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• RSS feeds in Orchard

  - by Bertrand Le Roy

  When we added RSS to Orchard, we wanted to make it easy for any module to expose any contents as a feed. We also wanted the rendering of the feed to be handled by Orchard in order to minimize the amount of work from the module developer. A typical example of such feed exposition is of course blog feeds. We have an IFeedManager interface for which you can get the built-in implementation through dependency injection. Look at the BlogController constructor for an example: public BlogController( IOrchardServices services, IBlogService blogService, IBlogSlugConstraint blogSlugConstraint, IFeedManager feedManager, RouteCollection routeCollection) { If you look a little further in that same controller, in the Item action, you’ll see a call to the Register method of the feed manager: _feedManager.Register(blog); This in reality is a call into an extension method that is specialized for blogs, but we could have made the two calls to the actual generic Register directly in the action instead, that is just an implementation detail: feedManager.Register(blog.Name, "rss", new RouteValueDictionary { { "containerid", blog.Id } }); feedManager.Register(blog.Name + " - Comments", "rss", new RouteValueDictionary { { "commentedoncontainer", blog.Id } }); What those two effective calls are doing is to register two feeds: one for the blog itself and one for the comments on the blog. For each call, the name of the feed is provided, then we have the type of feed (“rss”) and some values to be injected into the generic RSS route that will be used later to route the feed to the right providers. This is all you have to do to expose a new feed. If you’re only interested in exposing feeds, you can stop right there. If on the other hand you want to know what happens after that under the hood, carry on. What happens after that is that the feedmanager will take care of formatting the link tag for the feed (see FeedManager.GetRegisteredLinks). The GetRegisteredLinks method itself will be called from a specialized filter, FeedFilter. FeedFilter is an MVC filter and the event we’re interested in hooking into is OnResultExecuting, which happens after the controller action has returned an ActionResult and just before MVC executes that action result. In other words, our feed registration has already been called but the view is not yet rendered. Here’s the code for OnResultExecuting: model.Zones.AddAction("head:after", html => html.ViewContext.Writer.Write( _feedManager.GetRegisteredLinks(html))); This is another piece of code whose execution is differed. It is saying that whenever comes time to render the “head” zone, this code should be called right after. The code itself is rendering the link tags. As a result of all that, here’s what can be found in an Orchard blog’s head section: <link rel="alternate" type="application/rss+xml"     title="Tales from the Evil Empire"     href="/rss?containerid=5" /> <link rel="alternate" type="application/rss+xml"     title="Tales from the Evil Empire - Comments"     href="/rss?commentedoncontainer=5" /> The generic action that these two feeds point to is Index on FeedController. That controller has three important dependencies: an IFeedBuilderProvider, an IFeedQueryProvider and an IFeedItemProvider. Different implementations of these interfaces can provide different formats of feeds, such as RSS and Atom. The Match method enables each of the competing providers to provide a priority for themselves based on arbitrary criteria that can be found on the FeedContext. This means that a provider can be selected based not only on the desired format, but also on the nature of the objects being exposed as a feed or on something even more arbitrary such as the destination device (you could imagine for example giving shorter text only excerpts of posts on mobile devices, and full HTML on desktop). The key here is extensibility and dynamic competition and collaboration from unknown and loosely coupled parts. You’ll find this pattern pretty much everywhere in the Orchard architecture. The RssFeedBuilder implementation of IFeedBuilderProvider is also a regular controller with a Process action that builds a RssResult, which is itself a thin ActionResult wrapper around an XDocument. Let’s get back to the FeedController’s Index action. After having called into each known feed builder to get its priority on the currently requested feed, it will select the one with the highest priority. The next thing it needs to do is to actually fetch the data for the feed. This again is a collaborative effort from a priori unknown providers, the implementations of IFeedQueryProvider. There are several implementations by default in Orchard, the choice of which is again done through a Match method. ContainerFeedQuery for example chimes in when a “containerid” parameter is found in the context (see URL in the link tag above): public FeedQueryMatch Match(FeedContext context) { var containerIdValue = context.ValueProvider.GetValue("containerid"); if (containerIdValue == null) return null; return new FeedQueryMatch { FeedQuery = this, Priority = -5 }; } The actual work is done in the Execute method, which finds the right container content item in the Orchard database and adds elements for each of them. In other words, the feed query provider knows how to retrieve the list of content items to add to the feed. The last step is to translate each of the content items into feed entries, which is done by implementations of IFeedItemBuilder. There is no Match method this time. Instead, all providers are called with the collection of items (or more accurately with the FeedContext, but this contains the list of items, which is what’s relevant in most cases). Each provider can then choose to pick those items that it knows how to treat and transform them into the format requested. This enables the construction of heterogeneous feeds that expose content items of various types into a single feed. That will be extremely important when you’ll want to expose a single feed for all your site. So here are feeds in Orchard in a nutshell. The main point here is that there is a fair number of components involved, with some complexity in implementation in order to allow for extreme flexibility, but the part that you use to expose a new feed is extremely simple and light: declare that you want your content exposed as a feed and you’re done. There are cases where you’ll have to dive in and provide new implementations for some or all of the interfaces involved, but that requirement will only arise as needed. For example, you might need to create a new feed item builder to include your custom content type but that effort will be extremely focused on the specialized task at hand. The rest of the system won’t need to change. So what do you think?

