; private File resource_ = null; private static Map operationsParamNames_ = null; static { operationsParamNames_ = new HashMap(); operationsParamNames_.put("setProperty", new String[] {"key", "value"}); operationsParamNames_.put("getProperty", new String[] {"key"}); } public PropertyConfig(String relativePath) throws Exception { super(PropertyConfigMXBean.class , true); props_ = new Properties(); relativePath_ = relativePath; } public String setProperty(String key, String value) throws IOException { String oldValue = null; if (value == null) { oldValue = String.class.cast(props_.remove(key)); } else { oldValue = String.class.cast(props_.setProperty(key, value)); } save(); return oldValue; } public String getProperty(String key) { return props_.getProperty(key); } public Map getProperties() { return (Map) props_; } private void load() throws IOException { InputStream is = new FileInputStream(resource_); try { props_.load(is); } finally { is.close(); } } private void save() throws IOException { OutputStream os = new FileOutputStream(resource_); try { props_.store(os, null); } finally { os.close(); } } public ObjectName preRegister(MBeanServer server, ObjectName name) throws Exception { // MBean must be registered from an application thread // to have access to the application ClassLoader ClassLoader cl = Thread.currentThread().getContextClassLoader(); URL resourceUrl = cl.getResource(relativePath_); resource_ = new File(resourceUrl.toURI()); load(); return name; } public void postRegister(Boolean registrationDone) { } public void preDeregister() throws Exception {} public void postDeregister() {} protected String getParameterName(MBeanOperationInfo op, MBeanParameterInfo param, int sequence) { return operationsParamNames_.get(op.getName())[sequence]; } } The only reason we are still extending the StandardMBean class, is to override the default values for our operations parameters name. If this isn't a concern, then one could just write the following code: package blog.wls.jmx.appmbean; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.File; import java.net.URL; import java.util.Properties; import javax.management.MBeanServer; import javax.management.ObjectName; import javax.management.MBeanRegistration; import javax.management.StandardMBean; import javax.management.MBeanOperationInfo; import javax.management.MBeanParameterInfo; public class PropertyConfig implements PropertyConfigMXBean, MBeanRegistration { private String relativePath_ = null; private Properties props_ = null; private File resource_ = null; public PropertyConfig(String relativePath) throws Exception { props_ = new Properties(); relativePath_ = relativePath; } public String setProperty(String key, String value) throws IOException { String oldValue = null; if (value == null) { oldValue = String.class.cast(props_.remove(key)); } else { oldValue = String.class.cast(props_.setProperty(key, value)); } save(); return oldValue; } public String getProperty(String key) { return props_.getProperty(key); } public Map getProperties() { return (Map) props_; } private void load() throws IOException { InputStream is = new FileInputStream(resource_); try { props_.load(is); } finally { is.close(); } } private void save() throws IOException { OutputStream os = new FileOutputStream(resource_); try { props_.store(os, null); } finally { os.close(); } } public ObjectName preRegister(MBeanServer server, ObjectName name) throws Exception { // MBean must be registered from an application thread // to have access to the application ClassLoader ClassLoader cl = Thread.currentThread().getContextClassLoader(); URL resourceUrl = cl.getResource(relativePath_); resource_ = new File(resourceUrl.toURI()); load(); return name; } public void postRegister(Boolean registrationDone) { } public void preDeregister() throws Exception {} public void postDeregister() {} } Note: The above would also require changing the operations parameters name in the resource bundle classes. For instance: PropertyConfigMXBean.operation.setProperty.key would become: PropertyConfigMXBean.operation.setProperty.p0 Client based localization When accessing our MBean using JConsole started with the following command line: jconsole -J-Djava.class.path=$JAVA_HOME/lib/jconsole.jar:$JAVA_HOME/lib/tools.jar: $WL_HOME/server/lib/wljmxclient.jar -J-Djmx.remote.protocol.provider.pkgs=weblogic.management.remote -debug We see that our MBean descriptions are localized according to the WebLogic's server Locale. English in this case: Note: Consult Part I for information on how to use JConsole to browse/edit our MBean. Now if we specify the client's Locale as part of the JConsole command line as follow: jconsole -J-Djava.class.path=$JAVA_HOME/lib/jconsole.jar:$JAVA_HOME/lib/tools.jar: $WL_HOME/server/lib/wljmxclient.jar -J-Djmx.remote.protocol.provider.pkgs=weblogic.management.remote -J-Dweblogic.management.remote.locale=fr-FR -debug We see that our MBean descriptions are now localized according to the specified client's Locale. French in this case: We use the weblogic.management.remote.locale system property to specify the Locale that should be associated with the cient's JMX connections. The value is composed of the client's language code and its country code separated by the - character. The country code is not required, and can be omitted. For instance: -Dweblogic.management.remote.locale=fr We can also specify the client's Locale using a programmatic client as demonstrated below: package blog.wls.jmx.appmbean.client; import javax.management.MBeanServerConnection; import javax.management.ObjectName; import javax.management.MBeanInfo; import javax.management.remote.JMXConnector; import javax.management.remote.JMXServiceURL; import javax.management.remote.JMXConnectorFactory; import java.util.Hashtable; import java.util.Set; import java.util.Locale; public class JMXClient { public static void main(String[] args) throws Exception { JMXConnector jmxCon = null; try { JMXServiceURL serviceUrl = new JMXServiceURL( "service:jmx:iiop://127.0.0.1:7001/jndi/weblogic.management.mbeanservers.runtime"); System.out.println("Connecting to: " + serviceUrl); // properties associated with the connection Hashtable env = new Hashtable(); env.put(JMXConnectorFactory.PROTOCOL_PROVIDER_PACKAGES, "weblogic.management.remote"); String[] credentials = new String[2]; credentials[0] = "weblogic"; credentials[1] = "weblogic"; env.put(JMXConnector.CREDENTIALS, credentials); // specifies the client's Locale env.put("weblogic.management.remote.locale", Locale.FRENCH); jmxCon = JMXConnectorFactory.newJMXConnector(serviceUrl, env); jmxCon.connect(); MBeanServerConnection con = jmxCon.getMBeanServerConnection(); Set mbeans = con.queryNames( new ObjectName( "blog.wls.jmx.appmbean:name=myAppProperties,type=PropertyConfig,*"), null); for (ObjectName mbeanName : mbeans) { System.out.println("\n\nMBEAN: " + mbeanName); MBeanInfo minfo = con.getMBeanInfo(mbeanName); System.out.println("MBean Description: "+minfo.getDescription()); System.out.println("\n"); } } finally { // release the connection if (jmxCon != null) jmxCon.close(); } } } The above client code is part of the zip file associated with this blog, and can be run using the provided client.sh script. The resulting output is shown below: $ ./client.sh Connecting to: service:jmx:iiop://127.0.0.1:7001/jndi/weblogic.management.mbeanservers.runtime MBEAN: blog.wls.jmx.appmbean:type=PropertyConfig,name=myAppProperties MBean Description: Manage proprietes sauvegarde dans un fichier disque. $ Miscellaneous Using Description annotation to specify MBean descriptions Earlier we have seen how to name our MBean descriptions resource keys, so that WebLogic 10.3.3.0 automatically uses them to localize our MBean. In some cases we might want to implicitly specify the resource key, and resource bundle. For instance when operations are overloaded, and the operation name is no longer sufficient to uniquely identify a single operation. In this case we can use the Description annotation provided by WebLogic as follow: import weblogic.management.utils.Description; @Description(resourceKey="myapp.resources.TestMXBean.description", resourceBundleBaseName="myapp.resources.MBeanResources") public interface TestMXBean { @Description(resourceKey="myapp.resources.TestMXBean.threshold.description", resourceBundleBaseName="myapp.resources.MBeanResources" ) public int getthreshold(); @Description(resourceKey="myapp.resources.TestMXBean.reset.description", resourceBundleBaseName="myapp.resources.MBeanResources") public int reset( @Description(resourceKey="myapp.resources.TestMXBean.reset.id.description", resourceBundleBaseName="myapp.resources.MBeanResources", displayNameKey= "myapp.resources.TestMXBean.reset.id.displayName.description") int id); } The Description annotation should be applied to the MBean interface. It can be used to specify MBean, MBean attributes, MBean operations, and MBean operation parameters descriptions as demonstrated above. Retrieving the Locale associated with a JMX operation from the MBean code There are several cases where it is necessary to retrieve the Locale associated with a JMX call from the MBean implementation. For instance this can be useful when localizing exception messages. This can be done as follow: import weblogic.management.mbeanservers.JMXContextUtil; ...... // some MBean method implementation public String setProperty(String key, String value) throws IOException { Locale callersLocale = JMXContextUtil.getLocale(); // use callersLocale to localize Exception messages or // potentially some return values such a Date .... } Conclusion With this last part we conclude our three part series on how to write MBeans to manage J2EE applications. We are far from having exhausted this particular topic, but we have gone a long way and are now capable to take advantage of the latest functionality provided by WebLogic's application server to write user friendly MBeans.

