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• Pure Server-Side Filtering with RadGridView and WCF RIA Services

  Those of you who are familiar with WCF RIA Services know that the DomainDataSource control provides a FilterDescriptors collection that enables you to filter data returned by the query on the server. We have been using this DomainDataSource feature in our RIA Services with DomainDataSource online example for almost an year now. In the example, we are listening for RadGridViews Filtering event in order to intercept any filtering that is performed on the client and translate it to something that the DomainDataSource will understand, in this case a System.Windows.Data.FilterDescriptor being added or removed from its FilterDescriptors collection. Think of RadGridView.FilterDescriptors as client-side filtering and of DomainDataSource.FilterDescriptors as server-side filtering. We no longer need the client-side one. With the introduction of the Custom Filtering Controls feature many new possibilities have opened. With these custom controls we no longer need to do any filtering on the client. I have prepared a very small project that demonstrates how to filter solely on the server by using a custom filtering control. As I have already mentioned filtering on the server is done through the FilterDescriptors collection of the DomainDataSource control. This collection holds instances of type System.Windows.Data.FilterDescriptor. The FilterDescriptor has three important properties: PropertyPath: Specifies the name of the property that we want to filter on (the left operand). Operator: Specifies the type of comparison to use when filtering. An instance of FilterOperator Enumeration. Value: The value to compare with (the right operand). An instance of the Parameter Class. By adding filters, you can specify that only entities which meet the condition in the filter are loaded from the domain context. In case you are not familiar with these concepts you might find Brad Abrams blog interesting. Now, our requirements are to create some kind of UI that will manipulate the DomainDataSource.FilterDescriptors collection. When it comes to collections, my first choice of course would be RadGridView. If you are not familiar with the Custom Filtering Controls concept I would strongly recommend getting acquainted with my step-by-step tutorial Custom Filtering with RadGridView for Silverlight and checking the online example out. I have created a simple custom filtering control that contains a RadGridView and several buttons. This control is aware of the DomainDataSource instance, since it is operating on its FilterDescriptors collection. In fact, the RadGridView that is inside it is bound to this collection. In order to display filters that are relevant for the current column only, I have applied a filter to the grid. This filter is a Telerik.Windows.Data.FilterDescriptor and is used to filter the little grid inside the custom control. It should not be confused with the DomainDataSource.FilterDescriptors collection that RadGridView is actually bound to. These are the RIA filters. Additionally, I have added several other features. For example, if you have specified a DataFormatString on your original column, the Value column inside the custom control will pick it up and format the filter values accordingly. Also, I have transferred the data type of the column that you are filtering to the Value column of the custom control. This will help the little RadGridView determine what kind of editor to show up when you begin edit, for example a date picker for DateTime columns. Finally, I have added four buttons two of them can be used to add or remove filters and the other two will communicate the changes you have made to the server. Here is the full source code of the DomainDataSourceFilteringControl. The XAML: <UserControl x:Class="PureServerSideFiltering.DomainDataSourceFilteringControl"    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"     xmlns:telerikGrid="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.GridView"     xmlns:telerik="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls"     Width="300">     <Border x:Name="LayoutRoot"             BorderThickness="1"             BorderBrush="#FF8A929E"             Padding="5"             Background="#FFDFE2E5">           <Grid>             <Grid.RowDefinitions>                 <RowDefinition Height="Auto"/>                 <RowDefinition Height="150"/>                 <RowDefinition Height="Auto"/>             </Grid.RowDefinitions>               <StackPanel Grid.Row="0"                         Margin="2"                         Orientation="Horizontal"                         HorizontalAlignment="Center">                 <telerik:RadButton Name="addFilterButton"                                   Click="OnAddFilterButtonClick"                                   Content="Add Filter"                                   Margin="2"                                   Width="96"/>                 <telerik:RadButton Name="removeFilterButton"                                   Click="OnRemoveFilterButtonClick"                                   Content="Remove Filter"                                   Margin="2"                                   Width="96"/>             </StackPanel>               <telerikGrid:RadGridView Name="filtersGrid"                                     Grid.Row="1"                                     Margin="2"                                     ItemsSource="{Binding FilterDescriptors}"                                     AddingNewDataItem="OnFilterGridAddingNewDataItem"                                     ColumnWidth="*"                                     ShowGroupPanel="False"                                     AutoGenerateColumns="False"                                     CanUserResizeColumns="False"                                     CanUserReorderColumns="False"                                     CanUserFreezeColumns="False"                                     RowIndicatorVisibility="Collapsed"                                     IsFilteringAllowed="False"                                     CanUserSortColumns="False">                 <telerikGrid:RadGridView.Columns>                     <telerikGrid:GridViewComboBoxColumn DataMemberBinding="{Binding Operator}"                                                         UniqueName="Operator"/>                     <telerikGrid:GridViewDataColumn Header="Value"                                                     DataMemberBinding="{Binding Value.Value}"                                                     UniqueName="Value"/>                 </telerikGrid:RadGridView.Columns>             </telerikGrid:RadGridView>               <StackPanel Grid.Row="2"                         Margin="2"                         Orientation="Horizontal"                         HorizontalAlignment="Center">                 <telerik:RadButton Name="filterButton"                                   Click="OnApplyFiltersButtonClick"                                   Content="Apply Filters"                                   Margin="2"                                   Width="96"/>                 <telerik:RadButton Name="clearButton"                                   Click="OnClearFiltersButtonClick"                                   Content="Clear Filters"                                   Margin="2"                                   Width="96"/>             </StackPanel>           </Grid>       </Border> </UserControl>   And the code-behind: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Windows; using System.Windows.Controls; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Animation; using System.Windows.Shapes; using Telerik.Windows.Controls.GridView; using System.Windows.Data; using Telerik.Windows.Controls; using Telerik.Windows.Data;   namespace PureServerSideFiltering {     /// <summary>     /// A custom filtering control capable of filtering purely server-side.     /// </summary>     public partial class DomainDataSourceFilteringControl : UserControl, IFilteringControl     {         // The main player here.         DomainDataSource domainDataSource;           // This is the name of the property that this column displays.         private string dataMemberName;           // This is the type of the property that this column displays.         private Type dataMemberType;           /// <summary>         /// Identifies the <see cref="IsActive"/> dependency property.         /// </summary>         /// <remarks>         /// The state of the filtering funnel (i.e. full or empty) is bound to this property.         /// </remarks>         public static readonly DependencyProperty IsActiveProperty =             DependencyProperty.Register(                 "IsActive",                 typeof(bool),                 typeof(DomainDataSourceFilteringControl),                 new PropertyMetadata(false));           /// <summary>         /// Gets or sets a value indicating whether the filtering is active.         /// </summary>         /// <remarks>         /// Set this to true if you want to lit-up the filtering funnel.         /// </remarks>         public bool IsActive         {             get { return (bool)GetValue(IsActiveProperty); }             set { SetValue(IsActiveProperty, value); }         }           /// <summary>         /// Gets or sets the domain data source.         /// We need this in order to work on its FilterDescriptors collection.         /// </summary>         /// <value>The domain data source.</value>         public DomainDataSource DomainDataSource         {             get { return this.domainDataSource; }             set { this.domainDataSource = value; }         }           public System.Windows.Data.FilterDescriptorCollection FilterDescriptors         {             get { return this.DomainDataSource.FilterDescriptors; }         }           public DomainDataSourceFilteringControl()         {             InitializeComponent();         }           public void Prepare(GridViewBoundColumnBase column)         {             this.LayoutRoot.DataContext = this;               if (this.DomainDataSource == null)             {                 // Sorry, but we need a DomainDataSource. Can't do anything without it.                 return;             }               // This is the name of the property that this column displays.             this.dataMemberName = column.GetDataMemberName();               // This is the type of the property that this column displays.             // We need this in order to see which FilterOperators to feed to the combo-box column.             this.dataMemberType = column.DataType;               // We will use our magic Type extension method to see which operators are applicable for             // this data type. You can go to the extension method body and see what it does.             ((GridViewComboBoxColumn)this.filtersGrid.Columns["Operator"]).ItemsSource                 = this.dataMemberType.ApplicableFilterOperators();               // This is very nice as well. We will tell the Value column its data type. In this way             // RadGridView will pick up the best editor according to the data type. For example,             // if the data type of the value is DateTime, you will be editing it with a DatePicker.             // Nice!             ((GridViewDataColumn)this.filtersGrid.Columns["Value"]).DataType = this.dataMemberType;               // Yet another nice feature. We will transfer the original DataFormatString (if any) to             // the Value column. In this way if you have specified a DataFormatString for the original             // column, you will see all filter values formatted accordingly.             ((GridViewDataColumn)this.filtersGrid.Columns["Value"]).DataFormatString = column.DataFormatString;               // This is important. Since our little filtersGrid will be bound to the entire collection             // of this.domainDataSource.FilterDescriptors, we need to set a Telerik filter on the             // grid so that it will display FilterDescriptor which are relevane to this column ONLY!             Telerik.Windows.Data.FilterDescriptor columnFilter = new Telerik.Windows.Data.FilterDescriptor("PropertyPath"                 , Telerik.Windows.Data.FilterOperator.IsEqualTo                 , this.dataMemberName);             this.filtersGrid.FilterDescriptors.Add(columnFilter);               // We want to listen for this in order to activate and de-activate the UI funnel.             this.filtersGrid.Items.CollectionChanged += this.OnFilterGridItemsCollectionChanged;         }           /// <summary>         // Since the DomainDataSource is a little bit picky about adding uninitialized FilterDescriptors         // to its collection, we will prepare each new instance with some default values and then         // the user can change them later. Go to the event handler to see how we do this.         /// </summary>         void OnFilterGridAddingNewDataItem(object sender, GridViewAddingNewEventArgs e)         {             // We need to initialize the new instance with some values and let the user go on from here.             System.Windows.Data.FilterDescriptor newFilter = new System.Windows.Data.FilterDescriptor();               // This is a must. It should know what member it is filtering on.             newFilter.PropertyPath = this.dataMemberName;               // Initialize it with one of the allowed operators.             // TypeExtensions.ApplicableFilterOperators method for more info.             newFilter.Operator = this.dataMemberType.ApplicableFilterOperators().First();               if (this.dataMemberType == typeof(DateTime))             {                 newFilter.Value.Value = DateTime.Now;             }             else if (this.dataMemberType == typeof(string))             {                 newFilter.Value.Value = "<enter text>";             }             else if (this.dataMemberType.IsValueType)             {                 // We need something non-null for all value types.                 newFilter.Value.Value = Activator.CreateInstance(this.dataMemberType);             }               // Let the user edit the new filter any way he/she likes.             e.NewObject = newFilter;         }           void OnFilterGridItemsCollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)         {             // We are active only if we have any filters define. In this case the filtering funnel will lit-up.             this.IsActive = this.filtersGrid.Items.Count > 0;         }           private void OnApplyFiltersButtonClick(object sender, RoutedEventArgs e)         {             if (this.DomainDataSource.IsLoadingData)             {                 return;             }               // Comment this if you want the popup to stay open after the button is clicked.             this.ClosePopup();               // Since this.domainDataSource.AutoLoad is false, this will take into             // account all filtering changes that the user has made since the last             // Load() and pull the new data to the client.             this.DomainDataSource.Load();         }           private void OnClearFiltersButtonClick(object sender, RoutedEventArgs e)         {             if (this.DomainDataSource.IsLoadingData)             {                 return;             }               // We want to remove ONLY those filters from the DomainDataSource             // that this control is responsible for.             this.DomainDataSource.FilterDescriptors                 .Where(fd => fd.PropertyPath == this.dataMemberName) // Only "our" filters.                 .ToList()                 .ForEach(fd => this.DomainDataSource.FilterDescriptors.Remove(fd)); // Bye-bye!               // Comment this if you want the popup to stay open after the button is clicked.             this.ClosePopup();               // After we did our housekeeping, get the new data to the client.             this.DomainDataSource.Load();         }           private void OnAddFilterButtonClick(object sender, RoutedEventArgs e)         {             if (this.DomainDataSource.IsLoadingData)             {                 return;             }               // Let the user enter his/or her requirements for a new filter.             this.filtersGrid.BeginInsert();             this.filtersGrid.UpdateLayout();         }           private void OnRemoveFilterButtonClick(object sender, RoutedEventArgs e)         {             if (this.DomainDataSource.IsLoadingData)             {                 return;             }               // Find the currently selected filter and destroy it.             System.Windows.Data.FilterDescriptor filterToRemove = this.filtersGrid.SelectedItem as System.Windows.Data.FilterDescriptor;             if (filterToRemove != null                 && this.DomainDataSource.FilterDescriptors.Contains(filterToRemove))             {                 this.DomainDataSource.FilterDescriptors.Remove(filterToRemove);             }         }           private void ClosePopup()         {             System.Windows.Controls.Primitives.Popup popup = this.ParentOfType<System.Windows.Controls.Primitives.Popup>();             if (popup != null)             {                 popup.IsOpen = false;             }         }     } }   Finally, we need to tell RadGridViews Columns to use this custom control instead of the default one. Here is how to do it: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Windows; using System.Windows.Controls; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Animation; using System.Windows.Shapes; using System.Windows.Data; using Telerik.Windows.Data; using Telerik.Windows.Controls; using Telerik.Windows.Controls.GridView;   namespace PureServerSideFiltering {     public partial class MainPage : UserControl     {         public MainPage()         {             InitializeComponent();             this.grid.AutoGeneratingColumn += this.OnGridAutoGeneratingColumn;               // Uncomment this if you want the DomainDataSource to start pre-filtered.             // You will notice how our custom filtering controls will correctly read this information,             // populate their UI with the respective filters and lit-up the funnel to indicate that             // filtering is active. Go ahead and try it.             this.employeesDataSource.FilterDescriptors.Add(new System.Windows.Data.FilterDescriptor("Title", System.Windows.Data.FilterOperator.Contains, "Assistant"));             this.employeesDataSource.FilterDescriptors.Add(new System.Windows.Data.FilterDescriptor("HireDate", System.Windows.Data.FilterOperator.IsGreaterThan, new DateTime(1998, 12, 31)));             this.employeesDataSource.FilterDescriptors.Add(new System.Windows.Data.FilterDescriptor("HireDate", System.Windows.Data.FilterOperator.IsLessThanOrEqualTo, new DateTime(1999, 12, 31)));               this.employeesDataSource.Load();         }           /// <summary>         /// First of all, we will need to replace the default filtering control         /// of each column with out custom filtering control DomainDataSourceFilteringControl         /// </summary>         private void OnGridAutoGeneratingColumn(object sender, GridViewAutoGeneratingColumnEventArgs e)         {             GridViewBoundColumnBase dataColumn = e.Column as GridViewBoundColumnBase;             if (dataColumn != null)             {                 // We do not like ugly dates.                 if (dataColumn.DataType == typeof(DateTime))                 {                     dataColumn.DataFormatString = "{0:d}"; // Short date pattern.                       // Notice how this format will be later transferred to the Value column                     // of the grid that we have inside the DomainDataSourceFilteringControl.                 }                   // Replace the default filtering control with our.                 dataColumn.FilteringControl = new DomainDataSourceFilteringControl()                 {                     // Let the control know about the DDS, after all it will work directly on it.                     DomainDataSource = this.employeesDataSource                 };                   // Finally, lit-up the filtering funnel through the IsActive dependency property                 // in case there are some filters on the DDS that match our column member.                 string dataMemberName = dataColumn.GetDataMemberName();                 dataColumn.FilteringControl.IsActive =                     this.employeesDataSource.FilterDescriptors                     .Where(fd => fd.PropertyPath == dataMemberName)                     .Count() > 0;             }         }     } } The best part is that we are not only writing filters for the DomainDataSource we can read and load them. If the DomainDataSource has some pre-existing filters (like I have created in the code above), our control will read them and will populate its UI accordingly. Even the filtering funnel will light-up! Remember, the funnel is controlled by the IsActive property of our control. While this is just a basic implementation, the source code is absolutely yours and you can take it from here and extend it to match your specific business requirements. Below the main grid there is another debug grid. With its help you can monitor what filter descriptors are added and removed to the domain data source. Download Source Code. (You will have to have the AdventureWorks sample database installed on the default SQLExpress instance in order to run it.) Enjoy!Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Commercial Drupal Modules & Themes

