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• Creating a Dynamic DataRow for easier DataRow Syntax

  - by Rick Strahl

  I've been thrown back into an older project that uses DataSets and DataRows as their entity storage model. I have several applications internally that I still maintain that run just fine (and I sometimes wonder if this wasn't easier than all this ORM crap we deal with with 'newer' improved technology today - but I disgress) but use this older code. For the most part DataSets/DataTables/DataRows are abstracted away in a pseudo entity model, but in some situations like queries DataTables and DataRows are still surfaced to the business layer. Here's an example. Here's a business object method that runs dynamic query and the code ends up looping over the result set using the ugly DataRow Array syntax:public int UpdateAllSafeTitles() { int result = this.Execute("select pk, title, safetitle from " + Tablename + " where EntryType=1", "TPks"); if (result < 0) return result; result = 0; foreach (DataRow row in this.DataSet.Tables["TPks"].Rows) { string title = row["title"] as string; string safeTitle = row["safeTitle"] as string; int pk = (int)row["pk"]; string newSafeTitle = this.GetSafeTitle(title); if (newSafeTitle != safeTitle) { this.ExecuteNonQuery("update " + this.Tablename + " set safeTitle=@safeTitle where pk=@pk", this.CreateParameter("@safeTitle",newSafeTitle), this.CreateParameter("@pk",pk) ); result++; } } return result; } The problem with looping over DataRow objecs is two fold: The array syntax is tedious to type and not real clear to look at, and explicit casting is required in order to do anything useful with the values. I've highlighted the place where this matters. Using the DynamicDataRow class I'll show in a minute this code can be changed to look like this:public int UpdateAllSafeTitles() { int result = this.Execute("select pk, title, safetitle from " + Tablename + " where EntryType=1", "TPks"); if (result < 0) return result; result = 0; foreach (DataRow row in this.DataSet.Tables["TPks"].Rows) { dynamic entry = new DynamicDataRow(row); string newSafeTitle = this.GetSafeTitle(entry.title); if (newSafeTitle != entry.safeTitle) { this.ExecuteNonQuery("update " + this.Tablename + " set safeTitle=@safeTitle where pk=@pk", this.CreateParameter("@safeTitle",newSafeTitle), this.CreateParameter("@pk",entry.pk) ); result++; } } return result; } The code looks much a bit more natural and describes what's happening a little nicer as well. Well, using the new dynamic features in .NET it's actually quite easy to implement the DynamicDataRow class. Creating your own custom Dynamic Objects .NET 4.0 introduced the Dynamic Language Runtime (DLR) and opened up a whole bunch of new capabilities for .NET applications. The dynamic type is an easy way to avoid Reflection and directly access members of 'dynamic' or 'late bound' objects at runtime. There's a lot of very subtle but extremely useful stuff that dynamic does (especially for COM Interop scenearios) but in its simplest form it often allows you to do away with manual Reflection at runtime. In addition you can create DynamicObject implementations that can perform  custom interception of member accesses and so allow you to provide more natural access to more complex or awkward data structures like the DataRow that I use as an example here. Bascially you can subclass DynamicObject and then implement a few methods (TryGetMember, TrySetMember, TryInvokeMember) to provide the ability to return dynamic results from just about any data structure using simple property/method access. In the code above, I created a custom DynamicDataRow class which inherits from DynamicObject and implements only TryGetMember and TrySetMember. Here's what simple class looks like:/// <summary> /// This class provides an easy way to turn a DataRow /// into a Dynamic object that supports direct property /// access to the DataRow fields. /// /// The class also automatically fixes up DbNull values /// (null into .NET and DbNUll to DataRow) /// </summary> public class DynamicDataRow : DynamicObject { /// <summary> /// Instance of object passed in /// </summary> DataRow DataRow; /// <summary> /// Pass in a DataRow to work off /// </summary> /// <param name="instance"></param> public DynamicDataRow(DataRow dataRow) { DataRow = dataRow; } /// <summary> /// Returns a value from a DataRow items array. /// If the field doesn't exist null is returned. /// DbNull values are turned into .NET nulls. /// /// </summary> /// <param name="binder"></param> /// <param name="result"></param> /// <returns></returns> public override bool TryGetMember(GetMemberBinder binder, out object result) { result = null; try { result = DataRow[binder.Name]; if (result == DBNull.Value) result = null; return true; } catch { } result = null; return false; } /// <summary> /// Property setter implementation tries to retrieve value from instance /// first then into this object /// </summary> /// <param name="binder"></param> /// <param name="value"></param> /// <returns></returns> public override bool TrySetMember(SetMemberBinder binder, object value) { try { if (value == null) value = DBNull.Value; DataRow[binder.Name] = value; return true; } catch {} return false; } } To demonstrate the basic features here's a short test: [TestMethod] [ExpectedException(typeof(RuntimeBinderException))] public void BasicDataRowTests() { DataTable table = new DataTable("table"); table.Columns.Add( new DataColumn() { ColumnName = "Name", DataType=typeof(string) }); table.Columns.Add( new DataColumn() { ColumnName = "Entered", DataType=typeof(DateTime) }); table.Columns.Add(new DataColumn() { ColumnName = "NullValue", DataType = typeof(string) }); DataRow row = table.NewRow(); DateTime now = DateTime.Now; row["Name"] = "Rick"; row["Entered"] = now; row["NullValue"] = null; // converted in DbNull dynamic drow = new DynamicDataRow(row); string name = drow.Name; DateTime entered = drow.Entered; string nulled = drow.NullValue; Assert.AreEqual(name, "Rick"); Assert.AreEqual(entered,now); Assert.IsNull(nulled); // this should throw a RuntimeBinderException Assert.AreEqual(entered,drow.enteredd); } The DynamicDataRow requires a custom constructor that accepts a single parameter that sets the DataRow. Once that's done you can access property values that match the field names. Note that types are automatically converted - no type casting is needed in the code you write. The class also automatically converts DbNulls to regular nulls and vice versa which is something that makes it much easier to deal with data returned from a database. What's cool here isn't so much the functionality - even if I'd prefer to leave DataRow behind ASAP -  but the fact that we can create a dynamic type that uses a DataRow as it's 'DataSource' to serve member values. It's pretty useful feature if you think about it, especially given how little code it takes to implement. By implementing these two simple methods we get to provide two features I was complaining about at the beginning that are missing from the DataRow: Direct Property Syntax Automatic Type Casting so no explicit casts are required Caveats As cool and easy as this functionality is, it's important to understand that it doesn't come for free. The dynamic features in .NET are - well - dynamic. Which means they are essentially evaluated at runtime (late bound). Rather than static typing where everything is compiled and linked by the compiler/linker, member invokations are looked up at runtime and essentially call into your custom code. There's some overhead in this. Direct invocations - the original code I showed - is going to be faster than the equivalent dynamic code. However, in the above code the difference of running the dynamic code and the original data access code was very minor. The loop running over 1500 result records took on average 13ms with the original code and 14ms with the dynamic code. Not exactly a serious performance bottleneck. One thing to remember is that Microsoft optimized the DLR code significantly so that repeated calls to the same operations are routed very efficiently which actually makes for very fast evaluation. The bottom line for performance with dynamic code is: Make sure you test and profile your code if you think that there might be a performance issue. However, in my experience with dynamic types so far performance is pretty good for repeated operations (ie. in loops). While usually a little slower the perf hit is a lot less typically than equivalent Reflection work. Although the code in the second example looks like standard object syntax, dynamic is not static code. It's evaluated at runtime and so there's no type recognition until runtime. This means no Intellisense at development time, and any invalid references that call into 'properties' (ie. fields in the DataRow) that don't exist still cause runtime errors. So in the case of the data row you still get a runtime error if you mistype a column name:// this should throw a RuntimeBinderException Assert.AreEqual(entered,drow.enteredd); Dynamic - Lots of uses The arrival of Dynamic types in .NET has been met with mixed emotions. Die hard .NET developers decry dynamic types as an abomination to the language. After all what dynamic accomplishes goes against all that a static language is supposed to provide. On the other hand there are clearly scenarios when dynamic can make life much easier (COM Interop being one place). Think of the possibilities. What other data structures would you like to expose to a simple property interface rather than some sort of collection or dictionary? And beyond what I showed here you can also implement 'Method missing' behavior on objects with InvokeMember which essentially allows you to create dynamic methods. It's all very flexible and maybe just as important: It's easy to do. There's a lot of power hidden in this seemingly simple interface. Your move…© Rick Strahl, West Wind Technologies, 2005-2011Posted in CSharp  .NET   Tweet (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• Demystifying Silverlight Dependency Properties

  - by dwahlin

  I have the opportunity to teach a lot of people about Silverlight (amongst other technologies) and one of the topics that definitely confuses people initially is the concept of dependency properties. I confess that when I first heard about them my initial thought was “Why do we need a specialized type of property?” While you can certainly use standard CLR properties in Silverlight applications, Silverlight relies heavily on dependency properties for just about everything it does behind the scenes. In fact, dependency properties are an essential part of the data binding, template, style and animation functionality available in Silverlight. They simply back standard CLR properties. In this post I wanted to put together a (hopefully) simple explanation of dependency properties and why you should care about them if you’re currently working with Silverlight or looking to move to it.   What are Dependency Properties? XAML provides a great way to define layout controls, user input controls, shapes, colors and data binding expressions in a declarative manner. There’s a lot that goes on behind the scenes in order to make XAML work and an important part of that magic is the use of dependency properties. If you want to bind data to a property, style it, animate it or transform it in XAML then the property involved has to be a dependency property to work properly. If you’ve ever positioned a control in a Canvas using Canvas.Left or placed a control in a specific Grid row using Grid.Row then you’ve used an attached property which is a specialized type of dependency property. Dependency properties play a key role in XAML and the overall Silverlight framework. Any property that you bind, style, template, animate or transform must be a dependency property in Silverlight applications. You can programmatically bind values to controls and work with standard CLR properties, but if you want to use the built-in binding expressions available in XAML (one of my favorite features) or the Binding class available through code then dependency properties are a necessity. Dependency properties aren’t needed in every situation, but if you want to customize your application very much you’ll eventually end up needing them. For example, if you create a custom user control and want to expose a property that consumers can use to change the background color, you have to define it as a dependency property if you want bindings, styles and other features to be available for use. Now that the overall purpose of dependency properties has been discussed let’s take a look at how you can create them. Creating Dependency Properties When .NET first came out you had to write backing fields for each property that you defined as shown next: Brush _ScheduleBackground; public Brush ScheduleBackground { get { return _ScheduleBackground; } set { _ScheduleBackground = value; } } Although .NET 2.0 added auto-implemented properties (for example: public Brush ScheduleBackground { get; set; }) where the compiler would automatically generate the backing field used by get and set blocks, the concept is still the same as shown in the above code; a property acts as a wrapper around a field. Silverlight dependency properties replace the _ScheduleBackground field shown in the previous code and act as the backing store for a standard CLR property. The following code shows an example of defining a dependency property named ScheduleBackgroundProperty: public static readonly DependencyProperty ScheduleBackgroundProperty = DependencyProperty.Register("ScheduleBackground", typeof(Brush), typeof(Scheduler), null);   Looking through the code the first thing that may stand out is that the definition for ScheduleBackgroundProperty is marked as static and readonly and that the property appears to be of type DependencyProperty. This is a standard pattern that you’ll use when working with dependency properties. You’ll also notice that the property explicitly adds the word “Property” to the name which is another standard you’ll see followed. In addition to defining the property, the code also makes a call to the static DependencyProperty.Register method and passes the name of the property to register (ScheduleBackground in this case) as a string. The type of the property, the type of the class that owns the property and a null value (more on the null value later) are also passed. In this example a class named Scheduler acts as the owner. The code handles registering the property as a dependency property with the call to Register(), but there’s a little more work that has to be done to allow a value to be assigned to and retrieved from the dependency property. The following code shows the complete code that you’ll typically use when creating a dependency property. You can find code snippets that greatly simplify the process of creating dependency properties out on the web. The MVVM Light download available from http://mvvmlight.codeplex.com comes with built-in dependency properties snippets as well. public static readonly DependencyProperty ScheduleBackgroundProperty = DependencyProperty.Register("ScheduleBackground", typeof(Brush), typeof(Scheduler), null); public Brush ScheduleBackground { get { return (Brush)GetValue(ScheduleBackgroundProperty); } set { SetValue(ScheduleBackgroundProperty, value); } } The standard CLR property code shown above should look familiar since it simply wraps the dependency property. However, you’ll notice that the get and set blocks call GetValue and SetValue methods respectively to perform the appropriate operation on the dependency property. GetValue and SetValue are members of the DependencyObject class which is another key component of the Silverlight framework. Silverlight controls and classes (TextBox, UserControl, CompositeTransform, DataGrid, etc.) ultimately derive from DependencyObject in their inheritance hierarchy so that they can support dependency properties. Dependency properties defined in Silverlight controls and other classes tend to follow the pattern of registering the property by calling Register() and then wrapping the dependency property in a standard CLR property (as shown above). They have a standard property that wraps a registered dependency property and allows a value to be assigned and retrieved. If you need to expose a new property on a custom control that supports data binding expressions in XAML then you’ll follow this same pattern. Dependency properties are extremely useful once you understand why they’re needed and how they’re defined. Detecting Changes and Setting Defaults When working with dependency properties there will be times when you want to assign a default value or detect when a property changes so that you can keep the user interface in-sync with the property value. Silverlight’s DependencyProperty.Register() method provides a fourth parameter that accepts a PropertyMetadata object instance. PropertyMetadata can be used to hook a callback method to a dependency property. The callback method is called when the property value changes. PropertyMetadata can also be used to assign a default value to the dependency property. By assigning a value of null for the final parameter passed to Register() you’re telling the property that you don’t care about any changes and don’t have a default value to apply. Here are the different constructor overloads available on the PropertyMetadata class: PropertyMetadata Constructor Overload Description PropertyMetadata(Object) Used to assign a default value to a dependency property. PropertyMetadata(PropertyChangedCallback) Used to assign a property changed callback method. PropertyMetadata(Object, PropertyChangedCalback) Used to assign a default property value and a property changed callback.   There are many situations where you need to know when a dependency property changes or where you want to apply a default. Performing either task is easily accomplished by creating a new instance of the PropertyMetadata class and passing the appropriate values to its constructor. The following code shows an enhanced version of the initial dependency property code shown earlier that demonstrates these concepts: public Brush ScheduleBackground { get { return (Brush)GetValue(ScheduleBackgroundProperty); } set { SetValue(ScheduleBackgroundProperty, value); } } public static readonly DependencyProperty ScheduleBackgroundProperty = DependencyProperty.Register("ScheduleBackground", typeof(Brush), typeof(Scheduler), new PropertyMetadata(new SolidColorBrush(Colors.LightGray), ScheduleBackgroundChanged)); private static void ScheduleBackgroundChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { var scheduler = d as Scheduler; scheduler.Background = e.NewValue as Brush; } The code wires ScheduleBackgroundProperty to a property change callback method named ScheduleBackgroundChanged. What’s interesting is that this callback method is static (as is the dependency property) so it gets passed the instance of the object that owns the property that has changed (otherwise we wouldn’t be able to get to the object instance). In this example the dependency object is cast to a Scheduler object and its Background property is assigned to the new value of the dependency property. The code also handles assigning a default value of LightGray to the dependency property by creating a new instance of a SolidColorBrush. To Sum Up In this post you’ve seen the role of dependency properties and how they can be defined in code. They play a big role in XAML and the overall Silverlight framework. You can think of dependency properties as being replacements for fields that you’d normally use with standard CLR properties. In addition to a discussion on how dependency properties are created, you also saw how to use the PropertyMetadata class to define default dependency property values and hook a dependency property to a callback method. The most important thing to understand with dependency properties (especially if you’re new to Silverlight) is that they’re needed if you want a property to support data binding, animations, transformations and styles properly. Any time you create a property on a custom control or user control that has these types of requirements you’ll want to pick a dependency property over of a standard CLR property with a backing field. There’s more that can be covered with dependency properties including a related property called an attached property….more to come.

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• Dynamically creating a Generic Type at Runtime

  - by Rick Strahl

  I learned something new today. Not uncommon, but it's a core .NET runtime feature I simply did not know although I know I've run into this issue a few times and worked around it in other ways. Today there was no working around it and a few folks on Twitter pointed me in the right direction. The question I ran into is: How do I create a type instance of a generic type when I have dynamically acquired the type at runtime? Yup it's not something that you do everyday, but when you're writing code that parses objects dynamically at runtime it comes up from time to time. In my case it's in the bowels of a custom JSON parser. After some thought triggered by a comment today I realized it would be fairly easy to implement two-way Dictionary parsing for most concrete dictionary types. I could use a custom Dictionary serialization format that serializes as an array of key/value objects. Basically I can use a custom type (that matches the JSON signature) to hold my parsed dictionary data and then add it to the actual dictionary when parsing is complete. Generic Types at Runtime One issue that came up in the process was how to figure out what type the Dictionary<K,V> generic parameters take. Reflection actually makes it fairly easy to figure out generic types at runtime with code like this: if (arrayType.GetInterface("IDictionary") != null) { if (arrayType.IsGenericType) { var keyType = arrayType.GetGenericArguments()[0]; var valueType = arrayType.GetGenericArguments()[1]; … } } The GetArrayType method gets passed a type instance that is the array or array-like object that is rendered in JSON as an array (which includes IList, IDictionary, IDataReader and a few others). In my case the type passed would be something like Dictionary<string, CustomerEntity>. So I know what the parent container class type is. Based on the the container type using it's then possible to use GetGenericTypeArguments() to retrieve all the generic types in sequential order of definition (ie. string, CustomerEntity). That's the easy part. Creating a Generic Type and Providing Generic Parameters at RunTime The next problem is how do I get a concrete type instance for the generic type? I know what the type name and I have a type instance is but it's generic, so how do I get a type reference to keyvaluepair<K,V> that is specific to the keyType and valueType above? Here are a couple of things that come to mind but that don't work (and yes I tried that unsuccessfully first): Type elementType = typeof(keyvalue<keyType, valueType>); Type elementType = typeof(keyvalue<typeof(keyType), typeof(valueType)>); The problem is that this explicit syntax expects a type literal not some dynamic runtime value, so both of the above won't even compile. I turns out the way to create a generic type at runtime is using a fancy bit of syntax that until today I was completely unaware of: Type elementType = typeof(keyvalue<,>).MakeGenericType(keyType, valueType); The key is the type(keyvalue<,>) bit which looks weird at best. It works however and produces a non-generic type reference. You can see the difference between the full generic type and the non-typed (?) generic type in the debugger: The nonGenericType doesn't show any type specialization, while the elementType type shows the string, CustomerEntity (truncated above) in the type name. Once the full type reference exists (elementType) it's then easy to create an instance. In my case the parser parses through the JSON and when it completes parsing the value/object it creates a new keyvalue<T,V> instance. Now that I know the element type that's pretty trivial with: // Objects start out null until we find the opening tag resultObject = Activator.CreateInstance(elementType); Here the result object is picked up by the JSON array parser which creates an instance of the child object (keyvalue<K,V>) and then parses and assigns values from the JSON document using the types  key/value property signature. Internally the parser then takes each individually parsed item and adds it to a list of  List<keyvalue<K,V>> items. Parsing through a Generic type when you only have Runtime Type Information When parsing of the JSON array is done, the List needs to be turned into a defacto Dictionary<K,V>. This should be easy since I know that I'm dealing with an IDictionary, and I know the generic types for the key and value. The problem is again though that this needs to happen at runtime which would mean using several Convert.ChangeType() calls in the code to dynamically cast at runtime. Yuk. In the end I decided the easier and probably only slightly slower way to do this is a to use the dynamic type to collect the items and assign them to avoid all the dynamic casting madness: else if (IsIDictionary) { IDictionary dict = Activator.CreateInstance(arrayType) as IDictionary; foreach (dynamic item in items) { dict.Add(item.key, item.value); } return dict; } This code creates an instance of the generic dictionary type first, then loops through all of my custom keyvalue<K,V> items and assigns them to the actual dictionary. By using Dynamic here I can side step all the explicit type conversions that would be required in the three highlighted areas (not to mention that this nested method doesn't have access to the dictionary item generic types here). Static <- -> Dynamic Dynamic casting in a static language like C# is a bitch to say the least. This is one of the few times when I've cursed static typing and the arcane syntax that's required to coax types into the right format. It works but it's pretty nasty code. If it weren't for dynamic that last bit of code would have been a pretty ugly as well with a bunch of Convert.ChangeType() calls to litter the code. Fortunately this type of type convulsion is rather rare and reserved for system level code. It's not every day that you create a string to object parser after all :-)© Rick Strahl, West Wind Technologies, 2005-2011Posted in .NET  CSharp   Tweet (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• Why Fusion Middleware matters to Oracle Applications and Fusion Applications customers?