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• Patch an Existing NK.BIN

  - by Kate Moss' Open Space

  As you know, we can use MAKEIMG.EXE tool to create OS Image file, NK.BIN, or ROMIMAGE.EXE with a BIB for more accurate. But what if the image file is already created but need to be patched or you want to extract a file from NK.BIN? The Platform Builder provide many useful command line utilities, and today I am going to introduce one, BINMOD.EXE. http://msdn.microsoft.com/en-us/library/ee504622.aspx is the official page for BINMOD tool. As the page says, The BinMod Tool (binmod.exe) extracts files from a run-time image, and replaces files in a run-time image and its usage binmod [-i imagename] [-r replacement_filename.ext | -e extraction_filename.ext] This is a simple tool and is easy to use, if we want to extract a file from nk.bin, just type binmod –i nk.bin –e filename.ext And that's it! Or use can try -r command to replace a file inside NK.BIN. The small tool is good but there is a limitation; due to the files in MODULES section are fixed up during ROMIMAGE so the original file format is not preserved, therefore extract or replace file in MODULE section will be impossible. So just like this small tool, this post supposed to be end here, right? Nah... It is not that easy. Just try the above example, and you will find, the tool is not work! Double check the file is in FILES section and the NK.BIN is good, but it just quits. Before you throw away this useless toy, we can try to fix it! Yes, the source of this tool is available in your CE6, private\winceos\COREOS\nk\tools\romimage\binmod. As it is a tool run in your Windows so you need to Windows SDK or Visual Studio to build the code. (I am going to save you some time by skipping the detail as building a desktop console mode program is fairly trivial) The cbinmod.cpp is the core logic for this program and follow up the error message we got, it looks like the following code is suspected.   //   // Extra sanity check...   //   if((DWORD)(HIWORD(pTOCLoc->dllfirst) << 16) <= pTOCLoc->dlllast &&       (DWORD)(LOWORD(pTOCLoc->dllfirst) << 16) <= pTOCLoc->dlllast)   {     dprintf("Found pTOC  = 0x%08x\n", (DWORD)dwpTOC);     fFoundIt = true;     break;   }    else    {     dprintf("NOTICE! Record %d looked like a TOC except DLL first = 0x%08X, and DLL last = 0x%08X\r\n", i, pTOCLoc->dllfirst, pTOCLoc->dlllast);   } The logic checks if dllfirst <= dlllast but look closer, the code only separated the high/low WORD from dllfirst but does not apply the same to dlllast, is that on purpose or a bug? While the TOC is created by ROMIMAGE.EXE, so let's move to ROMIMAGE. In private\winceos\coreos\nk\tools\romimage\romimage\bin.cpp    Module::s_romhdr.dllfirst  = (HIWORD(xip_mem->dll_data_bottom) << 16) | HIWORD(xip_mem->kernel_dll_bottom);   Module::s_romhdr.dlllast   = (HIWORD(xip_mem->dll_data_top) << 16)    | HIWORD(xip_mem->kernel_dll_top); It is clear now, the high word of dll first is the upper 16 bits of XIP DLL bottom and the low word is the upper 16 bits of kernel dll bottom; also, the high word of dll last is the upper 16 bits of XIP DLL top and the low word is the upper 16 bits of kernel dll top. Obviously, the correct statement should be if((DWORD)(HIWORD(pTOCLoc->dllfirst) << 16) <= (DWORD)(HIWORD(pTOCLoc->dlllast) << 16) &&    (DWORD)(LOWORD(pTOCLoc->dllfirst) << 16) <= (DWORD)(LOWORD(pTOCLoc->dlllast) << 16)) So update the code like this should fix this issue or just like the comment, it is an extra sanity check, you can just get rid of it, either way can make the code moving forward and everything worked as advertised.  "Extracting out copies of files from the nk.bin... replacing files... etc." Since the NK.BIN can be compressed, so the BinMod needs the compress.dll to decompress the data, the DLL can be found in C:\program files\microsoft platform builder\6.00\cepb\idevs\imgutils.

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• What Counts For a DBA: Simplicity