  - by Ravish

  A discussion at Drupal.org forums prompted me to give my input about commercial ecosystem around Open Source Content Management Systems. WordPress and Joomla have been growing rapidly since past few years. But, growth rate of Drupal seems to be almost flat. Despite being the most powerful CMS around, Drupal is still not being adopted by masses. Many people will argue that Drupal is not targeted towards masses, but developers. I agree, Drupal is more of a development platform than a consumer CMS. Drupal is ‘many things to many people’, and I can build almost any type of website with it. Drupal is being used for building blogs, corporate websites, Intranet portals, social networking and even a project management system. Looking at the wide array of Drupal implementations, it deserves to be the most widely adopted CMS. I believe there are few challenges that Drupal community needs to overcome. To understand these challenges, I surveyed some webmasters who use Joomla or WordPress but not Drupal. I asked them why they don’t want to use Drupal, following are the responses I got from them: Drupal is too complicated, takes time to learn. Drupal is great, but its admin panel is overwhelming. I couldn’t find any nice themes for Drupal. There is no WYSIWYG editor in Drupal. Most Drupal modules do not work out of the box. There aren’t enough modules like Ubercart which provides any out of the box functionality. I tried modules like CCK, Views and Panels. After wasting several hours struggling with them, I decided to give up on Drupal. I don’t use Drupal because of pushbutton and Garland theme. I had hard time trying to customize Garland and it messed up the whole layout. There are no premium modules and themes for Drupal. Joomla has tons of awesome themes and modules. I don’t want a million hacks like CCK, Views, Tokens, Pathauto, ImageCache and CTools just to run a simple website. Most of the complaints from users are related to the learning and development curve involved with Drupal, and the lack of ecosystem. While most of the problems will be gone in Drupal 7, ecosystem is something that needs to be built by the Drupal community. Drupal distributions are a great step forward. There are few awesome Drupal distributions available like Open Publish, Open Atrium and Drupal Commons. I predict, there will be a wave of many powerful Drupal distributions after Drupal 7 release. Many of them will be user-friendly and commercial supported. Following is my post at Drupal.org forums: Quote from: http://drupal.org/node/863776#comment-3313836 Brian Gardner (StudioPress) and Woo Themes launched premium WordPress themes in 2007, the developer community did not accept it at first. Moreover, they were not even GPL licensed. There was an outcry in WordPress community against them. Following that, most premium theme providers switched to GPL licensing. Despite controversies, users voted for premium theme and plugins by buying them. Inspired by their success, hundreds of other developers started to sell premium themes and plugins. It is now the acceptable and in fact most popular business model among WordPress community. Matt Mullenweg once told me, they would not support premium themes. If he supported, developers would no more give out free GPL themes & plugins. He pointed me towards Joomla, there were hardly any nice free themes & modules available. Now two years forward, premium products are not just accepted but embraced by the WordPress community – http://wordpress.org/extend/themes/commercial/ The quality and number of themes & modules has increased, even the free ones. This also helped to boost the adoption and ecosystem of WordPress. Today, state of Drupal is like WordPress was in 2007. There are hardly any out of the box solutions available for Drupal. Ubercart, Open Publish and Open Atrium are the only ones I can think of. Many of the popular Drupal modules are patches and hole-fillers. Thankfully, these hole-filler modules are going to be in Drupal 7 core. Drupal 7 and distributions will spawn a new array of solutions built upon Drupal. Soon, we will have more like Ubercarts and Open Atriums. If commercial solutions can help fuel this ecosystem and growth, Drupal community will accept them eventually. This debate will not stop your customers from buying your product. If your product is awesome, they will vote for you by buying your product.

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• Book Review Charlene Li's New Book: Open Leadership

  - by david.talamelli

  A few weeks ago, I was surprised when I looked in our mail box. I had received an Advance Copy of Charlene Li's new book titled "Open Leadership: How Social Technology Can Transform the Way You Lead". Charlene sent a tweet a while back asking anyone interested in receiving the book to submit their details. I sent off my details and didn't think I would hear anything back, so it was a pleasant surprise. With that I almost feel bad that it has taken me 3 weeks to read her book. It took this long mainly because it has been hard to fit in some quality reading time for myself with work, the kids, volunteering, etc..... I am happy to report I have finished her book and wanted to run through my initial thoughts with you. I first came across Charlene Li after reading her book "Groundswell" a few years ago, her latest book "Open Leadership" is a follow on from Groundswell and to me it seems like a natural progression from the question "Ok the business landscape is changing, what do we do now?" For me these two books have a different writing style to them. Groundswell from memory spoke about broad social media concepts and adoption and alerted us to some of the changes taking place in the SM landscape. Open Leadership seems to be focussed on taking those broad concepts and finding ways to implement them into your environment. That is breaking broad concepts down into individual action items that can be measured and analysed. As the business world changes Leaders must change their approach and let go of control to more control. One of the things I love reading about is seeing real life examples of how people and organisations are making these things happen. In this book Charlene has collected some great collateral and case studies from companies such as Cisco, Best Buy, The Red Cross and The State Bank of India (as a side-note, I wish now that I submitted my input for the Leaders I work with here at Oracle - there are some great examples here of people who empower their staff). As society becomes more adept at using social media it is inevitable that Leaders must become open with their employees, clients and partners. From the book some of the key points I took away are (I actually took away a lot more from this book, this is just an overview) : 1) Organisations should encourage risk taking. Without being a "hacker", how can we improve ourselves, our processes, our business, etc... The old saying you only fail by not trying applies here. If Leaders create a culture where people are afraid to stick their neck out - how will you innovate? 2) Leaders need to lead by example - if you want to promote an open and transparent business, a Leader needs to exemplify the traits they would like to see out of their employees. 3) The definition of a Leader is changing, open leadership is about being a catalyst to change that uses networks to spread a vision as opposed to traditional leadership that is viewed as a role. 4) There is a cultural and business shift taking place. Information is more wide-spread and is being disseminated faster than any other time in the past. Leaders who are open and transparent will thrive in this new business environment. 5) Leadership is not defined by a title - it is defined by a person's actions. Also anyone can be a Leader or has Leadership potential in them- it is a matter of drawing that out of people. I found this book useful and I also found myself looking at my own actions and the actions of others around me (including my management) to see how open and transparent I am in my work. For me I am glad I read this book as it validated my own thoughts of the changes we are seeing take place. This book has certainly given me some new ideas and helped me push my own boundaries of what I can do. The book has a number of action plans at the end of some of the chapters such as "Conducting you Openness Audit" that I think have helped me take thoughts and ideas and turn them into concrete action items. I have included a link to the introduction of the book here if anyone wants to have a read of it. If anyone else has read this book, it would be great to hear your thoughts/comments/review. Leave your comments below. This article was originally posted on David Talamelli's Blog - David's Journal on Tap

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• Your thoughts on Best Practices for Scientific Computing?

  - by John Smith

  A recent paper by Wilson et al (2014) pointed out 24 Best Practices for scientific programming. It's worth to have a look. I would like to hear opinions about these points from experienced programmers in scientific data analysis. Do you think these advices are helpful and practical? Or are they good only in an ideal world? Wilson G, Aruliah DA, Brown CT, Chue Hong NP, Davis M, Guy RT, Haddock SHD, Huff KD, Mitchell IM, Plumbley MD, Waugh B, White EP, Wilson P (2014) Best Practices for Scientific Computing. PLoS Biol 12:e1001745. http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1001745 Box 1. Summary of Best Practices Write programs for people, not computers. (a) A program should not require its readers to hold more than a handful of facts in memory at once. (b) Make names consistent, distinctive, and meaningful. (c) Make code style and formatting consistent. Let the computer do the work. (a) Make the computer repeat tasks. (b) Save recent commands in a file for re-use. (c) Use a build tool to automate workflows. Make incremental changes. (a) Work in small steps with frequent feedback and course correction. (b) Use a version control system. (c) Put everything that has been created manually in version control. Don’t repeat yourself (or others). (a) Every piece of data must have a single authoritative representation in the system. (b) Modularize code rather than copying and pasting. (c) Re-use code instead of rewriting it. Plan for mistakes. (a) Add assertions to programs to check their operation. (b) Use an off-the-shelf unit testing library. (c) Turn bugs into test cases. (d) Use a symbolic debugger. Optimize software only after it works correctly. (a) Use a profiler to identify bottlenecks. (b) Write code in the highest-level language possible. Document design and purpose, not mechanics. (a) Document interfaces and reasons, not implementations. (b) Refactor code in preference to explaining how it works. (c) Embed the documentation for a piece of software in that software. Collaborate. (a) Use pre-merge code reviews. (b) Use pair programming when bringing someone new up to speed and when tackling particularly tricky problems. (c) Use an issue tracking tool. I'm relatively new to serious programming for scientific data analysis. When I tried to write code for pilot analyses of some of my data last year, I encountered tremendous amount of bugs both in my code and data. Bugs and errors had been around me all the time, but this time it was somewhat overwhelming. I managed to crunch the numbers at last, but I thought I couldn't put up with this mess any longer. Some actions must be taken. Without a sophisticated guide like the article above, I started to adopt "defensive style" of programming since then. A book titled "The Art of Readable Code" helped me a lot. I deployed meticulous input validations or assertions for every function, renamed a lot of variables and functions for better readability, and extracted many subroutines as reusable functions. Recently, I introduced Git and SourceTree for version control. At the moment, because my co-workers are much more reluctant about these issues, the collaboration practices (8a,b,c) have not been introduced. Actually, as the authors admitted, because all of these practices take some amount of time and effort to introduce, it may be generally hard to persuade your reluctant collaborators to comply them. I think I'm asking your opinions because I still suffer from many bugs despite all my effort on many of these practices. Bug fix may be, or should be, faster than before, but I couldn't really measure the improvement. Moreover, much of my time has been invested on defence, meaning that I haven't actually done much data analysis (offence) these days. Where is the point I should stop at in terms of productivity? I've already deployed: 1a,b,c, 2a, 3a,b,c, 4b,c, 5a,d, 6a,b, 7a,7b I'm about to have a go at: 5b,c Not yet: 2b,c, 4a, 7c, 8a,b,c (I could not really see the advantage of using GNU make (2c) for my purpose. Could anyone tell me how it helps my work with MATLAB?)