  - by Harish Gaur

  Did you miss this general session on Monday morning presented by Amit Zavery, VP of Oracle Fusion Middleware Product Management? There will be a recording made available shortly and in the meanwhile, here is a recap. Amit presented 5 strategies customers can leverage today to extend their applications. Figure 1: 5 Oracle Fusion Middleware strategies to extend Oracle Applications & Oracle Fusion Apps 1. Engage Everyone – Provide intuitive and social experience for application users using Oracle WebCenter 2. Extend Enterprise – Extend Oracle Applications to mobile devices using Oracle ADF Mobile 3. Orchestrate Processes – Automate key organization processes across on-premise & cloud applications using Oracle BPM Suite & Oracle SOA Suite 4. Secure the core – Provide single sign-on and self-service provisioning across multiple apps using Oracle Identity Management 5. Optimize Performance – Leverage Exalogic stack to consolidate multiple instance and improve performance of Oracle Applications Session included 3 demonstrations to illustrate these strategies. 1. First demo highlighted significance of mobile applications for unlocking existing investment in Applications such as EBS. Using a native iPhone application interacting with e-Business Suite, demo showed how expense approval can be mobile enabled with enhanced visibility using BI dashboards. 2. Second demo showed how you can extend a banking process in Siebel and Oracle Policy Automation with Oracle BPM Suite.Process starts in Siebel with a customer requesting a loan, and then jumps to OPA for loan recommendations and decision making and loan processing with approvals in handled in BPM Suite. Once approvals are completed Siebel is updated to complete the process. 3. Final demo showcased FMW components inside Fusion Applications, specifically WebCenter. Boeing, Underwriter Laboratories and Electronic Arts joined this quest and discussed 3 different approaches of leveraging Fusion Middleware stack to maximize their investment in Oracle Applications and/or Fusion Applications technology. Let’s briefly review what these customers shared during the session: 1. Extend Fusion Applications We know that Oracle Fusion Middleware is the underlying technology infrastructure for Oracle Fusion Applications. Architecturally, Oracle Fusion Apps leverages several components of Oracle Fusion Middleware from Oracle WebCenter for rich collaborative interface, Oracle SOA Suite & Oracle BPM Suite for orchestrating key underlying processes to Oracle BIEE for dash boarding and analytics. Boeing talked about how they are using Oracle BPM Suite 11g, a key component of Oracle Fusion Middleware with Oracle Fusion Apps to transform their supply chain. Tim Murnin, Director of Supply Chain talked about Boeing’s 5 year supply chain transformation journey. Boeing’s Integrated and Information Management division began with automation of critical RFQ process using Oracle BPM Suite. This 1st phase resulted in 38% reduction in labor costs for RFP. As a next step in this effort, Boeing is now creating a platform to enable electronic Order Management. Fusion Apps are playing a significant role in this phase. Boeing has gone live with Oracle Fusion Product Hub and efforts are underway with Oracle Fusion Distributed Order Orchestration (DOO). So, where does Oracle BPM Suite 11g fit in this equation? Let me explain. Business processes within Fusion Apps are designed using 2 standards: Business Process Execution Language (BPEL) and Business Process Modeling Notation (BPMN). These processes can be easily configured using declarative set of tools. Boeing leverages Oracle BPM Suite 11g (which supports BPMN 2.0) and Oracle SOA Suite (which supports BPEL) to “extend” these applications. Traditionally, customizations are done within an app using native technologies. But, instead of making process changes within Fusion Apps, Boeing has taken an approach of building “extensions” layer on top of the application. Fig 2: Boeing’s use of Oracle BPM Suite to orchestrate key supply chain processes across Fusion Apps 2. Maximize Oracle Applications investment Fusion Middleware appeals not only to Fusion Apps customers, but is also leveraged by Oracle E-Business Suite, PeopleSoft, Siebel and JD Edwards customers significantly. Using Oracle BPM Suite and Oracle SOA Suite is the recommended extension strategy for Oracle Fusion Apps and Oracle Applications Unlimited customers. Electronic Arts, E-Business Suite customer, spoke about their strategy to transform their order-to-cash process using Oracle SOA Suite, Oracle Foundation Packs and Oracle BAM. Udesh Naicker, Sr Director of IT at Elecronic Arts (EA), discussed how growth of social and digital gaming had started to put tremendous pressure on EA’s existing IT infrastructure. He discussed the challenge with millions of micro-transactions coming from several sources – Microsoft Xbox, Paypal, several service providers. EA found Order-2-Cash processes stretched to their limits. They lacked visibility into these transactions across the entire value chain. EA began by consolidating their E-Business Suite R11 instances into single E-Business Suite R12. EA needed to cater to a variety of service requirements, connectivity methods, file formats, and information latency. Their integration strategy was tactical, i.e., using file uploads, TIBCO, SQL scripts. After consolidating E-Business suite, EA standardized their integration approach with Oracle SOA Suite and Oracle AIA Foundation Pack. Oracle SOA Suite is the platform used to extend E-Business Suite R12 and standardize 60+ interfaces across several heterogeneous systems including PeopleSoft, Demantra, SF.com, Workday, and Managed EDI services spanning on-premise, hosted and cloud applications. EA believes that Oracle SOA Suite 11g based extension strategy has helped significantly in the followings ways: - It helped them keep customizations out of E-Business Suite, thereby keeping EBS R12 vanilla and upgrade safe - Developers are now proficient in technology which is also leveraged by Fusion Apps. This has helped them prepare for adoption of Fusion Apps in the future Fig 3: Using Oracle SOA Suite & Oracle e-Business Suite, Electronic Arts built new platform for order processing 3. Consolidate apps and improve scalability Exalogic is an optimal platform for customers to consolidate their application deployments and enhance performance. Underwriter Laboratories talked about their strategy to run their mission critical applications including e-Business Suite on Exalogic. Christian Anschuetz, CIO of Underwriter Laboratories (UL) shared how UL is on a growth path - $1B to $2.5B in 5 years- and planning a significant business transformation from a not-for-profit to a for-profit business. To support this growth, UL is planning to simplify its IT environment and the deployment complexity associated with ERP applications and technology it runs on. Their current applications were deployed on variety of hardware platforms and lacked comprehensive disaster recovery architecture. UL embarked on a mission to deploy E-Business Suite on Exalogic. UL’s solution is unique because it is one of the first to deploy a large number of Oracle applications and related Fusion Middleware technologies (SOA, BI, Analytical Applications AIA Foundation Pack and AIA EBS to Siebel UCM prebuilt integration) on the combined Exalogic and Exadata environment. UL is planning to move to a virtualized architecture toward the end of 2012 to securely host external facing applications like iStore Fig 4: Underwrites Labs deployed e-Business Suite on Exalogic to achieve performance gains Key takeaways are: - Fusion Middleware platform is certified with major Oracle Applications Unlimited offerings. Fusion Middleware is the underlying technological infrastructure for Fusion Apps - Customers choose Oracle Fusion Middleware to extend their applications (Apps Unlimited or Fusion Apps) to keep applications upgrade safe and prepare for Fusion Apps - Exalogic is an optimum platform to consolidate applications deployments and enhance performance

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• Why Fusion Middleware matters to Oracle Applications and Fusion Applications customers?

  - by Harish Gaur

  Did you miss this general session on Monday morning presented by Amit Zavery, VP of Oracle Fusion Middleware Product Management? There will be a recording made available shortly and in the meanwhile, here is a recap. Amit presented 5 strategies customers can leverage today to extend their applications. Figure 1: 5 Oracle Fusion Middleware strategies to extend Oracle Applications & Oracle Fusion Apps 1. Engage Everyone – Provide intuitive and social experience for application users using Oracle WebCenter 2. Extend Enterprise – Extend Oracle Applications to mobile devices using Oracle ADF Mobile 3. Orchestrate Processes – Automate key organization processes across on-premise & cloud applications using Oracle BPM Suite & Oracle SOA Suite 4. Secure the core – Provide single sign-on and self-service provisioning across multiple apps using Oracle Identity Management 5. Optimize Performance – Leverage Exalogic stack to consolidate multiple instance and improve performance of Oracle Applications Session included 3 demonstrations to illustrate these strategies. 1. First demo highlighted significance of mobile applications for unlocking existing investment in Applications such as EBS. Using a native iPhone application interacting with e-Business Suite, demo showed how expense approval can be mobile enabled with enhanced visibility using BI dashboards. 2. Second demo showed how you can extend a banking process in Siebel and Oracle Policy Automation with Oracle BPM Suite.Process starts in Siebel with a customer requesting a loan, and then jumps to OPA for loan recommendations and decision making and loan processing with approvals in handled in BPM Suite. Once approvals are completed Siebel is updated to complete the process. 3. Final demo showcased FMW components inside Fusion Applications, specifically WebCenter. Boeing, Underwriter Laboratories and Electronic Arts joined this quest and discussed 3 different approaches of leveraging Fusion Middleware stack to maximize their investment in Oracle Applications and/or Fusion Applications technology. Let’s briefly review what these customers shared during the session: 1. Extend Fusion Applications We know that Oracle Fusion Middleware is the underlying technology infrastructure for Oracle Fusion Applications. Architecturally, Oracle Fusion Apps leverages several components of Oracle Fusion Middleware from Oracle WebCenter for rich collaborative interface, Oracle SOA Suite & Oracle BPM Suite for orchestrating key underlying processes to Oracle BIEE for dash boarding and analytics. Boeing talked about how they are using Oracle BPM Suite 11g, a key component of Oracle Fusion Middleware with Oracle Fusion Apps to transform their supply chain. Tim Murnin, Director of Supply Chain talked about Boeing’s 5 year supply chain transformation journey. Boeing’s Integrated and Information Management division began with automation of critical RFQ process using Oracle BPM Suite. This 1st phase resulted in 38% reduction in labor costs for RFP. As a next step in this effort, Boeing is now creating a platform to enable electronic Order Management. Fusion Apps are playing a significant role in this phase. Boeing has gone live with Oracle Fusion Product Hub and efforts are underway with Oracle Fusion Distributed Order Orchestration (DOO). So, where does Oracle BPM Suite 11g fit in this equation? Let me explain. Business processes within Fusion Apps are designed using 2 standards: Business Process Execution Language (BPEL) and Business Process Modeling Notation (BPMN). These processes can be easily configured using declarative set of tools. Boeing leverages Oracle BPM Suite 11g (which supports BPMN 2.0) and Oracle SOA Suite (which supports BPEL) to “extend” these applications. Traditionally, customizations are done within an app using native technologies. But, instead of making process changes within Fusion Apps, Boeing has taken an approach of building “extensions” layer on top of the application. Fig 2: Boeing’s use of Oracle BPM Suite to orchestrate key supply chain processes across Fusion Apps 2. Maximize Oracle Applications investment Fusion Middleware appeals not only to Fusion Apps customers, but is also leveraged by Oracle E-Business Suite, PeopleSoft, Siebel and JD Edwards customers significantly. Using Oracle BPM Suite and Oracle SOA Suite is the recommended extension strategy for Oracle Fusion Apps and Oracle Applications Unlimited customers. Electronic Arts, E-Business Suite customer, spoke about their strategy to transform their order-to-cash process using Oracle SOA Suite, Oracle Foundation Packs and Oracle BAM. Udesh Naicker, Sr Director of IT at Elecronic Arts (EA), discussed how growth of social and digital gaming had started to put tremendous pressure on EA’s existing IT infrastructure. He discussed the challenge with millions of micro-transactions coming from several sources – Microsoft Xbox, Paypal, several service providers. EA found Order-2-Cash processes stretched to their limits. They lacked visibility into these transactions across the entire value chain. EA began by consolidating their E-Business Suite R11 instances into single E-Business Suite R12. EA needed to cater to a variety of service requirements, connectivity methods, file formats, and information latency. Their integration strategy was tactical, i.e., using file uploads, TIBCO, SQL scripts. After consolidating E-Business suite, EA standardized their integration approach with Oracle SOA Suite and Oracle AIA Foundation Pack. Oracle SOA Suite is the platform used to extend E-Business Suite R12 and standardize 60+ interfaces across several heterogeneous systems including PeopleSoft, Demantra, SF.com, Workday, and Managed EDI services spanning on-premise, hosted and cloud applications. EA believes that Oracle SOA Suite 11g based extension strategy has helped significantly in the followings ways: - It helped them keep customizations out of E-Business Suite, thereby keeping EBS R12 vanilla and upgrade safe - Developers are now proficient in technology which is also leveraged by Fusion Apps. This has helped them prepare for adoption of Fusion Apps in the future Fig 3: Using Oracle SOA Suite & Oracle e-Business Suite, Electronic Arts built new platform for order processing 3. Consolidate apps and improve scalability Exalogic is an optimal platform for customers to consolidate their application deployments and enhance performance. Underwriter Laboratories talked about their strategy to run their mission critical applications including e-Business Suite on Exalogic. Christian Anschuetz, CIO of Underwriter Laboratories (UL) shared how UL is on a growth path - $1B to $2.5B in 5 years- and planning a significant business transformation from a not-for-profit to a for-profit business. To support this growth, UL is planning to simplify its IT environment and the deployment complexity associated with ERP applications and technology it runs on. Their current applications were deployed on variety of hardware platforms and lacked comprehensive disaster recovery architecture. UL embarked on a mission to deploy E-Business Suite on Exalogic. UL’s solution is unique because it is one of the first to deploy a large number of Oracle applications and related Fusion Middleware technologies (SOA, BI, Analytical Applications AIA Foundation Pack and AIA EBS to Siebel UCM prebuilt integration) on the combined Exalogic and Exadata environment. UL is planning to move to a virtualized architecture toward the end of 2012 to securely host external facing applications like iStore Fig 4: Underwrites Labs deployed e-Business Suite on Exalogic to achieve performance gains Key takeaways are: - Fusion Middleware platform is certified with major Oracle Applications Unlimited offerings. Fusion Middleware is the underlying technological infrastructure for Fusion Apps - Customers choose Oracle Fusion Middleware to extend their applications (Apps Unlimited or Fusion Apps) to keep applications upgrade safe and prepare for Fusion Apps - Exalogic is an optimum platform to consolidate applications deployments and enhance performance TAGS: Fusion Apps, Exalogic, BPM Suite, SOA Suite, e-Business Suite Integration

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• Adding an Admin user to an ASP.NET MVC 4 application using a single drop-in file

  - by Jon Galloway

  I'm working on an ASP.NET MVC 4 tutorial and wanted to set it up so just dropping a file in App_Start would create a user named "Owner" and assign them to the "Administrator" role (more explanation at the end if you're interested). There are reasons why this wouldn't fit into most application scenarios: It's not efficient, as it checks for (and creates, if necessary) the user every time the app starts up The username, password, and role name are hardcoded in the app (although they could be pulled from config) Automatically creating an administrative account in code (without user interaction) could lead to obvious security issues if the user isn't informed However, with some modifications it might be more broadly useful - e.g. creating a test user with limited privileges, ensuring a required account isn't accidentally deleted, or - as in my case - setting up an account for demonstration or tutorial purposes. Challenge #1: Running on startup without requiring the user to install or configure anything I wanted to see if this could be done just by having the user drop a file into the App_Start folder and go. No copying code into Global.asax.cs, no installing addition NuGet packages, etc. That may not be the best approach - perhaps a NuGet package with a dependency on WebActivator would be better - but I wanted to see if this was possible and see if it offered the best experience. Fortunately ASP.NET 4 and later provide a PreApplicationStartMethod attribute which allows you to register a method which will run when the application starts up. You drop this attribute in your application and give it two parameters: a method name and the type that contains it. I created a static class named PreApplicationTasks with a static method named, then dropped this attribute in it: [assembly: PreApplicationStartMethod(typeof(PreApplicationTasks), "Initializer")] That's it. One small gotcha: the namespace can be a problem with assembly attributes. I decided my class didn't need a namespace. Challenge #2: Only one PreApplicationStartMethod per assembly In .NET 4, the PreApplicationStartMethod is marked as AllMultiple=false, so you can only have one PreApplicationStartMethod per assembly. This was fixed in .NET 4.5, as noted by Jon Skeet, so you can have as many PreApplicationStartMethods as you want (allowing you to keep your users waiting for the application to start indefinitely!). The WebActivator NuGet package solves the multiple instance problem if you're in .NET 4 - it registers as a PreApplicationStartMethod, then calls any methods you've indicated using [assembly: WebActivator.PreApplicationStartMethod(type, method)]. David Ebbo blogged about that here:  Light up your NuGets with startup code and WebActivator. In my scenario (bootstrapping a beginner level tutorial) I decided not to worry about this and stick with PreApplicationStartMethod. Challenge #3: PreApplicationStartMethod kicks in before configuration has been read This is by design, as Phil explains. It allows you to make changes that need to happen very early in the pipeline, well before Application_Start. That's fine in some cases, but it caused me problems when trying to add users, since the Membership Provider configuration hadn't yet been read - I got an exception stating that "Default Membership Provider could not be found." The solution here is to run code that requires configuration in a PostApplicationStart method. But how to do that? Challenge #4: Getting PostApplicationStartMethod without requiring WebActivator The WebActivator NuGet package, among other things, provides a PostApplicationStartMethod attribute. That's generally how I'd recommend running code that needs to happen after Application_Start: [assembly: WebActivator.PostApplicationStartMethod(typeof(TestLibrary.MyStartupCode), "CallMeAfterAppStart")] This works well, but I wanted to see if this would be possible without WebActivator. Hmm. Well, wait a minute - WebActivator works in .NET 4, so clearly it's registering and calling PostApplicationStartup tasks somehow. Off to the source code! Sure enough, there's even a handy comment in ActivationManager.cs which shows where PostApplicationStartup tasks are being registered: public static void Run() { if (!_hasInited) { RunPreStartMethods(); // Register our module to handle any Post Start methods. But outside of ASP.NET, just run them now if (HostingEnvironment.IsHosted) { Microsoft.Web.Infrastructure.DynamicModuleHelper.DynamicModuleUtility.RegisterModule(typeof(StartMethodCallingModule)); } else { RunPostStartMethods(); } _hasInited = true; } } Excellent. Hey, that DynamicModuleUtility seems familiar... Sure enough, K. Scott Allen mentioned it on his blog last year. This is really slick - a PreApplicationStartMethod can register a new HttpModule in code. Modules are run right after application startup, so that's a perfect time to do any startup stuff that requires configuration to be read. As K. Scott says, it's this easy: using System; using System.Web; using Microsoft.Web.Infrastructure.DynamicModuleHelper; [assembly:PreApplicationStartMethod(typeof(MyAppStart), "Start")] public class CoolModule : IHttpModule { // implementation not important // imagine something cool here } public static class MyAppStart { public static void Start() { DynamicModuleUtility.RegisterModule(typeof(CoolModule)); } } Challenge #5: Cooperating with SimpleMembership The ASP.NET MVC Internet template includes SimpleMembership. SimpleMembership is a big improvement over traditional ASP.NET Membership. For one thing, rather than forcing a database schema, it can work with your database schema. In the MVC 4 Internet template case, it uses Entity Framework Code First to define the user model. SimpleMembership bootstrap includes a call to InitializeDatabaseConnection, and I want to play nice with that. There's a new [InitializeSimpleMembership] attribute on the AccountController, which calls \Filters\InitializeSimpleMembershipAttribute.cs::OnActionExecuting(). That comment in that method that says "Ensure ASP.NET Simple Membership is initialized only once per app start" which sounds like good advice. I figured the best thing would be to call that directly: new Mvc4SampleApplication.Filters.InitializeSimpleMembershipAttribute().OnActionExecuting(null); I'm not 100% happy with this - in fact, it's my least favorite part of this solution. There are two problems - first, directly calling a method on a filter, while legal, seems odd. Worse, though, the Filter lives in the application's namespace, which means that this code no longer works well as a generic drop-in. The simplest workaround would be to duplicate the relevant SimpleMembership initialization code into my startup code, but I'd rather not. I'm interested in your suggestions here. Challenge #6: Module Init methods are called more than once When debugging, I noticed (and remembered) that the Init method may be called more than once per page request - it's run once per instance in the app pool, and an individual page request can cause multiple resource requests to the server. While SimpleMembership does have internal checks to prevent duplicate user or role entries, I'd rather not cause or handle those exceptions. So here's the standard single-use lock in the Module's init method: void IHttpModule.Init(HttpApplication context) { lock (lockObject) { if (!initialized) { //Do stuff } initialized = true; } } Putting it all together With all of that out of the way, here's the code I came up with: using Mvc4SampleApplication.Filters; using System.Web; using System.Web.Security; using WebMatrix.WebData; [assembly: PreApplicationStartMethod(typeof(PreApplicationTasks), "Initializer")] public static class PreApplicationTasks { public static void Initializer() { Microsoft.Web.Infrastructure.DynamicModuleHelper.DynamicModuleUtility .RegisterModule(typeof(UserInitializationModule)); } } public class UserInitializationModule : IHttpModule { private static bool initialized; private static object lockObject = new object(); private const string _username = "Owner"; private const string _password = "p@ssword123"; private const string _role = "Administrator"; void IHttpModule.Init(HttpApplication context) { lock (lockObject) { if (!initialized) { new InitializeSimpleMembershipAttribute().OnActionExecuting(null); if (!WebSecurity.UserExists(_username)) WebSecurity.CreateUserAndAccount(_username, _password); if (!Roles.RoleExists(_role)) Roles.CreateRole(_role); if (!Roles.IsUserInRole(_username, _role)) Roles.AddUserToRole(_username, _role); } initialized = true; } } void IHttpModule.Dispose() { } } The Verdict: Is this a good thing? Maybe. I think you'll agree that the journey was undoubtedly worthwhile, as it took us through some of the finer points of hooking into application startup, integrating with membership, and understanding why the WebActivator NuGet package is so useful Will I use this in the tutorial? I'm leaning towards no - I think a NuGet package with a dependency on WebActivator might work better: It's a little more clear what's going on Installing a NuGet package might be a little less error prone than copying a file A novice user could uninstall the package when complete It's a good introduction to NuGet, which is a good thing for beginners to see This code either requires either duplicating a little code from that filter or modifying the file to use the namespace Honestly I'm undecided at this point, but I'm glad that I can weigh the options. If you're interested: Why are you doing this? I'm updating the MVC Music Store tutorial to ASP.NET MVC 4, taking advantage of a lot of new ASP.NET MVC 4 features and trying to simplify areas that are giving people trouble. One change that addresses both needs us using the new OAuth support for membership as much as possible - it's a great new feature from an application perspective, and we get a fair amount of beginners struggling with setting up membership on a variety of database and development setups, which is a distraction from the focus of the tutorial - learning ASP.NET MVC. Side note: Thanks to some great help from Rick Anderson, we had a draft of the tutorial that was looking pretty good earlier this summer, but there were enough changes in ASP.NET MVC 4 all the way up to RTM that there's still some work to be done. It's high priority and should be out very soon. The one issue I ran into with OAuth is that we still need an Administrative user who can edit the store's inventory. I thought about a number of solutions for that - making the first user to register the admin, or the first user to use the username "Administrator" is assigned to the Administrator role - but they both ended up requiring extra code; also, I worried that people would use that code without understanding it or thinking about whether it was a good fit.