  - by Louis Davidson

  Too many computer processes do an apparently simple task in a bizarrely complex way. They remind me of this strip by one of my favorite artists: Rube Goldberg. In order to keep the boss from knowing one was late, a process is devised whereby the cuckoo clock kisses a live cuckoo bird, who then pulls a string, which triggers a hat flinging, which in turn lands on a rod that removes a typewriter cover…and so on. We rely on creating automated processes to keep on top of tasks. DBAs have a lot of tasks to perform: backups, performance tuning, data movement, system monitoring, and of course, avoiding being noticed.  Every day, there are many steps to perform to maintain the database infrastructure, including: checking physical structures, re-indexing tables where needed, backing up the databases, checking those backups, running the ETL, and preparing the daily reports and yes, all of these processes have to complete before you can call it a day, and probably before many others have started that same day. Some of these tasks are just naturally complicated on their own. Other tasks become complicated because the database architecture is excessively rigid, and we often discover during “production testing” that certain processes need to be changed because the written requirements barely resembled the actual customer requirements.   Then, with no time to change that rigid structure, we are forced to heap layer upon layer of code onto the problematic processes. Instead of a slight table change and a new index, we end up with 4 new ETL processes, 20 temp tables, 30 extra queries, and 1000 lines of SQL code.  Report writers then need to build reports and make magical numbers appear from those toxic data structures that are overly complex and probably filled with inconsistent data. What starts out as a collection of fairly simple tasks turns into a Goldbergian nightmare of daily processes that are likely to cause your dinner to be interrupted by the smartphone doing the vibration dance that signifies trouble at the mill. So what to do? Well, if it is at all possible, simplify the problem by either going into the code and refactoring the complex code to simple, or taking all of the processes and simplifying them into small, independent, easily-tested steps.  The former approach usually requires an agreement on changing underlying structures that requires countless mind-numbing meetings; while the latter can generally be done to any complex process without the same frustration or anger, though it will still leave you with lots of steps to complete, the ability to test each step independently will definitely increase the quality of the overall process (and with each step reporting status back, finding an actual problem within the process will be definitely less unpleasant.) We all know the principle behind simplifying a sequence of processes because we learned it in math classes in our early years of attending school, starting with elementary school. In my 4 years (ok, 9 years) of undergraduate work, I remember pretty much one thing from my many math classes that I apply daily to my career as a data architect, data programmer, and as an occasional indentured DBA: “show your work”. This process of showing your work was my first lesson in simplification. Each step in the process was in fact, far simpler than the entire process.  When you were working an equation that took both sides of 4 sheets of paper, showing your work was important because the teacher could see every step, judge it, and mark it accordingly.  So often I would make an error in the first few lines of a problem which meant that the rest of the work was actually moving me closer to a very wrong answer, no matter how correct the math was in the subsequent steps. Yet, when I got my grade back, I would sometimes be pleasantly surprised. I passed, yet missed every problem on the test. But why? While I got the fact that 1+1=2 wrong in every problem, the teacher could see that I was using the right process. In a computer process, the process is very similar. We take complex processes, show our work by storing intermediate values, and test each step independently. When a process has 100 steps, each step becomes a simple step that is tested and verified, such that there will be 100 places where data is stored, validated, and can be checked off as complete. If you get step 1 of 100 wrong, you can fix it and be confident (that if you did your job of testing the other steps better than the one you had to repair,) that the rest of the process works. If you have 100 steps, and store the state of the process exactly once, the resulting testable chunk of code will be far more complex and finding the error will require checking all 100 steps as one, and usually it would be easier to find a specific needle in a stack of similarly shaped needles.  The goal is to strive for simplicity either in the solution, or at least by simplifying every process down to as many, independent, testable, simple tasks as possible.  For the tasks that really can’t be done completely independently, minimally take those tasks and break them down into simpler steps that can be tested independently.  Like working out division problems longhand, have each step of the larger problem verified and tested.

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• What should you bring to the table as a Software Architect?

  - by Ahmad Mageed

  There have been many questions with good answers about the role of a Software Architect (SA) on StackOverflow and Programmers SE. I am trying to ask a slightly more focused question than those. The very definition of a SA is broad so for the sake of this question let's define a SA as follows: A Software Architect guides the overall design of a project, gets involved with coding efforts, conducts code reviews, and selects the technologies to be used. In other words, I am not talking about managerial rest and vest at the crest (further rhyming words elided) types of SAs. If I were to pursue any type of SA position I don't want to be away from coding. I might sacrifice some time to interface with clients and Business Analysts etc., but I am still technically involved and I'm not just aware of what's going on through meetings. With these points in mind, what should a SA bring to the table? Should they come in with a mentality of "laying down the law" (so to speak) and enforcing the usage of certain tools to fit "their way," i.e., coding guidelines, source control, patterns, UML documentation, etc.? Or should they specify initial direction and strategy then be laid back and jump in as needed to correct the ship's direction? Depending on the organization this might not work. An SA who relies on TFS to enforce everything may struggle to implement their plan at an employer that only uses StarTeam. Similarly, an SA needs to be flexible depending on the stage of the project. If it's a fresh project they have more choices, whereas they might have less for existing projects. Here are some SA stories I have experienced as a way of sharing some background in hopes that answers to my questions might also shed some light on these issues: I've worked with an SA who code reviewed literally every single line of code of the team. The SA would do this for not just our project but other projects in the organization (imagine the time spent on this). At first it was useful to enforce certain standards, but later it became crippling. FxCop was how the SA would find issues. Don't get me wrong, it was a good way to teach junior developers and force them to think of the consequences of their chosen approach, but for senior developers it was seen as somewhat draconian. One particular SA was against the use of a certain library, claiming it was slow. This forced us to write tons of code to achieve things differently while the other library would've saved us a lot of time. Fast forward to the last month of the project and the clients were complaining about performance. The only solution was to change certain functionality to use the originally ignored approach despite early warnings from the devs. By that point a lot of code was thrown out and not reusable, leading to overtime and stress. Sadly the estimates used for the project were based on the old approach which my project was forbidden from using so it wasn't an appropriate indicator for estimation. I would hear the PM say "we've done this before," when in reality they had not since we were using a new library and the devs working on it were not the same devs used on the old project. The SA who would enforce the usage of DTOs, DOs, BOs, Service layers and so on for all projects. New devs had to learn this architecture and the SA adamantly enforced usage guidelines. Exceptions to usage guidelines were made when it was absolutely difficult to follow the guidelines. The SA was grounded in their approach. Classes for DTOs and all CRUD operations were generated via CodeSmith and database schemas were another similar ball of wax. However, having used this setup everywhere, the SA was not open to new technologies such as LINQ to SQL or Entity Framework. I am not using this post as a platform for venting. There were positive and negative aspects to my experiences with the SA stories mentioned above. My questions boil down to: What should an SA bring to the table? How can they strike a balance in their decision making? Should one approach an SA job (as defined earlier) with the mentality that they must enforce certain ground rules? Anything else to consider? Thanks! I'm sure these job tasks are easily extended to people who are senior devs or technical leads, so feel free to answer at that capacity as well.

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• DevConnections Session Slides, Samples and Links