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• Enabling Service Availability in WCF Services

  - by cibrax

  It is very important for the enterprise to know which services are operational at any given point. There are many factors that can affect the availability of the services, some of them are external like a database not responding or any dependant service not working. However, in some cases, you only want to know whether a service is up or down, so a simple heart-beat mechanism with “Ping” messages would do the trick. Unfortunately, WCF does not provide a built-in mechanism to support this functionality, and you probably don’t to implement a “Ping” operation in any service that you have out there. For solving this in a generic way, there is a WCF extensibility point that comes to help us, the “Operation Invokers”. In a nutshell, an operation invoker is the class responsible invoking the service method with a set of parameters and generate the output parameters with the return value. What I am going to do here is to implement a custom operation invoker that intercepts any call to the service, and detects whether a “Ping” header was attached to the message. If the “Ping” header is detected, the operation invoker returns a new header to tell the client that the service is alive, and the real operation execution is omitted. In that way, we have a simple heart beat mechanism based on the messages that include a "Ping” header, so the client application can determine at any point whether the service is up or down. My operation invoker wraps the default implementation attached by default to any operation by WCF. internal class PingOperationInvoker : IOperationInvoker { IOperationInvoker innerInvoker; object[] outputs = null; object returnValue = null; public const string PingHeaderName = "Ping"; public const string PingHeaderNamespace = "http://tellago.serviceModel"; public PingOperationInvoker(IOperationInvoker innerInvoker, OperationDescription description) { this.innerInvoker = innerInvoker; outputs = description.SyncMethod.GetParameters() .Where(p => p.IsOut) .Select(p => DefaultForType(p.ParameterType)).ToArray(); var returnValue = DefaultForType(description.SyncMethod.ReturnType); } private static object DefaultForType(Type targetType) { return targetType.IsValueType ? Activator.CreateInstance(targetType) : null; } public object Invoke(object instance, object[] inputs, out object[] outputs) { object returnValue; if (Invoke(out returnValue, out outputs)) { return returnValue; } else { return this.innerInvoker.Invoke(instance, inputs, out outputs); } } private bool Invoke(out object returnValue, out object[] outputs) { object untypedProperty = null; if (OperationContext.Current .IncomingMessageProperties.TryGetValue(HttpRequestMessageProperty.Name, out untypedProperty)) { var httpRequestProperty = untypedProperty as HttpRequestMessageProperty; if (httpRequestProperty != null) { if (httpRequestProperty.Headers[PingHeaderName] != null) { outputs = this.outputs; if (OperationContext.Current .IncomingMessageProperties.TryGetValue(HttpRequestMessageProperty.Name, out untypedProperty)) { var httpResponseProperty = untypedProperty as HttpResponseMessageProperty; httpResponseProperty.Headers.Add(PingHeaderName, "Ok"); } returnValue = this.returnValue; return true; } } } var headers = OperationContext.Current.IncomingMessageHeaders; if (headers.FindHeader(PingHeaderName, PingHeaderNamespace) > -1) { outputs = this.outputs; MessageHeader<string> header = new MessageHeader<string>("Ok"); var untyped = header.GetUntypedHeader(PingHeaderName, PingHeaderNamespace); OperationContext.Current.OutgoingMessageHeaders.Add(untyped); returnValue = this.returnValue; return