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• Amazon Web Services (AWS) Plug-in for Oracle Enterprise Manager

  - by Anand Akela

  v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} Normal 0 false 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:10.0pt; font-family:"Calibri","sans-serif"; mso-bidi-font-family:"Times New Roman";} Contributed by Sunil Kunisetty and Daniel Chan Introduction and ArchitectureAs more and more enterprises deploy some of their non-critical workload on Amazon Web Services (AWS), it’s becoming critical to monitor those public AWS resources along side with their on-premise resources. Oracle recently announced Oracle Enterprise Manager Plug-in for Amazon Web Services (AWS) allows you to achieve that goal. The on-premise Oracle Enterprise Manager (EM12c) acts as a single tool to get a comprehensive view of your public AWS resources as well as your private cloud resources.  By deploying the plug-in within your Cloud Control environment, you gain the following management features: Monitor EBS, EC2 and RDS instances on Amazon Web Services Gather performance metrics and configuration details for AWS instances Raise alerts and violations based on thresholds set on monitoring Generate reports based on the gathered data Users of this Plug-in can leverage the rich Enterprise Manager features such as system promotion, incident generation based on thresholds, integration with 3rd party ticketing applications etc. AWS Monitoring via this Plug-in is enabled via Amazon CloudWatch API and the users of this Plug-in are responsible for supplying credentials for accessing AWS and the CloudWatch API. This Plug-in can only be deployed on an EM12C R2 platform and agent version should be at minimum 12c R2.Here is a pictorial view of the overall architecture: Amazon Elastic Block Store (EBS) Amazon Elastic Compute Cloud (EC2) Amazon Relational Database Service (RDS) Here are a few key features: Rich and exhaustive list of metrics. Metrics can be gathered from an Agent running outside AWS. Critical configuration information. Custom Home Pages with charts and AWS configuration information. Generate incidents based on thresholds set on monitoring data. Discovery and Monitoring AWS instances can be added to EM12C either via the EM12c User Interface (UI) or the EM12c Command Line Interface ( EMCLI)  by providing the AWS credentials (Secret Key and Access Key Id) as well as resource specific properties as target properties. Here is a quick mapping of target types and properties for each AWS resources AWS Resource Type Target Type Resource specific properties EBS Resource Amazon EBS Service CloudWatch base URI, EC2 Base URI, Period, Volume Id, Proxy Server and Port EC2 Resource Amazon EC2 Service CloudWatch base URI, EC2 Base URI, Period, Instance  Id, Proxy Server and Port RDS Resource Amazon RDS Service CloudWatch base URI, RDS Base URI, Period, Instance  Id, Proxy Server and Port Proxy server and port are optional and are only needed if the agent is within the firewall. Here is an emcli example to add an EC2 target. Please read the Installation and Readme guide for more details and step-by-step instructions to deploy  the plugin and adding the AWS the instances. ./emcli add_target \       -name="<target name>" \       -type="AmazonEC2Service" \       -host="<host>" \       -properties="ProxyHost=<proxy server>;ProxyPort=<proxy port>;EC2_BaseURI=http://ec2.<region>.amazonaws.com;BaseURI=http://monitoring.<region>.amazonaws.com;InstanceId=<EC2 instance Id>;Period=<data point periond>"  \     -subseparator=properties="=" ./emcli set_monitoring_credential \                 -set_name="AWSKeyCredentialSet"  \                 -target_name="<target name>"  \                 -target_type="AmazonEC2Service" \                 -cred_type="AWSKeyCredential"  \                 -attributes="AccessKeyId:<access key id>;SecretKey:<secret key>" Emcli utility is found under the ORACLE_HOME of EM12C install. Once the instance is discovered, the target will show up under the ‘All Targets’ list under “Amazon EC2 Service’. Once the instances are added, one can navigate to the custom homepages for these resource types. The custom home pages not only include critical metrics, but also vital configuration parameters and incidents raised for these instances.  By mapping the configuration parameters as instance properties, we can slice-and-dice and group various AWS instance by leveraging the EM12C Config search feature. The following configuration properties and metrics are collected for these Resource types. Resource Type Configuration Properties Metrics EBS Resource Volume Id, Volume Type, Device Name, Size, Availability Zone Response: Status Utilization: QueueLength, IdleTime Volume Statistics: ReadBrandwith, WriteBandwidth, ReadThroughput, WriteThroughput Operation Statistics: ReadSize, WriteSize, ReadLatency, WriteLatency EC2 Resource Instance ID, Owner Id, Root Device type, Instance Type. Availability Zone Response: Status CPU Utilization: CPU Utilization Disk I/O:  DiskReadBytes, DiskWriteBytes, DiskReadOps, DiskWriteOps, DiskReadRate, DiskWriteRate, DiskIOThroughput, DiskReadOpsRate, DiskWriteOpsRate, DiskOperationThroughput Network I/O : NetworkIn, NetworkOut, NetworkInRate, NetworkOutRate, NetworkThroughput RDS Resource Instance ID, Database Engine Name, Database Engine Version, Database Instance Class, Allocated Storage Size, Availability Zone Response: Status Disk I/O:  ReadIOPS, WriteIOPS, ReadLatency, WriteLatency, ReadThroughput, WriteThroughput DB Utilization:  BinLogDiskUsage, CPUUtilization, DatabaseConnections, FreeableMemory, ReplicaLag, SwapUsage Custom Home Pages As mentioned above, we have custom home pages for these target types that include basic configuration information,  last 24 hours availability, top metrics and the incidents generated. Here are few snapshots. EBS Instance Home Page: EC2 Instance Home Page: RDS Instance Home Page: Further Reading: 1)      AWS Plugin download 2)      Installation and  Read Me. 3)      Screenwatch on SlideShare 4)      Extensibility Programmer's Guide 5)      Amazon Web Services

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• CodePlex Daily Summary for Saturday, May 22, 2010

  CodePlex Daily Summary for Saturday, May 22, 2010New ProjectsDocument Toolkit Extensions: Document Toolkit Extensions provide a variety of samples, document converters and helpers for Document Toolkit, a fast, feature-rich and 100% clien...dream: dreamEnhanced Web Controls: The Enhanced Web Control Library Contains web controls that enhance the functionality of the microsoft input controls. New functionality includes l...Europe Engulfed: Europe Engulfed is a PC version of the classic GMT board war game of the same name simulating World War II in the European theater. It is develope...eXpress Persistent Objects (XPO) Toolkit: eXpress Persistent Objects (XPO) Toolkit provides extensions to the DevExpress Object-Relational Mapping Suite.FBGraph.NET: Write apps for Facebook's Graph API using .NET. Includes support for C#, VB.NET, ASP.NET WebForms and ASP.NET MVC.HugeFlow.OOB: Silverlight OOB Library It supports useful custom controls. WindowChrome, InstallScreen. LivePad: LivePad, It can be used to record your life journey. LivePad，可以用来记录您的人生历程。Management listings: The project is management adsMerthin: Merthin is an F# based Framework which boundaries are not defined yet. For now a bit of linear algebra.Mobile Exchange: Mobile Exchange is a .NET Compact Framework library and sample application for accessing the Stack Exchange API available on sites like Stack Overf...PC/SC Micro: PC/SC Micro is an API and a library. The API is a subset of the PC/SC Lite API and allows a .NET Micro Framework application to communicate with ...SerialPortLogger: SerialPortLogger is a simple monitoring application which montors the serial port and outputs to a database.SharePoint NNTP List Sync: Syncronizes NNTP groups with SharePoint lists and offers post/reply capability. Sets item date as post date and attempts to lookup user in local d...Simple Help System: Simple Help System (SHS) je jednoduchý nápovědný systém jak pro vývojáře tak pro obyčejné lidi. Vyvýjeno v C#.SoulHackers Demon Unite(Chinese version): SoulHackers Demon Unite calculate program, for Chinese version on PlayStationTPager: Mercurial pager with color support on WindowsWork Item Query Administration: Work Item Query Administration (wiqadmin) is command-line utility to manage work item queries in Team Foundation Server. For any TeamProject you ca...XPlatformCPP: A cross platform C++ rendering API, that uses either OpenGL 2.1 or Direct3D 9.0c as a backend. Works with Win32API (Windows), Xlib (Linux,etc...), ...Xshell: Xshell is a replacement for the Windows Explorer shell designed for Media Center/Home Theater PCs.عبر السـدم: عبر السدم هي لعبة ثلاثية الأبعاد من إنجاز أعضاء الشبكة العربية لمطوري الألعاب بالاعتماد على تقنية XNA. http://www.agdn-online.com http://www.ag...New ReleasesAzure Publish-Subscribe: Azure Pub-Sub Developer Manual v0.1: Very early alpha of the documentation. It's an early look at the architecture only.Chaow Framework: Chaow Framework V1.00: Project Description Chaow Framework is the set of class libraries designed for enhancing standard .NET framework. It allows you to write more simpl...Document Toolkit Extensions: Document Toolkit Extensions Beta 1: The first public beta release of Document Toolkit and Document Toolkit Extensions.DotNetNuke Russian Language packs: Core Russian Language Pack for DNN 05.04.02: Core Russian Language Pack for DNN 05.04.02 Добавлены несколько ресурсов из новой редакции... Исправлены ошибки и описки.DynamicJson: Release 1.2.0.0: Fix - Deserialize(cast) can't convert to dynamic[] Fix - Deserialize(cast) throw exception if has getonly propertyEnhanced Web Controls: Enhanced Web Controls: This download includes the Enhanced Web Control Library DLL. Also inlcuded is the most recently tested version of the Ajax Control Toolkit, you may...Europe Engulfed: Europe Engulfed: This is the first release for the Codeplex-based project. It includes all source code changes up to and including Change Set 50762. To use: copy ...Extend SmallBasic: Teaching Extensions v.017: added a quiz for spiderweb recipeFree Silverlight & WPF Chart Control - Visifire: Visifire SL and WPF Charts v3.1.0 Released: Hi, This release contains the following enhancements: Mouse events for TrendLine have been implemented. You can go through Visifire documentation...Free Silverlight & WPF Chart Control - Visifire: Visifire SL and WPF Charts v3.5.3 Released: Hi, This release contains the following enhancements: Mouse events for TrendLine have been implemented. You can go through Visifire documentation...GreedyRSS: GreedyRSS 2.1: SuchSofts GreedyRSS平台整体更新至2.1版，重写了大量代码，可见还不够成熟稳定。此外还有以下几点主要更新： 增加一个辅助类Settings，参见http://semify.spaces.live.com/blog/cns!7CB96C25969B3811!2345.entry...HugeFlow.OOB: HugeFlow.OOB 0.9 Beta for SL4: First release!NLog - Advanced .NET Logging: Nightly Build 2010.05.21.001: Changes since the last build:2010-05-20 23:20:17 Jarek Kowalski added tests for CsvLayout, refactored TargetWithLayoutHeaderAndFooter 2010-05-20 2...patterns & practices SharePoint Guidance: SPG 2010 Drop11: SharePoint Guidance Drop Notes Microsoft patterns and practices What's in this Drop: Docs/CHM ** *DropLocation\CHM\SharePointGuidance.chm ...Persian Date/Time support for MsSQL: Build 59 (STABLE): Removed CreateDateTimeWmS() ! Use public static PersianDateTime CreateDateTime(int year, int month, int day, int hour, int min, int sec) instead. ...PiPiBugNet: 增加了创建新Bug界面: 增加了创建新Bug界面，尚未编写代码Rule 18 - Love your clipboard: Rule 18 (Beta version): This is the beta of the next release for Rule 18. Use if you feel comfortable with software that has minimal real world testing applied. Current...Scrum Sprint Monitor: v1.0.0.48591: What is new in this release? #6132 - Bug with open work hours; Added support for MSF for Agile process template; Improved data reporting in the...sGSHOPedit: sGSHOPedit v1.0 (Alpha): -SharePoint NNTP List Sync: 1.0 Release: You may need to change the posting server within the layouts, it is hard coded A webpart wsp is not provided because you should customize the sou...Silverlight Report Library: Version 2.0: - Upgraded to Silverlight 4.0 RTW - ReportHeader control added which is templateable - PagePrinting and PagePrinted events added - PageBreak ad...Snoop, the WPF Spy Utility: Snoop 2.5.1: This is a minor bug fix release for Snoop. In particular, I have fixed the installers so that they create separately named shortcuts ... for each ...SoulHackers Demon Unite(Chinese version): WCFTestClient: This program is using WCF and .NET 4.0. This version is include unite 2 and unite 3 and check what can unite. Element unite is not included yet.SqlServerExtensions: V 0.1 beta: Version 0.1 BetaStackOverflow.Net: StackOverflow.Net for Silverlight public beta: The beta version of StackOverflow.Net for silverlight 4StackOverflow.Net: StackOverflow.Net for Windows Phone 7 public beta: The Windows Phone 7 version of StackOverflow.netStackOverflow.Net: StackOverflow.Net public beta: A public beta to go along with with the public beta of the Stack Exchange APIStyleCop+: StyleCop+ 0.8: Added new extended rule for SA1502. SP1502 has an option which allows constructors to be placed on a single line.SynthExport: SynthExport 1.1.0: Added support for extraction of camera parameters The number of images in coordinate systems is now shown Added status label Improved user ex...TPager: TPager-20100521: First releaseVCC: Latest build, v2.1.30521.0: Automatic drop of latest buildWcfDoc: 1.0.5: Targeting .NET 4.0.Work Item Query Administration: 1.0: This is the first release an contains the following commands: list import export rename deleteMost Popular ProjectsRawrWBFS ManagerAJAX Control ToolkitMicrosoft SQL Server Product Samples: DatabaseSilverlight ToolkitWindows Presentation Foundation (WPF)patterns & practices – Enterprise LibraryPHPExcelMicrosoft SQL Server Community & SamplesASP.NETMost Active ProjectsRawrpatterns & practices – Enterprise Librarypatterns & practices: Windows Azure Security GuidanceCaliburn: An Application Framework for WPF and SilverlightSQL Server PowerShell ExtensionsGMap.NET - Great Maps for Windows Forms & PresentationBlogEngine.NETCodeReviewNB_Store - Free DotNetNuke Ecommerce Catalog ModulePHPExcel

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• Caching NHibernate Named Queries