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• C# 4.0: Named And Optional Arguments

  - by Paulo Morgado

  As part of the co-evolution effort of C# and Visual Basic, C# 4.0 introduces Named and Optional Arguments. First of all, let’s clarify what are arguments and parameters: Method definition parameters are the input variables of the method. Method call arguments are the values provided to the method parameters. In fact, the C# Language Specification states the following on §7.5: The argument list (§7.5.1) of a function member invocation provides actual values or variable references for the parameters of the function member. Given the above definitions, we can state that: Parameters have always been named and still are. Parameters have never been optional and still aren’t. Named Arguments Until now, the way the C# compiler matched method call definition arguments with method parameters was by position. The first argument provides the value for the first parameter, the second argument provides the value for the second parameter, and so on and so on, regardless of the name of the parameters. If a parameter was missing a corresponding argument to provide its value, the compiler would emit a compilation error. For this call: Greeting("Mr.", "Morgado", 42); this method: public void Greeting(string title, string name, int age) will receive as parameters: title: “Mr.” name: “Morgado” age: 42 What this new feature allows is to use the names of the parameters to identify the corresponding arguments in the form: name:value Not all arguments in the argument list must be named. However, all named arguments must be at the end of the argument list. The matching between arguments (and the evaluation of its value) and parameters will be done first by name for the named arguments and than by position for the unnamed arguments. This means that, for this method definition: public static void Method(int first, int second, int third) this call declaration: int i = 0; Method(i, third: i++, second: ++i); will have this code generated by the compiler: int i = 0; int CS$0$0000 = i++; int CS$0$0001 = ++i; Method(i, CS$0$0001, CS$0$0000); which will give the method the following parameter values: first: 2 second: 2 third: 0 Notice the variable names. Although invalid being invalid C# identifiers, they are valid .NET identifiers and thus avoiding collision between user written and compiler generated code. Besides allowing to re-order of the argument list, this feature is very useful for auto-documenting the code, for example, when the argument list is very long or not clear, from the call site, what the arguments are. Optional Arguments Parameters can now have default values: public static void Method(int first, int second = 2, int third = 3) Parameters with default values must be the last in the parameter list and its value is used as the value of the parameter if the corresponding argument is missing from the method call declaration. For this call declaration: int i = 0; Method(i, third: ++i); will have this code generated by the compiler: int i = 0; int CS$0$0000 = ++i; Method(i, 2, CS$0$0000); which will give the method the following parameter values: first: 1 second: 2 third: 1 Because, when method parameters have default values, arguments can be omitted from the call declaration, this might seem like method overloading or a good replacement for it, but it isn’t. Although methods like this: public static StreamReader OpenTextFile( string path, Encoding encoding = null, bool detectEncoding = true, int bufferSize = 1024) allow to have its calls written like this: OpenTextFile("foo.txt", Encoding.UTF8); OpenTextFile("foo.txt", Encoding.UTF8, bufferSize: 4096); OpenTextFile( bufferSize: 4096, path: "foo.txt", detectEncoding: false); The complier handles default values like constant fields taking the value and useing it instead of a reference to the value. So, like with constant fields, methods with parameters with default values are exposed publicly (and remember that internal members might be publicly accessible – InternalsVisibleToAttribute). If such methods are publicly accessible and used by another assembly, those values will be hard coded in the calling code and, if the called assembly has its default values changed, they won’t be assumed by already compiled code. At the first glance, I though that using optional arguments for “bad” written code was great, but the ability to write code like that was just pure evil. But than I realized that, since I use private constant fields, it’s OK to use default parameter values on privately accessed methods.

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• Troubleshooting Application Timeouts in SQL Server

  - by Tara Kizer

  I recently received the following email from a blog reader: "We are having an OLTP database instance, using SQL Server 2005 with little to moderate traffic (10-20 requests/min). There are also bulk imports that occur at regular intervals in this DB and the import duration ranges between 10secs to 1 min, depending on the data size. Intermittently (2-3 times in a week), we face an issue, where queries get timed out (default of 30 secs set in application). On analyzing, we found two stored procedures, having queries with multiple table joins inside them of taking a long time (5-10 mins) in getting executed, when ideally the execution duration ranges between 5-10 secs. Execution plan of the same displayed Clustered Index Scan happening instead of Clustered Index Seek. All required Indexes are found to be present and Index fragmentation is also minimal as we Rebuild Indexes regularly alongwith Updating Statistics. With no other alternate options occuring to us, we restarted SQL server and thereafter the performance was back on track. But sometimes it was still giving timeout errors for some hits and so we also restarted IIS and that stopped the problem as of now." Rather than respond directly to the blog reader, I thought it would be more interesting to share my thoughts on this issue in a blog. There are a few things that I can think of that could cause abnormal timeouts: Blocking Bad plan in cache Outdated statistics Hardware bottleneck To determine if blocking is the issue, we can easily run sp_who/sp_who2 or a query directly on sysprocesses (select * from master..sysprocesses where blocking <> 0).  If blocking is present and consistent, then you'll need to determine whether or not to kill the parent blocking process.  Killing a process will cause the transaction to rollback, so you need to proceed with caution.  Killing the parent blocking process is only a temporary solution, so you'll need to do more thorough analysis to figure out why the blocking was present.  You should look into missing indexes and perhaps consider changing the database's isolation level to READ_COMMITTED_SNAPSHOT. The blog reader mentions that the execution plan shows a clustered index scan when a clustered index seek is normal for the stored procedure.  A clustered index scan might have been chosen either because that is what is in cache already or because of out of date statistics.  The blog reader mentions that bulk imports occur at regular intervals, so outdated statistics is definitely something that could cause this issue.  The blog reader may need to update statistics after imports are done if the imports are changing a lot of data (greater than 10%).  If the statistics are good, then the query optimizer might have chosen to scan rather than seek in a previous execution because the scan was determined to be less costly due to the value of an input parameter.  If this parameter value is rare, then its execution plan in cache is what we call a bad plan.  You want the best plan in cache for the most frequent parameter values.  If a bad plan is a recurring problem on your system, then you should consider rewriting the stored procedure.  You might want to break up the code into multiple stored procedures so that each can have a different execution plan in cache. To remove a bad plan from cache, you can recompile the stored procedure.  An alternative method is to run DBCC FREEPROCACHE which drops the procedure cache.  It is better to recompile stored procedures rather than dropping the procedure cache as dropping the procedure cache affects all plans in cache rather than just the ones that were bad, so there will be a temporary performance penalty until the plans are loaded into cache again. To determine if there is a hardware bottleneck occurring such as slow I/O or high CPU utilization, you will need to run Performance Monitor on the database server.  Hopefully you already have a baseline of the server so you know what is normal and what is not.  Be on the lookout for I/O requests taking longer than 12 milliseconds and CPU utilization over 90%.  The servers that I support typically are under 30% CPU utilization, but your baseline could be higher and be within a normal range. If restarting the SQL Server service fixes the problem, then the problem was most likely due to blocking or a bad plan in the procedure cache.  Rather than restarting the SQL Server service, which causes downtime, the blog reader should instead analyze the above mentioned things.  Proceed with caution when restarting the SQL Server service as all transactions that have not completed will be rolled back at startup.  This crash recovery process could take longer than normal if there was a long-running transaction running when the service was stopped.  Until the crash recovery process is completed on the database, it is unavailable to your applications. If restarting IIS fixes the problem, then the problem might not have been inside SQL Server.  Prior to taking this step, you should do analysis of the above mentioned things. If you can think of other reasons why the blog reader is facing this issue a few times a week, I'd love to hear your thoughts via a blog comment.

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• Cant correctly install Lazarus

  - by user206316

  I have a little problem with installing and running Lazarus. I just upgrade ubuntu from 13.04 to 13.10. When i had 13.04, i could install lazarus without any problems, but in 13.10 lazarus magicaly dissapeared, and when i tried install it from ubuntu software center, it said something like in my software resources lazarus-ide-0.9.30.4 doesnt exist. After some research on net i tried delete all files from earlier installations, download deb packages from sourceforge and install them, but when i want to instal fpc-src, error shows up with output: (Reading database ... 100% (Reading database ... 239063 files and directories currently installed.) Unpacking fpc-src (from .../Stiahnut/Lazarus/fpc-src.deb) ... dpkg: error processing /home/richi/Stiahnut/Lazarus/fpc-src.deb (--install): trying to overwrite '/usr/share/fpcsrc/2.6.2/rtl/nativent/tthread.inc', which is also in package fpc-source-2.6.2 2.6.2-5 dpkg-deb (subprocess): decompressing archive member: internal gzip write error: Broken pipe dpkg-deb: error: subprocess <decompress> returned error exit status 2 dpkg-deb (subprocess): cannot copy archive member from '/home/richi/Stiahnut/Lazarus/fpc-src.deb' to decompressor pipe: failed to write (Broken pipe) when i started lazarus, it of course tell me that it cant find fpc compier and fpc sources. So, please, i really need program for school and i dont wanna reinstall os anymore or something like that :( (Ubuntu 13.10 64bit) P.S: im not skilled in linux so if u know some commands to fix it just write them for copy and paste :) P.P.S:Sorry for bad English, im Slovak xD P.P.P.S: Thank so much for any answers update: output from sudo dpkg -l | grep "^rc" richi@Richi-Ubuntu:~/lazarus1.0.12$ sudo dpkg -l | grep "^rc" rc account-plugin-generic-oauth 0.10bzr13.03.26-0ubuntu1.1 amd64 GNOME Control Center account plugin for single signon - generic OAuth rc appmenu-gtk:amd64 12.10.3daily13.04.03-0ubuntu1 amd64 Export GTK menus over DBus rc appmenu-gtk3:amd64 12.10.3daily13.04.03-0ubuntu1 amd64 Export GTK menus over DBus rc fp-compiler-2.6.0 2.6.0-9 amd64 Free Pascal - compiler rc fp-utils-2.6.0 2.6.0-9 amd64 Free Pascal - utilities rc lazarus-ide-0.9.30.4 0.9.30.4-4 amd64 IDE for Free Pascal - common IDE files rc lazarus-ide-1.0.10 1.0.10+dfsg-1 amd64 IDE for Free Pascal - common IDE files rc lcl-utils-0.9.30.4 0.9.30.4-4 amd64 Lazarus Components Library - command line build tools rc lcl-utils-1.0.10 1.0.10+dfsg-1 amd64 Lazarus Components Library - command line build tools rc libbamf3-1:amd64 0.4.0daily13.06.19~13.04-0ubuntu1 amd64 Window matching library - shared library rc libboost-filesystem1.49.0 1.49.0-4 amd64 filesystem operations (portable paths, iteration over directories, etc) in C++ rc libboost-signals1.49.0 1.49.0-4 amd64 managed signals and slots library for C++ rc libboost-system1.49.0 1.49.0-4 amd64 Operating system (e.g. diagnostics support) library rc libboost-thread1.49.0 1.49.0-4 amd64 portable C++ multi-threading rc libbrlapi0.5:amd64 4.4-8ubuntu4 amd64 braille display access via BRLTTY - shared library rc libcamel-1.2-40 3.6.4-0ubuntu1.1 amd64 Evolution MIME message handling library rc libcolumbus0-0 0.4.0daily13.04.16~13.04-0ubuntu1 amd64 error tolerant matching engine - shared library rc libdns95 1:9.9.2.dfsg.P1-2ubuntu2.1 amd64 DNS Shared Library used by BIND rc libdvbpsi7 0.2.2-1 amd64 library for MPEG TS and DVB PSI tables decoding and generating rc libebackend-1.2-5 3.6.4-0ubuntu1.1 amd64 Utility library for evolution data servers rc libedata-book-1.2-15 3.6.4-0ubuntu1.1 amd64 Backend library for evolution address books rc libedata-cal-1.2-18 3.6.4-0ubuntu1.1 amd64 Backend library for evolution calendars rc libgc1c3:amd64 1:7.2d-0ubuntu5 amd64 conservative garbage collector for C and C++ rc libgd2-xpm:amd64 2.0.36~rc1~dfsg-6.1ubuntu1 amd64 GD Graphics Library version 2 rc libgd2-xpm:i386 2.0.36~rc1~dfsg-6.1ubuntu1 i386 GD Graphics Library version 2 rc libgnome-desktop-3-4 3.6.3-0ubuntu1 amd64 Utility library for loading .desktop files - runtime files rc libgphoto2-2:amd64 2.4.14-2 amd64 gphoto2 digital camera library rc libgphoto2-2:i386 2.4.14-2 i386 gphoto2 digital camera library rc libgphoto2-port0:amd64 2.4.14-2 amd64 gphoto2 digital camera port library rc libgphoto2-port0:i386 2.4.14-2 i386 gphoto2 digital camera port library rc libgtksourceview-3.0-0:amd64 3.6.3-0ubuntu1 amd64 shared libraries for the GTK+ syntax highlighting widget rc libgweather-3-1 3.6.2-0ubuntu1 amd64 GWeather shared library rc libharfbuzz0:amd64 0.9.13-1 amd64 OpenType text shaping engine rc libibus-1.0-0:amd64 1.4.2-0ubuntu2 amd64 Intelligent Input Bus - shared library rc libical0 0.48-2 amd64 iCalendar library implementation in C (runtime) rc libimobiledevice3 1.1.4-1ubuntu6.2 amd64 Library for communicating with the iPhone and iPod Touch rc libisc92 1:9.9.2.dfsg.P1-2ubuntu2.1 amd64 ISC Shared Library used by BIND rc libkms1:amd64 2.4.46-1 amd64 Userspace interface to kernel DRM buffer management rc libllvm3.2:i386 1:3.2repack-7ubuntu1 i386 Low-Level Virtual Machine (LLVM), runtime library rc libmikmod2:amd64 3.1.12-5 amd64 Portable sound library rc libpackagekit-glib2-14:amd64 0.7.6-3ubuntu1 amd64 Library for accessing PackageKit using GLib rc libpoppler28:amd64 0.20.5-1ubuntu3 amd64 PDF rendering library rc libraw5:amd64 0.14.7-0ubuntu1.13.04.2 amd64 raw image decoder library rc librhythmbox-core6 2.98-0ubuntu5 amd64 support library for the rhythmbox music player rc libsdl-mixer1.2:amd64 1.2.12-7ubuntu1 amd64 Mixer library for Simple DirectMedia Layer 1.2, libraries rc libsnmp15 5.4.3~dfsg-2.7ubuntu1 amd64 SNMP (Simple Network Management Protocol) library rc libsyncdaemon-1.0-1 4.2.0-0ubuntu1 amd64 Ubuntu One synchronization daemon library rc libunity-core-6.0-5 7.0.0daily13.06.19~13.04-0ubuntu1 amd64 Core library for the Unity interface. rc libusb-0.1-4:i386 2:0.1.12-23.2ubuntu1 i386 userspace USB programming library rc libwayland0:amd64 1.0.5-0ubuntu1 amd64 wayland compositor infrastructure - shared libraries rc linux-image-3.8.0-19-generic 3.8.0-19.30 amd64 Linux kernel image for version 3.8.0 on 64 bit x86 SMP rc linux-image-3.8.0-31-generic 3.8.0-31.46 amd64 Linux kernel image for version 3.8.0 on 64 bit x86 SMP rc linux-image-extra-3.8.0-19-generic 3.8.0-19.30 amd64 Linux kernel image for version 3.8.0 on 64 bit x86 SMP rc linux-image-extra-3.8.0-31-generic 3.8.0-31.46 amd64 Linux kernel image for version 3.8.0 on 64 bit x86 SMP rc screen-resolution-extra 0.15ubuntu1 all Extension for the GNOME screen resolution applet rc unity-common 7.0.0daily13.06.19~13.04-0ubuntu1 all Common files for the Unity interface.