true; } returnValue = null; outputs = null; return false; } } The implementation above looks for the “Ping” header either in the Http Request or the Soap message. The next step is to implement a behavior for attaching this operation invoker to the services we want to monitor. [AttributeUsage(AttributeTargets.Method | AttributeTargets.Class, AllowMultiple = false, Inherited = true)] public class PingBehavior : Attribute, IServiceBehavior, IOperationBehavior { public void AddBindingParameters(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase, Collection<ServiceEndpoint> endpoints, BindingParameterCollection bindingParameters) { } public void ApplyDispatchBehavior(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase) { } public void Validate(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase) { foreach (var endpoint in serviceDescription.Endpoints) { foreach (var operation in endpoint.Contract.Operations) { if (operation.Behaviors.Find<PingBehavior>() == null) operation.Behaviors.Add(this); } } } public void AddBindingParameters(OperationDescription operationDescription, BindingParameterCollection bindingParameters) { } public void ApplyClientBehavior(OperationDescription operationDescription, ClientOperation clientOperation) { } public void ApplyDispatchBehavior(OperationDescription operationDescription, DispatchOperation dispatchOperation) { dispatchOperation.Invoker = new PingOperationInvoker(dispatchOperation.Invoker, operationDescription); } public void Validate(OperationDescription operationDescription) { } } As an operation invoker can only be added in an “operation behavior”, a trick I learned in the past is that you can implement a service behavior as well and use the “Validate” method to inject it in all the operations, so the final configuration is much easier and cleaner. You only need to decorate the service with a simple attribute to enable the “Ping” functionality. [PingBehavior] public class HelloWorldService : IHelloWorld { public string Hello(string name) { return "Hello " + name; } } On the other hand, the client application needs to send a dummy message with a “Ping” header to detect whether the service is available or not. In order to simplify this task, I created a extension method in the WCF client channel to do this work. public static class ClientChannelExtensions { const string PingNamespace = "http://tellago.serviceModel"; const string PingName = "Ping"; public static bool IsAvailable<TChannel>(this IClientChannel channel, Action<TChannel> operation) { try { using (OperationContextScope scope = new OperationContextScope(channel)) { MessageHeader<string> header = new MessageHeader<string>(PingName); var untyped = header.GetUntypedHeader(PingName, PingNamespace); OperationContext.Current.OutgoingMessageHeaders.Add(untyped); try { operation((TChannel)channel); var headers = OperationContext.Current.IncomingMessageHeaders; if (headers.Any(h => h.Name == PingName && h.Namespace == PingNamespace)) { return true; } else { return false; } } catch (CommunicationException) { return false; } } } catch (Exception) { return false; } } } This extension method basically adds a “Ping” header to the request message, executes the operation passed as argument (Action<TChannel> operation), and looks for the corresponding “Ping” header in the response to see the results. The client application can use this extension with a single line of code, var client = new ServiceReference.HelloWorldClient(); var isAvailable = client.InnerChannel.IsAvailable<IHelloWorld>((c) => c.Hello(null)); The “isAvailable” variable will tell the client application whether the service is available or not. You can download the complete implementation from this location.    