  - by Rick Strahl

  Finally coming up for air this week, after catching up with being on the road for the better part of three weeks. Here are my slides, samples and links for my four DevConnections Session two weeks ago in Vegas. I ended up doing one extra un-prepared for session on WebAPI and AJAX, as some of the speakers were either delayed or unable to make it at all to Vegas due to Sandy's mayhem. It was pretty hectic in the speaker room as Erik (our event coordinator extrodinaire) was scrambling to fill session slots with speakers :-). Surprisingly it didn't feel like the storm affected attendance drastically though, but I guess it's hard to tell without actual numbers. The conference was a lot of fun - it's been a while since I've been speaking at one of these larger conferences. I'd been taking a hiatus, and I forgot how much I enjoy actually giving talks. Preparing - well not  quite so much, especially since I ended up essentially preparing or completely rewriting for all three of these talks and I was stressing out a bit as I was sick the week before the conference and didn't get as much time to prepare as I wanted to. But - as always seems to be the case - it all worked out, but I guess those that attended have to be the judge of that… It was great to catch up with my speaker friends as well - man I feel out of touch. I got to spend a bunch of time with Dan Wahlin, Ward Bell, Julie Lerman and for about 10 minutes even got to catch up with the ever so busy Michele Bustamante. Lots of great technical discussions including a fun and heated REST controversy with Ward and Howard Dierking. There were also a number of great discussions with attendees, describing how they're using the technologies touched in my talks in live applications. I got some great ideas from some of these and I wish there would have been more opportunities for these kinds of discussions. One thing I miss at these Vegas events though is some sort of coherent event where attendees and speakers get to mingle. These Vegas conferences are just like "go to sessions, then go out and PARTY on the town" - it's Vegas after all! But I think that it's always nice to have at least one evening event where everybody gets to hang out together and trade stories and geek talk. Overall there didn't seem to be much opportunity for that beyond lunch or the small and short exhibit hall events which it seemed not many people actually went to. Anyways, a good time was had. I hope those of you that came to my sessions learned something useful. There were lots of great questions and discussions after the sessions - always appreciate hearing the real life scenarios that people deal with in relation to the abstracted scenarios in sessions. Here are the Session abstracts, a few comments and the links for downloading slides and  samples. It's not quite like being there, but I hope this stuff turns out to be useful to some of you. I'll be following up a couple of these sessions with white papers in the following weeks. Enjoy. ASP.NET Architecture: How ASP.NET Works at the Low Level Abstract:Interested in how ASP.NET works at a low level? ASP.NET is extremely powerful and flexible technology, but it's easy to forget about the core framework that underlies the higher level technologies like ASP.NET MVC, WebForms, WebPages, Web Services that we deal with on a day to day basis. The ASP.NET core drives all the higher level handlers and frameworks layered on top of it and with the core power comes some complexity in the form of a very rich object model that controls the flow of a request through the ASP.NET pipeline from Windows HTTP services down to the application level. To take full advantage of it, it helps to understand the underlying architecture and model. This session discusses the architecture of ASP.NET along with a number of useful tidbits that you can use for building and debugging your ASP.NET applications more efficiently. We look at overall architecture, how requests flow from the IIS (7 and later) Web Server to the ASP.NET runtime into HTTP handlers, modules and filters and finally into high-level handlers like MVC, Web Forms or Web API. Focus of this session is on the low-level aspects on the ASP.NET runtime, with examples that demonstrate the bootstrapping of ASP.NET, threading models, how Application Domains are used, startup bootstrapping, how configuration files are applied and how all of this relates to the applications you write either using low-level tools like HTTP handlers and modules or high-level pages or services sitting at the top of the ASP.NET runtime processing chain. Comments:I was surprised to see so many people show up for this session - especially since it was the last session on the last day and a short 1 hour session to boot. The room was packed and it was to see so many people interested the abstracts of architecture of ASP.NET beyond the immediate high level application needs. Lots of great questions in this talk as well - I only wish this session would have been the full hour 15 minutes as we just a little short of getting through the main material (didn't make it to Filters and Error handling). I haven't done this session in a long time and I had to pretty much re-figure all the system internals having to do with the ASP.NET bootstrapping in light for the changes that came with IIS 7 and later. The last time I did this talk was with IIS6, I guess it's been a while. I love doing this session, mainly because in my mind the core of ASP.NET overall is so cleanly designed to provide maximum flexibility without compromising performance that has clearly stood the test of time in the 10 years or so that .NET has been around. While there are a lot of moving parts, the technology is easy to manage once you understand the core components and the core model hasn't changed much even while the underlying architecture that drives has been almost completely revamped especially with the introduction of IIS 7 and later. Download Samples and Slides   Introduction to using jQuery with ASP.NET Abstract:In this session you'll learn how to take advantage of jQuery in your ASP.NET applications. Starting with an overview of jQuery client features via many short and fun examples, you'll find out about core features like the power of selectors for document element selection, manipulating these elements with jQuery's wrapped set methods in a browser independent way, how to hook up and handle events easily and generally apply concepts of unobtrusive JavaScript principles to client scripting. The second half of the session then delves into jQuery's AJAX features and several different ways how you can interact with ASP.NET on the server. You'll see examples of using ASP.NET MVC for serving HTML and JSON AJAX content, as well as using the new ASP.NET Web API to serve JSON and hypermedia content. You'll also see examples of client side templating/databinding with Handlebars and Knockout. Comments:This session was in a monster of a room and to my surprise it was nearly packed, given that this was a 100 level session. I can see that it's a good idea to continue to do intro sessions to jQuery as there appeared to be quite a number of folks who had not worked much with jQuery yet and who most likely could greatly benefit from using it. Seemed seemed to me the session got more than a few people excited to going if they hadn't yet :-).  Anyway I just love doing this session because it's mostly live coding and highly interactive - not many sessions that I can build things up from scratch and iterate on in an hour. jQuery makes that easy though. Resources: Slides and Code Samples Introduction to jQuery White Paper Introduction to ASP.NET Web API   Hosting the Razor Scripting Engine in Your Own Applications Abstract:The Razor Engine used in ASP.NET MVC and ASP.NET Web Pages is a free-standing scripting engine that can be disassociated from these Web-specific implementations and can be used in your own applications. Razor allows for a powerful mix of code and text rendering that makes it a wonderful tool for any sort of text generation, from creating HTML output in non-Web applications, to rendering mail merge-like functionality, to code generation for developer tools and even as a plug-in scripting engine. In this session, we'll look at the components that make up the Razor engine and how you can bootstrap it in your own applications to hook up templating. You'll find out how to create custom templates and manage Razor requests that can be pre-compiled, detecting page changes and act in ways similar to a full runtime. We look at ways that you can pass data into the engine and retrieve both the rendered output as well as result values in a package that makes it easy to plug Razor into your own applications. Comments:That this session was picked was a bit of a surprise to me, since it's a bit of a niche topic. Even more of a surprise was that during the session quite a few people who attended had actually used Razor externally and were there to find out more about how the process works and how to extend it. In the session I talk a bit about a custom Razor hosting implementation (Westwind.RazorHosting) and drilled into the various components required to build a custom Razor Hosting engine and a runtime around it. This sessions was a bit of a chore to prepare for as there are lots of technical implementation details that needed to be dealt with and squeezing that into an hour 15 is a bit tight (and that aren't addressed even by some of the wrapper libraries that exist). Found out though that there's quite a bit of interest in using a templating engine outside of web applications, or often side by side with the HTML output generated by frameworks like MVC or WebForms. An extra fun part of this session was that this was my first session and when I went to set up I realized I forgot my mini-DVI to VGA adapter cable to plug into the projector in my room - 6 minutes before the session was about to start. So I ended up sprinting the half a mile + back to my room - and back at a full sprint. I managed to be back only a couple of minutes late, but when I started I was out of breath for the first 10 minutes or so, while trying to talk. Musta sounded a bit funny as I was trying to not gasp too much :-) Resources: Slides and Code Samples Westwind.RazorHosting GitHub Project Original RazorHosting Blog Post   Introduction to ASP.NET Web API for AJAX Applications Abstract:WebAPI provides a new framework for creating REST based APIs, but it can also act as a backend to typical AJAX operations. This session covers the core features of Web API as it relates to typical AJAX application development. We’ll cover content-negotiation, routing and a variety of output generation options as well as managing data updates from the client in the context of a small Single Page Application style Web app. Finally we’ll look at some of the extensibility features in WebAPI to customize and extend Web API in a number and useful useful ways. Comments:This session was a fill in for session slots not filled due MIA speakers stranded by Sandy. I had samples from my previous Web API article so decided to go ahead and put together a session from it. Given that I spent only a couple of hours preparing and putting slides together I was glad it turned out as it did - kind of just ran itself by way of the examples I guess as well as nice audience interactions and questions. Lots of interest - and also some confusion about when Web API makes sense. Both this session and the jQuery session ended up getting a ton of questions about when to use Web API vs. MVC, whether it would make sense to switch to Web API for all AJAX backend work etc. In my opinion there's no need to jump to Web API for existing applications that already have a good AJAX foundation. Web API is awesome for real externally consumed APIs and clearly defined application AJAX APIs. For typical application level AJAX calls, it's still a good idea, but ASP.NET MVC can serve most if not all of that functionality just as well. There's no need to abandon MVC (or even ASP.NET AJAX or third party AJAX backends) just to move to Web API. For new projects Web API probably makes good sense for isolation of AJAX calls, but it really depends on how the application is set up. In some cases sharing business logic between the HTML and AJAX interfaces with a single MVC API can be cleaner than creating two completely separate code paths to serve essentially the same business logic. Resources: Slides and Code Samples Sample Code on GitHub Introduction to ASP.NET Web API White Paper© Rick Strahl, West Wind Technologies, 2005-2012Posted in Conferences  ASP.NET   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• SQL SERVER – What is Incremental Statistics? – Performance improvements in SQL Server 2014 – Part 1