  - by TStewartDev

  I recently started a new job and one of my first tasks was to implement a "popular products" design. The parameters were that it be done with NHibernate and be cached for 24 hours at a time because the query will be pretty taxing and the results do not need to be constantly up to date. This ended up being tougher than it sounds. The database schema meant a minimum of four joins with filtering and ordering criteria. I decided to use a stored procedure rather than letting NHibernate create the SQL for me. Here is a summary of what I learned (even if I didn't ultimately use all of it): You can't, at the time of this writing, use Fluent NHibernate to configure SQL named queries or imports You can return persistent entities from a stored procedure and there are a couple ways to do that You can populate POCOs using the results of a stored procedure, but it isn't quite as obvious You can reuse your named query result mapping other places (avoid duplication) Caching your query results is not at all obvious Testing to see if your cache is working is a pain NHibernate does a lot of things right. Having unified, up-to-date, comprehensive, and easy-to-find documentation is not one of them. By the way, if you're new to this, I'll use the terms "named query" and "stored procedure" (from NHibernate's perspective) fairly interchangeably. Technically, a named query can execute any SQL, not just a stored procedure, and a stored procedure doesn't have to be executed from a named query, but for reusability, it seems to me like the best practice. If you're here, chances are good you're looking for answers to a similar problem. You don't want to read about the path, you just want the result. So, here's how to get this thing going. The Stored Procedure NHibernate has some guidelines when using stored procedures. For Microsoft SQL Server, you have to return a result set. The scalar value that the stored procedure returns is ignored as are any result sets after the first. Other than that, it's nothing special. CREATE PROCEDURE GetPopularProducts @StartDate DATETIME, @MaxResults INT AS BEGIN SELECT [ProductId], [ProductName], [ImageUrl] FROM SomeTableWithJoinsEtc END The Result Class - PopularProduct You have two options to transport your query results to your view (or wherever is the final destination): you can populate an existing mapped entity class in your model, or you can create a new entity class. If you go with the existing model, the advantage is that the query will act as a loader and you'll get full proxied access to the domain model. However, this can be a disadvantage if you require access to the related entities that aren't loaded by your results. For example, my PopularProduct has image references. Unless I tie them into the query (thus making it even more complicated and expensive to run), they'll have to be loaded on access, requiring more trips to the database. Since we're trying to avoid trips to the database by using a second-level cache, we should use the second option, which is to create a separate entity for results. This approach is (I believe) in the spirit of the Command-Query Separation principle, and it allows us to flatten our data and optimize our report-generation process from data source to view. public class PopularProduct { public virtual int ProductId { get; set; } public virtual string ProductName { get; set; } public virtual string ImageUrl { get; set; } } The NHibernate Mappings (hbm) Next up, we need to let NHibernate know about the query and where the results will go. Below is the markup for the PopularProduct class. Notice that I'm using the <resultset> element and that it has a name attribute. The name allows us to drop this into our query map and any others, giving us reusability. Also notice the <import> element which lets NHibernate know about our entity class. <?xml version="1.0" encoding="utf-8" ?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"> <import class="PopularProduct, Infrastructure.NHibernate, Version=1.0.0.0"/> <resultset name="PopularProductResultSet"> <return-scalar column="ProductId" type="System.Int32"/> <return-scalar column="ProductName" type="System.String"/> <return-scalar column="ImageUrl" type="System.String"/> </resultset> </hibernate-mapping>  And now the PopularProductsMap: <?xml version="1.0" encoding="utf-8" ?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"> <sql-query name="GetPopularProducts" resultset-ref="PopularProductResultSet" cacheable="true" cache-mode="normal"> <query-param name="StartDate" type="System.DateTime" /> <query-param name="MaxResults" type="System.Int32" /> exec GetPopularProducts @StartDate = :StartDate, @MaxResults = :MaxResults </sql-query> </hibernate-mapping>  The two most important things to notice here are the resultset-ref attribute, which links in our resultset mapping, and the cacheable attribute. The Query Class – PopularProductsQuery So far, this has been fairly obvious if you're familiar with NHibernate. This next part, maybe not so much. You can implement your query however you want to; for me, I wanted a self-encapsulated Query class, so here's what it looks like: public class PopularProductsQuery : IPopularProductsQuery { private static readonly IResultTransformer ResultTransformer; private readonly ISessionBuilder _sessionBuilder;   static PopularProductsQuery() { ResultTransformer = Transformers.AliasToBean<PopularProduct>(); }   public PopularProductsQuery(ISessionBuilder sessionBuilder) { _sessionBuilder = sessionBuilder; }   public IList<PopularProduct> GetPopularProducts(DateTime startDate, int maxResults) { var session = _sessionBuilder.GetSession(); var popularProducts = session .GetNamedQuery("GetPopularProducts") .SetCacheable(true) .SetCacheRegion("PopularProductsCacheRegion") .SetCacheMode(CacheMode.Normal) .SetReadOnly(true) .SetResultTransformer(ResultTransformer) .SetParameter("StartDate", startDate.Date) .SetParameter("MaxResults", maxResults) .List<PopularProduct>();   return popularProducts; } }  Okay, so let's look at each line of the query execution. The first, GetNamedQuery, matches up with our NHibernate mapping for the sql-query. Next, we set it as cacheable (this is probably redundant since our mapping also specified it, but it can't hurt, right?). Then we set the cache region which we'll get to in the next section. Set the cache mode (optional, I believe), and my cache is read-only, so I set that as well. The result transformer is very important. This tells NHibernate how to transform your query results into a non-persistent entity. You can see I've defined ResultTransformer in the static constructor using the AliasToBean transformer. The name is obviously leftover from Java/Hibernate. Finally, set your parameters and then call a result method which will execute the query. Because this is set to cached, you execute this statement every time you run the query and NHibernate will know based on your parameters whether to use its cached version or a fresh version. The Configuration – hibernate.cfg.xml and Web.config You need to explicitly enable second-level caching in your hibernate configuration: <hibernate-configuration xmlns="urn:nhibernate-configuration-2.2"> <session-factory> [...] <property name="dialect">NHibernate.Dialect.MsSql2005Dialect</property> <property name="cache.provider_class">NHibernate.Caches.SysCache.SysCacheProvider,NHibernate.Caches.SysCache</property> <property name="cache.use_query_cache">true</property> <property name="cache.use_second_level_cache">true</property> [...] </session-factory> </hibernate-configuration> Both properties "use_query_cache" and "use_second_level_cache" are necessary. As this is for a web deployement, we're using SysCache which relies on ASP.NET's caching. Be aware of this if you're not deploying to the web! You'll have to use a different cache provider. We also need to tell our cache provider (in this cache, SysCache) about our caching region: <syscache> <cache region="PopularProductsCacheRegion" expiration="86400" priority="5" /> </syscache> Here I've set the cache to be valid for 24 hours. This XML snippet goes in your Web.config (or in a separate file referenced by Web.config, which helps keep things tidy). The Payoff That should be it! At this point, your queries should run once against the database for a given set of parameters and then use the cache thereafter until it expires. You can, of course, adjust settings to work in your particular environment. Testing Testing your application to ensure it is using the cache is a pain, but if you're like me, you want to know that it's actually working. It's a bit involved, though, so I'll create a separate post for it if comments indicate there is interest.

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• GoldenGate 12c Trail Encryption and Credentials with Oracle Wallet

  - by hamsun

  I have been asked more than once whether the Oracle Wallet supports GoldenGate trail encryption. Although GoldenGate has supported encryption with the ENCKEYS file for years, Oracle GoldenGate 12c now also supports encryption using the Oracle Wallet. This helps improve security and makes it easier to administer. Two types of wallets can be configured in Oracle GoldenGate 12c: The wallet that holds the master keys, used with trail or TCP/IP encryption and decryption, stored in the new 12c dirwlt/cwallet.sso file.   The wallet that holds the Oracle Database user IDs and passwords stored in the ‘credential store’ stored in the new 12c dircrd/cwallet.sso file.   A wallet can be created using a ‘create wallet’  command.  Adding a master key to an existing wallet is easy using ‘open wallet’ and ‘add masterkey’ commands.   GGSCI (EDLVC3R27P0) 42> open wallet Opened wallet at location 'dirwlt'. GGSCI (EDLVC3R27P0) 43> add masterkey Master key 'OGG_DEFAULT_MASTERKEY' added to wallet at location 'dirwlt'.   Existing GUI Wallet utilities that come with other products such as the Oracle Database “Oracle Wallet Manager” do not work on this version of the wallet. The default Oracle Wallet can be changed.   GGSCI (EDLVC3R27P0) 44> sh ls -ltr ./dirwlt/* -rw-r----- 1 oracle oinstall 685 May 30 05:24 ./dirwlt/cwallet.sso GGSCI (EDLVC3R27P0) 45> info masterkey Masterkey Name:                 OGG_DEFAULT_MASTERKEY Creation Date:                  Fri May 30 05:24:04 2014 Version:        Creation Date:                  Status: 1               Fri May 30 05:24:04 2014        Current   The second wallet file is used for the credential used to connect to a database, without exposing the user id or password. Once it is configured, this file can be copied so that credentials are available to connect to the source or target database.   GGSCI (EDLVC3R27P0) 48> sh cp ./dircrd/cwallet.sso $GG_EURO_HOME/dircrd GGSCI (EDLVC3R27P0) 49> sh ls -ltr ./dircrd/* -rw-r----- 1 oracle oinstall 709 May 28 05:39 ./dircrd/cwallet.sso   The encryption wallet file can also be copied to the target machine so the replicat has access to the master key to decrypt records that are encrypted in the trail. Similar to the old ENCKEYS file, the master keys wallet created on the source host must either be stored in a centrally available disk or copied to all GoldenGate target hosts. The wallet is in a platform-independent format, although it is not certified for the iSeries, z/OS, and NonStop platforms.   GGSCI (EDLVC3R27P0) 50> sh cp ./dirwlt/cwallet.sso $GG_EURO_HOME/dirwlt   The new 12c UserIdAlias parameter is used to locate the credential in the wallet so the source user id and password does not need to be stored as a parameter as long as it is in the wallet.   GGSCI (EDLVC3R27P0) 52> view param extwest extract extwest exttrail ./dirdat/ew useridalias gguamer table west.*; The EncryptTrail parameter is used to encrypt the trail using the Advanced Encryption Standard and can be used with a primary extract or pump extract. GGSCI (EDLVC3R27P0) 54> view param pwest extract pwest encrypttrail AES256 rmthost easthost, mgrport 15001 rmttrail ./dirdat/pe passthru table west.*;   Once the extracts are running, records can be encrypted using the wallet.   GGSCI (EDLVC3R27P0) 60> info extract *west EXTRACT    EXTWEST   Last Started 2014-05-30 05:26   Status RUNNING Checkpoint Lag       00:00:17 (updated 00:00:01 ago) Process ID           24982 Log Read Checkpoint  Oracle Integrated Redo Logs                      2014-05-30 05:25:53                      SCN 0.0 (0) EXTRACT    PWEST     Last Started 2014-05-30 05:26   Status RUNNING Checkpoint Lag       24:02:32 (updated 00:00:05 ago) Process ID           24983 Log Read Checkpoint  File ./dirdat/ew000004                      2014-05-29 05:23:34.748949  RBA 1483   The ‘info masterkey’ command is used to confirm the wallet contains the key after copying it to the target machine. The key is needed to decrypt the data in the trail before the replicat applies the changes to the target database.   GGSCI (EDLVC3R27P0) 41> open wallet Opened wallet at location 'dirwlt'. GGSCI (EDLVC3R27P0) 42> info masterkey Masterkey Name:                 OGG_DEFAULT_MASTERKEY Creation Date:                  Fri May 30 05:24:04 2014 Version:        Creation Date:                  Status: 1               Fri May 30 05:24:04 2014        Current   Once the replicat is running, records can be decrypted using the wallet.   GGSCI (EDLVC3R27P0) 44> info reast REPLICAT   REAST     Last Started 2014-05-30 05:28   Status RUNNING INTEGRATED Checkpoint Lag       00:00:00 (updated 00:00:02 ago) Process ID           25057 Log Read Checkpoint  File ./dirdat/pe000004                      2014-05-30 05:28:16.000000  RBA 1546   There is no need for the DecryptTrail parameter when using the Oracle Wallet, unlike when using the ENCKEYS file.   GGSCI (EDLVC3R27P0) 45> view params reast replicat reast assumetargetdefs discardfile ./dirrpt/reast.dsc, purge useridalias ggueuro map west.*, target east.*;   Once a record is inserted into the source table and committed, the encryption can be verified using logdump and then querying the target table.   AMER_SQL>insert into west.branch values (50, 80071); 1 row created.   AMER_SQL>commit; Commit complete.   The following encrypted record can be found using logdump. Logdump 40 >n 2014/05/30 05:28:30.001.154 Insert               Len    28 RBA 1546 Name: WEST.BRANCH After  Image:                                             Partition 4   G  s    0a3e 1ba3 d924 5c02 eade db3f 61a9 164d 8b53 4331 | .>...$\....?a..M.SC1   554f e65a 5185 0257                               | UO.ZQ..W  Bad compressed block, found length of  7075 (x1ba3), RBA 1546   GGS tokens: TokenID x52 'R' ORAROWID         Info x00  Length   20  4141 4157 7649 4141 4741 4141 4144 7541 4170 0001 | AAAWvIAAGAAAADuAAp..  TokenID x4c 'L' LOGCSN           Info x00  Length    7  3231 3632 3934 33                                 | 2162943  TokenID x36 '6' TRANID           Info x00  Length   10  3130 2e31 372e 3135 3031                          | 10.17.1501  The replicat automatically decrypted this record from the trail and then inserted the row to the target table using the wallet. This select verifies the row was inserted into the target database and the data is not encrypted. EURO_SQL>select * from branch where branch_number=50; BRANCH_NUMBER                  BRANCH_ZIP -------------                                   ----------    50                                              80071   Book a seat in an upcoming Oracle GoldenGate 12c: Fundamentals for Oracle course now to learn more about GoldenGate 12c new features including how to use GoldenGate with the Oracle wallet, credentials, integrated extracts, integrated replicats, the Oracle Universal Installer, and other new features. Looking for another course? View all Oracle GoldenGate training.   Randy Richeson joined Oracle University as a Senior Principal Instructor in March 2005. He is an Oracle Certified Professional (10g-12c) and a GoldenGate Certified Implementation Specialist (10-11g). He has taught GoldenGate since 2010 and also has experience teaching other technical curriculums including GoldenGate Monitor, Veridata, JD Edwards, PeopleSoft, and the Oracle Application Server.

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• C#/.NET Little Wonders: Fun With Enum Methods

  - by James Michael Hare

  Once again lets dive into the Little Wonders of .NET, those small things in the .NET languages and BCL classes that make development easier by increasing readability, maintainability, and/or performance. So probably every one of us has used an enumerated type at one time or another in a C# program.  The enumerated types we create are a great way to represent that a value can be one of a set of discrete values (or a combination of those values in the case of bit flags). But the power of enum types go far beyond simple assignment and comparison, there are many methods in the Enum class (that all enum types “inherit” from) that can give you even more power when dealing with them. IsDefined() – check if a given value exists in the enum Are you reading a value for an enum from a data source, but are unsure if it is actually a valid value or not?  Casting won’t tell you this, and Parse() isn’t guaranteed to balk either if you give it an int or a combination of flags.  So what can we do? Let’s assume we have a small enum like this for result codes we want to return back from our business logic layer: 1: public enum ResultCode 2: { 3: Success, 4: Warning, 5: Error 6: } In this enum, Success will be zero (unless given another value explicitly), Warning will be one, and Error will be two. So what happens if we have code like this where perhaps we’re getting the result code from another data source (could be database, could be web service, etc)? 1: public ResultCode PerformAction() 2: { 3: // set up and call some method that returns an int. 4: int result = ResultCodeFromDataSource(); 5:  6: // this will suceed even if result is < 0 or > 2. 7: return (ResultCode) result; 8: } So what happens if result is –1 or 4?  Well, the cast does not fail, so what we end up with would be an instance of a ResultCode that would have a value that’s outside of the bounds of the enum constants we defined. This means if you had a block of code like: 1: switch (result) 2: { 3: case ResultType.Success: 4: // do success stuff 5: break; 6:  7: case ResultType.Warning: 8: // do warning stuff 9: break; 10:  11: case ResultType.Error: 12: // do error stuff 13: break; 14: } That you would hit none of these blocks (which is a good argument for always having a default in a switch by the way). So what can you do?  Well, there is a handy static method called IsDefined() on the Enum class which will tell you if an enum value is defined.  1: public ResultCode PerformAction() 2: { 3: int result = ResultCodeFromDataSource(); 4:  5: if (!Enum.IsDefined(typeof(ResultCode), result)) 6: { 7: throw new InvalidOperationException("Enum out of range."); 8: } 9:  10: return (ResultCode) result; 11: } In fact, this is often recommended after you Parse() or cast a value to an enum as there are ways for values to get past these methods that may not be defined. If you don’t like the syntax of passing in the type of the enum, you could clean it up a bit by creating an extension method instead that would allow you to call IsDefined() off any isntance of the enum: 1: public static class EnumExtensions 2: { 3: // helper method that tells you if an enum value is defined for it's enumeration 4: public static bool IsDefined(this Enum value) 5: { 6: return Enum.IsDefined(value.GetType(), value); 7: } 8: }   HasFlag() – an easier way to see if a bit (or bits) are set Most of us who came from the land of C programming have had to deal extensively with bit flags many times in our lives.  As such, using bit flags may be almost second nature (for a quick refresher on bit flags in enum types see one of my old posts here). However, in higher-level languages like C#, the need to manipulate individual bit flags is somewhat diminished, and the code to check for bit flag enum values may be obvious to an advanced developer but cryptic to a novice developer. For example, let’s say you have an enum for a messaging platform that contains bit flags: 1: // usually, we pluralize flags enum type names 2: [Flags] 3: public enum MessagingOptions 4: { 5: None = 0, 6: Buffered = 0x01, 7: Persistent = 0x02, 8: Durable = 0x04, 9: Broadcast = 0x08 10: } We can combine these bit flags using the bitwise OR operator (the ‘|’ pipe character): 1: // combine bit flags using 2: var myMessenger = new Messenger(MessagingOptions.Buffered | MessagingOptions.Broadcast); Now, if we wanted to check the flags, we’d have to test then using the bit-wise AND operator (the ‘&’ character): 1: if ((options & MessagingOptions.Buffered) == MessagingOptions.Buffered) 2: { 3: // do code to set up buffering... 4: // ... 5: } While the ‘|’ for combining flags is easy enough to read for advanced developers, the ‘&’ test tends to be easy for novice developers to get wrong.  First of all you have to AND the flag combination with the value, and then typically you should test against the flag combination itself (and not just for a non-zero)!  This is because the flag combination you are testing with may combine multiple bits, in which case if only one bit is set, the result will be non-zero but not necessarily all desired bits! Thanks goodness in .NET 4.0 they gave us the HasFlag() method.  This method can be called from an enum instance to test to see if a flag is set, and best of all you can avoid writing the bit wise logic yourself.  Not to mention it will be more readable to a novice developer as well: 1: if (options.HasFlag(MessagingOptions.Buffered)) 2: { 3: // do code to set up buffering... 4: // ... 5: } It is much more concise and unambiguous, thus increasing your maintainability and readability. It would be nice to have a corresponding SetFlag() method, but unfortunately generic types don’t allow you to specialize on Enum, which makes it a bit more difficult.  It can be done but you have to do some conversions to numeric and then back to the enum which makes it less of a payoff than having the HasFlag() method.  But if you want to create it for symmetry, it would look something like this: 1: public static T SetFlag<T>(this Enum value, T flags) 2: { 3: if (!value.GetType().IsEquivalentTo(typeof(T))) 4: { 5: throw new ArgumentException("Enum value and flags types don't match."); 6: } 7:  8: // yes this is ugly, but unfortunately we need to use an intermediate boxing cast 9: return (T)Enum.ToObject(typeof (T), Convert.ToUInt64(value) | Convert.ToUInt64(flags)); 10: } Note that since the enum types are value types, we need to assign the result to something (much like string.Trim()).  Also, you could chain several SetFlag() operations together or create one that takes a variable arg list if desired. Parse() and ToString() – transitioning from string to enum and back Sometimes, you may want to be able to parse an enum from a string or convert it to a string - Enum has methods built in to let you do this.  Now, many may already know this, but may not appreciate how much power are in these two methods. For example, if you want to parse a string as an enum, it’s easy and works just like you’d expect from the numeric types: 1: string optionsString = "Persistent"; 2:  3: // can use Enum.Parse, which throws if finds something it doesn't like... 4: var result = (MessagingOptions)Enum.Parse(typeof (MessagingOptions), optionsString); 5:  6: if (result == MessagingOptions.Persistent) 7: { 8: Console.WriteLine("It worked!"); 9: } Note that Enum.Parse() will throw if it finds a value it doesn’t like.  But the values it likes are fairly flexible!  You can pass in a single value, or a comma separated list of values for flags and it will parse them all and set all bits: 1: // for string values, can have one, or comma separated. 2: string optionsString = "Persistent, Buffered"; 3:  4: var result = (MessagingOptions)Enum.Parse(typeof (MessagingOptions), optionsString); 5:  6: if (result.HasFlag(MessagingOptions.Persistent) && result.HasFlag(MessagingOptions.Buffered)) 7: { 8: Console.WriteLine("It worked!"); 9: } Or you can parse in a string containing a number that represents a single value or combination of values to set: 1: // 3 is the combination of Buffered (0x01) and Persistent (0x02) 2: var optionsString = "3"; 3:  4: var result = (MessagingOptions) Enum.Parse(typeof (MessagingOptions), optionsString); 5:  6: if (result.HasFlag(MessagingOptions.Persistent) && result.HasFlag(MessagingOptions.Buffered)) 7: { 8: Console.WriteLine("It worked again!"); 9: } And, if you really aren’t sure if the parse will work, and don’t want to handle an exception, you can use TryParse() instead: 1: string optionsString = "Persistent, Buffered"; 2: MessagingOptions result; 3:  4: // try parse returns true if successful, and takes an out parm for the result 5: if (Enum.TryParse(optionsString, out result)) 6: { 7: if (result.HasFlag(MessagingOptions.Persistent) && result.HasFlag(MessagingOptions.Buffered)) 8: { 9: Console.WriteLine("It worked!"); 10: } 11: } So we covered parsing a string to an enum, what about reversing that and converting an enum to a string?  The ToString() method is the obvious and most basic choice for most of us, but did you know you can pass a format string for enum types that dictate how they are written as a string?: 1: MessagingOptions value = MessagingOptions.Buffered | MessagingOptions.Persistent; 2:  3: // general format, which is the default, 4: Console.WriteLine("Default : " + value); 5: Console.WriteLine("G (default): " + value.ToString("G")); 6:  7: // Flags format, even if type does not have Flags attribute. 8: Console.WriteLine("F (flags) : " + value.ToString("F")); 9:  10: // integer format, value as number. 11: Console.WriteLine("D (num) : " + value.ToString("D")); 12:  13: // hex format, value as hex 14: Console.WriteLine("X (hex) : " + value.ToString("X")); Which displays: 1: Default : Buffered, Persistent 2: G (default): Buffered, Persistent 3: F (flags) : Buffered, Persistent 4: D (num) : 3 5: X (hex) : 00000003 Now, you may not really see a difference here between G and F because I used a [Flags] enum, the difference is that the “F” option treats the enum as if it were flags even if the [Flags] attribute is not present.  Let’s take a non-flags enum like the ResultCode used earlier: 1: // yes, we can do this even if it is not [Flags] enum. 2: ResultCode value = ResultCode.Warning | ResultCode.Error; And if we run that through the same formats again we get: 1: Default : 3 2: G (default): 3 3: F (flags) : Warning, Error 4: D (num) : 3 5: X (hex) : 00000003 Notice that since we had multiple values combined, but it was not a [Flags] marked enum, the G and default format gave us a number instead of a value name.  This is because the value was not a valid single-value constant of the enum.  However, using the F flags format string, it broke out the value into its component flags even though it wasn’t marked [Flags]. So, if you want to get an enum to display appropriately for whether or not it has the [Flags] attribute, use G which is the default.  If you always want it to attempt to break down the flags, use F.  For numeric output, obviously D or  X are the best choice depending on whether you want decimal or hex. Summary Hopefully, you learned a couple of new tricks with using the Enum class today!  I’ll add more little wonders as I think of them and thanks for all the invaluable input!   Technorati Tags: C#,.NET,Little Wonders,Enum,BlackRabbitCoder