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• C# Extension Methods - To Extend or Not To Extend...

  - by James Michael Hare

  I've been thinking a lot about extension methods lately, and I must admit I both love them and hate them. They are a lot like sugar, they taste so nice and sweet, but they'll rot your teeth if you eat them too much.   I can't deny that they aren't useful and very handy. One of the major components of the Shared Component library where I work is a set of useful extension methods. But, I also can't deny that they tend to be overused and abused to willy-nilly extend every living type.   So what constitutes a good extension method? Obviously, you can write an extension method for nearly anything whether it is a good idea or not. Many times, in fact, an idea seems like a good extension method but in retrospect really doesn't fit.   So what's the litmus test? To me, an extension method should be like in the movies when a person runs into their twin, separated at birth. You just know you're related. Obviously, that's hard to quantify, so let's try to put a few rules-of-thumb around them.   A good extension method should:     Apply to any possible instance of the type it extends.     Simplify logic and improve readability/maintainability.     Apply to the most specific type or interface applicable.     Be isolated in a namespace so that it does not pollute IntelliSense.     So let's look at a few examples in relation to these rules.   The first rule, to me, is the most important of all. Once again, it bears repeating, a good extension method should apply to all possible instances of the type it extends. It should feel like the long lost relative that should have been included in the original class but somehow was missing from the family tree.    Take this nifty little int extension, I saw this once in a blog and at first I really thought it was pretty cool, but then I started noticing a code smell I couldn't quite put my finger on. So let's look:       public static class IntExtensinos     {         public static int Seconds(int num)         {             return num * 1000;         }           public static int Minutes(int num)         {             return num * 60000;         }     }     This is so you could do things like:       ...     Thread.Sleep(5.Seconds());     ...     proxy.Timeout = 1.Minutes();     ...     Awww, you say, that's cute! Well, that's the problem, it's kitschy and it doesn't always apply (and incidentally you could achieve the same thing with TimeStamp.FromSeconds(5)). It's syntactical candy that looks cool, but tends to rot and pollute the code. It would allow things like:       total += numberOfTodaysOrders.Seconds();     which makes no sense and should never be allowed. The problem is you're applying an extension method to a logical domain, not a type domain. That is, the extension method Seconds() doesn't really apply to ALL ints, it applies to ints that are representative of time that you want to convert to milliseconds.    Do you see what I mean? The two problems, in a nutshell, are that a) Seconds() called off a non-time value makes no sense and b) calling Seconds() off something to pass to something that does not take milliseconds will be off by a factor of 1000 or worse.   Thus, in my mind, you should only ever have an extension method that applies to the whole domain of that type.   For example, this is one of my personal favorites:       public static bool IsBetween<T>(this T value, T low, T high)         where T : IComparable<T>     {         return value.CompareTo(low) >= 0 && value.CompareTo(high) <= 0;     }   This allows you to check if any IComparable<T> is within an upper and lower bound. Think of how many times you type something like:       if (response.Employee.Address.YearsAt >= 2         && response.Employee.Address.YearsAt <= 10)     {     ...     }     Now, you can instead type:       if(response.Employee.Address.YearsAt.IsBetween(2, 10))     {     ...     }     Note that this applies to all IComparable<T> -- that's ints, chars, strings, DateTime, etc -- and does not depend on any logical domain. In addition, it satisfies the second point and actually makes the code more readable and maintainable.   Let's look at the third point. In it we said that an extension method should fit the most specific interface or type possible. Now, I'm not saying if you have something that applies to enumerables, you create an extension for List, Array, Dictionary, etc (though you may have reasons for doing so), but that you should beware of making things TOO general.   