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• Dynamic Grouping and Columns

  - by Tim Dexter

  Some good collaboration between myself and Kan Nishida (Oracle BIP Consulting) over at bipconsulting on a question that came in yesterday to an internal mailing list. Is there a way to allow columns to be place into a template dynamically? This would be similar to the Answers Column selector. A customer has said Crystal can do this and I am trying to see how BI Pub can do the same. Example: Report has Regions as a dimension in a table, they want the user to select a parameter that will insert either Units or Dollars without having to create multiple templates. Now whether Crystal can actually do it or not is another question, can Publisher? Yes we can! Kan took the first stab. His approach, was to allow to swap out columns in a table in the report. Some quick steps: 1. Create a parameter from BIP server UI 2. Declare the parameter in RTF template You can check this post to see how you can declare the parameter from the server. http://bipconsulting.blogspot.com/2010/02/how-to-pass-user-input-values-to-report.html 3. Use the parameter value to condition if a particular column needs to be displayed or not. You can use <?if@column:.....?> syntax for Column level IF condition. The if@column is covered in user documentation. This would allow a developer to create a report with the parameter or multiple parameters to allow the user to pick a column to be included in the report. I took a slightly different tack, with the mention of the column selector in the Answers report I took that to mean that the user wanted to select more of a dimensional column and then have the report recalculate all its totals and subtotals based on that selected column. This is a little bit more involved and involves some smart XSL and XPATH expressions, but still very doable. The user can select a column as a parameter, that is passed to the template rather than the query. The parameter value that is actually passed is the element name that you want to regroup the data by. Inside the template we then reference that parameter value in our for-each-group loop. That's where we need the trixy XSL/XPATH code to get the regrouping to happen. At this juncture, I need to hat tip to Klaus, for his article on dynamic sorting that he wrote back in 2006. I basically took his sorting code and applied it to the for-each loop. You can follow both of Kan's first two steps above i.e. Create a parameter from BIP server UI - this just needs to be based on a 'list' type list of value with name/value pairs e.g. Department/DEPARTMENT_NAME, Job/JOB_TITLE, etc. The user picks the 'friendly' value and the server passes the element name to the template. Declare the parameter in RTF template - been here before lots of times right? <?param@begin:group1;'"DEPARTMENT_NAME"'?> I have used a default value so that I can test the funtionality inside the template builder (notice the single and double quotes.) Next step is to use the template builder to build a re-grouped report layout. It does not matter if its hard coded right now; we will add in the dynamic piece next. Once you have a functioning template that is re-grouping correctly. Open up the for-each-group field and modify it to use the parameter: <?for-each-group:ROW;./*[name(.) = $group1]?> 'group1' is my grouping parameter, declared above. We need the XPATH expression to find the column in the XML structure we want to group that matches the one passed by the parameter. Its essentially looking through the data tree for a match. We can show the actual grouping value in the report output with a similar XPATH expression <?./*[name(.) = $group1]?> In my example, I took things a little further so that I could have a dynamic label for the parameter value. For instance if I am using MANAGER as the parameter I want to show: Manager: Tim Dexter My XML elements are readable e.g. DEPARTMENT_NAME. Its a simple case of replacing the underscore with a space and then 'initcapping' the result: <?xdoxslt:init_cap(translate($group1,'_',' '))?> With this in place, the user can now select a grouping column in the BIP report viewer and the layout will re-group the data and any calculations based on that column. I built a group above report but you could equally build the group left version to truly mimic the Answers column selector. If you are interested you can get an example report, sample data and layout template here. Of course, you can combine Klaus' dynamic sorting, Kan's conditional column approach and this dynamic grouping to build a real kick ass report for users that will keep them happy for hours..

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• SQL SERVER – Guest Post by Sandip Pani – SQL Server Statistics Name and Index Creation

  - by pinaldave

  Sometimes something very small or a common error which we observe in daily life teaches us new things. SQL Server Expert Sandip Pani (winner of Joes 2 Pros Contests) has come across similar experience. Sandip has written a guest post on an error he faced in his daily work. Sandip is working for QSI Healthcare as an Associate Technical Specialist and have more than 5 years of total experience. He blogs at SQLcommitted.com and contribute in various forums. His social media hands are LinkedIn, Facebook and Twitter. Once I faced following error when I was working on performance tuning project and attempt to create an Index. Mug 1913, Level 16, State 1, Line 1 The operation failed because an index or statistics with name ‘Ix_Table1_1′ already exists on table ‘Table1′. The immediate reaction to the error was that I might have created that index earlier and when I researched it further I found the same as the index was indeed created two times. This totally makes sense. This can happen due to many reasons for example if the user is careless and executes the same code two times as well, when he attempts to create index without checking if there was index already on the object. However when I paid attention to the details of the error, I realize that error message also talks about statistics along with the index. I got curious if the same would happen if I attempt to create indexes with the same name as statistics already created. There are a few other questions also prompted in my mind. I decided to do a small demonstration of the subject and build following demonstration script. The goal of my experiment is to find out the relation between statistics and the index. Statistics is one of the important input parameter for the optimizer during query optimization process. If the query is nontrivial then only optimizer uses statistics to perform a cost based optimization to select a plan. For accuracy and further learning I suggest to read MSDN. Now let’s find out the relationship between index and statistics. We will do the experiment in two parts. i) Creating Index ii) Creating Statistics We will be using the following T-SQL script for our example. IF (OBJECT_ID('Table1') IS NOT NULL) DROP TABLE Table1 GO CREATE TABLE Table1 (Col1 INT NOT NULL, Col2 VARCHAR(20) NOT NULL) GO We will be using following two queries to check if there are any index or statistics on our sample table Table1. -- Details of Index SELECT OBJECT_NAME(OBJECT_ID) AS TableName, Name AS IndexName, type_desc FROM sys.indexes WHERE OBJECT_NAME(OBJECT_ID) = 'table1' GO -- Details of Statistics SELECT OBJECT_NAME(OBJECT_ID) TableName, Name AS StatisticsName FROM sys.stats WHERE OBJECT_NAME(OBJECT_ID) = 'table1' GO When I ran above two scripts on the table right after it was created it did not give us any result which was expected. Now let us begin our test. 1) Create an index on the table Create following index on the table. CREATE NONCLUSTERED INDEX Ix_Table1_1 ON Table1(Col1) GO Now let us use above two scripts and see their results. We can see that when we created index at the same time it created statistics also with the same name. Before continuing to next set of demo – drop the table using following script and re-create the table using a script provided at the beginning of the table. DROP TABLE table1 GO 2) Create a statistic on the table Create following statistics on the table. CREATE STATISTICS Ix_table1_1 ON Table1 (Col1) GO Now let us use above two scripts and see their results. We can see that when we created statistics Index is not created. The behavior of this experiment is different from the earlier experiment. Clean up the table setup using the following script: DROP TABLE table1 GO Above two experiments teach us very valuable lesson that when we create indexes, SQL Server generates the index and statistics (with the same name as the index name) together. Now due to the reason if we have already had statistics with the same name but not the index, it is quite possible that we will face the error to create the index even though there is no index with the same name. A Quick Check To validate that if we create statistics first and then index after that with the same name, it will throw an error let us run following script in SSMS. Make sure to drop the table and clean up our sample table at the end of the experiment. -- Create sample table CREATE TABLE TestTable (Col1 INT NOT NULL, Col2 VARCHAR(20) NOT NULL) GO -- Create Statistics CREATE STATISTICS IX_TestTable_1 ON TestTable (Col1) GO -- Create Index CREATE NONCLUSTERED INDEX IX_TestTable_1 ON TestTable(Col1) GO -- Check error /*Msg 1913, Level 16, State 1, Line 2 The operation failed because an index or statistics with name 'IX_TestTable_1' already exists on table 'TestTable'. */ -- Clean up DROP TABLE TestTable GO While creating index it will throw the following error as statistics with the same name is already created. In simple words – when we create index the name of the index should be different from any of the existing indexes and statistics. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Error Messages, SQL Index, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL Statistics

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• Announcing the June 2012 Release of the Ajax Control Toolkit

  - by Stephen.Walther

  I’m excited to announce the June 2012 release of the Ajax Control Toolkit. You can download the new release by visiting http://AjaxControlToolkit.CodePlex.com or (better) download the new release with NuGet: Install-Package AjaxControlToolkit The Ajax Control Toolkit continues to be super popular. The previous release (May 2012) had over 87,000 downloads from CodePlex.com and over 16,000 downloads from NuGet. That’s over 100,000 downloads in less than 2 months. Security Improvements for the HtmlEditorExtender Unfortunately, in the previous release, we made the HtmlEditorExtender too secure! We upgraded the version of the Microsoft Anti-Cross Site Scripting Library included in the Ajax Control Toolkit to the latest version (version 4.2.1) and the latest version turned out to be way too aggressive about stripping HTML. It not only strips dangerous tags such as <script> tags, it also strips innocent tags such as <b> tags. When the latest version of the Microsoft Anti-Cross Site Scripting Library is used with the HtmlEditorExtender, the library strips all rich content from the HtmlEditorExtender control which defeats the purpose of using the control. Therefore, we had to find a replacement for the Microsoft Anti-Cross Site Scripting Library. In this release, we’ve created a new HTML sanitizer built on the HTML Agility Pack. If you were using the AntiXssSanitizerProvider then you will need to substitute the HtmlAgilityPackSanitizerProvider. In particular, you need to modify the sanitizer sections in your Web.config file like this: <configuration> <configSections> <sectionGroup name="system.web"> <section name="sanitizer" requirePermission="false" type="AjaxControlToolkit.Sanitizer.ProviderSanitizerSection, AjaxControlToolkit" /> </sectionGroup> </configSections> <system.web> <sanitizer defaultProvider="HtmlAgilityPackSanitizerProvider"> <providers> <add name="HtmlAgilityPackSanitizerProvider" type="AjaxControlToolkit.Sanitizer.HtmlAgilityPackSanitizerProvider"></add> </providers> </sanitizer> </system.web> </configuration> We made one other backwards-breaking change to improve the security of the HtmlEditorExtender. We want to make sure that users don’t accidently use the HtmlEditorExtender without an HTML sanitizer by accident. Therefore, if you don’t configure a HTML sanitizer provider in the web.config file then you’ll get the following error: If you really want to use the HtmlEditorExtender without using an HTML sanitizer – for example, you are using the HtmlEditorExtender for an Intranet application and you trust all of your fellow employees – then you can explicitly indicate that you don’t want to enable HTML sanitization by setting the EnableSanitization property to false like this: <ajaxToolkit:HtmlEditorExtender TargetControlID="txtComments" EnableSanitization="false" runat="server" /> Please don’t ever set the EnableSanitization property to false for a public website. If you disable HTML sanitization then you are making your website an easy target for Cross-Site Scripting attacks. Lots of Fixes for the ComboBox Control In the latest release, we also made several important bug fixes and feature enhancements to the ComboBox control. Here’s the list of issues that we fixed: 22930 — ComboBox doesn’t close its drop down list when losing input focus to another ComboBox control 23140 — ComboBox Issues – Delete, Backspace, Period 23142 — ComboxBox SelectedIndex = -1 does not clear text 24440 — ComboBox postback on enter 25295 — ComboBox problems when container is hidden at page load 25469 — ComboBox – MaxLength ignored 26686 — Backspace and Delete exception when optionList is null 27148 — Combobox breaks if ClientIDMode is static Fixes to Other Controls In this release, we also made bug fixes and enhancements to the UpdatePanelAnimation, Tabs, and Seadragon controls: 21310 — OnUpdated animation starts before OnUpdating has finished 26690 — Seadragon Control’s openTileSource() method doesn’t work (with fix) Title is required We also fixed an issue with the Tabs control which would result in an InvalidOperation exception. Summary I want to thank the Superexpert team for the hard work that they put into this release. In particular, I want to thank them for their effort in researching, building, and writing unit tests for the HtmlAgilityPack HTML sanitizer.