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• Libgdx - 2D Mesh rendering overlap glitch

  - by user46858

  I am trying to render a 2D circle segment mesh (quarter circle)using Libgdx/Opengl ES 2.0 but I seem to be getting an overlapping issue as seen in the picture attached. I cant seem to find the cause of the problem but the overlapping disappears/reappears if I drag and resize the window to random sizes. The problem occurs on both pc and android. The strange thing is the first two segments atleast dont seem to be causing any overlapping only the third and/or forth segment.......even though they are all rendered using the same mesh object..... I have spent ages trying to find the cause of the problem before posting here for help so ANY help/advice in finding the cause of this problem would be really appreciated. public class MyGdxGame extends Game { private SpriteBatch batch; private Texture texture; private OrthographicCamera myCamera; private float w; private float h; private ShaderProgram circleSegShader; private Mesh circleScaleSegMesh; private Stage stage; private float TotalSegments; Vector3 virtualres; @Override public void create() { w = Gdx.graphics.getWidth(); h = Gdx.graphics.getHeight(); batch = new SpriteBatch(); ViewPortsize = new Vector2(); TotalSegments = 4.0f; virtualres = new Vector3(1280.0f, 720.0f, 0.0f); myCamera = new OrthographicCamera(); myCamera.setToOrtho(false, w, h); texture = new Texture(Gdx.files.internal("data/libgdx.png")); texture.setFilter(TextureFilter.Linear, TextureFilter.Linear); circleScaleSegMesh = createCircleMesh_V3(0.0f,0.0f,200.0f, 30.0f,3, (360.0f /TotalSegments) ); circleSegShader = loadShaderFromFile(new String("circleseg.vert"), new String("circleseg.frag")); shaderProgram.pedantic = false; stage = new Stage(); stage.setViewport(new ExtendViewport(w, h)); Gdx.input.setInputProcessor(stage); } @Override public void render() { .... //render renderInit(); renderCircleScaledSegment(); } @Override public void resize(int width, int height) { stage.getViewport().update(width, height, true); myCamera.position.set( virtualres.x/2.0f, virtualres.y/2.0f, 0.0f); myCamera.update(); } public void renderInit(){ Gdx.gl20.glClearColor(1.0f, 1.0f, 1.0f, 0.0f); Gdx.gl20.glClear(GL20.GL_COLOR_BUFFER_BIT | GL20.GL_DEPTH_BUFFER_BIT); batch.setShader(null); batch.setProjectionMatrix(myCamera.combined); } public void renderCircleScaledSegment(){ Gdx.gl20.glEnable(GL20.GL_DEPTH_TEST); Gdx.gl20.glBlendFunc(GL20.GL_SRC_ALPHA, GL20.GL_ONE_MINUS_SRC_ALPHA); Gdx.gl20.glEnable(GL20.GL_BLEND); batch.begin(); circleSegShader.begin(); Matrix4 modelMatrix = new Matrix4(); Matrix4 cameraMatrix = new Matrix4(); Matrix4 cameraMatrix2 = new Matrix4(); Matrix4 cameraMatrix3 = new Matrix4(); Matrix4 cameraMatrix4 = new Matrix4(); cameraMatrix = myCamera.combined.cpy(); modelMatrix.idt().rotate(new Vector3(0.0f,0.0f,1.0f), 0.0f - ((360.0f /TotalSegments)/ 2.0f)).trn(virtualres.x/2.0f,virtualres.y/2.0f, 0.0f); cameraMatrix.mul(modelMatrix); cameraMatrix2 = myCamera.combined.cpy(); modelMatrix.idt().rotate(new Vector3(0.0f,0.0f,1.0f), 0.0f - ((360.0f /TotalSegments)/ 2.0f) +(360.0f /TotalSegments) ).trn(virtualres.x/2.0f,virtualres.y/2.0f, 0.0f); cameraMatrix2.mul(modelMatrix); cameraMatrix3 = myCamera.combined.cpy(); modelMatrix.idt().rotate(new Vector3(0.0f,0.0f,1.0f), 0.0f - ((360.0f /TotalSegments)/ 2.0f) +(2*(360.0f /TotalSegments))).trn(virtualres.x/2.0f,virtualres.y/2.0f, 0.0f); cameraMatrix3.mul(modelMatrix); cameraMatrix4 = myCamera.combined.cpy(); modelMatrix.idt().rotate(new Vector3(0.0f,0.0f,1.0f),0.0f - ((360.0f /TotalSegments)/ 2.0f) +(3*(360.0f /TotalSegments)) ).trn(virtualres.x/2.0f,virtualres.y/2.0f, 0.0f); cameraMatrix4.mul(modelMatrix); Vector3 box2dpos = new Vector3(0.0f, 0.0f, 0.0f); circleSegShader.setUniformMatrix("u_projTrans", cameraMatrix); circleSegShader.setUniformf("u_box2dpos", box2dpos); circleSegShader.setUniformi("u_texture", 0); texture.bind(); circleScaleSegMesh.render(circleSegShader, GL20.GL_TRIANGLES); circleSegShader.setUniformMatrix("u_projTrans", cameraMatrix2); circleSegShader.setUniformf("u_box2dpos", box2dpos); circleSegShader.setUniformi("u_texture", 0); texture.bind(); circleScaleSegMesh.render(circleSegShader, GL20.GL_TRIANGLES); circleSegShader.setUniformMatrix("u_projTrans", cameraMatrix3); circleSegShader.setUniformf("u_box2dpos", box2dpos); circleSegShader.setUniformi("u_texture", 0); texture.bind(); circleScaleSegMesh.render(circleSegShader, GL20.GL_TRIANGLES); circleSegShader.setUniformMatrix("u_projTrans", cameraMatrix4); circleSegShader.setUniformf("u_box2dpos", box2dpos); circleSegShader.setUniformi("u_texture", 0); texture.bind(); circleScaleSegMesh.render(circleSegShader, GL20.GL_TRIANGLES); circleSegShader.end(); batch.flush(); batch.end(); Gdx.gl20.glDisable(GL20.GL_DEPTH_TEST); Gdx.gl20.glDisable(GL20.GL_BLEND); } public Mesh createCircleMesh_V3(float cx, float cy, float r_out, float r_in, int num_segments, float segmentSizeDegrees){ float theta = (float) (2.0f * MathUtils.PI / (num_segments * (360.0f / segmentSizeDegrees))); float c = MathUtils.cos(theta);//precalculate the sine and cosine float s = MathUtils.sin(theta); float t,t2; float x = r_out;//we start at angle = 0 float y = 0; float x2 = r_in;//we start at angle = 0 float y2 = 0; float[] meshCoords = new float[num_segments *2 *3 *7]; int arrayIndex = 0; //array for triangles without indices for(int ii = 0; ii < num_segments; ii++) { meshCoords[arrayIndex] = x2+cx; meshCoords[arrayIndex +1] = y2+cy; meshCoords[arrayIndex +2] = 0.0f; meshCoords[arrayIndex +3] = 63.0f/255.0f; meshCoords[arrayIndex +4] = 139.0f/255.0f; meshCoords[arrayIndex +5] = 217.0f/255.0f; meshCoords[arrayIndex +6] = 0.7f; arrayIndex = arrayIndex + 7; meshCoords[arrayIndex] = x+cx; meshCoords[arrayIndex +1] = y+cy; meshCoords[arrayIndex +2] = 0.0f; meshCoords[arrayIndex +3] = 63.0f/255.0f; meshCoords[arrayIndex +4] = 139.0f/255.0f; meshCoords[arrayIndex +5] = 217.0f/255.0f; meshCoords[arrayIndex +6] = 0.7f; arrayIndex = arrayIndex + 7; t = x; x = c * x - s * y; y = s * t + c * y; meshCoords[arrayIndex] = x+cx; meshCoords[arrayIndex +1] = y+cy; meshCoords[arrayIndex +2] = 0.0f; meshCoords[arrayIndex +3] = 63.0f/255.0f; meshCoords[arrayIndex +4] = 139.0f/255.0f; meshCoords[arrayIndex +5] = 217.0f/255.0f; meshCoords[arrayIndex +6] = 0.7f; arrayIndex = arrayIndex + 7; meshCoords[arrayIndex] = x2+cx; meshCoords[arrayIndex +1] = y2+cy; meshCoords[arrayIndex +2] = 0.0f; meshCoords[arrayIndex +3] = 63.0f/255.0f; meshCoords[arrayIndex +4] = 139.0f/255.0f; meshCoords[arrayIndex +5] = 217.0f/255.0f; meshCoords[arrayIndex +6] = 0.7f; arrayIndex = arrayIndex + 7; meshCoords[arrayIndex] = x+cx; meshCoords[arrayIndex +1] = y+cy; meshCoords[arrayIndex +2] = 0.0f; meshCoords[arrayIndex +3] = 63.0f/255.0f; meshCoords[arrayIndex +4] = 139.0f/255.0f; meshCoords[arrayIndex +5] = 217.0f/255.0f; meshCoords[arrayIndex +6] = 0.7f; arrayIndex = arrayIndex + 7; t2 = x2; x2 = c * x2 - s * y2; y2 = s * t2 + c * y2; meshCoords[arrayIndex] = x2+cx; meshCoords[arrayIndex +1] = y2+cy; meshCoords[arrayIndex +2] = 0.0f; meshCoords[arrayIndex +3] = 63.0f/255.0f; meshCoords[arrayIndex +4] = 139.0f/255.0f; meshCoords[arrayIndex +5] = 217.0f/255.0f; meshCoords[arrayIndex +6] = 0.7f; arrayIndex = arrayIndex + 7; } Mesh myMesh = new Mesh(VertexDataType.VertexArray, false, meshCoords.length, 0, new VertexAttribute(VertexAttributes.Usage.Position, 3, "a_position"), new VertexAttribute(VertexAttributes.Usage.Color, 4, "a_color")); myMesh.setVertices(meshCoords); return myMesh; } }

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• Building KPIs to monitor your business Its not really about the Technology

  When I have discussions with people about Business Intelligence, one of the questions the inevitably come up is about building KPIs and how to accomplish that. From a technical level the concept of a KPI is very simple, almost too simple in that it is like the tip of an iceberg floating above the water. The key to that iceberg is not really the tip, but the mass of the iceberg that is hidden beneath the surface upon which the tip sits. The analogy of the iceberg is not meant to indicate that the foundation of the KPI is overly difficult or complex. The disparity in size in meant to indicate that the larger thing that needs to be defined is not the technical tip, but the underlying business definition of what the KPI means. From a technical perspective the KPI consists of primarily the following items: Actual Value This is the actual value data point that is being measured. An example would be something like the amount of sales. Target Value This is the target goal for the KPI. This is a number that can be measured against Actual Value. An example would be $10,000 in monthly sales. Target Indicator Range This is the definition of ranges that define what type of indicator the user will see comparing the Actual Value to the Target Value. Most often this is defined by stoplight, but can be any indicator that is going to show a status in a quick fashion to the user. Typically this would be something like: Red Light = Actual Value more than 5% below target; Yellow Light = Within 5% of target either direction; Green Light = More than 5% higher than Target Value Status\Trend Indicator This is an optional attribute of a KPI that is typically used to show some kind of trend. The vast majority of these indicators are used to show some type of progress against a previous period. As an example, the status indicator might be used to show how the monthly sales compare to last month. With this type of indicator there needs to be not only a definition of what the ranges are for your status indictor, but then also what value the number needs to be compared against. So now we have an idea of what data points a KPI consists of from a technical perspective lets talk a bit about tools. As you can see technically there is not a whole lot to them and the choice of technology is not as important as the definition of the KPIs, which we will get to in a minute. There are many different types of tools in the Microsoft BI stack that you can use to expose your KPI to the business. These include Performance Point, SharePoint, Excel, and SQL Reporting Services. There are pluses and minuses to each technology and the right technology is based a lot on your goals and how you want to deliver the information to the users. Additionally, there are other non-Microsoft tools that can be used to expose KPI indicators to your business users. Regardless of the technology used as your front end, the heavy lifting of KPI is in the business definition of the values and benchmarks for that KPI. The discussion about KPIs is very dependent on the history of an organization and how much they are exposed to the attributes of a KPI. Often times when discussing KPIs with a business contact who has not been exposed to KPIs the discussion tends to also be a session educating the business user about what a KPI is and what goes into the definition of a KPI. The majority of times the business user has an idea of what their actual values are and they have been tracking those numbers for some time, generally in Excel and all manually. So they will know the amount of sales last month along with sales two years ago in the same month. Where the conversation tends to get stuck is when you start discussing what the target value should be. The actual value is answering the What and How much questions. When you are talking about the Target values you are asking the question Is this number good or bad. Typically, the user will know whether or not the value is good or bad, but most of the time they are not able to quantify what is good or bad. Their response is usually something like I just know. Because they have been watching the sales quantity for years now, they can tell you that a 5% decrease in sales this month might actually be a good thing, maybe because the salespeople are all waiting until next month when the new versions come out. It can sometimes be very hard to break the business people of this habit. One of the fears generally is that the status indicator is not subjective. Thus, in the scenario above, the business user is going to be fearful that their boss, just looking at a negative red indicator, is going to haul them out to the woodshed for a bad month. But, on the flip side, if all you are displaying is the amount of sales, only a person with knowledge of last month sales and the target amount for this month would have any idea if $10,000 in sales is good or not. Here is where a key point about KPIs needs to be communicated to both the business user and any user who might be viewing the results of that KPI. The KPI is just one tool that is used to report on business performance. The KPI is meant as a quick indicator of one business statistic. It is not meant to tell the entire story. It does not answer the question Why. Its primary purpose is to objectively and quickly expose an area of the business that might warrant more review. There is always going to be the need to do further analysis on any potential negative or neutral KPI. So, hopefully, once you have convinced your business user to come up with some target numbers and ranges for status indicators, you then need to take the next step and help them answer the Why question. The main question here to ask is, Okay, you see the indicator and you need to discover why the number is what is, where do you go?. The answer is usually a combination of sources. A sales manager might have some of the following items at their disposal (Marketing report showing a decrease in the promotional discounts for the month, Pricing Report showing the reduction of prices of older models, an Inventory Report showing the discontinuation of a particular product line, or a memo showing the ending of a large affiliate partnership. The answers to the question Why are never as simple as a single indicator value. Bring able to quickly get to this information is all about designing how a user accesses the KPIs and then also how easily they can get to the additional information they need. This is where a Dashboard mentality can come in handy. For example, the business user can have a dashboard that shows their KPIs, but also has links to some of the common reports that they run regarding Sales Data. The users boss may have the same KPIs on their dashboard, but instead of links to individual reports they are going to have a link to a status report that was created by the user that pulls together all the data about the KPI in a summary format the users boss can review. So some of the key things to think about when building or evaluating KPIs for your organization: Technology should not be the driving factor KPIs are of little value without some indicator for whether a value is good, bad or neutral. KPIs only give an answer to the Is this number good\bad? question Make sure the ability to drill into the Why of a KPI is close at hand and relevant to the user who is viewing the KPI. The KPI is a key business tool when defined properly to help monitor business performance across the enterprise in an objective and consistent manner. At times it might feel like the process of defining the business aspects of a KPI can sometimes be arduous, the payoff in the end can far outweigh the costs. Some of the benefits of going through this process are a better understanding of the key metrics for an organization and the measure of those metrics and a consistent snapshot of business performance that can be utilized across the organization. And I think that these are benefits to any organization regardless of the technology or the implementation.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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• Connect to running web role on Azure using Remote Desktop Connection and VS2012