For example, let's say we had an extension method like this:       public static T ConvertTo<T>(this object value)     {         return (T)Convert.ChangeType(value, typeof(T));     }         This lets you do more fluent conversions like:       double d = "5.0".ConvertTo<double>();     However, if you dig into Reflector (LOVE that tool) you will see that if the type you are calling on does not implement IConvertible, what you convert to MUST be the exact type or it will throw an InvalidCastException. Now this may or may not be what you want in this situation, and I leave that up to you. Things like this would fail:       object value = new Employee();     ...     // class cast exception because typeof(IEmployee) != typeof(Employee)     IEmployee emp = value.ConvertTo<IEmployee>();       Yes, that's a downfall of working with Convertible in general, but if you wanted your fluent interface to be more type-safe so that ConvertTo were only callable on IConvertibles (and let casting be a manual task), you could easily make it:         public static T ConvertTo<T>(this IConvertible value)     {         return (T)Convert.ChangeType(value, typeof(T));     }         This is what I mean by choosing the best type to extend. Consider that if we used the previous (object) version, every time we typed a dot ('.') on an instance we'd pull up ConvertTo() whether it was applicable or not. By filtering our extension method down to only valid types (those that implement IConvertible) we greatly reduce our IntelliSense pollution and apply a good level of compile-time correctness.   Now my fourth rule is just my general rule-of-thumb. Obviously, you can make extension methods as in-your-face as you want. I included all mine in my work libraries in its own sub-namespace, something akin to:       namespace Shared.Core.Extensions { ... }     This is in a library called Shared.Core, so just referencing the Core library doesn't pollute your IntelliSense, you have to actually do a using on Shared.Core.Extensions to bring the methods in. This is very similar to the way Microsoft puts its extension methods in System.Linq. This way, if you want 'em, you use the appropriate namespace. If you don't want 'em, they won't pollute your namespace.   To really make this work, however, that namespace should only include extension methods and subordinate types those extensions themselves may use. If you plant other useful classes in those namespaces, once a user includes it, they get all the extensions too.   Also, just as a personal preference, extension methods that aren't simply syntactical shortcuts, I like to put in a static utility class and then have extension methods for syntactical candy. For instance, I think it imaginable that any object could be converted to XML:       namespace Shared.Core     {         // A collection of XML Utility classes         public static class XmlUtility         {             ...             // Serialize an object into an xml string             public static string ToXml(object input)             {                 var xs = new XmlSerializer(input.GetType());                   // use new UTF8Encoding here, not Encoding.UTF8. The later includes                 // the BOM which screws up subsequent reads, the former does not.                 using (var memoryStream = new MemoryStream())                 using (var xmlTextWriter = new XmlTextWriter(memoryStream, new UTF8Encoding()))                 {                     xs.Serialize(xmlTextWriter, input);                     return Encoding.UTF8.GetString(memoryStream.ToArray());                 }             }             ...         }     }   I also wanted to be able to call this from an object like:       value.ToXml();     But here's the problem, if i made this an extension method from the start with that one little keyword "this", it would pop into IntelliSense for all objects which could be very polluting. Instead, I put the logic into a utility class so that users have the choice of whether or not they want to use it as just a class and not pollute IntelliSense, then in my extensions namespace, I add the syntactical candy:       namespace Shared.Core.Extensions     {         public static class XmlExtensions         {             public static string ToXml(this object value)             {                 return XmlUtility.ToXml(value);             }         }     }   So now it's the best of both worlds. On one hand, they can use the utility class if they don't want to pollute IntelliSense, and on the other hand they can include the Extensions namespace and use as an extension if they want. The neat thing is it also adheres to the Single Responsibility Principle. The XmlUtility is responsible for converting objects to XML, and the XmlExtensions is responsible for extending object's interface for ToXml().