  - by Pinal Dave

  This is the first part of the series Incremental Statistics. Here is the index of the complete series. What is Incremental Statistics? – Performance improvements in SQL Server 2014 – Part 1 Simple Example of Incremental Statistics – Performance improvements in SQL Server 2014 – Part 2 DMV to Identify Incremental Statistics – Performance improvements in SQL Server 2014 – Part 3 Statistics are considered one of the most important aspects of SQL Server Performance Tuning. You might have often heard the phrase, with related to performance tuning. “Update Statistics before you take any other steps to tune performance”. Honestly, I have said above statement many times and many times, I have personally updated statistics before I start to do any performance tuning exercise. You may agree or disagree to the point, but there is no denial that Statistics play an extremely vital role in the performance tuning. SQL Server 2014 has a new feature called Incremental Statistics. I have been playing with this feature for quite a while and I find that very interesting. After spending some time with this feature, I decided to write about this subject over here. New in SQL Server 2014 – Incremental Statistics Well, it seems like lots of people wants to start using SQL Server 2014′s new feature of Incremetnal Statistics. However, let us understand what actually this feature does and how it can help. I will try to simplify this feature first before I start working on the demo code. Code for all versions of SQL Server Here is the code which you can execute on all versions of SQL Server and it will update the statistics of your table. The keyword which you should pay attention is WITH FULLSCAN. It will scan the entire table and build brand new statistics for you which your SQL Server Performance Tuning engine can use for better estimation of your execution plan. UPDATE STATISTICS TableName(StatisticsName) WITH FULLSCAN Who should learn about this? Why? If you are using partitions in your database, you should consider about implementing this feature. Otherwise, this feature is pretty much not applicable to you. Well, if you are using single partition and your table data is in a single place, you still have to update your statistics the same way you have been doing. If you are using multiple partitions, this may be a very useful feature for you. In most cases, users have multiple partitions because they have lots of data in their table. Each partition will have data which belongs to itself. Now it is very common that each partition are populated separately in SQL Server. Real World Example For example, if your table contains data which is related to sales, you will have plenty of entries in your table. It will be a good idea to divide the partition into multiple filegroups for example, you can divide this table into 3 semesters or 4 quarters or even 12 months. Let us assume that we have divided our table into 12 different partitions. Now for the month of January, our first partition will be populated and for the month of February our second partition will be populated. Now assume, that you have plenty of the data in your first and second partition. Now the month of March has just started and your third partition has started to populate. Due to some reason, if you want to update your statistics, what will you do? In SQL Server 2012 and earlier version You will just use the code of WITH FULLSCAN and update the entire table. That means even though you have only data in third partition you will still update the entire table. This will be VERY resource intensive process as you will be updating the statistics of the partition 1 and 2 where data has not changed at all. In SQL Server 2014 You will just update the partition of Partition 3. There is a special syntax where you can now specify which partition you want to update now. The impact of this is that it is smartly merging the new data with old statistics and update the entire statistics without doing FULLSCAN of your entire table. This has a huge impact on performance. Remember that the new feature in SQL Server 2014 does not change anything besides the capability to update a single partition. However, there is one feature which is indeed attractive. Previously, when table data were changed 20% at that time, statistics update were triggered. However, now the same threshold is applicable to a single partition. That means if your partition faces 20% data, change it will also trigger partition level statistics update which, when merged to your final statistics will give you better performance. In summary If you are not using a partition, this feature is not applicable to you. If you are using a partition, this feature can be very helpful to you. Tomorrow: We will see working code of SQL Server 2014 Incremental Statistics. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: SQL Statistics, Statistics

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• WPF: Timers

  - by Ilya Verbitskiy

  I believe, once your WPF application will need to execute something periodically, and today I would like to discuss how to do that. There are two possible solutions. You can use classical System.Threading.Timer class or System.Windows.Threading.DispatcherTimer class, which is the part of WPF. I have created an application to show you how to use the API.     Let’s take a look how you can implement timer using System.Threading.Timer class. First of all, it has to be initialized.   1: private Timer timer; 2:   3: public MainWindow() 4: { 5: // Form initialization code 6: 7: timer = new Timer(OnTimer, null, Timeout.InfiniteTimeSpan, Timeout.InfiniteTimeSpan); 8: }   Timer’s constructor accepts four parameters. The first one is the callback method which is executed when timer ticks. I will show it to you soon. The second parameter is a state which is passed to the callback. It is null because there is nothing to pass this time. The third parameter is the amount of time to delay before the callback parameter invokes its methods. I use System.Threading.Timeout helper class to represent infinite timeout which simply means the timer is not going to start at the moment. And the final fourth parameter represents the time interval between invocations of the methods referenced by callback. Infinite timeout timespan means the callback method will be executed just once. Well, the timer has been created. Let’s take a look how you can start the timer.   1: private void StartTimer(object sender, RoutedEventArgs e) 2: { 3: timer.Change(TimeSpan.Zero, new TimeSpan(0, 0, 1)); 4:   5: // Disable the start buttons and enable the reset button. 6: }   The timer is started by calling its Change method. It accepts two arguments: the amount of time to delay before the invoking the callback method and the time interval between invocations of the callback. TimeSpan.Zero means we start the timer immediately and TimeSpan(0, 0, 1) tells the timer to tick every second. There is one method hasn’t been shown yet. This is the callback method OnTimer which does a simple task: it shows current time in the center of the screen. Unfortunately you cannot simple write something like this:   1: clock.Content = DateTime.Now.ToString("hh:mm:ss");   The reason is Timer runs callback method on a separate thread, and it is not possible to access GUI controls from a non-GUI thread. You can avoid the problem using System.Windows.Threading.Dispatcher class.   1: private void OnTimer(object state) 2: { 3: Dispatcher.Invoke(() => ShowTime()); 4: } 5:   6: private void ShowTime() 7: { 8: clock.Content = DateTime.Now.ToString("hh:mm:ss"); 9: }   You can build similar application using System.Windows.Threading.DispatcherTimer class. The class represents a timer which is integrated into the Dispatcher queue. It means that your callback method is executed on GUI thread and you can write a code which updates your GUI components directly.   1: private DispatcherTimer dispatcherTimer; 2:   3: public MainWindow() 4: { 5: // Form initialization code 6:   7: dispatcherTimer = new DispatcherTimer { Interval = new TimeSpan(0, 0, 1) }; 8: dispatcherTimer.Tick += OnDispatcherTimer; 9: } Dispatcher timer has nicer and cleaner API. All you need is to specify tick interval and Tick event handler. The you just call Start method to start the timer.   private void StartDispatcher(object sender, RoutedEventArgs e) { dispatcherTimer.Start(); // Disable the start buttons and enable the reset button. } And, since the Tick event handler is executed on GUI thread, the code which sets the actual time is straightforward.   1: private void OnDispatcherTimer(object sender, EventArgs e) 2: { 3: ShowTime(); 4: } We’re almost done. Let’s take a look how to stop the timers. It is easy with the Dispatcher Timer.   1: dispatcherTimer.Stop(); And slightly more complicated with the Timer. You should use Change method again.   1: timer.Change(Timeout.InfiniteTimeSpan, Timeout.InfiniteTimeSpan); What is the best way to add timer into an application? The Dispatcher Timer has simple interface, but its advantages are disadvantages at the same time. You should not use it if your Tick event handler executes time-consuming operations. It freezes your window which it is executing the event handler method. You should think about using System.Threading.Timer in this case. The code is available on GitHub.