  - by Magnus Karlsson

  We want to be able to collect IntelliTrace information from our running app and also use remote desktop to connect to the IIS and look around(probably debugging). 1. Create certificate 1.1 Right-click the cloud project (marked in red) and select “Configure remote desktop”. 1.2 In the drop down list of certificates, choose <create> at the bottom. 1.3. Follow the instructions, you can set it up with default values. 1.4 When done. Choose the certificate and click “Copy to File…” as seen in the left of the picture above. 1.5. Save the file with any name you want. Now we will save it to local storage to be able to import it to our solution through the azure configuration manager in step 3. 2. Save certificate to local storage Now we need to attach it to our local certificate storage to be able to reach it from our confiuguration manager in visual studio. Microsoft provides the following steps for doing this: http://support.microsoft.com/kb/232137 In order to view the Certificates store on the local computer, perform the following steps: Click Start, and then click Run. Type "MMC.EXE" (without the quotation marks) and click OK. Click Console in the new MMC you created, and then click Add/Remove Snap-in. In the new window, click Add. Highlight the Certificates snap-in, and then click Add. Choose the Computer option and click Next. Select Local Computer on the next screen, and then click OK. Click Close , and then click OK. You have now added the Certificates snap-in, which will allow you to work with any certificates in your computer's certificate store. You may want to save this MMC for later use. Now that you have access to the Certificates snap-in, you can import the server certificate into you computer's certificate store by following these steps: Open the Certificates (Local Computer) snap-in and navigate to Personal, and then Certificates. Note: Certificates may not be listed. If it is not, that is because there are no certificates installed. Right-click Certificates (or Personal if that option does not exist.) Choose All Tasks, and then click Import. When the wizard starts, click Next. Browse to the PFX file you created containing your server certificate and private key. Click Next. Enter the password you gave the PFX file when you created it. Be sure the Mark the key as exportable option is selected if you want to be able to export the key pair again from this computer. As an added security measure, you may want to leave this option unchecked to ensure that no one can make a backup of your private key. Click Next, and then choose the Certificate Store you want to save the certificate to. You should select Personal because it is a Web server certificate. If you included the certificates in the certification hierarchy, it will also be added to this store. Click Next. You should see a summary of screen showing what the wizard is about to do. If this information is correct, click Finish. You will now see the server certificate for your Web server in the list of Personal Certificates. It will be denoted by the common name of the server (found in the subject section of the certificate). Now that you have the certificate backup imported into the certificate store, you can enable Internet Information Services 5.0 to use that certificate (and the corresponding private key). To do this, perform the following steps: Open the Internet Services Manager (under Administrative Tools) and navigate to the Web site you want to enable secure communications (SSL/TLS) on. Right-click on the site and click Properties. You should now see the properties screen for the Web site. Click the Directory Security tab. Under the Secure Communications section, click Server Certificate. This will start the Web Site Certificate Wizard. Click Next. Choose the Assign an existing certificate option and click Next. You will now see a screen showing that contents of your computer's personal certificate store. Highlight your Web server certificate (denoted by the common name), and then click Next. You will now see a summary screen showing you all the details about the certificate you are installing. Be sure that this information is correct or you may have problems using SSL or TLS in HTTP communications. Click Next, and then click OK to exit the wizard. You should now have an SSL/TLS-enabled Web server. Be sure to protect your PFX files from any unwanted personnel. Image of a typical MMC.EXE with the certificates up.   3. Import the certificate to you visual studio project. 3.1 Now right click your equivalent to the MvcWebRole1 (as seen in the first picture under the red oval) and choose properties. 3.2 Choose Certificates. Right click the ellipsis to the right of the “thumbprint” and you should be able to select your newly created certificate here. After selecting it- save the file.   4. Upload the certificate to your Azure subscription. 4.1 Go to the azure management portal, click the services menu icon to the left and choose the service. Click Upload in the bottom menu.     5. Connect to server. Since I tried to use account settings(have to use another name) we have to set up a new name for the connection. No biggie. 5.1 Go to azure management portal, select your service and in the bottom menu, choose “REMOTE”. This will display the configuration for remote connection. It will actually change your ServiceConfiguration.cscfg file. After you change It here it might be good to choose download and replace the one in your project. Set a name that is not your windows azure account name and not Administrator. 5.2 Goto visual studio, click Server Explorer. Choose as selected in the picture below and click “COnnect using remote desktop”.   5.2 You will now be able to log in with the name and password set up in step 5.1. and voila! Windows server 2012, IIS and other nice stuff!   To do this one I’ve been using http://msdn.microsoft.com/en-us/library/windowsazure/ff683671.aspx where you can collect some of this information and additional one.

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• How do you handle authentication across domains?

  - by William Ratcliff

  I'm trying to save users of our services from having to have multiple accounts/passwords. I'm in a large organization and there's one group that handles part of user authentication for users who are from outside the facility (primarily for administrative functions). They store a secure cookie to establish a session and communicate only via HTTPS via the browser. Sessions expire either through: 1) explicit logout of the user 2) Inactivity 3) Browser closes My team is trying to write a web application to help users analyze data that they've taken (or are currently taking) while at our facility. We need to determine if a user is 1) authenticated 2) Some identifier for that user so we can store state for them (what analysis they are working on, etc.) So, the problem is how do you authenticate across domains (the authentication server for the other application lives in a border region between public and private--we will live in the public region). We have come up with some scenarios and I'd like advice about what is best practice, or if there is one we haven't considered. Let's start with the case where the user is authenticated with the authentication server. 1) The authentication server leaves a public cookie in the browser with their primary key for a user. If this is deemed sensitive, they encrypt it on their server and we have the key to decrypt it on our server. When the user visits our site, we check for this public cookie. We extract the user_id and use a public api for the authentication server to request if the user is logged in. If they are, they send us a response with: response={ userid :we can then map this to our own user ids. If necessary, we can request additional information such as email-address/display name once (to notify them if long running jobs are done, or to share results with other people, like with google_docs). account_is_active:Make sure that the account is still valid session_is_active: Is their session still active? If we query this for a valid user, this will have a side effect that we will reset the last_time_session_activated value and thus prolong their session with the authentication server last_time_session_activated: let us know how much time they have left ip_address_session_started_from:make sure the person at our site is coming from the same ip as they started the session at } Given this response, we either accept them as authenticated and move on with our app, or redirect them to the login page for the authentication server (question: if we give an encrypted portion of the response (signed by us) with the page to redirect them to, do we open any gaping security holes in the authentication server)? The flaw that we've found with this is that if the user visits evilsite.com and they look at the session cookie and send a query to the public api of the authentication server, they can keep the session alive and if our original user leaves the machine without logging out, then the next user will be able to access their session (this was possible before, but having the session alive eternally makes this worse). 2) The authentication server redirects all requests made to our domain to us and we send responses back through them to the user. Essentially, they act as a proxy. The advantage of this is that we can handshake with the authentication server, so it's safe to be trusted with the email address/name of the user and they don't have to reenter it So, if the user tries to go to: authentication_site/mysite_page1 they are redirected to mysite. Which would you choose, or is there a better way? The goal is to minimize the "Yet Another Password/Yet another username" problem... Thanks!!!!

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• How to deploy custom MBean to Tomcat?

  - by Christian

  Hi, I'm trying to deploy a custom mbean to a tomcat. This mbean is not part of a webapp. It should be instantiated when tomcat starts. My problem is, I can't find any complete documentation about how to deploy such a mbean. I'm getting different exceptions, depending on my configuration. Has anyone hints, a complete documentation or has implemented a mbean by himself and can post an example? I configured tomcat to read a configuration from his conf directory: <Engine name="Catalina" defaultHost="localhost" mbeansFile="${catalina.base}/conf/mbeans-descriptors.xml"> The content is as follows: <?xml version="1.0"?> <!-- <!DOCTYPE mbeans-descriptors PUBLIC "-//Apache Software Foundation//DTD Model MBeans Configuration File" "http://jakarta.apache.org/commons/dtds/mbeans-descriptors.dtd"> --> <!-- Descriptions of JMX MBeans --> <mbeans-descriptors> <mbean name="Performance" description="Caculate JVM throughput" type="Performance"> <attribute name="throughput" description="calculated throughput (ratio between gc times and uptime of JVM)" type="double" writeable="false"/> </mbean> </mbeans-descriptors> When name in the xml file and class name match, I get this excption: SEVERE: Error creating mbean Performance javax.management.MalformedObjectNameException: Key properties cannot be empty at javax.management.ObjectName.construct(ObjectName.java:467) at javax.management.ObjectName.<init>(ObjectName.java:1403) at org.apache.tomcat.util.modeler.modules.MbeansSource.execute(MbeansSource.java:202) at org.apache.tomcat.util.modeler.modules.MbeansSource.load(MbeansSource.java:137) at org.apache.catalina.core.StandardEngine.readEngineMbeans(StandardEngine.java:517) at org.apache.catalina.core.StandardEngine.init(StandardEngine.java:321) at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:411) at org.apache.catalina.core.StandardService.start(StandardService.java:519) at org.apache.catalina.core.StandardServer.start(StandardServer.java:710) at org.apache.catalina.startup.Catalina.start(Catalina.java:581) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.commons.daemon.support.DaemonLoader.start(DaemonLoader.java:177) When changing the name attribute in the xml file to test.example:type=Performance, I get this exception: SEVERE: Error creating mbean test.example:type=Performance javax.management.NotCompliantMBeanException: MBean class must have public constructor at com.sun.jmx.mbeanserver.Introspector.testCreation(Introspector.java:127) at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.createMBean(DefaultMBeanServerInterceptor.java:284) at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.createMBean(DefaultMBeanServerInterceptor.java:199) at com.sun.jmx.mbeanserver.JmxMBeanServer.createMBean(JmxMBeanServer.java:393) at org.apache.tomcat.util.modeler.modules.MbeansSource.execute(MbeansSource.java:207) at org.apache.tomcat.util.modeler.modules.MbeansSource.load(MbeansSource.java:137) at org.apache.catalina.core.StandardEngine.readEngineMbeans(StandardEngine.java:517) at org.apache.catalina.core.StandardEngine.init(StandardEngine.java:321) at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:411) at org.apache.catalina.core.StandardService.start(StandardService.java:519) at org.apache.catalina.core.StandardServer.start(StandardServer.java:710) at org.apache.catalina.startup.Catalina.start(Catalina.java:581) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.commons.daemon.support.DaemonLoader.start(DaemonLoader.java:177) The documentation from apache is not really helpful, as it just explains a small part. I'm aware of this question but it doesn't help me. The answer I gave worked just for a short time, after that I got some other exceptions. For additional info, the java interface public interface PerformanceMBean { public double getThroughput(); } and implementing class /* some import statements */ public class Performance implements PerformanceMBean { public double getThroughput() { ... } }

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• Routing not working correctly using the laravel framework

  - by samayres1992

  I'm using the book wrote by one of the guys that created laravel, so I'd like to think for the most part this code isn't horribly wrong. My server is setup with nginx serving all static files and apache2 serving php. My config for each are the following: apache2: <VirtualHost *> # Host that will serve this project. ServerName litl.it # The location of our projects public directory. DocumentRoot /var/www/litl.it/laravel/public # Useful logs for debug. CustomLog /var/log/apache.access.log common ErrorLog /var/log/apache.error.log # Rewrites for pretty URLs, better not to rely on .htaccess. <Directory /var/www/litl.it/laravel/public> <IfModule mod_rewrite.c> Options -MultiViews RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-f RewriteRule ^ index.php [L] </IfModule> </Directory> nginx: server { # Port that the web server will listen on. listen 80; # Host that will serve this project. server_name litl.it *.litl.it; # Useful logs for debug. access_log /var/log/nginx.access.log; error_log /var/log/nginx.error.log; rewrite_log on; # The location of our projects public directory. root /var/www/litl.it/laravel/public; # Point index to the Laravel front controller. index index.php; location / { # URLs to attempt, including pretty ones. try_files $uri $uri/ /index.php?$query_string; } # Remove trailing slash to please routing system. if (!-d $request_filename) { rewrite ^/(.+)/$ /$1 permanent; } # PHP FPM configuration. location ~* \.php$ { proxy_pass http://127.0.0.1:8080; include /etc/nginx/proxy_params; try_files index index.php $uri =404; include /etc/nginx/fastcgi_params; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME $document_root/php/$fastcgi_script_name; } # We don't need .ht files with nginx. location ~ /\.ht { deny all; } location @proxy { proxy_pass http://127.0.0.1:8080; include /etc/nginx/proxy_params; } error_page 403 /error/403.html; error_page 404 /error/404.html; error_page 405 /error/405.html; error_page 500 501 502 503 504 /error/5xx.html; location ^~ /error/ { internal; root /var/www/litl.it/lavarel/public/error; } } I'm including these server configs, as I feel this maybe the issue? Here is my incredibly basic routing file that should return "routing is working" on domain.com/test but instead it just returns the homepage. <?php Route::get('/', function() { return View::make('hello'); }); Route::get('/test', function() { return "routing is working"; }); Any ideas where I'm going wrong, I'm following this tutorial very closely and I'm confused why there is issue. Thanks!

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• Samba doesnt require password on xbmc but does on ubuntu

  - by Chris

  I have samba setup on a fedora 13 machine, and I use it to share with my xbmc client in the family room. When I set this up there no password or anything was required I merely entered in paths such as: smb://<host>/<share> and all worked. Now on my ubuntu 10.04 machine when I try to access the same hosts, for example through smbmount though I receive an error. smbmount //media/Music ~/Music/ # media is in my /etc/hosts and resolves to # correct IP address for the machine I receive error: operation not permitted after pressing enter when it prompts for password. Here is my entry from /etc/samba/smb.conf: [global] workgroup = WORKGROUP server string = Samba Server Version %v # log files split per-machine: log file = /var/log/samba/log.%m # maximum size of 50KB per log file, then rotate: max log size = 50 security = user passdb backend = tdbsam ; security = domain ; passdb backend = tdbsam ; realm = MY_REALM ; password server = <NT-Server-Name> ; security = user ; passdb backend = tdbsam ; domain master = yes ; domain logons = yes ; logon script = %m.bat ; logon script = %u.bat ; logon path = \\%L\Profiles\%u ; logon path = ; add user script = /usr/sbin/useradd "%u" -n -g users ; add group script = /usr/sbin/groupadd "%g" ; add machine script = /usr/sbin/useradd -n -c "Workstation (%u)" -M -d /nohome -s /bin/false "%u" ; delete user script = /usr/sbin/userdel "%u" ; delete user from group script = /usr/sbin/userdel "%u" "%g" ; delete group script = /usr/sbin/groupdel "%g" ; local master = no ; os level = 33 ; preferred master = yes ; wins support = yes ; wins server = w.x.y.z ; wins proxy = yes ; dns proxy = yes load printers = yes cups options = raw ; printcap name = /etc/printcap # obtain a list of printers automatically on UNIX System V systems: ; printcap name = lpstat ; printing = cups ; map archive = no ; map hidden = no ; map read only = no ; map system = no ; store dos attributes = yes #============================ Share Definitions ============================== [homes] comment = Home Directories browseable = no writable = yes ; valid users = %S ; valid users = MYDOMAIN\%S # Un-comment the following and create the netlogon directory for Domain Logons: ; [netlogon] ; comment = Network Logon Service ; path = /var/lib/samba/netlogon ; guest ok = yes ; writable = no ; share modes = no # Un-comment the following to provide a specific roving profile share. # The default is to use the user's home directory: ; [Profiles] ; path = /var/lib/samba/profiles ; browseable = no ; guest ok = yes # A publicly accessible directory that is read only, except for users in the # "staff" group (which have write permissions): ; [public] ; comment = Public Stuff ; path = /home/samba ; public = yes ; writable = yes ; printable = no ; write list = +staff [tv] comment = TV path = /media/Isos/tv public = yes writable = yes printable = no write list = +media [music] comment = Music path = /media/Storage/music/ public = yes writable = yes printable = no write list = +media [pictures] comment = Pictures path = /media/Storage/pictures public = yes writable = yes printable = no write list = +media

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• BIND no longer responds to AXFR Requests

  - by djsumdog

  Recently we moved our primary external DNS server. It has three caching DNS slaves in front of it provided by our ISP. They've told us they've started getting access denied requests when doing zone transfers (AXFR). If I add in my own IPs to the allow-transfer list, I also get a transfer failed when using dig with the AXFR argument. Here is what my bind configuration looks like: options { directory "/var/lib/named"; dump-file "/var/log/named_dump.db"; zone-statistics yes; statistics-file "/var/log/named.stats"; listen-on-v6 { any; }; notify-source 10.19.0.68 port 53; querylog yes; notify yes; allow-transfer { 127.0.0.1; //localhost 1.1.1.1; //public dns slave 1 2.2.2.2; //public dns slave 2 3.3.3.3; //public dns slave 3 }; also-notify { 1.1.1.1; //public dns slave 1 2.2.2.2; //public dns slave 2 3.3.3.3; //public dns slave 3 }; include "/etc/named.d/forwarders.conf"; }; logging { channel simple_log { file "/var/log/bind.log" versions 10 size 3m; severity info; print-time yes; print-severity yes; print-category yes; }; category default{ simple_log; }; channel log_zone_transfers { file "/var/log/axfr.log" versions 10 size 3m; print-time yes; print-category yes; print-severity yes; }; category xfer-out { log_zone_transfers; }; channel log_notify { file "/var/log/notify.log" versions 10 size 3m; print-time yes; print-category yes; print-severity yes; }; category notify { log_notify; }; channel queries { file "/var/log/queries.log" versions 10 size 30m; print-time yes; severity info; print-category yes; print-severity yes; }; category queries { queries; }; }; zone "." in { type hint; file "root.hint"; }; zone "localhost" in { type master; file "localhost.zone"; }; zone "0.0.127.in-addr.arpa" in { type master; file "127.0.0.zone"; }; include "/etc/named.conf.include"; zone "example.net " { type master; file "/var/lib/named/master/example.net.hosts"; }; zone "example.com " { type master; file "/var/lib/named/master/example.com.hosts"; }; ## -- other master files -- And the errors in the xfer log look like the following: 29-Oct-2012 14:20:02.806 xfer-out: info: client 1.1.1.1#59069: bad zone transfer request: 'example.com./IN': non-authoritative zone (NOTAUTH) I've tried adding allow-transfer parameters directly on the zone files and still get failed transfers. Any idea what I'm doing wrong?