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• Exception Handling And Other Contentious Political Topics

  - by Justin Jones

  So about three years ago, around the time of my last blog post, I promised a friend I would write this post. Keeping promises is a good thing, and this is my first step towards easing back into regular blogging. I fully expect him to return from Pennsylvania to buy me a beer over this. However, it’s been an… ahem… eventful three years or so, and blogging, unfortunately, got pushed to the back burner on my priority list, along with a few other career minded activities. Now that the personal drama of the past three years is more or less resolved, it’s time to put a few things back on the front burner. What I consider to be proper exception handling practices is relatively well known these days. There are plenty of blog posts out there already on this topic which more or less echo my opinions on this topic. I’ll try to include a few links at the bottom of the post. Several years ago I had an argument with a co-worker who posited that exceptions should be caught at every level and logged. This might seem like sanity on the surface, but the resulting error log looked something like this: Error: System.SomeException Followed by small stack trace. Error: System.SomeException Followed by slightly bigger stack trace. Error: System.SomeException Followed by slightly bigger stack trace. Error: System.SomeException Followed by slightly bigger stack trace. Error: System.SomeException Followed by slightly bigger stack trace. Error: System.SomeException Followed by slightly bigger stack trace. Error: System.SomeException Followed by slightly bigger stack trace. Error: System.SomeException Followed by slightly bigger stack trace.   These were all the same exception. The problem with this approach is that the error log, if you run any kind of analytics on in, becomes skewed depending on how far up the stack trace your exception was thrown. To mitigate this problem, we came up with the concept of the “PreLoggedException”. Basically, we would log the exception at the very top level and subsequently throw the exception back up the stack encapsulated in this pre-logged type, which our logging system knew to ignore. Now the error log looked like this: Error: System.SomeException Followed by small stack trace. Much cleaner, right? Well, there’s still a problem. When your exception happens in production and you go about trying to figure out what happened, you’ve lost more or less all context for where and how this exception was thrown, because all you really know is what method it was thrown in, but really nothing about who was calling the method or why. What gives you this clue is the entire stack trace, which we’re losing here. I believe that was further mitigated by having the logging system pull a system stack trace and add it to the log entry, but what you’re actually getting is the stack for how you got to the logging code. You’re still losing context about the actual error. Not to mention you’re executing a whole slew of catch blocks which are sloooooooowwwww……… In other words, we started with a bad idea and kept band-aiding it until it didn’t suck quite so bad. When I argued for not catching exceptions at every level but rather catching them following a certain set of rules, my co-worker warned me “do yourself a favor, never express that view in any future interviews.” I suppose this is my ultimate dismissal of that advice, but I’m not too worried. My approach for exception handling follows three basic rules: Only catch an exception if 1. You can do something about it. 2. You can add useful information to it. 3. You’re at an application boundary. Here’s what that means: 1. Only catch an exception if you can do something about it. We’ll start with a trivial example of a login system that uses a file. Please, never actually do this in production code, it’s just concocted example. So if our code goes to open a file and the file isn’t there, we get a FileNotFound exception. If the calling code doesn’t know what to do with this, it should bubble up. However, if we know how to create the file from scratch we can create the file and continue on our merry way. When you run into situations like this though, What should really run through your head is “How can I avoid handling an exception at all?” In this case, it’s a trivial matter to simply check for the existence of the file before trying to open it. If we detect that the file isn’t there, we can accomplish the same thing without having to handle in in a catch block. 2. Only catch an exception if you can do something about it. Continuing with the poorly thought out file based login system we contrived in part 1, if the code calls a Login(…) method and the FileNotFound exception is thrown higher up the stack, the code that calls Login must account for a FileNotFound exception. This is kind of counterintuitive because the calling code should not need to know the internals of the Login method, and the data file is an implementation detail. What makes more sense, assuming that we didn’t implement any of the good advice from step 1, is for Login to catch the FileNotFound exception and wrap it in a new exception. For argument’s sake we’ll say LoginSystemFailureException. (Sorry, couldn’t think of anything better at the moment.) This gives us two stack traces, preserving the original stack trace in the inner exception, and also is much more informative to the calling code. 3. Only catch an exception if you’re at an application boundary. At some point we have to catch all the exceptions, even the ones we don’t know what to do with. WinForms, ASP.Net, and most other UI technologies have some kind of built in mechanism for catching unhandled exceptions without fatally terminating the application. It’s still a good idea to somehow gracefully exit the application in this case if possible though, because you can no longer be sure what state your application is in, but nothing annoys a user more than an application just exploding. These unhandled exceptions need to be logged, and this is a good place to catch them. Ideally you never want this option to be exercised, but code as though it will be. When you log these exceptions, give them a “Fatal” status (e.g. Log4Net) and make sure these bugs get handled in your next release. That’s it in a nutshell. If you do it right each exception will only get logged once and with the largest stack trace possible which will make those 2am emergency severity 1 debugging sessions much shorter and less frustrating. Here’s a few people who also have interesting things to say on this topic:  http://blogs.msdn.com/b/ericlippert/archive/2008/09/10/vexing-exceptions.aspx http://www.codeproject.com/Articles/9538/Exception-Handling-Best-Practices-in-NET I know there’s more but I can’t find them at the moment.