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• Installing SharePoint 2013 on Windows 2012- standalone installation

  - by sreejukg

  In this article, I am going to share my experience while installing SharePoint 2013 on Windows 2012. This was the first time I tried SharePoint 2013. So I thought sharing the same will benefit somebody who would like to install SharePoint 2013 as a standalone installation. Standalone installation is meant for evaluation/development purposes. For production environments, you need to follow the best practices and create required service accounts. Microsoft has published the deployment guide for SharePoint 2013, you can download this from the below link. http://www.microsoft.com/en-us/download/details.aspx?id=30384 Since this is for development environment, I am not going to create any service account, I logged in to Windows 2012 as an administrator and just placed my installation DVD on the drive. When I run the setup from the DVD, the below splash screen appears. This reflects the new UI changes happening with all Microsoft based applications; the interface matches the metro style applications (Windows 8 style). As you can see the options are same as that of the SharePoint 2010 installation screen. Click on the “install software prerequisites” link to get all the prerequisites get installed. You need a valid internet connection to do this. Clicking on the install software prerequisites will bring the following dialog. Click Next, you will see the terms and conditions. Select I accept check box and click Next. The installation will start immediately. For any reason, if you stop the installation and start it later, the product preparation tool will check whether a particular component is installed and if yes, then the installation of that particular component will be skipped. If you do not have internet connection, you will face the download error as follows. At any point of failure, the error log will be available for you to review. If all OK, you will reach the below dialog, this means some components will be installed once the PC is rebooted. Be noted that the clicking on finish will not ask you for further confirmation. So make sure to save all your work before clicking on finish button. Once the server is restarted, the product preparation tool will start automatically and you will see the following dialog. Now go to the SharePoint 2013 splash page and click on “Install SharePoint Server” link. You need to enter the product key here. Enter the product key as you received and click continue. Select the Checkbox for the license agreement and click on continue button. Now you need to select the installation type. Select Stand-alone and click on “Install Now” button. A dialog will pop up that updates you with the process and progress. The installation took around 15-20 minutes with 2 GB or Ram installed in the server, seems fair. Once the installation is over, you will see the following Dialog. Make sure you select the Run the products and configuration wizard. If you miss to select the check box, you can find the products and configuration wizard from the start tiles. The products and configuration wizard will start. If you get any dialog saying some of the services will be stopped, you just accept it. Since we selected standalone installation, it will not ask for any user input, as it already knows the database to be configured. Once the configuration is over without any problems you will see the configuration successful message. Also you can find the link to central administration on the Start Screen.     Troubleshooting During my first setup process, I got the below error. System.ArgumentException: The SDDL string contains an invalid sid or a sid that cannot be translated. Parameter name: sddlForm at System.Security.AccessControl.RawSecurityDescriptor.BinaryFormFromSddlForm(String sddlForm) at System.Security.AccessControl.RawSecurityDescriptor..ctor(String sddlForm) at Microsoft.SharePoint.Win32.SPNetApi32.CreateShareSecurityDescriptor(String[] readNames, String[] changeNames, String[] fullControlNames, String& sddl) at Microsoft.SharePoint.Win32.SPNetApi32.CreateFileShare(String name, String description, String path) at Microsoft.SharePoint.Administration.SPServer.CreateFileShare(String name, String description, String path) at Microsoft.Office.Server.Search.Administration.AnalyticsAdministration.CreateAnalyticsUNCShare(String dirParentLocation, String shareName) at Microsoft.Office.Server.Search.Administration.AnalyticsAdministration.ProvisionAnalyticsShare(SearchServiceApplication serviceApplication) ………………………………………… ………………………………………… The configuration wizard displayed the error as below. The error occurred in step 8 of the configuration wizard and by the time the central administration is already provisioned. So from the start, I was able to open the central administration website, but the search service application was showing as error. I found a good blog that specifies the reason for error. http://kbdump.com/sharepoint2013-standalone-config-error-create-sample-data/ The workaround specified in the blog works fine. I think SharePoint must be provisioning Search using the Network Service account, so instead of giving permission to everyone, you could try giving permission to Network Service account(I didn’t try this yet, buy you could try and post your feedback here). In production environment you will have specific accounts that have access rights as recommended by Microsoft guidelines. Installation of SharePoint 2013 is pretty straight forward. Hope you enjoyed the article!

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• Part 14: Execute a PowerShell script

  In the series the following parts have been published Part 1: Introduction Part 2: Add arguments and variables Part 3: Use more complex arguments Part 4: Create your own activity Part 5: Increase AssemblyVersion Part 6: Use custom type for an argument Part 7: How is the custom assembly found Part 8: Send information to the build log Part 9: Impersonate activities (run under other credentials) Part 10: Include Version Number in the Build Number Part 11: Speed up opening my build process template Part 12: How to debug my custom activities Part 13: Get control over the Build Output Part 14: Execute a PowerShell script Part 15: Fail a build based on the exit code of a console application With PowerShell you can add powerful scripting to your build to for example execute a deployment. If you want more information on PowerShell, please refer to http://technet.microsoft.com/en-us/library/aa973757.aspx For this example we will create a simple PowerShell script that prints “Hello world!”. To create the script, create a new text file and name it “HelloWorld.ps1”. Add to the contents of the script: Write-Host “Hello World!” To test the script do the following: Open the command prompt To run the script you must change the execution policy. To do this execute in the command prompt: powershell set-executionpolicy remotesigned Now go to the directory where you have saved the PowerShell script Execute the following command powershell .\HelloWorld.ps1 In this example I use a relative path, but when the path to the PowerShell script contains spaces, you need to change the syntax to powershell "& '<full path to script>' " for example: powershell "& ‘C:\sources\Build Customization\SolutionToBuild\PowerShell Scripts\HellloWorld.ps1’ " In this blog post, I create a new solution and that solution includes also this PowerShell script. I want to create an argument on the Build Process Template that holds the path to the PowerShell script. In the Build Process Template I will add an InvokeProcess activity to execute the PowerShell command. This InvokeProcess activity needs the location of the script as an argument for the PowerShell command. Since you don’t know the full path at the build server of this script, you can either specify in the argument the relative path of the script, but it is hard to find out what the relative path is. I prefer to specify the location of the script in source control and then convert that server path to a local path. To do this conversion you can use the ConvertWorkspaceItem activity. So to complete the task, open the Build Process Template CustomTemplate.xaml that we created in earlier parts, follow the following steps Add a new argument called “DeploymentScript” and set the appropriate settings in the metadata. See Part 2: Add arguments and variables  for more information. Scroll down beneath the TryCatch activity called “Try Compile, Test, and Associate Changesets and Work Items” Add a new If activity and set the condition to "Not String.IsNullOrEmpty(DeploymentScript)" to ensure it will only run when the argument is passed. Add in the Then branch of the If activity a new Sequence activity and rename it to “Start deployment” Click on the activity and add a new variable called DeploymentScriptFilename (scoped to the “Start deployment” Sequence Add a ConvertWorkspaceItem activity on the “Start deployment” Sequence Add a InvokeProcess activity beneath the ConvertWorkspaceItem activity in the “Start deployment” Sequence Click on the ConvertWorkspaceItem activity and change the properties DisplayName = Convert deployment script filename Input = DeploymentScript Result = DeploymentScriptFilename Workspace = Workspace Click on the InvokeProcess activity and change the properties Arguments = String.Format(" ""& '{0}' "" ", DeploymentScriptFilename) DisplayName = Execute deployment script FileName = "PowerShell" To see results from the powershell command drop a WriteBuildMessage activity on the "Handle Standard Output" and pass the stdOutput variable to the Message property. Do the same for a WriteBuildError activity on the "Handle Error Output" To publish it, check in the Build Process Template This leads to the following result We now go to the build definition that depends on the template and set the path of the deployment script to the server path to the HelloWorld.ps1. (If you want to see the result of the PowerShell script, change the Logging verbosity to Detailed or Diagnostic). Save and run the build. A lot of the deployment scripts you have will have some kind of arguments (like username / password or environment variables) that you want to define in the Build Definition. To make the PowerShell configurable, you can follow the following steps. Create a new script and give it the name "HelloWho.ps1". In the contents of the file add the following lines: param (         $person     ) $message = [System.String]::Format(“Hello {0}!", $person) Write-Host $message When you now run the script on the command prompt, you will see the following So lets change the Build Process Template to accept one parameter for the deployment script. You can of course make it configurable to add a for-loop that reads through a collection of parameters but that is out of scope of this blog post. Add a new Argument called DeploymentScriptParameter In the InvokeProcess activity where the PowerShell command is executed, modify the Arguments property to String.Format(" ""& '{0}' '{1}' "" ", DeploymentScriptFilename, DeploymentScriptParameter) Check in the Build Process Template Now modify the build definition and set the Parameter of the deployment to any value and run the build. You can download the full solution at BuildProcess.zip. It will include the sources of every part and will continue to evolve.

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• Good ol fashioned debugging

  - by Tim Dexter

  I have been helping out one of our new customers over the last day or two and I have even managed to get to the bottom of their problem FTW! They use BIEE and BIP and wanted to mount a BIP report in a dashboard page, so far so good, BIP does that! Just follow the instructions in the BIEE user guide. The wrinkle is that they want to enter some fixed instruction strings into the dashboard prompts to help the user. These are added as fixed values to the prompt as the default values so they appear first. Once the user makes a selection, the default strings disappear. Its a fair requirement but the BIP report chokes Now, the BIP report had been setup with the Autorun checkbox, unchecked. I expected the BIP report to wait for the Go button to be hit but it was trying to run immediately and failing. That was the first issue. You can not stop the BIP report from trying to run in a dashboard. Even if the Autorun is turned off, it seems that dashboard still makes the request to BIP to run the report. Rather than BIP refusing because its waiting for input it goes ahead anyway, I guess the mechanism does not check the autorun flag when the request is coming from the dashboard. It appears that between BIEE and BIP, they collectively ignore the autorun flag. A bug? might be, at least an enhancement request. With that in mind, how could we get BIP to not at least not fail? This fact was stumping me on the parameter error, if the autorun flag was being respected then why was BIP complaining about the parameter values it should not even be doing anything until the Go button is clicked. I now knew that the autorun flag was being ignored, it was a simple case of putting BIP into debug mode. I use the OC4J server on my laptop so debug msgs are routed through the dos box used to start the OC4J container. When I changed a value on the dashboard prompt I spotted some debug text rushing by that subsequently disappeared from the log once the operation was complete. Another bug? I needed to catch that text as it went by, using the print screen function with some software to grab multiple screens as the log appeared and then disappeared. The upshot is that when you change the dashboard prompt value, BIP validates the value against its own LOVs, if its not in the list then it throws the error. Because 'Fill this first' and 'Fill this second' ie fixed strings from the dashboard prompts, are not in the LOV lists and because the report is auto running as soon as the dashboard page is brought up, the report complains about invalid parameters. To get around this, I needed to get the strings into the LOVs. Easily done with a UNION clause: select 'Fill this first' from SH.Products Products UNION select Products."Prod Category" as "Prod Category" from SH.Products Products Now when BIP wants to validate the prompt value, the LOV query fires and finds the fixed string -> No Error. No data, but definitely no errors :0) If users do run with the fixed values, you can capture that in the template. If there is no data in the report, either the fixed values were used or the parameters selected resulted in no rows. You can capture this in the template and display something like. 'Either your parameter values resulted in no data or you have not changed the default values' Thats the upside, the downside is that if your users run the report in the BP UI they re going to see the fixed strings. You could alleviate that by having BIP display the fixed strings in top of its parameter drop boxes (just set them as the default value for the parameter.) But they will not disappear like they do in the dashboard prompts, see below. If the expected autorun behaviour worked ie wait for the Go button, then we would not have to workaround it but for now, its a pretty good solution. It was an enjoyable hour or so for me, took me back to my developer daze, when we used to race each other for the most number of bug fixes. I used to run a distant 2nd behind 'Bugmeister Chen Hu' but led the chasing pack by a reasonable distance.

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• Change the User Interface Language in Vista or Windows 7

  - by Matthew Guay

  Would you like to change the user interface language in any edition of Windows 7 or Vista on your computer?  Here’s a free app that can help you do this quickly and easily. If your native language is not the one most spoken in your area, you’ve likely purchased a PC with Windows preinstalled with a language that is difficult or impossible for you to use.  Windows 7 and Vista Ultimate include the ability to install multiple user interface languages and switch between them. However, all other editions are stuck with the language they shipped with.  With the free Vistalizator app, you can add several different interface languages to any edition of Vista or Windows 7 and easily switch between them. Note:  In this test, we used an US English copy of both Windows 7 Home Premium and Windows Vista Home Premium, and it works the same on any edition. The built-in language switching in the Ultimate Editions lets you set a user interface language for each user account, but this will only switch it for all users.  Add a User Interface Language to Windows To add an interface language to any edition of Windows 7 and Vista, first download Vistalizator (link below).  Then, from the same page, download the language pack of your choice.  The language packs are specific for each service pack of Windows, so make sure to choose the correct version and service pack you have installed. Once the downloads are finished, launch the Vistalizator program. You do not need to install it; simply run it and you’re ready to go.  Click the Add languages button to add a language to Windows. Select the user interface language pack you downloaded, and click Open. Depending on the language you selected, it may not automatically update with Windows Update when a service pack is released.  If so, you will have to remove the language pack and reinstall the new one for that service pack at that time.  Click Ok to continue. Make sure you’ve selected the correct language, and click Install language. Vistalizator will extract and install the language pack.  This took around 5 to 10 minutes in our test. Once the language pack is installed, click Yes to make it the default display language. Now, you have two languages installed in Windows.  You may be prompted to check for updates to the language pack; if so, click Update languages and Vistalizator will automatically check for and install any updates. When finished, exit Vistalizator to finish switching the language.  Click Yes to automatically reboot and apply the changes. When you computer reboots, it will show your new language, which in our test is Thai.  Here’s our Windows 7 Home Premium machine with the Thai language pack installed and running. You can even add a right to left language, such as Arabic, to Windows.  Simply repeat the steps to add another language pack.    Vistalizator was originally designed for Windows Vista, and works great with Windows 7 too.  The language packs for Vista are larger downloads than their Windows 7 counterparts.  Here’s our Vista Home Premium in English… And here’s how it looks after installing the Simplified Chinese language pack with Vistalizator. Revert to Your Original Language If you wish to return to the language that your computer shipped with, or want to switch to another language you’ve installed, run Vistalizator again.  Select the language you wish to use, and click Change language.   When you close Vistalizator, you will again be asked to reboot.  Once you’ve rebooted, you’ll see your new (or original) language ready to use.  Here’s our Windows 7 Home Premium desktop, back in it’s original English interface. Conclusion This is a great way to change your computer’s language into your own native language, and is especially useful for expatriates around the world.  Also, if you’d like to simply change or add an input language instead of changing the language throughout your computer, check out our tutorial on How to Add Keyboard Languages to XP, Vista, and Windows 7. Download Vistalizator Similar Articles Productive Geek Tips Enable Military Time in Windows 7 or VistaWhy Does My Password Expire in Windows?Use Windows Vista Aero through Remote Desktop ConnectionDisable User Account Control (UAC) the Easy Way on Win 7 or VistaAdd keyboard languages to XP, Vista, and Windows 7 TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Home Networks – How do they look like & the problems they cause Check Your IMAP Mail Offline In Thunderbird Follow Finder Finds You Twitter Users To Follow Combine MP3 Files Easily QuicklyCode Provides Cheatsheets & Other Programming Stuff Download Free MP3s from Amazon