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• Using HTML 5 SessionState to save rendered Page Content

  - by Rick Strahl

  HTML 5 SessionState and LocalStorage are very useful and super easy to use to manage client side state. For building rich client side or SPA style applications it's a vital feature to be able to cache user data as well as HTML content in order to swap pages in and out of the browser's DOM. What might not be so obvious is that you can also use the sessionState and localStorage objects even in classic server rendered HTML applications to provide caching features between pages. These APIs have been around for a long time and are supported by most relatively modern browsers and even all the way back to IE8, so you can use them safely in your Web applications. SessionState and LocalStorage are easy The APIs that make up sessionState and localStorage are very simple. Both object feature the same API interface which  is a simple, string based key value store that has getItem, setItem, removeitem, clear and  key methods. The objects are also pseudo array objects and so can be iterated like an array with  a length property and you have array indexers to set and get values with. Basic usage  for storing and retrieval looks like this (using sessionStorage, but the syntax is the same for localStorage - just switch the objects):// set var lastAccess = new Date().getTime(); if (sessionStorage) sessionStorage.setItem("myapp_time", lastAccess.toString()); // retrieve in another page or on a refresh var time = null; if (sessionStorage) time = sessionStorage.getItem("myapp_time"); if (time) time = new Date(time * 1); else time = new Date(); sessionState stores data that is browser session specific and that has a liftetime of the active browser session or window. Shut down the browser or tab and the storage goes away. localStorage uses the same API interface, but the lifetime of the data is permanently stored in the browsers storage area until deleted via code or by clearing out browser cookies (not the cache). Both sessionStorage and localStorage space is limited. The spec is ambiguous about this - supposedly sessionStorage should allow for unlimited size, but it appears that most WebKit browsers support only 2.5mb for either object. This means you have to be careful what you store especially since other applications might be running on the same domain and also use the storage mechanisms. That said 2.5mb worth of character data is quite a bit and would go a long way. The easiest way to get a feel for how sessionState and localStorage work is to look at a simple example. You can go check out the following example online in Plunker: http://plnkr.co/edit/0ICotzkoPjHaWa70GlRZ?p=preview which looks like this: Plunker is an online HTML/JavaScript editor that lets you write and run Javascript code and similar to JsFiddle, but a bit cleaner to work in IMHO (thanks to John Papa for turning me on to it). The sample has two text boxes with counts that update session/local storage every time you click the related button. The counts are 'cached' in Session and Local storage. The point of these examples is that both counters survive full page reloads, and the LocalStorage counter survives a complete browser shutdown and restart. Go ahead and try it out by clicking the Reload button after updating both counters and then shutting down the browser completely and going back to the same URL (with the same browser). What you should see is that reloads leave both counters intact at the counted values, while a browser restart will leave only the local storage counter intact. The code to deal with the SessionStorage (and LocalStorage not shown here) in the example is isolated into a couple of wrapper methods to simplify the code: function getSessionCount() { var count = 0; if (sessionStorage) { var count = sessionStorage.getItem("ss_count"); count = !count ? 0 : count * 1; } $("#txtSession").val(count); return count; } function setSessionCount(count) { if (sessionStorage) sessionStorage.setItem("ss_count", count.toString()); } These two functions essentially load and store a session counter value. The two key methods used here are: sessionStorage.getItem(key); sessionStorage.setItem(key,stringVal); Note that the value given to setItem and return by getItem has to be a string. If you pass another type you get an error. Don't let that limit you though - you can easily enough store JSON data in a variable so it's quite possible to pass complex objects and store them into a single sessionStorage value:var user = { name: "Rick", id="ricks", level=8 } sessionStorage.setItem("app_user",JSON.stringify(user)); to retrieve it:var user = sessionStorage.getItem("app_user"); if (user) user = JSON.parse(user); Simple! If you're using the Chrome Developer Tools (F12) you can also check out the session and local storage state on the Resource tab:   You can also use this tool to refresh or remove entries from storage. What we just looked at is a purely client side implementation where a couple of counters are stored. For rich client centric AJAX applications sessionStorage and localStorage provide a very nice and simple API to store application state while the application is running. But you can also use these storage mechanisms to manage server centric HTML applications when you combine server rendering with some JavaScript to perform client side data caching. You can both store some state information and data on the client (ie. store a JSON object and carry it forth between server rendered HTML requests) or you can use it for good old HTTP based caching where some rendered HTML is saved and then restored later. Let's look at the latter with a real life example. Why do I need Client-side Page Caching for Server Rendered HTML? I don't know about you, but in a lot of my existing server driven applications I have lists that display a fair amount of data. Typically these lists contain links to then drill down into more specific data either for viewing or editing. You can then click on a link and go off to a detail page that provides more concise content. So far so good. But now you're done with the detail page and need to get back to the list, so you click on a 'bread crumbs trail' or an application level 'back to list' button and… …you end up back at the top of the list - the scroll position, the current selection in some cases even filters conditions - all gone with the wind. You've left behind the state of the list and are starting from scratch in your browsing of the list from the top. Not cool! Sound familiar? This a pretty common scenario with server rendered HTML content where it's so common to display lists to drill into, only to lose state in the process of returning back to the original list. Look at just about any traditional forums application, or even StackOverFlow to see what I mean here. Scroll down a bit to look at a post or entry, drill in then use the bread crumbs or tab to go back… In some cases returning to the top of a list is not a big deal. On StackOverFlow that sort of works because content is turning around so quickly you probably want to actually look at the top posts. Not always though - if you're browsing through a list of search topics you're interested in and drill in there's no way back to that position. Essentially anytime you're actively browsing the items in the list, that's when state becomes important and if it's not handled the user experience can be really disrupting. Content Caching If you're building client centric SPA style applications this is a fairly easy to solve problem - you tend to render the list once and then update the page content to overlay the detail content, only hiding the list temporarily until it's used again later. It's relatively easy to accomplish this simply by hiding content on the page and later making it visible again. But if you use server rendered content, hanging on to all the detail like filters, selections and scroll position is not quite as easy. Or is it??? This is where sessionStorage comes in handy. What if we just save the rendered content of a previous page, and then restore it when we return to this page based on a special flag that tells us to use the cached version? Let's see how we can do this. A real World Use Case Recently my local ISP asked me to help out with updating an ancient classifieds application. They had a very busy, local classifieds app that was originally an ASP classic application. The old app was - wait for it: frames based - and even though I lobbied against it, the decision was made to keep the frames based layout to allow rapid browsing of the hundreds of posts that are made on a daily basis. The primary reason they wanted this was precisely for the ability to quickly browse content item by item. While I personally hate working with Frames, I have to admit that the UI actually works well with the frames layout as long as you're running on a large desktop screen. You can check out the frames based desktop site here: http://classifieds.gorge.net/ However when I rebuilt the app I also added a secondary view that doesn't use frames. The main reason for this of course was for mobile displays which work horribly with frames. So there's a somewhat mobile friendly interface to the interface, which ditches the frames and uses some responsive design tweaking for mobile capable operation: http://classifeds.gorge.net/mobile  (or browse the base url with your browser width under 800px)   Here's what the mobile, non-frames view looks like:   As you can see this means that the list of classifieds posts now is a list and there's a separate page for drilling down into the item. And of course… originally we ran into that usability issue I mentioned earlier where the browse, view detail, go back to the list cycle resulted in lost list state. Originally in mobile mode you scrolled through the list, found an item to look at and drilled in to display the item detail. Then you clicked back to the list and BAM - you've lost your place. Because there are so many items added on a daily basis the full list is never fully loaded, but rather there's a "Load Additional Listings"  entry at the button. Not only did we originally lose our place when coming back to the list, but any 'additionally loaded' items are no longer there because the list was now rendering  as if it was the first page hit. The additional listings, and any filters, the selection of an item all were lost. Major Suckage! Using Client SessionStorage to cache Server Rendered Content To work around this problem I decided to cache the rendered page content from the list in SessionStorage. Anytime the list renders or is updated with Load Additional Listings, the page HTML is cached and stored in Session Storage. Any back links from the detail page or the login or write entry forms then point back to the list page with a back=true query string parameter. If the server side sees this parameter it doesn't render the part of the page that is cached. Instead the client side code retrieves the data from the sessionState cache and simply inserts it into the page. It sounds pretty simple, and the overall the process is really easy, but there are a few gotchas that I'll discuss in a minute. But first let's look at the implementation. Let's start with the server side here because that'll give a quick idea of the doc structure. As I mentioned the server renders data from an ASP.NET MVC view. On the list page when returning to the list page from the display page (or a host of other pages) looks like this: https://classifieds.gorge.net/list?back=True The query string value is a flag, that indicates whether the server should render the HTML. Here's what the top level MVC Razor view for the list page looks like:@model MessageListViewModel @{ ViewBag.Title = "Classified Listing"; bool isBack = !string.IsNullOrEmpty(Request.QueryString["back"]); } <form method="post" action="@Url.Action("list")"> <div id="SizingContainer"> @if (!isBack) { @Html.Partial("List_CommandBar_Partial", Model) <div id="PostItemContainer" class="scrollbox" xstyle="-webkit-overflow-scrolling: touch;"> @Html.Partial("List_Items_Partial", Model) @if (Model.RequireLoadEntry) { <div class="postitem loadpostitems" style="padding: 15px;"> <div id="LoadProgress" class="smallprogressright"></div> <div class="control-progress"> Load additional listings... </div> </div> } </div> } </div> </form> As you can see the query string triggers a conditional block that if set is simply not rendered. The content inside of #SizingContainer basically holds  the entire page's HTML sans the headers and scripts, but including the filter options and menu at the top. In this case this makes good sense - in other situations the fact that the menu or filter options might be dynamically updated might make you only cache the list rather than essentially the entire page. In this particular instance all of the content works and produces the proper result as both the list along with any filter conditions in the form inputs are restored. Ok, let's move on to the client. On the client there are two page level functions that deal with saving and restoring state. Like the counter example I showed earlier, I like to wrap the logic to save and restore values from sessionState into a separate function because they are almost always used in several places.page.saveData = function(id) { if (!sessionStorage) return; var data = { id: id, scroll: $("#PostItemContainer").scrollTop(), html: $("#SizingContainer").html() }; sessionStorage.setItem("list_html",JSON.stringify(data)); }; page.restoreData = function() { if (!sessionStorage) return; var data = sessionStorage.getItem("list_html"); if (!data) return null; return JSON.parse(data); }; The data that is saved is an object which contains an ID which is the selected element when the user clicks and a scroll position. These two values are used to reset the scroll position when the data is used from the cache. Finally the html from the #SizingContainer element is stored, which makes for the bulk of the document's HTML. In this application the HTML captured could be a substantial bit of data. If you recall, I mentioned that the server side code renders a small chunk of data initially and then gets more data if the user reads through the first 50 or so items. The rest of the items retrieved can be rather sizable. Other than the JSON deserialization that's Ok. Since I'm using SessionStorage the storage space has no immediate limits. Next is the core logic to handle saving and restoring the page state. At first though this would seem pretty simple, and in some cases it might be, but as the following code demonstrates there are a few gotchas to watch out for. Here's the relevant code I use to save and restore:$( function() { … var isBack = getUrlEncodedKey("back", location.href); if (isBack) { // remove the back key from URL setUrlEncodedKey("back", "", location.href); var data = page.restoreData(); // restore from sessionState if (!data) { // no data - force redisplay of the server side default list window.location = "list"; return; } $("#SizingContainer").html(data.html); var el = $(".postitem[data-id=" + data.id + "]"); $(".postitem").removeClass("highlight"); el.addClass("highlight"); $("#PostItemContainer").scrollTop(data.scroll); setTimeout(function() { el.removeClass("highlight"); }, 2500); } else if (window.noFrames) page.saveData(null); // save when page loads $("#SizingContainer").on("click", ".postitem", function() { var id = $(this).attr("data-id"); if (!id) return true; if (window.noFrames) page.saveData(id); var contentFrame = window.parent.frames["Content"]; if (contentFrame) contentFrame.location.href = "show/" + id; else window.location.href = "show/" + id; return false; }); … The code starts out by checking for the back query string flag which triggers restoring from the client cache. If cached the cached data structure is read from sessionStorage. It's important here to check if data was returned. If the user had back=true on the querystring but there is no cached data, he likely bookmarked this page or otherwise shut down the browser and came back to this URL. In that case the server didn't render any detail and we have no cached data, so all we can do is redirect to the original default list view using window.location. If we continued the page would render no data - so make sure to always check the cache retrieval result. Always! If there is data the it's loaded and the data.html data is restored back into the document by simply injecting the HTML back into the document's #SizingContainer element:$("#SizingContainer").html(data.html); It's that simple and it's quite quick even with a fully loaded list of additional items and on a phone. The actual HTML data is stored to the cache on every page load initially and then again when the user clicks on an element to navigate to a particular listing. The former ensures that the client cache always has something in it, and the latter updates with additional information for the selected element. For the click handling I use a data-id attribute on the list item (.postitem) in the list and retrieve the id from that. That id is then used to navigate to the actual entry as well as storing that Id value in the saved cached data. The id is used to reset the selection by searching for the data-id value in the restored elements. The overall process of this save/restore process is pretty straight forward and it doesn't require a bunch of code, yet it yields a huge improvement in the usability of the site on mobile devices (or anybody who uses the non-frames view). Some things to watch out for As easy as it conceptually seems to simply store and retrieve cached content, you have to be quite aware what type of content you are caching. The code above is all that's specific to cache/restore cycle and it works, but it took a few tweaks to the rest of the script code and server code to make it all work. There were a few gotchas that weren't immediately obvious. Here are a few things to pay attention to: Event Handling Logic Timing of manipulating DOM events Inline Script Code Bookmarking to the Cache Url when no cache exists Do you have inline script code in your HTML? That script code isn't going to run if you restore from cache and simply assign or it may not run at the time you think it would normally in the DOM rendering cycle. JavaScript Event Hookups The biggest issue I ran into with this approach almost immediately is that originally I had various static event handlers hooked up to various UI elements that are now cached. If you have an event handler like:$("#btnSearch").click( function() {…}); that works fine when the page loads with server rendered HTML, but that code breaks when you now load the HTML from cache. Why? Because the elements you're trying to hook those events to may not actually be there - yet. Luckily there's an easy workaround for this by using deferred events. With jQuery you can use the .on() event handler instead:$("#SelectionContainer").on("click","#btnSearch", function() {…}); which monitors a parent element for the events and checks for the inner selector elements to handle events on. This effectively defers to runtime event binding, so as more items are added to the document bindings still work. For any cached content use deferred events. Timing of manipulating DOM Elements Along the same lines make sure that your DOM manipulation code follows the code that loads the cached content into the page so that you don't manipulate DOM elements that don't exist just yet. Ideally you'll want to check for the condition to restore cached content towards the top of your script code, but that can be tricky if you have components or other logic that might not all run in a straight line. Inline Script Code Here's another small problem I ran into: I use a DateTime Picker widget I built a while back that relies on the jQuery date time picker. I also created a helper function that allows keyboard date navigation into it that uses JavaScript logic. Because MVC's limited 'object model' the only way to embed widget content into the page is through inline script. This code broken when I inserted the cached HTML into the page because the script code was not available when the component actually got injected into the page. As the last bullet - it's a matter of timing. There's no good work around for this - in my case I pulled out the jQuery date picker and relied on native <input type="date" /> logic instead - a better choice these days anyway, especially since this view is meant to be primarily to serve mobile devices which actually support date input through the browser (unlike desktop browsers of which only WebKit seems to support it). Bookmarking Cached Urls When you cache HTML content you have to make a decision whether you cache on the client and also not render that same content on the server. In the Classifieds app I didn't render server side content so if the user comes to the page with back=True and there is no cached content I have to a have a Plan B. Typically this happens when somebody ends up bookmarking the back URL. The easiest and safest solution for this scenario is to ALWAYS check the cache result to make sure it exists and if not have a safe URL to go back to - in this case to the plain uncached list URL which amounts to effectively redirecting. This seems really obvious in hindsight, but it's easy to overlook and not see a problem until much later, when it's not obvious at all why the page is not rendering anything. Don't use <body> to replace Content Since we're practically replacing all the HTML in the page it may seem tempting to simply replace the HTML content of the <body> tag. Don't. The body tag usually contains key things that should stay in the page and be there when it loads. Specifically script tags and elements and possibly other embedded content. It's best to create a top level DOM element specifically as a placeholder container for your cached content and wrap just around the actual content you want to replace. In the app above the #SizingContainer is that container. Other Approaches The approach I've used for this application is kind of specific to the existing server rendered application we're running and so it's just one approach you can take with caching. However for server rendered content caching this is a pattern I've used in a few apps to retrofit some client caching into list displays. In this application I took the path of least resistance to the existing server rendering logic. Here are a few other ways that come to mind: Using Partial HTML Rendering via AJAXInstead of rendering the page initially on the server, the page would load empty and the client would render the UI by retrieving the respective HTML and embedding it into the page from a Partial View. This effectively makes the initial rendering and the cached rendering logic identical and removes the server having to decide whether this request needs to be rendered or not (ie. not checking for a back=true switch). All the logic related to caching is made on the client in this case. Using JSON Data and Client RenderingThe hardcore client option is to do the whole UI SPA style and pull data from the server and then use client rendering or databinding to pull the data down and render using templates or client side databinding with knockout/angular et al. As with the Partial Rendering approach the advantage is that there's no difference in the logic between pulling the data from cache or rendering from scratch other than the initial check for the cache request. Of course if the app is a  full on SPA app, then caching may not be required even - the list could just stay in memory and be hidden and reactivated. I'm sure there are a number of other ways this can be handled as well especially using  AJAX. AJAX rendering might simplify the logic, but it also complicates search engine optimization since there's no content loaded initially. So there are always tradeoffs and it's important to look at all angles before deciding on any sort of caching solution in general. State of the Session SessionState and LocalStorage are easy to use in client code and can be integrated even with server centric applications to provide nice caching features of content and data. In this post I've shown a very specific scenario of storing HTML content for the purpose of remembering list view data and state and making the browsing experience for lists a bit more friendly, especially if there's dynamically loaded content involved. If you haven't played with sessionStorage or localStorage I encourage you to give it a try. There's a lot of cool stuff that you can do with this beyond the specific scenario I've covered here… Resources Overview of localStorage (also applies to sessionStorage) Web Storage Compatibility Modernizr Test Suite© Rick Strahl, West Wind Technologies, 2005-2013Posted in JavaScript  HTML5  ASP.NET  MVC   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• Inside the Concurrent Collections: ConcurrentDictionary