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• Master-slave vs. peer-to-peer archictecture: benefits and problems

  - by Ashok_Ora

  Normal 0 false false false EN-US X-NONE X-NONE Almost two decades ago, I was a member of a database development team that introduced adaptive locking. Locking, the most popular concurrency control technique in database systems, is pessimistic. Locking ensures that two or more conflicting operations on the same data item don’t “trample” on each other’s toes, resulting in data corruption. In a nutshell, here’s the issue we were trying to address. In everyday life, traffic lights serve the same purpose. They ensure that traffic flows smoothly and when everyone follows the rules, there are no accidents at intersections. As I mentioned earlier, the problem with typical locking protocols is that they are pessimistic. Regardless of whether there is another conflicting operation in the system or not, you have to hold a lock! Acquiring and releasing locks can be quite expensive, depending on how many objects the transaction touches. Every transaction has to pay this penalty. To use the earlier traffic light analogy, if you have ever waited at a red light in the middle of nowhere with no one on the road, wondering why you need to wait when there’s clearly no danger of a collision, you know what I mean. The adaptive locking scheme that we invented was able to minimize the number of locks that a transaction held, by detecting whether there were one or more transactions that needed conflicting eyou could get by without holding any lock at all. In many “well-behaved” workloads, there are few conflicts, so this optimization is a huge win. If, on the other hand, there are many concurrent, conflicting requests, the algorithm gracefully degrades to the “normal” behavior with minimal cost. We were able to reduce the number of lock requests per TPC-B transaction from 178 requests down to 2! Wow! This is a dramatic improvement in concurrency as well as transaction latency. The lesson from this exercise was that if you can identify the common scenario and optimize for that case so that only the uncommon scenarios are more expensive, you can make dramatic improvements in performance without sacrificing correctness. So how does this relate to the architecture and design of some of the modern NoSQL systems? NoSQL systems can be broadly classified as master-slave sharded, or peer-to-peer sharded systems. NoSQL systems with a peer-to-peer architecture have an interesting way of handling changes. Whenever an item is changed, the client (or an intermediary) propagates the changes synchronously or asynchronously to multiple copies (for availability) of the data. Since the change can be propagated asynchronously, during some interval in time, it will be the case that some copies have received the update, and others haven’t. What happens if someone tries to read the item during this interval? The client in a peer-to-peer system will fetch the same item from multiple copies and compare them to each other. If they’re all the same, then every copy that was queried has the same (and up-to-date) value of the data item, so all’s good. If not, then the system provides a mechanism to reconcile the discrepancy and to update stale copies. So what’s the problem with this? There are two major issues: First, IT’S HORRIBLY PESSIMISTIC because, in the common case, it is unlikely that the same data item will be updated and read from different locations at around the same time! For every read operation, you have to read from multiple copies. That’s a pretty expensive, especially if the data are stored in multiple geographically separate locations and network latencies are high. Second, if the copies are not all the same, the application has to reconcile the differences and propagate the correct value to the out-dated copies. This means that the application program has to handle discrepancies in the different versions of the data item and resolve the issue (which can further add to cost and operation latency). Resolving discrepancies is only one part of the problem. What if the same data item was updated independently on two different nodes (copies)? In that case, due to the asynchronous nature of change propagation, you might land up with different versions of the data item in different copies. In this case, the application program also has to resolve conflicts and then propagate the correct value to the copies that are out-dated or have incorrect versions. This can get really complicated. My hunch is that there are many peer-to-peer-based applications that don’t handle this correctly, and worse, don’t even know it. Imagine have 100s of millions of records in your database – how can you tell whether a particular data item is incorrect or out of date? And what price are you willing to pay for ensuring that the data can be trusted? Multiple network messages per read request? Discrepancy and conflict resolution logic in the application, and potentially, additional messages? All this overhead, when all you were trying to do was to read a data item. Wouldn’t it be simpler to avoid this problem in the first place? Master-slave architectures like the Oracle NoSQL Database handles this very elegantly. A change to a data item is always sent to the master copy. Consequently, the master copy always has the most current and authoritative version of the data item. The master is also responsible for propagating the change to the other copies (for availability and read scalability). Client drivers are aware of master copies and replicas, and client drivers are also aware of the “currency” of a replica. In other words, each NoSQL Database client knows how stale a replica is. This vastly simplifies the job of the application developer. If the application needs the most current version of the data item, the client driver will automatically route the request to the master copy. If the application is willing to tolerate some staleness of data (e.g. a version that is no more than 1 second out of date), the client can easily determine which replica (or set of replicas) can satisfy the request, and route the request to the most efficient copy. This results in a dramatic simplification in application logic and also minimizes network requests (the driver will only send the request to exactl the right replica, not many). So, back to my original point. A well designed and well architected system minimizes or eliminates unnecessary overhead and avoids pessimistic algorithms wherever possible in order to deliver a highly efficient and high performance system. If you’ve every programmed an Oracle NoSQL Database application, you’ll know the difference! /* 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-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;}