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• Testing Entity Framework applications, pt. 3: NDbUnit

  - by Thomas Weller

  This is the third of a three part series that deals with the issue of faking test data in the context of a legacy app that was built with Microsoft's Entity Framework (EF) on top of an MS SQL Server database – a scenario that can be found very often. Please read the first part for a description of the sample application, a discussion of some general aspects of unit testing in a database context, and of some more specific aspects of the here discussed EF/MSSQL combination. Lately, I wondered how you would ‘mock’ the data layer of a legacy application, when this data layer is made up of an MS Entity Framework (EF) model in combination with a MS SQL Server database. Originally, this question came up in the context of how you could enable higher-level integration tests (automated UI tests, to be exact) for a legacy application that uses this EF/MSSQL combo as its data store mechanism – a not so uncommon scenario. The question sparked my interest, and I decided to dive into it somewhat deeper. What I've found out is, in short, that it's not very easy and straightforward to do it – but it can be done. The two strategies that are best suited to fit the bill involve using either the (commercial) Typemock Isolator tool or the (free) NDbUnit framework. The use of Typemock was discussed in the previous post, this post now will present the NDbUnit approach... NDbUnit is an Apache 2.0-licensed open-source project, and like so many other Nxxx tools and frameworks, it is basically a C#/.NET port of the corresponding Java version (DbUnit namely). In short, it helps you in flexibly managing the state of a database in that it lets you easily perform basic operations (like e.g. Insert, Delete, Refresh, DeleteAll)  against your database and, most notably, lets you feed it with data from external xml files. Let's have a look at how things can be done with the help of this framework. Preparing the test data Compared to Typemock, using NDbUnit implies a totally different approach to meet our testing needs.  So the here described testing scenario requires an instance of an SQL Server database in operation, and it also means that the Entity Framework model that sits on top of this database is completely unaffected. First things first: For its interactions with the database, NDbUnit relies on a .NET Dataset xsd file. See Step 1 of their Quick Start Guide for a description of how to create one. With this prerequisite in place then, the test fixture's setup code could look something like this: [TestFixture, TestsOn(typeof(PersonRepository))] [Metadata("NDbUnit Quickstart URL",           "http://code.google.com/p/ndbunit/wiki/QuickStartGuide")] [Description("Uses the NDbUnit library to provide test data to a local database.")] public class PersonRepositoryFixture {     #region Constants     private const string XmlSchema = @"..\..\TestData\School.xsd";     #endregion // Constants     #region Fields     private SchoolEntities _schoolContext;     private PersonRepository _personRepository;     private INDbUnitTest _database;     #endregion // Fields     #region Setup/TearDown     [FixtureSetUp]     public void FixtureSetUp()     {         var connectionString = ConfigurationManager.ConnectionStrings["School_Test"].ConnectionString;         _database = new SqlDbUnitTest(connectionString);         _database.ReadXmlSchema(XmlSchema);         var entityConnectionStringBuilder = new EntityConnectionStringBuilder         {             Metadata = "res://*/School.csdl|res://*/School.ssdl|res://*/School.msl",             Provider = "System.Data.SqlClient",             ProviderConnectionString = connectionString         };         _schoolContext = new SchoolEntities(entityConnectionStringBuilder.ConnectionString);         _personRepository = new PersonRepository(this._schoolContext);     }     [FixtureTearDown]     public void FixtureTearDown()     {         _database.PerformDbOperation(DbOperationFlag.DeleteAll);         _schoolContext.Dispose();     }     ...  As you can see, there is slightly more fixture setup code involved if your tests are using NDbUnit to provide the test data: Because we're dealing with a physical database instance here, we first need to pick up the test-specific connection string from the test assemblies' App.config, then initialize an NDbUnit helper object with this connection along with the provided xsd file, and also set up the SchoolEntities and the PersonRepository instances accordingly. The _database field (an instance of the INdUnitTest interface) will be our single access point to the underlying database: We use it to perform all the required operations against the data store. To have a flexible mechanism to easily insert data into the database, we can write a helper method like this: private void InsertTestData(params string[] dataFileNames) {     _database.PerformDbOperation(DbOperationFlag.DeleteAll);     if (dataFileNames == null)     {         return;     }     try     {         foreach (string fileName in dataFileNames)         {             if (!File.Exists(fileName))             {                 throw new FileNotFoundException(Path.GetFullPath(fileName));             }             _database.ReadXml(fileName);             _database.PerformDbOperation(DbOperationFlag.InsertIdentity);         }     }     catch     {         _database.PerformDbOperation(DbOperationFlag.DeleteAll);         throw;     } } This lets us easily insert test data from xml files, in any number and in a  controlled order (which is important because we eventually must fulfill referential constraints, or we must account for some other stuff that imposes a specific ordering on data insertion). Again, as with Typemock, I won't go into API details here. - Unfortunately, there isn't too much documentation for NDbUnit anyway, other than the already mentioned Quick Start Guide (and the source code itself, of course) - a not so uncommon problem with smaller Open Source Projects. Last not least, we need to provide the required test data in xml form. A snippet for data from the People table might look like this, for example: <?xml version="1.0" encoding="utf-8" ?> <School xmlns="http://tempuri.org/School.xsd">   <Person>     <PersonID>1</PersonID>     <LastName>Abercrombie</LastName>     <FirstName>Kim</FirstName>     <HireDate>1995-03-11T00:00:00</HireDate>   </Person>   <Person>     <PersonID>2</PersonID>     <LastName>Barzdukas</LastName>     <FirstName>Gytis</FirstName>     <EnrollmentDate>2005-09-01T00:00:00</EnrollmentDate>   </Person>   <Person>     ... You can also have data from various tables in one single xml file, if that's appropriate for you (but beware of the already mentioned ordering issues). It's true that your test assembly may end up with dozens of such xml files, each containing quite a big amount of text data. But because the files are of very low complexity, and with the help of a little bit of Copy/Paste and Excel magic, this appears to be well manageable. Executing some basic tests Here are some of the possible tests that can be written with the above preparations in place: private const string People = @"..\..