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• Record and Play your WebLogic Console Tasks Like a DVR

  - by james.bayer

  Automation using WebLogic Scripting Tool Today on the Oracle internal mailing list for WebLogic Server questions someone asked how to automate the configuration of the thread model for WebLogic Server and they were having trouble with the jython scripting syntax.  I’ve previously written about this feature called Work Managers and the associated constraints.  However, I did not show how to automate the process of configuring this without the console using WebLogic Scripting Tool – the jython scripting automation environment abbreviated as WLST.  I’ve written some very basic introductions to WLST before and there is also an Oracle By Example on the subject, but this is a bit more advanced.  Fear not because there is a really easy-to-use feature of the WLS console that lets you “Record” user actions just like a DVR.  Using these recordings of the web-based console, you can easily create a script even if you are unfamiliar with the WLST syntax and API.  I’m a big fan of both DVR’s and automation as can be evidenced with this old Halloween picture taken during simpler times.  Obviously the Cast Away and The Big Labowski references show some age.  I was a big Tivo fan-boy back in the day and I still think it’s the best DVR. I strongly believe that WebLogic Scripting Tool (WLST) is an absolutely essential tool for automating administration tasks in anything beyond a development environment.  Even in development environments you can make a case that it makes sense to start the automation for environments downstream.  I promise you that once you start using it for any tasks that you do even semi-regularly, you won’t go back to clicking through the console.  It’s simply so much more efficient and less error-prone to run a script. Let’s say you need to create a Work Manager and MaxThreadsConstraint – the easy way to do it is configure it in the WLS console first while capturing the commands with a recording.  See the images for the simple steps – click to enlarge. Record Console Configurations to a File Review the Recordings and Make Slight Modifications In order to make the recorded .py file directly callable as a stand-alone script I added calls to the connect() and edit() functions at the beginning and calls to disconnect() and exit() at the end – otherwise the main section of the script was provided by the console recording.  Below is the resulting file I saved as d:/temp/wm.py connect('weblogic','welcome1', 't3://localhost:7001') edit() startEdit()   cd('/SelfTuning/wl_server') cmo.createMaxThreadsConstraint('MaxThreadsConstraint-0')   cd('/SelfTuning/wl_server/MaxThreadsConstraints/MaxThreadsConstraint-0') set('Targets',jarray.array([ObjectName('com.bea:Name=examplesServer,Type=Server')], ObjectName)) cmo.setCount(5) cmo.unSet('ConnectionPoolName')   cd('/SelfTuning/wl_server') cmo.createWorkManager('WorkManager-0') cd('/SelfTuning/wl_server/WorkManagers/WorkManager-0') set('Targets',jarray.array([ObjectName('com.bea:Name=examplesServer,Type=Server')], ObjectName))   cmo.setMaxThreadsConstraint(getMBean('/SelfTuning/wl_server/MaxThreadsConstraints/MaxThreadsConstraint-0')) cmo.setIgnoreStuckThreads(false)   activate() disconnect() exit() Run the Script If you want to test it be sure to delete the Work Manager and MaxThreadConstraint that you had previously created in the console.  Do something like the following - set up the environment and tell WLST to execute the script which happens in the first 2 lines, the rest doesn’t require any user input: D:\Oracle\wls11g\wlserver_10.3\samples\domains\wl_server\bin>setDomainEnv.cmd D:\Oracle\wls11g\wlserver_10.3\samples\domains\wl_server>java weblogic.WLST d:\temp\wm.py   Initializing WebLogic Scripting Tool (WLST) ...   Welcome to WebLogic Server Administration Scripting Shell   Type help() for help on available commands   Connecting to t3://localhost:7001 with userid weblogic ... Successfully connected to Admin Server 'examplesServer' that belongs to domain 'wl_server'.   Warning: An insecure protocol was used to connect to the server. To ensure on-the-wire security, the SSL port or Admin port should be used instead.   Location changed to edit tree. This is a writable tree with DomainMBean as the root. To make changes you will need to start an edit session via startEdit().   For more help, use help(edit)   Starting an edit session ... Started edit session, please be sure to save and activate your changes once you are done. Activating all your changes, this may take a while ... The edit lock associated with this edit session is released once the activation is completed. Activation completed Disconnected from weblogic server: examplesServer     Exiting WebLogic Scripting Tool.   Now if you go back and look in the console the changes have been made and we now have a compete script.  Of course there is a full MBean reference and you can learn the nuances of jython and WLST, but why not the WLS console do most of the work for you!  Happy scripting.

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• ASP.NET MVC 3 Hosting :: ASP.NET MVC 3 First Look

  - by mbridge

  MVC 3 View Enhancements MVC 3 introduces two improvements to the MVC view engine: - Ability to select the view engine to use. MVC 3 allows you to select from any of your  installed view engines from Visual Studio by selecting Add > View (including the newly introduced ASP.NET “Razor” engine”): - Support for the next ASP.NET “Razor” syntax. The newly previewed Razor syntax is a concise lightweight syntax. MVC 3 Control Enhancements - Global Filters: ASP.NET MVC 3  allows you to specify that a filter which applies globally to all Controllers within an app by adding it to the GlobalFilters collection.  The RegisterGlobalFilters() method is now included in the default Global.asax class template and so provides a convenient place to do this since is will then be called by the Application_Start() method: void RegisterGlobalFilters(GlobalFilterCollection filters) { filters.Add(new HandleLoggingAttribute()); filters.Add(new HandleErrorAttribute()); } void Application_Start() { RegisterGlobalFilters (GlobalFilters.Filters); } - Dynamic ViewModel Property : MVC 3 augments the ViewData API with a new “ViewModel” property on Controller which is of type “dynamic” – and therefore enables you to use the new dynamic language support in C# and VB pass ViewData items using a cleaner syntax than the current dictionary API. Public ActionResult Index() { ViewModel.Message = "Hello World"; return View(); } - New ActionResult Types : MVC 3 includes three new ActionResult types and helper methods: 1. HttpNotFoundResult – indicates that a resource which was requested by the current URL was not found. HttpNotFoundResult will return a 404 HTTP status code to the calling client. 2. PermanentRedirects – The HttpRedirectResult class contains a new Boolean “Permanent” property which is used to indicate that a permanent redirect should be done. Permanent redirects use a HTTP 301 status code.  The Controller class  includes three new methods for performing these permanent redirects: RedirectPermanent(), RedirectToRoutePermanent(), andRedirectToActionPermanent(). All  of these methods will return an instance of the HttpRedirectResult object with the Permanent property set to true. 3. HttpStatusCodeResult – used for setting an explicit response status code and its associated description. MVC 3 AJAX and JavaScript Enhancements MVC 3 ships with built-in JSON binding support which enables action methods to receive JSON-encoded data and then model-bind it to action method parameters. For example a jQuery client-side JavaScript could define a “save” event handler which will be invoked when the save button is clicked on the client. The code in the event handler then constructs a client-side JavaScript “product” object with 3 fields with their values retrieved from HTML input elements. Finally, it uses jQuery’s .ajax() method to POST a JSON based request which contains the product to a /theStore/UpdateProduct URL on the server: $('#save').click(function () { var product = { ProdName: $('#Name').val() Price: $('#Price').val(), } $.ajax({ url: '/theStore/UpdateProduct', type: "POST"; data: JSON.stringify(widget), datatype: "json", contentType: "application/json; charset=utf-8", success: function () { $('#message').html('Saved').fadeIn(), }, error: function () { $('#message').html('Error').fadeIn(), } }); return false; }); MVC will allow you to implement the /theStore/UpdateProduct URL on the server by using an action method as below. The UpdateProduct() action method will accept a strongly-typed Product object for a parameter. MVC 3 can now automatically bind an incoming JSON post value to the .NET Product type on the server without having to write any custom binding. [HttpPost] public ActionResult UpdateProduct(Product product) { // save logic here return null } MVC 3 Model Validation Enhancements MVC 3 builds on the MVC 2 model validation improvements by adding   support for several of the new validation features within the System.ComponentModel.DataAnnotations namespace in .NET 4.0: - Support for the new DataAnnotations metadata attributes like DisplayAttribute. - Support for the improvements made to the ValidationAttribute class which now supports a new IsValid overload that provides more info on  the current validation context, like what object is being validated. - Support for the new IValidatableObject interface which enables you to perform model-level validation and also provide validation error messages which are specific to the state of the overall model. MVC 3 Dependency Injection Enhancements MVC 3 includes better support for applying Dependency Injection (DI) and also integrating with Dependency Injection/IOC containers. Currently MVC 3 Preview 1 has support for DI in the below places: - Controllers (registering & injecting controller factories and injecting controllers) - Views (registering & injecting view engines, also for injecting dependencies into view pages) - Action Filters (locating and  injecting filters) And this is another important blog about Microsoft .NET and technology: - Windows 2008 Blog - SharePoint 2010 Blog - .NET 4 Blog And you can visit here if you're looking for ASP.NET MVC 3 hosting

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• 2d movement solution

  - by Phil

  Hi! I'm making a simple top-down tank game on the ipad where the user controls the movement of the tank with the left "joystick" and the rotation of the turret with the right one. I've spent several hours just trying to get it to work decently but now I turn to the pros :) I have two referencial objects, one for the movement and one for the rotation. The referencial objects always stay max two units away from the tank and I use them to tell the tank in what direction to move. I chose this approach to decouple movement and rotational behaviour from the raw input of the joysticks, I believe this will make it simpler to implement whatever behaviour I want for the tank. My problem is 1; the turret rotates the long way to the target. With this I mean that the target can be -5 degrees away in rotation and still it rotates 355 degrees instead of -5 degrees. I can't figure out why. The other problem is with the movement. It just doesn't feel right to have the tank turn while moving. I'd like to have a solution that would work as well for the AI as for the player. A blackbox function for the movement where the player only specifies in what direction it should move and it moves there under the constraints that are imposed on it. I am using the standard joystick class found in the Unity iPhone package. This is the code I'm using for the movement: public class TankFollow : MonoBehaviour { //Check angle difference and turn accordingly public GameObject followPoint; public float speed; public float turningSpeed; void Update() { transform.position = Vector3.Slerp(transform.position, followPoint.transform.position, speed * Time.deltaTime); //Calculate angle var forwardA = transform.forward; var forwardB = (followPoint.transform.position - transform.position); var angleA = Mathf.Atan2(forwardA.x, forwardA.z) * Mathf.Rad2Deg; var angleB = Mathf.Atan2(forwardB.x, forwardB.z) * Mathf.Rad2Deg; var angleDiff = Mathf.DeltaAngle(angleA, angleB); //print(angleDiff.ToString()); if (angleDiff > 5) { //Rotate to transform.Rotate(new Vector3(0, (-turningSpeed * Time.deltaTime),0)); //transform.rotation = new Quaternion(transform.rotation.x, transform.rotation.y + adjustment, transform.rotation.z, transform.rotation.w); } else if (angleDiff < 5) { transform.Rotate(new Vector3(0, (turningSpeed * Time.deltaTime),0)); //transform.rotation = new Quaternion(transform.rotation.x, transform.rotation.y + adjustment, transform.rotation.z, transform.rotation.w); } else { } transform.position = new Vector3(transform.position.x, 0, transform.position.z); } } And this is the code I'm using to rotate the turret: void LookAt() { var forwardA = -transform.right; var forwardB = (toLookAt.transform.position - transform.position); var angleA = Mathf.Atan2(forwardA.x, forwardA.z) * Mathf.Rad2Deg; var angleB = Mathf.Atan2(forwardB.x, forwardB.z) * Mathf.Rad2Deg; var angleDiff = Mathf.DeltaAngle(angleA, angleB); //print(angleDiff.ToString()); if (angleDiff - 180 > 1) { //Rotate to transform.Rotate(new Vector3(0, (turretSpeed * Time.deltaTime),0)); //transform.rotation = new Quaternion(transform.rotation.x, transform.rotation.y + adjustment, transform.rotation.z, transform.rotation.w); } else if (angleDiff - 180 < -1) { transform.Rotate(new Vector3(0, (-turretSpeed * Time.deltaTime),0)); //transform.rotation = new Quaternion(transform.rotation.x, transform.rotation.y + adjustment, transform.rotation.z, transform.rotation.w); print((angleDiff - 180).ToString()); } else { } } Since I want the turret reference point to turn in relation to the tank (when you rotate the body, the turret should follow and not stay locked on since it makes it impossible to control when you've got two thumbs to work with), I've made the TurretFollowPoint a child of the Turret object, which in turn is a child of the body. I'm thinking that I'm making it too difficult for myself with the reference points but I'm imagining that it's a good idea. Please be honest about this point. So I'll be grateful for any help I can get! I'm using Unity3d iPhone. Thanks!