  - by Simon Cooper

  Using locks to implement a thread-safe collection is rather like using a sledgehammer - unsubtle, easy to understand, and tends to make any other tool redundant. Unlike the previous two collections I looked at, ConcurrentStack and ConcurrentQueue, ConcurrentDictionary uses locks quite heavily. However, it is careful to wield locks only where necessary to ensure that concurrency is maximised. This will, by necessity, be a higher-level look than my other posts in this series, as there is quite a lot of code and logic in ConcurrentDictionary. Therefore, I do recommend that you have ConcurrentDictionary open in a decompiler to have a look at all the details that I skip over. The problem with locks There's several things to bear in mind when using locks, as encapsulated by the lock keyword in C# and the System.Threading.Monitor class in .NET (if you're unsure as to what lock does in C#, I briefly covered it in my first post in the series): Locks block threads The most obvious problem is that threads waiting on a lock can't do any work at all. No preparatory work, no 'optimistic' work like in ConcurrentQueue and ConcurrentStack, nothing. It sits there, waiting to be unblocked. This is bad if you're trying to maximise concurrency. Locks are slow Whereas most of the methods on the Interlocked class can be compiled down to a single CPU instruction, ensuring atomicity at the hardware level, taking out a lock requires some heavy lifting by the CLR and the operating system. There's quite a bit of work required to take out a lock, block other threads, and wake them up again. If locks are used heavily, this impacts performance. Deadlocks When using locks there's always the possibility of a deadlock - two threads, each holding a lock, each trying to aquire the other's lock. Fortunately, this can be avoided with careful programming and structured lock-taking, as we'll see. So, it's important to minimise where locks are used to maximise the concurrency and performance of the collection. Implementation As you might expect, ConcurrentDictionary is similar in basic implementation to the non-concurrent Dictionary, which I studied in a previous post. I'll be using some concepts introduced there, so I recommend you have a quick read of it. So, if you were implementing a thread-safe dictionary, what would you do? The naive implementation is to simply have a single lock around all methods accessing the dictionary. This would work, but doesn't allow much concurrency. Fortunately, the bucketing used by Dictionary allows a simple but effective improvement to this - one lock per bucket. This allows different threads modifying different buckets to do so in parallel. Any thread making changes to the contents of a bucket takes the lock for that bucket, ensuring those changes are thread-safe. The method that maps each bucket to a lock is the GetBucketAndLockNo method: private void GetBucketAndLockNo( int hashcode, out int bucketNo, out int lockNo, int bucketCount) { // the bucket number is the hashcode (without the initial sign bit) // modulo the number of buckets bucketNo = (hashcode & 0x7fffffff) % bucketCount; // and the lock number is the bucket number modulo the number of locks lockNo = bucketNo % m_locks.Length; } However, this does require some changes to how the buckets are implemented. The 'implicit' linked list within a single backing array used by the non-concurrent Dictionary adds a dependency between separate buckets, as every bucket uses the same backing array. Instead, ConcurrentDictionary uses a strict linked list on each bucket: This ensures that each bucket is entirely separate from all other buckets; adding or removing an item from a bucket is independent to any changes to other buckets. Modifying the dictionary All the operations on the dictionary follow the same basic pattern: void AlterBucket(TKey key, ...) { int bucketNo, lockNo; 1: GetBucketAndLockNo( key.GetHashCode(), out bucketNo, out lockNo, m_buckets.Length); 2: lock (m_locks[lockNo]) { 3: Node headNode = m_buckets[bucketNo]; 4: Mutate the node linked list as appropriate } } For example, when adding another entry to the dictionary, you would iterate through the linked list to check whether the key exists already, and add the new entry as the head node. When removing items, you would find the entry to remove (if it exists), and remove the node from the linked list. Adding, updating, and removing items all follow this pattern. Performance issues There is a problem we have to address at this point. If the number of buckets in the dictionary is fixed in the constructor, then the performance will degrade from O(1) to O(n) when a large number of items are added to the dictionary. As more and more items get added to the linked lists in each bucket, the lookup operations will spend most of their time traversing a linear linked list. To fix this, the buckets array has to be resized once the number of items in each bucket has gone over a certain limit. (In ConcurrentDictionary this limit is when the size of the largest bucket is greater than the number of buckets for each lock. This check is done at the end of the TryAddInternal method.) Resizing the bucket array and re-hashing everything affects every bucket in the collection. Therefore, this operation needs to take out every lock in the collection. Taking out mutiple locks at once inevitably summons the spectre of the deadlock; two threads each hold a lock, and each trying to acquire the other lock. How can we eliminate this? Simple - ensure that threads never try to 'swap' locks in this fashion. When taking out multiple locks, always take them out in the same order, and always take out all the locks you need before starting to release them. In ConcurrentDictionary, this is controlled by the AcquireLocks, AcquireAllLocks and ReleaseLocks methods. Locks are always taken out and released in the order they are in the m_locks array, and locks are all released right at the end of the method in a finally block. At this point, it's worth pointing out that the locks array is never re-assigned, even when the buckets array is increased in size. The number of locks is fixed in the constructor by the concurrencyLevel parameter. This simplifies programming the locks; you don't have to check if the locks array has changed or been re-assigned before taking out a lock object. And you can be sure that when a thread takes out a lock, another thread isn't going to re-assign the lock array. This would create a new series of lock objects, thus allowing another thread to ignore the existing locks (and any threads controlling them), breaking thread-safety. Consequences of growing the array Just because we're using locks doesn't mean that race conditions aren't a problem. We can see this by looking at the GrowTable method. The operation of this method can be boiled down to: private void GrowTable(Node[] buckets) { try { 1: Acquire first lock in the locks array // this causes any other thread trying to take out // all the locks to block because the first lock in the array // is always the one taken out first // check if another thread has already resized the buckets array // while we were waiting to acquire the first lock 2: if (buckets != m_buckets) return; 3: Calculate the new size of the backing array 4: Node[] array = new array[size]; 5: Acquire all the remaining locks 6: Re-hash the contents of the existing buckets into array 7: m_buckets = array; } finally { 8: Release all locks } } As you can see, there's already a check for a race condition at step 2, for the case when the GrowTable method is called twice in quick succession on two separate threads. One will successfully resize the buckets array (blocking the second in the meantime), when the second thread is unblocked it'll see that the array has already been resized & exit without doing anything. There is another case we need to consider; looking back at the AlterBucket method above, consider the following situation: Thread 1 calls AlterBucket; step 1 is executed to get the bucket and lock numbers. Thread 2 calls GrowTable and executes steps 1-5; thread 1 is blocked when it tries to take out the lock in step 2. Thread 2 re-hashes everything, re-assigns the buckets array, and releases all the locks (steps 6-8). Thread 1 is unblocked and continues executing, but the calculated bucket and lock numbers are no longer valid. Between calculating the correct bucket and lock number and taking out the lock, another thread has changed where everything is. Not exactly thread-safe. Well, a similar problem was solved in ConcurrentStack and ConcurrentQueue by storing a local copy of the state, doing the necessary calculations, then checking if that state is still valid. We can use a similar idea here: void AlterBucket(TKey key, ...) { while (true) { Node[] buckets = m_buckets; int bucketNo, lockNo; GetBucketAndLockNo( key.GetHashCode(), out bucketNo, out lockNo, buckets.Length); lock (m_locks[lockNo]) { // if the state has changed, go back to the start if (buckets != m_buckets) continue; Node headNode = m_buckets[bucketNo]; Mutate the node linked list as appropriate } break; } } TryGetValue and GetEnumerator And so, finally, we get onto TryGetValue and GetEnumerator. I've left these to the end because, well, they don't actually use any locks. How can this be? Whenever you change a bucket, you need to take out the corresponding lock, yes? Indeed you do. However, it is important to note that TryGetValue and GetEnumerator don't actually change anything. Just as immutable objects are, by definition, thread-safe, read-only operations don't need to take out a lock because they don't change anything. All lockless methods can happily iterate through the buckets and linked lists without worrying about locking anything. However, this does put restrictions on how the other methods operate. Because there could be another thread in the middle of reading the dictionary at any time (even if a lock is taken out), the dictionary has to be in a valid state at all times. Every change to state has to be made visible to other threads in a single atomic operation (all relevant variables are marked volatile to help with this). This restriction ensures that whatever the reading threads are doing, they never read the dictionary in an invalid state (eg items that should be in the collection temporarily removed from the linked list, or reading a node that has had it's key & value removed before the node itself has been removed from the linked list). Fortunately, all the operations needed to change the dictionary can be done in that way. Bucket resizes are made visible when the new array is assigned back to the m_buckets variable. Any additions or modifications to a node are done by creating a new node, then splicing it into the existing list using a single variable assignment. Node removals are simply done by re-assigning the node's m_next pointer. Because the dictionary can be changed by another thread during execution of the lockless methods, the GetEnumerator method is liable to return dirty reads - changes made to the dictionary after GetEnumerator was called, but before the enumeration got to that point in the dictionary. It's worth listing at this point which methods are lockless, and which take out all the locks in the dictionary to ensure they get a consistent view of the dictionary: Lockless: TryGetValue GetEnumerator The indexer getter ContainsKey Takes out every lock (lockfull?): Count IsEmpty Keys Values CopyTo ToArray Concurrent principles That covers the overall implementation of ConcurrentDictionary. I haven't even begun to scratch the surface of this sophisticated collection. That I leave to you. However, we've looked at enough to be able to extract some useful principles for concurrent programming: Partitioning When using locks, the work is partitioned into independant chunks, each with its own lock. Each partition can then be modified concurrently to other partitions. Ordered lock-taking When a method does need to control the entire collection, locks are taken and released in a fixed order to prevent deadlocks. Lockless reads Read operations that don't care about dirty reads don't take out any lock; the rest of the collection is implemented so that any reading thread always has a consistent view of the collection. That leads us to the final collection in this little series - ConcurrentBag. Lacking a non-concurrent analogy, it is quite different to any other collection in the class libraries. Prepare your thinking hats!

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• .NET Code Evolution

  - by Alois Kraus

  Originally posted on: http://geekswithblogs.net/akraus1/archive/2013/07/24/153504.aspxAt my day job I do look at a lot of code written by other people. Most of the code is quite good and some is even a masterpiece. And there is also code which makes you think WTF… oh it was written by me. Hm not so bad after all. There are many excuses reasons for bad code. Most often it is time pressure followed by not enough ambition (who cares) or insufficient training. Normally I do care about code quality quite a lot which makes me a (perceived) slow worker who does write many tests and refines the code quite a lot because of the design deficiencies. Most of the deficiencies I do find by putting my design under stress while checking for invariants. It does also help a lot to step into the code with a debugger (sometimes also Windbg). I do this much more often when my tests are red. That way I do get a much better understanding what my code really does and not what I think it should be doing. This time I do want to show you how code can evolve over the years with different .NET Framework versions. Once there was  time where .NET 1.1 was new and many C++ programmers did switch over to get rid of not initialized pointers and memory leaks. There were also nice new data structures available such as the Hashtable which is fast lookup table with O(1) time complexity. All was good and much code was written since then. At 2005 a new version of the .NET Framework did arrive which did bring many new things like generics and new data structures. The “old” fashioned way of Hashtable were coming to an end and everyone used the new Dictionary<xx,xx> type instead which was type safe and faster because the object to type conversion (aka boxing) was no longer necessary. I think 95% of all Hashtables and dictionaries use string as key. Often it is convenient to ignore casing to make it easy to look up values which the user did enter. An often followed route is to convert the string to upper case before putting it into the Hashtable. Hashtable Table = new Hashtable(); void Add(string key, string value) { Table.Add(key.ToUpper(), value); } This is valid and working code but it has problems. First we can pass to the Hashtable a custom IEqualityComparer to do the string matching case insensitive. Second we can switch over to the now also old Dictionary type to become a little faster and we can keep the the original keys (not upper cased) in the dictionary. Dictionary<string, string> DictTable = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase); void AddDict(string key, string value) { DictTable.Add(key, value); } Many people do not user the other ctors of Dictionary because they do shy away from the overhead of writing their own comparer. They do not know that .NET has for strings already predefined comparers at hand which you can directly use. Today in the many core area we do use threads all over the place. Sometimes things break in subtle ways but most of the time it is sufficient to place a lock around the offender. Threading has become so mainstream that it may sound weird that in the year 2000 some guy got a huge incentive for the idea to reduce the time to process calibration data from 12 hours to 6 hours by using two threads on a dual core machine. Threading does make it easy to become faster at the expense of correctness. Correct and scalable multithreading can be arbitrarily hard to achieve depending on the problem you are trying to solve. Lets suppose we want to process millions of items with two threads and count the processed items processed by all threads. A typical beginners code might look like this: int Counter; void IJustLearnedToUseThreads() { var t1 = new Thread(ThreadWorkMethod); t1.Start(); var t2 = new Thread(ThreadWorkMethod); t2.Start(); t1.Join(); t2.Join(); if (Counter != 2 * Increments) throw new Exception("Hmm " + Counter + " != " + 2 * Increments); } const int Increments = 10 * 1000 * 1000; void ThreadWorkMethod() { for (int i = 0; i < Increments; i++) { Counter++; } } It does throw an exception with the message e.g. “Hmm 10.222.287 != 20.000.000” and does never finish. The code does fail because the assumption that Counter++ is an atomic operation is wrong. The ++ operator is just a shortcut for Counter = Counter + 1 This does involve reading the counter from a memory location into the CPU, incrementing value on the CPU and writing the new value back to the memory location. When we do look at the generated assembly code we will see only inc dword ptr [ecx+10h] which is only one instruction. Yes it is one instruction but it is not atomic. All modern CPUs have several layers of caches (L1,L2,L3) which try to hide the fact how slow actual main memory accesses are. Since cache is just another word for redundant copy it can happen that one CPU does read a value from main memory into the cache, modifies it and write it back to the main memory. The problem is that at least the L1 cache is not shared between CPUs so it can happen that one CPU does make changes to values which did change in meantime in the main memory. From the exception you can see we did increment the value 20 million times but half of the changes were lost because we did overwrite the already changed value from the other thread. This is a very common case and people do learn to protect their  data with proper locking.   void Intermediate() { var time = Stopwatch.StartNew(); Action acc = ThreadWorkMethod_Intermediate; var ar1 = acc.BeginInvoke(null, null); var ar2 = acc.BeginInvoke(null, null); ar1.AsyncWaitHandle.WaitOne(); ar2.AsyncWaitHandle.WaitOne(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Intermediate did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Intermediate() { for (int i = 0; i < Increments; i++) { lock (this) { Counter++; } } } This is better and does use the .NET Threadpool to get rid of manual thread management. It does give the expected result but it can result in deadlocks because you do lock on this. This is in general a bad idea since it can lead to deadlocks when other threads use your class instance as lock object. It is therefore recommended to create a private object as lock object to ensure that nobody else can lock your lock object. When you read more about threading you will read about lock free algorithms. They are nice and can improve performance quite a lot but you need to pay close attention to the CLR memory model. It does make quite weak guarantees in general but it can still work because your CPU architecture does give you more invariants than the CLR memory model. For a simple counter there is an easy lock free alternative present with the Interlocked class in .NET. As a general rule you should not try to write lock free algos since most likely you will fail to get it right on all CPU architectures. void Experienced() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); t1.Wait(); t2.Wait(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Experienced did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Experienced() { for (int i = 0; i < Increments; i++) { Interlocked.Increment(ref Counter); } } Since time does move forward we do not use threads explicitly anymore but the much nicer Task abstraction which was introduced with .NET 4 at 2010. It is educational to look at the generated assembly code. The Interlocked.Increment method must be called which does wondrous things right? Lets see: lock inc dword ptr [eax] The first thing to note that there is no method call at all. Why? Because the JIT compiler does know very well about CPU intrinsic functions. Atomic operations which do lock the memory bus to prevent other processors to read stale values are such things. Second: This is the same increment call prefixed with a lock instruction. The only reason for the existence of the Interlocked class is that the JIT compiler can compile it to the matching CPU intrinsic functions which can not only increment by one but can also do an add, exchange and a combined compare and exchange operation. But be warned that the correct usage of its methods can be tricky. If you try to be clever and look a the generated IL code and try to reason about its efficiency you will fail. Only the generated machine code counts. Is this the best code we can write? Perhaps. It is nice and clean. But can we make it any faster? Lets see how good we are doing currently. Level Time in s IJustLearnedToUseThreads Flawed Code Intermediate 1,5 (lock) Experienced 0,3 (Interlocked.Increment) Master 0,1 (1,0 for int[2]) That lock free thing is really a nice thing. But if you read more about CPU cache, cache coherency, false sharing you can do even better. int[] Counters = new int[12]; // Cache line size is 64 bytes on my machine with an 8 way associative cache try for yourself e.g. 64 on more modern CPUs void Master() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Master, 0); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Master, Counters.Length - 1); t1.Wait(); t2.Wait(); Counter = Counters[0] + Counters[Counters.Length - 1]; if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Master did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Master(object number) { int index = (int) number; for (int i = 0; i < Increments; i++) { Counters[index]++; } } The key insight here is to use for each core its own value. But if you simply use simply an integer array of two items, one for each core and add the items at the end you will be much slower than the lock free version (factor 3). Each CPU core has its own cache line size which is something in the range of 16-256 bytes. When you do access a value from one location the CPU does not only fetch one value from main memory but a complete cache line (e.g. 16 bytes). This means that you do not pay for the next 15 bytes when you access them. This can lead to dramatic performance improvements and non obvious code which is faster although it does have many more memory reads than another algorithm. So what have we done here? We have started with correct code but it was lacking knowledge how to use the .NET Base Class Libraries optimally. Then we did try to get fancy and used threads for the first time and failed. Our next try was better but it still had non obvious issues (lock object exposed to the outside). Knowledge has increased further and we have found a lock free version of our counter which is a nice and clean way which is a perfectly valid solution. The last example is only here to show you how you can get most out of threading by paying close attention to your used data structures and CPU cache coherency. Although we are working in a virtual execution environment in a high level language with automatic memory management it does pay off to know the details down to the assembly level. Only if you continue to learn and to dig deeper you can come up with solutions no one else was even considering. I have studied particle physics which does help at the digging deeper part. Have you ever tried to solve Quantum Chromodynamics equations? Compared to that the rest must be easy ;-). Although I am no longer working in the Science field I take pride in discovering non obvious things. This can be a very hard to find bug or a new way to restructure data to make something 10 times faster. Now I need to get some sleep ….

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• Switch from VOLUME_KMSCLIENT to RETAIL channel

  - by trogper

  On my laptop I had Windows 8 Pro KMS activated, then I intalled WMC, which changed it to RETAIL channel, so I don't need KMS I repeated this on my desktop, which was VOLUME_KMSCLIENT and I thought it would convert it to RETAIL, but now it's just Windows 8 Pro WMC KMS. slmgr -dli partial p.key doesn't match that one I entered I can't update to 8.1 (through win store) when I have VOLUME_KMSCLIENT channel. How do I change it? edit: wmc key that I used is blocked

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• Networking issues with Linux server (CentOS 5.3)

  - by sxanness

  I have a Linux server hosting our bug tracking software (CentOS 5.2 Kernel 2.6.18-128.4.1.el5) that I have having some strange network problems with. The machine is configured with two NICS, one for the public interface and the other for our server back end network. The problem is that after doing a service network restart I can ping the public interface and it sends anywhere from 200-500 ICMP packets and then all of a sudden I start getting a request timed out error. Strange but as soon as I connect to the private interface the ping starts working again to the public interface. I clearly have a routing issue somewhere. I have a Juniper Router with the following configuration. Interface 0/0 -- Connect subnet to the ISP at our co-location Interface 0/2 -- For our DRAC network Interface 0/3 -- The Server-backend network (plugs directly into a switch that feeds to all the NICs that are on the 10.3.20.x network. Interface 0/4 -- Plugs directly into another switch that feeds our public interfaces, that interface as all the gateways from our public ip rangs as secondary IP addresses. I hope that someone can ask the right questions that can lead me to check things and figure out what is going on. Has anyone had similar problems and what kind of things should I be checking? Routing issue or something even more complicated? [root@fogbugz ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0 # Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ DEVICE=eth0 BOOTPROTO=static IPADDR=72.249.134.98 NETMASK=255.255.255.248 BROADCAST=72.249.134.103 HWADDR=00:16:3E:AA:BB:EE ONBOOT=yes [root@fogbugz ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth1 # Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ DEVICE=eth1 BOOTPROTO=static BROADCAST=10.3.20.255 HWADDR=00:17:3E:AA:BB:EE IPADDR=10.3.20.25 NETMASK=255.255.255.0 NETWORK=10.3.20.0 ONBOOT=yes [root@fogbugz ~]# cat /etc/sysconfig/network NETWORKING=yes NETWORKING_IPV6=no HOSTNAME=fogbugz.dfw.hisg-it.net GATEWAY=72.249.134.97 [root@fogbugz ~]# route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 72.249.134.96 0.0.0.0 255.255.255.248 U 0 0 0 eth0 10.3.20.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth1 10.0.0.0 10.3.20.1 255.0.0.0 UG 0 0 0 eth1 0.0.0.0 72.249.134.97 0.0.0.0 UG 0 0 0 eth0

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• Networking issues with Linux server (CentOS 5.3)

  - by sxanness

  I have a Linux server hosting our bug tracking software (CentOS 5.2 Kernel 2.6.18-128.4.1.el5) that I have having some strange network problems with. The machine is configured with two NICS, one for the public interface and the other for our server back end network. The problem is that after doing a service network restart I can ping the public interface and it sends anywhere from 200-500 ICMP packets and then all of a sudden I start getting a request timed out error. Strange but as soon as I connect to the private interface the ping starts working again to the public interface. I clearly have a routing issue somewhere. I have a Juniper Router with the following configuration. Interface 0/0 -- Connect subnet to the ISP at our co-location Interface 0/2 -- For our DRAC network Interface 0/3 -- The Server-backend network (plugs directly into a switch that feeds to all the NICs that are on the 10.3.20.x network. Interface 0/4 -- Plugs directly into another switch that feeds our public interfaces, that interface as all the gateways from our public ip rangs as secondary IP addresses. I hope that someone can ask the right questions that can lead me to check things and figure out what is going on. Has anyone had similar problems and what kind of things should I be checking? Routing issue or something even more complicated? [root@fogbugz ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0 # Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ DEVICE=eth0 BOOTPROTO=static IPADDR=72.249.134.98 NETMASK=255.255.255.248 BROADCAST=72.249.134.103 HWADDR=00:16:3E:AA:BB:EE ONBOOT=yes [root@fogbugz ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth1 # Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ DEVICE=eth1 BOOTPROTO=static BROADCAST=10.3.20.255 HWADDR=00:17:3E:AA:BB:EE IPADDR=10.3.20.25 NETMASK=255.255.255.0 NETWORK=10.3.20.0 ONBOOT=yes [root@fogbugz ~]# cat /etc/sysconfig/network NETWORKING=yes NETWORKING_IPV6=no HOSTNAME=fogbugz.dfw.hisg-it.net GATEWAY=72.249.134.97 [root@fogbugz ~]# route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 72.249.134.96 0.0.0.0 255.255.255.248 U 0 0 0 eth0 10.3.20.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth1 10.0.0.0 10.3.20.1 255.0.0.0 UG 0 0 0 eth1 0.0.0.0 72.249.134.97 0.0.0.0 UG 0 0 0 eth0

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