\TestData\School.People.xml"; ... [Test, MultipleAsserts, TestsOn("PersonRepository.GetNameList")] public void GetNameList_ListOrdering_ReturnsTheExpectedFullNames() {     InsertTestData(People);     List<string> names =         _personRepository.GetNameList(NameOrdering.List);     Assert.Count(34, names);     Assert.AreEqual("Abercrombie, Kim", names.First());     Assert.AreEqual("Zheng, Roger", names.Last()); } [Test, MultipleAsserts, TestsOn("PersonRepository.GetNameList")] [DependsOn("RemovePerson_CalledOnce_DecreasesCountByOne")] public void GetNameList_NormalOrdering_ReturnsTheExpectedFullNames() {     InsertTestData(People);     List<string> names =         _personRepository.GetNameList(NameOrdering.Normal);     Assert.Count(34, names);     Assert.AreEqual("Alexandra Walker", names.First());     Assert.AreEqual("Yan Li", names.Last()); } [Test, TestsOn("PersonRepository.AddPerson")] public void AddPerson_CalledOnce_IncreasesCountByOne() {     InsertTestData(People);     int count = _personRepository.Count;     _personRepository.AddPerson(new Person { FirstName = "Thomas", LastName = "Weller" });     Assert.AreEqual(count + 1, _personRepository.Count); } [Test, TestsOn("PersonRepository.RemovePerson")] public void RemovePerson_CalledOnce_DecreasesCountByOne() {     InsertTestData(People);     int count = _personRepository.Count;     _personRepository.RemovePerson(new Person { PersonID = 33 });     Assert.AreEqual(count - 1, _personRepository.Count); } Not much difference here compared to the corresponding Typemock versions, except that we had to do a bit more preparational work (and also it was harder to get the required knowledge). But this picture changes quite dramatically if we look at some more demanding test cases: Ok, and what if things are becoming somewhat more complex? Tests like the above ones represent the 'easy' scenarios. They may account for the biggest portion of real-world use cases of the application, and they are important to make sure that it is generally sound. But usually, all these nasty little bugs originate from the more complex parts of our code, or they occur when something goes wrong. So, for a testing strategy to be of real practical use, it is especially important to see how easy or difficult it is to mimick a scenario which represents a more complex or exceptional case. The following test, for example, deals with the case that there is some sort of invalid input from the caller: [Test, MultipleAsserts, TestsOn("PersonRepository.GetCourseMembers")] [Row(null, typeof(ArgumentNullException))] [Row("", typeof(ArgumentException))] [Row("NotExistingCourse", typeof(ArgumentException))] public void GetCourseMembers_WithGivenVariousInvalidValues_Throws(string courseTitle, Type expectedInnerExceptionType) {     var exception = Assert.Throws<RepositoryException>(() =>                                 _personRepository.GetCourseMembers(courseTitle));     Assert.IsInstanceOfType(expectedInnerExceptionType, exception.InnerException); } Apparently, this test doesn't need an 'Arrange' part at all (see here for the same test with the Typemock tool). It acts just like any other client code, and all the required business logic comes from the database itself. This doesn't always necessarily mean that there is less complexity, but only that the complexity happens in a different part of your test resources (in the xml files namely, where you sometimes have to spend a lot of effort for carefully preparing the required test data). Another example, which relies on an underlying 1-n relationship, might be this: [Test, MultipleAsserts, TestsOn("PersonRepository.GetCourseMembers")] public void GetCourseMembers_WhenGivenAnExistingCourse_ReturnsListOfStudents() {     InsertTestData(People, Course, Department, StudentGrade);     List<Person> persons = _personRepository.GetCourseMembers("Macroeconomics");     Assert.Count(4, persons);     Assert.ForAll(         persons,         @p => new[] { 10, 11, 12, 14 }.Contains(@p.PersonID),         "Person has none of the expected IDs."); } If you compare this test to its corresponding Typemock version, you immediately see that the test itself is much simpler, easier to read, and thus much more intention-revealing. The complexity here lies hidden behind the call to the InsertTestData() helper method and the content of the used xml files with the test data. And also note that you might have to provide additional data which are not even directly relevant to your test, but are required only to fulfill some integrity needs of the underlying database. Conclusion The first thing to notice when comparing the NDbUnit approach to its Typemock counterpart obviously deals with performance: Of course, NDbUnit is much slower than Typemock. Technically,  it doesn't even make sense to compare the two tools. But practically, it may well play a role and could or could not be an issue, depending on how much tests you have of this kind, how often you run them, and what role they play in your development cycle. Also, because the dataset from the required xsd file must fully match the database schema (even in parts that otherwise wouldn't be relevant to you), it can be quite cumbersome to be in a team where different people are working with the database in parallel. My personal experience is – as already said in the first part – that Typemock gives you a better development experience in a 'dynamic' scenario (when you're working in some kind of TDD-style, you're oftentimes executing the tests from your dev box, and your database schema changes frequently), whereas the NDbUnit approach is a good and solid solution in more 'static' development scenarios (when you need to execute the tests less frequently or only on a separate build server, and/or the underlying database schema can be kept relatively stable), for example some variations of higher-level integration or User-Acceptance tests. But in any case, opening Entity Framework based applications for testing requires a fair amount of resources, planning, and preparational work – it's definitely not the kind of stuff that you would call 'easy to test'. Hopefully, future versions of EF will take testing concerns into account. Otherwise, I don't see too much of a future for the framework in the long run, even though it's quite popular at the moment... The sample solution A sample solution (VS 2010) with the code from this article series is available via my Bitbucket account from here (Bitbucket is a hosting site for Mercurial repositories. The repositories may also be accessed with the Git and Subversion SCMs - consult the documentation for details. In addition, it is possible to download the solution simply as a zipped archive – via the 'get source' button on the very right.). The solution contains some more tests against the PersonRepository class, which are not shown here. Also, it contains database scripts to create and fill the School sample database. To compile and run, the solution expects the Gallio/MbUnit framework to be installed (which is free and can be downloaded from here), the NDbUnit framework (which is also free and can be downloaded from here), and the Typemock Isolator tool (a fully functional 30day-trial is available here). Moreover, you will need an instance of the Microsoft SQL Server DBMS, and you will have to adapt the connection strings in the test projects App.config files accordingly.