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• Integrate Microsoft Translator into your ASP.Net application

  - by sreejukg

  In this article I am going to explain how easily you can integrate the Microsoft translator API to your ASP.Net application. Why we need a translation API? Once you published a website, you are opening a channel to the global audience. So making the web content available only in one language doesn’t cover all your audience. Especially when you are offering products/services it is important to provide contents in multiple languages. Users will be more comfortable when they see the content in their native language. How to achieve this, hiring translators and translate the content to all your user’s languages will cost you lot of money, and it is not a one time job, you need to translate the contents on the go. What is the alternative, we need to look for machine translation. Thankfully there are some translator engines available that gives you API level access, so that automatically you can translate the content and display to the user. Microsoft Translator API is an excellent set of web service APIs that allows developers to use the machine translation technology in their own applications. The Microsoft Translator API is offered through Windows Azure market place. In order to access the data services published in Windows Azure market place, you need to have an account. The registration process is simple, and it is common for all the services offered through the market place. Last year I had written an article about Bing Search API, where I covered the registration process. You can refer the article here. http://weblogs.asp.net/sreejukg/archive/2012/07/04/integrate-bing-search-api-to-asp-net-application.aspx Once you registered with Windows market place, you will get your APP ID. Now you can visit the Microsoft Translator page and click on the sign up button. http://datamarket.azure.com/dataset/bing/microsofttranslator As you can see, there are several options available for you to subscribe. There is a free version available, great. Click on the sign up button under the package that suits you. Clicking on the sign up button will bring the sign up form, where you need to agree on the terms and conditions and go ahead. You need to have a windows live account in order to sign up for any service available in Windows Azure market place. Once you signed up successfully, you will receive the thank you page. You can download the C# class library from here so that the integration can be made without writing much code. The C# file name is TranslatorContainer.cs. At any point of time, you can visit https://datamarket.azure.com/account/datasets to see the applications you are subscribed to. Click on the Use link next to each service will give you the details of the application. You need to not the primary account key and URL of the service to use in your application. Now let us start our ASP.Net project. I have created an empty ASP.Net web application using Visual Studio 2010 and named it Translator Sample, any name could work. By default, the web application in solution explorer looks as follows. Now right click the project and select Add -> Existing Item and then browse to the TranslatorContainer.cs. Now let us create a page where user enter some data and perform the translation. I have added a new web form to the project with name Translate.aspx. I have placed one textbox control for user to type the text to translate, the dropdown list to select the target language, a label to display the translated text and a button to perform the translation. For the dropdown list I have selected some languages supported by Microsoft translator. You can get all the supported languages with their codes from the below link. http://msdn.microsoft.com/en-us/library/hh456380.aspx The form looks as below in the design surface of Visual Studio. All the class libraries in the windows market place requires reference to System.Data.Services.Client, let us add the reference. You can find the documentation of how to use the downloaded class library from the below link. http://msdn.microsoft.com/en-us/library/gg312154.aspx Let us evaluate the translatorContainer.cs file. You can refer the code and it is self-explanatory. Note the namespace name used (Microsoft), you need to add the namespace reference to your page. I have added the following event for the translate button. The code is self-explanatory. You are creating an object of TranslatorContainer class by passing the translation service URL. Now you need to set credentials for your Translator container object, which will be your account key. The TranslatorContainer support a method that accept a text input, source language and destination language and returns DataServiceQuery<Translation>. Let us see this working, I just ran the application and entered Good Morning in the Textbox. Selected target language and see the output as follows. It is easy to build great translator applications using Microsoft translator API, and there is a reasonable amount of translation you can perform in your application for free. For enterprises, you can subscribe to the appropriate package and make your application multi-lingual.

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• Upgrading to Oracle Enterprise Manager 12c Release 2: Top Tips One Must Know

  - by AnkurGupta

  Recently Oracle announced incremental release of Enterprise Manager 12c called Enterprise Manager 12c Release 2 (EM12c R2) which includes several new exciting features (Press announcement). Right before the official release, we upgraded an internal production site from EM 12c R1 to EM 12c R2 and had an extremely pleasant experience. Let me share few key takeaways as well as few tips from this upgrade exercise. I - Why Should You Upgrade To Enterprise Manager 12c Release 2 While an upgrade is usually recommended primarily to take benefit of the latest features (which is valid for this upgrade as well), I found several other compelling reasons purely from deployment perspective. Standardize your EM deployment:  Enterprise Manager comprises of several different components (OMS, agents, plug-ins, etc) and it might be possible that these are at varied patch levels in your environment. For instance, in case of an environment containing Bundle Patch 1 (customer announcement), there is a good chance that you may not have all the components up-to-date. There are two possible reasons. Bundle Patch 1 involved patching different components (OMS, agents, plug-ins) with multiple one-off patches which may not have been applied to all components yet. Bundle Patch 1 for different platforms were not released together. Which means you may not have got the chance to patch all the components on different platforms. Note: BP1 patches are not mandatory to upgrade to EM12c R2 release EM 12c R2 provides an excellent opportunity to standardize your Cloud Control environment (OMS, repository and agents) and plug-ins to latest versions in single shot. All platform releases are made available simultaneously: For the very first time in the history of EM release, all the platforms were released on day one itself, which means you do not need to wait for platform specific binaries for EM OMS or Agent to perform install or upgrades in a heterogeneous environment. Highly refined and automated process – Upgrade process is by far the smoothest and the cleanest as compared to previous releases of Enterprise manager. Following are the ones that stand out. Automatic Plug-in management – Plug-in upgrade along with new plug-in deployment is supported in upgrade installer wizard which means bulk of the updates to OMS and repository can be done in the same workflow. Saves time and minimizes user inputs. Plug-in Upgrade or Migrate Auto Update: While doing the OMS and repository upgrade, you can use Auto Update screen in Oracle Universal Installer to check for any updates/patches. That will help you to avoid the know issues and will make sure that your upgrade is successful. Allows mass upgrade of EM Agents – A new dedicated menu has been added in the EM console for agent upgrade. Agent upgrade workflow is extremely simple that requires agent name as the only input. ADM / JVMD Manager/Agent upgrade – complete process is supported via UI screens. EM12c R2 Upgrade Guide is much simpler to follow as compared to those for earlier releases. This is attributed to the simpler upgrade process. Robust and Performing Platform: EM12c R2 release not only includes several new features, but also provides a more stable platform which incorporates several fixes and enhancements in the Enterprise Manager framework. II - Few Tips To Remember In my last post (blog link) I shared few tips and tricks from my experience applying the Bundle Patch. Recently I upgraded the same site to EM 12c R2 and found few points that you must take note of, while planning this upgrade. The tips below are also applicable to EM 12c R1 environments that do not have Bundle Patch 1 patches applied. Verify the monitored application certification – Specific targets like E-Business Suite have not yet been certified as managed target in EM 12c R2. Therefore make sure to recheck the Enterprise Manager certification Matrix on My Oracle Support before planning the upgrade. Plan downtime – Because EM 12c R2 is an incremental release of EM 12c, for EM 12c R1 to EM 12c R2 upgrade supports only 1-system upgrade approach, which mean there will be downtime. OMS name change after upgrade – In case of multi OMS environments, additional OMS is renamed after upgrade, which has few implications when you upgrade JVMD and ADP agents on OMS. This is well documented in upgrade guide but make sure you read through all the notes. Upgrading BI Publisher– EM12c R2 is certified with BI Publisher 11.1.1.6.0 only. Therefore in case you are using EM 12c R1 which is integrated with BI Publisher 11.1.1.5.0, you must upgrade the BI Publisher to 11.1.1.6.0. Follow the steps from Advanced Installation and Configuration Guide here. Perform Post upgrade Tasks – Make sure to perform post upgrade steps mentioned in documentation here. These include critical changes that must be done right after upgrade to get the right configuration. For instance Database plug-in should be upgraded to Revision 3 (12.1.0.2.0 [u120804]). Delete old OMS Home – EM12c R1 to EM12c R2 is an out of place upgrade, which means it creates a new oracle home for OMS, plug-ins, etc. Therefore please ensure that You have sufficient extra space for new OMS before starting the upgrade process. You clean up the old OMS home after the upgrade process. Steps are available here. DO NOT remove the agent home on OMS host, because agent is upgraded in-place. If you have standby OMS setup then do look into the steps to upgrade the standby OMS from the upgrade guide before going ahead. Read the right documentation – Make sure to follow the Upgrade guide which provides the most comprehensive information on EM12c R2 upgrade process. Additionally you can refer other resources to get familiar with upgrade concepts. Recorded webcast - Oracle Enterprise Manager Cloud Control 12c Release 2 Installation and Upgrade Overview Presentation - Understanding Enterprise Manager 12.1.0.2 Upgrade We are very excited about this latest release and will look forward to hear back any feedback from your upgrade experience!

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• SQL Developer Data Modeler v3.3 Early Adopter: Collaborative Design via Excel?

  - by thatjeffsmith

  As you may have heard last week, we have a new version of Oracle SQL Developer Data Modeler now available as an Early Adopter release. Version 3.3 has quite a few new features and I’ll be previewing them here. Today’s topic is our new Excel integration. It builds off of last week’s lesson: Search, so you may want to go read that first. They say it takes a village to raise a child. I say it takes a team to build a data model. You have your techie folks, your business folks, your in-betweeners, and your database geeks. Who gets to define how customers are represented and stored in your database? That data lives forever, so you better get it right from the beginning, or you’ll be living in a hacker’s paradise for years to come. Lots of good rantings, ravings, and advice on this topic in general on Karen Lopez’s (@datachick) blog. But let’s say you are the primary modeler on a project. You dutifully interview the business folks for their requirements. You sit down and start to model and think you’re pretty close. Now you need someone to confirm your assumptions and provide some feedback. Do you send your model over? Take a screenshot and blow it up on a whiteboard? Export to HTML and let them take a magic marker to their monitors? Or maybe you bite the bullet and install your modeling software on their desktops and take the hours or days required to train them up on how to use the the tool. Wouldn’t it be nice if they could just mark up their corrections in Excel and let you suck the updates back in? This is what we have started to build in Oracle SQL Developer Data Modeler. Let’s say you have a new table called ‘UT_STARTUPS.’ It looks a little something like this: A table in Oracle SQL Developer Data Modeler What I would like to do is have my team or co-worker review how I have defined those columns. Perhaps TIMESTAMP is overkill or maybe the column names themselves aren’t up to snuff. What I am going to do is now search for all the columns in my table, then export that to Excel. So do a search for UT_STARTUPS. Search, filter, then Report With the filter set to ‘Columns,’ if I do a report I’ll be only getting the columns that are resolving to my search term. So as long as my table name is unique in the model, I should get what I’m looking for. Here’s what I see when I click on the Report button: XLS or XLSX, either format is just fine I want to decide how the Column data is exported to Excel though, so I’m going to create a report template that I can use going forward. So click the ‘Manage’ button and setup a new template. I’m going to call mine ‘CollaborativeDevelopment.’ The templates allow me to define what properties are included in the reports. Once this is set, I’ll have the XLS file generated, and get to work Now let the Excel junkies do their stuff Note that not ALL of the report properties are update-able (yes, I made up a new word there) via Excel. We’ll have the full list of properties documented going forward, but in my Excel sheet, note that I can’t change the table name or the data types for the columns. I’m going to update some column names and supply ‘nice’ comments so the database users know what’s what. Here’s my input for the designer/architect/database dude: Be kind, please rew…use comments. Save the file, email it back to your modeler. Update the model from Excel That’s right, it’s a right mouse click from your model in the tree If everything goes right, you’ll see a nice confirmation message: It’s alive! Another to-do item on tap – making this dialog more informative. We’ll be showing exactly what in your model was updated from Excel. Let’s take another look at the model now Voila! Why are we doing this again? The goal is to reduce the number of round-trips from the modeler and the business process owner. One is used to working with Excel – why not allow them to mark up their changes in the tool they already know? This is an early adopter release and I anticipate this feature getting a good bit of tuning up before we release. Why don’t you download 3.3, give it a whirl, and let us know what you think?

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• How-to call server side Java from JavaScript

  - by frank.nimphius

  Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} The af:serverListener tag in Oracle ADF Faces allows JavaScript to call into server side Java. The example shown below uses an af:clientListener tag to invoke client side JavaScript in response to a key stroke in an Input Text field. The script then call a defined af:serverListener by its name defined in the type attribute. The server listener can be defined anywhere on the page, though from a code readability perspective it sounds like a good idea to put it close to from where it is invoked. <af:inputText id="it1" label="...">   <af:clientListener method="handleKeyUp" type="keyUp"/>   <af:serverListener type="MyCustomServerEvent"                      method="#{mybean.handleServerEvent}"/> </af:inputText> The JavaScript function below reads the event source from the event object that gets passed into the called JavaScript function. The call to the server side Java method, which is defined on a managed bean, is issued by a JavaScript call to AdfCustomEvent. The arguments passed to the custom event are the event source, the name of the server listener, a message payload formatted as an array of key:value pairs, and true/false indicating whether or not to make the call immediate in the request lifecycle. <af:resource type="javascript">     function handleKeyUp (evt) {    var inputTextComponen = event.getSource();       AdfCustomEvent.queue(inputTextComponent,                         "MyCustomServerEvent ",                         {fvalue:component.getSubmittedValue()},                         false);    event.cancel();}   </af:resource> The server side managed bean method uses a single argument signature with the argument type being ClientEvent. The client event provides information about the event source object - as provided in the call to AdfCustomEvent, as well as the payload keys and values. The payload is accessible from a call to getParameters, which returns a HashMap to get the values by its key identifiers.  public void handleServerEvent(ClientEvent ce){    String message = (String) ce.getParameters().get("fvalue");   ...  } Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Find the tag library at: http://download.oracle.com/docs/cd/E15523_01/apirefs.1111/e12419/tagdoc/af_serverListener.html

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• C# 4.0: Covariance And Contravariance In Generics