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• Java2Days 2012 Trip Report

  - by reza_rahman

  Java2Days 2012 was held in beautiful Sofia, Bulgaria on October 25-26. For those of you not familiar with it, this is the third installment of the premier Java conference for the Balkan region. It is an excellent effort by admirable husband and wife team Emo Abadjiev and Iva Abadjieva as well as the rest of the Java2Days team including Yoana Ivanova and Nadia Kostova. Thanks to their hard work, the conference continues to grow vigorously with almost a thousand enthusiastic, bright young people attending this year and no less than three tracks on Java, the Cloud and Mobile. The conference is a true gem in this region of the world and I am very proud to have been a part of it again, along with the other world class speakers the event rightfully attracts. It was my honor to present the first talk of the conference. It was a full-house session on Java EE 7 and 8 titled "JavaEE.Next(): Java EE 7, 8, and Beyond". The talk was primarily along the same lines as Arun Gupta's JavaOne 2012 technical keynote. I covered the changes in JMS 2, the Java API for WebSocket (JSR 356), the Java API for JSON Processing (JSON-P), JAX-RS 2, JCache, JPA 2.1, JTA 1.2, JSF 2.2, Java Batch, Bean Validation 1.1 and the rest of the APIs in Java EE 7. I also briefly talked about the possible contents of Java EE 8. My stretch goal was to gather some feedback on some open issues in the Java EE EG (more on that soon) but I ran out of time in the short format forty-five minute session. The talk was received well and I had some pretty good discussions afterwards. The slides for the talk are here: JavaEE.Next(): Java EE 7, 8, and Beyond from reza_rahman To my delight, the Java2Days folks were very interested in my domain-driven design/Java EE 6 talk (titled "Domain Driven Design with Java EE 6"). I've had this talk in my inventory for a long time now but it always gets overridden by less theoretical talks on APIs, tools, etc. The talk has three parts -- a brief overview of DDD theory, mapping DDD to Java EE and actual running DDD code in Java EE 6/GlassFish. For the demo, I converted the well-known DDD sample application (http://dddsample.sourceforge.net/) written mostly in Spring 2 and Hibernate 2 to Java EE 6. My eventual plan is to make the code available via a top level java.net project. Even despite the broad topic and time constraints, the talk went very well. It was a full house, the Q & A was excellent and one of the other speakers even told me they thought this was the best talk of the conference! The slides for the talk are here: Domain Driven Design with Java EE 6 from Reza Rahman The code examples are available here: https://blogs.oracle.com/reza/resource/dddsample.zip for now, as a simple zip file. Give me a shout if you would like to get it up and running. It was also a great honor to present the last session of the conference. It was a talk on the Java API for WebSocket/JSR 356 titled "Building HTML5/WebSocket Applications with JSR 356 and GlassFish". The talk is based on Danny Coward's JavaOne 2012 talk. The talk covers the basic of WebSocket, the JSR 356 API and a simple demo using Tyrus/GlassFish. The talk went very well and there were some very good questions afterwards. The slides for the talk are here: Building HTML5/WebSocket Applications with GlassFish and JSR 356 from Reza Rahman The code samples are available here: https://blogs.oracle.com/arungupta/resource/totd183-HelloWebSocket.zip. You'll need the latest promoted GlassFish 4 build to run the code. Give me a shout if you need help. Besides presenting my talks, I got to attend some great sessions on OSGi, HTML5, cloud, agile and Java 8. I got an invite to speak at the Macedonia JUG when possible. Victor Grazi of InfoQ wrote about my sessions and Java2Days here: http://www.infoq.com/news/2012/11/Java2DaysConference. Stoyan Rachev was very kind to blog about my sessions here: http://www.stoyanr.com/2012/11/java2days-2012-java-ee.html. I definitely enjoyed Java2Days 2012 and hope to be part of the conference next year!

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• Introducing jLight &ndash; Talking to the DOM using Silverlight and jQuery.

  - by Timmy Kokke

  Introduction With the recent news about Silverlight on the Windows Phone and all the great Out-Of-Browser features in the upcoming Silverlight 4 you almost forget Silverlight is a browser plugin. It most often runs in a web browser and often as a control. In many cases you need to communicate with the browser to get information about textboxes, events or details about the browser itself. To do this you can use JavaScript from Silverlight. Although Silverlight works the same on every browser, JavaScript does not and it won’t be long before problems arise. To overcome differences in browser I like to use jQuery. The only downside of doing this is that there’s a lot more code needed that you would normally use when you write jQuery in JavaScript. Lately, I had to catch changes is the browser scrollbar and act to the new position. I also had to move the scrollbar when the user dragged around in the Silverlight application. With jQuery it was peanuts to get and set the right attributes, but I found that I had to write a lot of code on Silverlight side.  With a few refactoring I had a separated out the plumbing into a new class and could call only a few methods on that to get the same thing done. The idea for jLight was born. jLight vs. jQuery The main purpose of jLight is to take the ease of use of jQuery and bring it into Silverlight for handling DOM interaction. For example, to change the text color of a DIV to red, in jQuery you would write: jQuery("div").css("color","red"); In jLight the same thing looks like so: jQuery.Select("div").Css("color","red");   Another example. To change the offset in of the last SPAN you could write this in jQuery : jQuery("span:last").offset({left : 10, top : 100});   In jLight this would do the same: jQuery.Select("span:last").Offset(new {left = 10, top = 100 });   Callbacks Nothing too special so far. To get the same thing done using the “normal” HtmlPage.Window.Eval, it wouldn’t require too much effort. But to wire up a handler for events from the browser it’s a whole different story. Normally you need to register ScriptMembers, ScriptableTypes or write some code in JavaScript. jLight takes care of the plumbing and provide you with an simple interface in the same way jQuery would. If you would like to handle the scroll event of the BODY of your html page, you’ll have to bind the event using jQuery and have a function call back to a registered function in Silverlight. In the example below I assume there’s a method “SomeMethod” and it is registered as a ScriptableObject as “RegisteredFromSilverlight” from Silverlight.   jQuery("body:first").scroll(function() { var sl = document.getElementbyId("SilverlightControl"); sl.content.RegisteredFromSilverlight.SomeMethod($(this)); });       Using jLight  in Silverlight the code would be even simpler. The registration of RegisteredFromSilverlight  as ScriptableObject can be omitted.  Besides that, you don’t have to write any JavaScript or evaluate strings with JavaScript.   jQuery.Select("body:first").scroll(SomeMethod);   Lambdas Using a lambda in Silverlight can make it even simpler.  Each is the jQuery equivalent of foreach in C#. It calls a function for every element found by jQuery. In this example all INPUT elements of the text type are selected. The FromObject method is used to create a jQueryObject from an object containing a ScriptObject. The Val method from jQuery is used to get the value of the INPUT elements.   jQuery.Select("input:text").Each((element, index) => { textBox1.Text += jQueryObject.FromObject(element).Val(); return null; });   Ajax One thing jQuery is often used for is making Ajax calls. Making calls to services to external services can be done from Silverlight, but as easy as using jQuery. As an example I would like to show how jLight does this. Below is the entire code behind. It searches my name on twitter and shows the result. This example can be found in the source of the project. The GetJson method passes a Silverlight JsonValue to a callback. This callback instantiates Twit objects and adds them to a ListBox called TwitList.   public partial class DemoPage2 : UserControl { public DemoPage2() { InitializeComponent(); jQuery.Load(); }   private void CallButton_Click(object sender, RoutedEventArgs e) { jQuery.GetJson("http://search.twitter.com/search.json?lang=en&q=sorskoot", Done); }   private void Done(JsonValue arg) { var tweets = new List<Twit>(); foreach (JsonObject result in arg["results"]) { tweets.Add(new Twit() { Text = (string)result["text"], Image = (string)result["profile_image_url"], User = (string)result["from_user"] } ); } TwitList.ItemsSource = tweets; } }   public class Twit { public string User { get; set; } public string Image { get; set; } public string Text { get; set; } }   Conclusion Although jLight is still in development it can be used already.There isn’t much documentation yet, but if you know jQuery jLight isn’t very hard to use.  If you would like to try it, please let me know what you think and report any problems you run in to. jLight can be found at:   http://jlight.codeplex.com

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