  - by Paulo Morgado

  C# 4.0 (and .NET 4.0) introduced covariance and contravariance to generic interfaces and delegates. But what is this variance thing? According to Wikipedia, in multilinear algebra and tensor analysis, covariance and contravariance describe how the quantitative description of certain geometrical or physical entities changes when passing from one coordinate system to another.(*) But what does this have to do with C# or .NET? In type theory, a the type T is greater (>) than type S if S is a subtype (derives from) T, which means that there is a quantitative description for types in a type hierarchy. So, how does covariance and contravariance apply to C# (and .NET) generic types? In C# (and .NET), variance applies to generic type parameters and not to the resulting generic type. A generic type parameter is: covariant if the ordering of the generic types follows the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. contravariant if the ordering of the generic types is reversed from the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. invariant if neither of the above apply. If this definition is applied to arrays, we can see that arrays have always been covariant because this is valid code: object[] objectArray = new string[] { "string 1", "string 2" }; objectArray[0] = "string 3"; objectArray[1] = new object(); However, when we try to run this code, the second assignment will throw an ArrayTypeMismatchException. Although the compiler was fooled into thinking this was valid code because an object is being assigned to an element of an array of object, at run time, there is always a type check to guarantee that the runtime type of the definition of the elements of the array is greater or equal to the instance being assigned to the element. In the above example, because the runtime type of the array is array of string, the first assignment of array elements is valid because string = string and the second is invalid because string = object. This leads to the conclusion that, although arrays have always been covariant, they are not safely covariant – code that compiles is not guaranteed to run without errors. In C#, the way to define that a generic type parameter as covariant is using the out generic modifier: public interface IEnumerable<out T> { IEnumerator<T> GetEnumerator(); } public interface IEnumerator<out T> { T Current { get; } bool MoveNext(); } Notice the convenient use the pre-existing out keyword. Besides the benefit of not having to remember a new hypothetic covariant keyword, out is easier to remember because it defines that the generic type parameter can only appear in output positions — read-only properties and method return values. In a similar way, the way to define a type parameter as contravariant is using the in generic modifier: public interface IComparer<in T> { int Compare(T x, T y); } Once again, the use of the pre-existing in keyword makes it easier to remember that the generic type parameter can only be used in input positions — write-only properties and method non ref and non out parameters. Because covariance and contravariance apply only to the generic type parameters, a generic type definition can have both covariant and contravariant generic type parameters in its definition: public delegate TResult Func<in T, out TResult>(T arg); A generic type parameter that is not marked covariant (out) or contravariant (in) is invariant. All the types in the .NET Framework where variance could be applied to its generic type parameters have been modified to take advantage of this new feature. In summary, the rules for variance in C# (and .NET) are: Variance in type parameters are restricted to generic interface and generic delegate types. A generic interface or generic delegate type can have both covariant and contravariant type parameters. Variance applies only to reference types; if you specify a value type for a variant type parameter, that type parameter is invariant for the resulting constructed type. Variance does not apply to delegate combination. That is, given two delegates of types Action<Derived> and Action<Base>, you cannot combine the second delegate with the first although the result would be type safe. Variance allows the second delegate to be assigned to a variable of type Action<Derived>, but delegates can combine only if their types match exactly. If you want to learn more about variance in C# (and .NET), you can always read: Covariance and Contravariance in Generics — MSDN Library Exact rules for variance validity — Eric Lippert Events get a little overhaul in C# 4, Afterward: Effective Events — Chris Burrows Note: Because variance is a feature of .NET 4.0 and not only of C# 4.0, all this also applies to Visual Basic 10.

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• 2d tank movement and turret solution

  - by Phil

  Hi! I'm making a simple top-down tank game on the ipad where the user controls the movement of the tank with the left "joystick" and the rotation of the turret with the right one. I've spent several hours just trying to get it to work decently but now I turn to the pros :) I have two referencial objects, one for the movement and one for the rotation. The referencial objects always stay max two units away from the tank and I use them to tell the tank in what direction to move. I chose this approach to decouple movement and rotational behaviour from the raw input of the joysticks, I believe this will make it simpler to implement whatever behaviour I want for the tank. My problem is 1; the turret rotates the long way to the target. With this I mean that the target can be -5 degrees away in rotation and still it rotates 355 degrees instead of -5 degrees. I can't figure out why. The other problem is with the movement. It just doesn't feel right to have the tank turn while moving. I'd like to have a solution that would work as well for the AI as for the player. A blackbox function for the movement where the player only specifies in what direction it should move and it moves there under the constraints that are imposed on it. I am using the standard joystick class found in the Unity iPhone package. This is the code I'm using for the movement: public class TankFollow : MonoBehaviour { //Check angle difference and turn accordingly public GameObject followPoint; public float speed; public float turningSpeed; void Update() { transform.position = Vector3.Slerp(transform.position, followPoint.transform.position, speed * Time.deltaTime); //Calculate angle var forwardA = transform.forward; var forwardB = (followPoint.transform.position - transform.position); var angleA = Mathf.Atan2(forwardA.x, forwardA.z) * Mathf.Rad2Deg; var angleB = Mathf.Atan2(forwardB.x, forwardB.z) * Mathf.Rad2Deg; var angleDiff = Mathf.DeltaAngle(angleA, angleB); //print(angleDiff.ToString()); if (angleDiff > 5) { //Rotate to transform.Rotate(new Vector3(0, (-turningSpeed * Time.deltaTime),0)); //transform.rotation = new Quaternion(transform.rotation.x, transform.rotation.y + adjustment, transform.rotation.z, transform.rotation.w); } else if (angleDiff < 5) { transform.Rotate(new Vector3(0, (turningSpeed * Time.deltaTime),0)); //transform.rotation = new Quaternion(transform.rotation.x, transform.rotation.y + adjustment, transform.rotation.z, transform.rotation.w); } else { } transform.position = new Vector3(transform.position.x, 0, transform.position.z); } } And this is the code I'm using to rotate the turret: void LookAt() { var forwardA = -transform.right; var forwardB = (toLookAt.transform.position - transform.position); var angleA = Mathf.Atan2(forwardA.x, forwardA.z) * Mathf.Rad2Deg; var angleB = Mathf.Atan2(forwardB.x, forwardB.z) * Mathf.Rad2Deg; var angleDiff = Mathf.DeltaAngle(angleA, angleB); //print(angleDiff.ToString()); if (angleDiff - 180 > 1) { //Rotate to transform.Rotate(new Vector3(0, (turretSpeed * Time.deltaTime),0)); //transform.rotation = new Quaternion(transform.rotation.x, transform.rotation.y + adjustment, transform.rotation.z, transform.rotation.w); } else if (angleDiff - 180 < -1) { transform.Rotate(new Vector3(0, (-turretSpeed * Time.deltaTime),0)); //transform.rotation = new Quaternion(transform.rotation.x, transform.rotation.y + adjustment, transform.rotation.z, transform.rotation.w); print((angleDiff - 180).ToString()); } else { } } Since I want the turret reference point to turn in relation to the tank (when you rotate the body, the turret should follow and not stay locked on since it makes it impossible to control when you've got two thumbs to work with), I've made the TurretFollowPoint a child of the Turret object, which in turn is a child of the body. I'm thinking that I'm making it too difficult for myself with the reference points but I'm imagining that it's a good idea. Please be honest about this point. So I'll be grateful for any help I can get! I'm using Unity3d iPhone. Thanks!

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• Html.RenderAction Failed when Validation Failed

  - by Shaun

  RenderAction method had been introduced when ASP.NET MVC 1.0 released in its MvcFuture assembly and then final announced along with the ASP.NET MVC 2.0. Similar as RenderPartial, the RenderAction can display some HTML markups which defined in a partial view in any parent views. But the RenderAction gives us the ability to populate the data from an action which may different from the action which populating the main view. For example, in Home/Index.aspx we can invoke the Html.RenderPartial(“MyPartialView”) but the data of MyPartialView must be populated by the Index action of the Home controller. If we need the MyPartialView to be shown in Product/Create.aspx we have to copy (or invoke) the relevant code from the Index action in Home controller to the Create action in the Product controller which is painful. But if we are using Html.RenderAction we can tell the ASP.NET MVC from which action/controller the data should be populated. in that way in the Home/Index.aspx and Product/Create.aspx views we just need to call Html.RenderAction(“CreateMyPartialView”, “MyPartialView”) so it will invoke the CreateMyPartialView action in MyPartialView controller regardless from which main view. But in my current project we found a bug when I implement a RenderAction method in the master page to show something that need to connect to the backend data center when the validation logic was failed on some pages. I created a sample application below.   Demo application I created an ASP.NET MVC 2 application and here I need to display the current date and time on the master page. I created an action in the Home controller named TimeSlot and stored the current date into ViewDate. This method was marked as HttpGet as it just retrieves some data instead of changing anything. 1: [HttpGet] 2: public ActionResult TimeSlot() 3: { 4: ViewData["timeslot"] = DateTime.Now; 5: return View("TimeSlot"); 6: } Next, I created a partial view under the Shared folder to display the date and time string. 1: <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<dynamic>" %> 2:  3: <span>Now: <% 1: : ViewData["timeslot"].ToString() %></span> Then at the master page I used Html.RenderAction to display it in front of the logon link. 1: <div id="logindisplay"> 2: <% 1: Html.RenderAction("TimeSlot", "Home"); %> 3:  4: <% 1: Html.RenderPartial("LogOnUserControl"); %> 5: </div> It’s fairly simple and works well when I navigated to any pages. But when I moved to the logon page and click the LogOn button without input anything in username and password the validation failed and my website crashed with the beautiful yellow page. (I really like its color style and fonts…)   How ASP.NET MVC executes Html.RenderAction In this example all other pages were rendered successful which means the ASP.NET MVC found the TimeSolt action under the Home controller except this situation. The only different is that when I clicked the LogOn button the browser send an HttpPost request to the server. Is that the reason of this bug? I created another action in Home controller with the same action name but for HttpPost. 1: [HttpPost] 2: [ActionName("TimeSlot")] 3: public ActionResult TimeSlot(object dummy) 4: { 5: return TimeSlot(); 6: } Or, I can use the AcceptVerbsAttribute on the TimeSlot action to let it allow both HttpGet and HttpPost. 1: [AcceptVerbs("GET", "POST")] 2: public ActionResult TimeSlot() 3: { 4: ViewData["timeslot"] = DateTime.Now; 5: return View("TimeSlot"); 6: } And then repeat what I did before and this time it worked well. Why we need the action for HttpPost here as it’s just data retrieving? That is because of how ASP.NET MVC executes the RenderAction method. In the source code of ASP.NET MVC we can see when proforming the RenderAction ASP.NET MVC creates a RequestContext instance from the current RequestContext and created a ChildActionMvcHandler instance which inherits from MvcHandler class. Then the ASP.NET MVC processes the handler through the HttpContext.Server.Execute method. That means it performs the action as a stand-alone request asynchronously and flush the result into the  TextWriter which is being used to render the current page. Since when I clicked the LogOn the request was in HttpPost so when ASP.NET MVC processed the ChildActionMvcHandler it would find the action which allow the current request method, which is HttpPost. Then our TimeSlot method in HttpGet would not be matched.   Summary In this post I introduced a bug in my currently developing project regards the new Html.RenderAction method provided within ASP.NET MVC 2 when processing a HttpPost request. In ASP.NET MVC world the underlying Http information became more important than in ASP.NET WebForm world. We need to pay more attention on which kind of request it currently created and how ASP.NET MVC processes.   Hope this helps, Shaun   All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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• Exitus Acta Probat: The Post-Processing Module

  - by Phil Factor

  Sometimes, one has to make certain ethical compromises to ensure the success of a corporate IT project. Exitus Acta Probat (literally 'the result validates the deeds' meaning that the ends justify the means)It was a while back, whilst working as a Technical Architect for a well-known international company, that I was given the task of designing the architecture of a rather specialized accounting system. We'd tried an off-the-shelf (OTS) Windows-based solution which crashed with dispiriting regularity, and didn't quite do what the business required. After a great deal of research and planning, we commissioned a Unux-based system that used X-terminals for the desktops of  the participating staff. X terminals are now obsolete, but were then hot stuff; stripped-down Unix workstations that provided client GUIs for networked applications long before the days of AJAX, Flash, Air and DHTML. I've never known a project go so smoothly: I'd been initially rather nervous about going the Unix route, believing then that  Unix programmers were excitable creatures who were prone to  indulge in role-play enactments of elves and wizards at the weekend, but the programmers I met from the company that did the work seemed to be rather donnish, earnest, people who quickly grasped our requirements and were faultlessly professional in their work.After thinking lofty thoughts for a while, there was considerable pummeling of keyboards by our suppliers, and a beautiful robust application was delivered to us ahead of dates.Soon, the department who had commissioned the work received shiny new X Terminals to replace their rather depressing lavatory-beige PCs. I modestly hung around as the application was commissioned and deployed to the department in order to receive the plaudits. They didn't come. Something was very wrong with the project. I couldn't put my finger on the problem, and the users weren't doing any more than desperately and futilely searching the application to find a fault with it.Many times in my life, I've come up against a predicament like this: The roll-out of an application goes wrong and you are hearing nothing that helps you to discern the cause but nit-*** noise. There is a limit to the emotional heat you can pack into a complaint about text being in the wrong font, or an input form being slightly cramped, but they tried their best. The answer is, of course, one that every IT executive should have tattooed prominently where they can read it in emergencies: In Vino Veritas (literally, 'in wine the truth', alcohol loosens the tongue. A roman proverb) It was time to slap the wallet and get the department down the pub with the tab in my name. It was an eye-watering investment, but hedged with an over-confident IT director who relished my discomfort. To cut a long story short, The real reason gushed out with the third round. We had deprived them of their PCs, which had been good for very little from the pure business perspective, but had provided them with many hours of happiness playing computer-based minesweeper and solitaire. There is no more agreeable way of passing away the interminable hours of wage-slavery than minesweeper or solitaire, and the employees had applauded the munificence of their employer who had provided them with the means to play it. I had, unthinkingly, deprived them of it.I held an emergency meeting with our suppliers the following day. I came over big with the notion that it was in their interests to provide a solution. They played it cool, probably knowing that it was my head on the block, not theirs. In the end, they came up with a compromise. they would temporarily descend from their lofty, cerebral stamping grounds  in order to write a server-based Minesweeper and Solitaire game for X Terminals, and install it in a concealed place within the system. We'd have to pay for it, though. I groaned. How could we do that? "Could we call it a 'post-processing module?" suggested their account executive.And so it came to pass. The application was a resounding success. Every now and then, the staff were able to indulge in some 'post-processing', with what turned out to be a very fine implementation of both minesweeper and solitaire. There were several refinements: A single click in a 'boss' button turned the games into what looked just like a financial spreadsheet.  They even threw in a multi-user version of Battleships. The extra payment for the post-processing module went through the change-control process without anyone untoward noticing, and peace once more descended. Only one thing niggles. Those games were good. Do they still survive, somewhere in a Linux library? If so, I'd like to claim a small part in their production.

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