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• A Bite With No Teeth&ndash;Demystifying Non-Compete Clauses

  - by D'Arcy Lussier

  *DISCLAIMER: I am not a lawyer and this post in no way should be considered legal advice. I’m also in Canada, so references made are to Canadian court cases. I received a signed letter the other day, a reminder from my previous employer about some clauses associated with my employment and entry into an employee stock purchase program. So since this is in effect for the next 12 months, I guess I’m not starting that new job tomorrow. I’m kidding of course. How outrageous, how presumptuous, pompous, and arrogant that a company – any company – would actually place these conditions upon an employee. And yet, this is not uncommon. Especially in the IT industry, we see time and again similar wording in our employment agreements. But…are these legal? Is there any teeth behind the threat of the bite? Luckily, the answer seems to be ‘No’. I want to highlight two cases that support this. The first is Lyons v. Multari. In a nutshell, Dentist hires younger Dentist to be an associate. In their short, handwritten agreement, a non-compete clause was written stating “Protective Covenant. 3 yrs. – 5mi” (meaning you can’t set up shop within 5 miles for 3 years). Well, the young dentist left and did start an oral surgery office within 5 miles and within 3 years. Off to court they go! The initial judge sided with the older dentist, but on appeal it was overturned. Feel free to read the transcript of the decision here, but let me highlight one portion from section [19]: The general rule in most common law jurisdictions is that non-competition clauses in employment contracts are void. The sections following [19] explain further, and discuss Elsley v. J.G. Collins Insurance Agency Ltd. and its impact on Canadian law in this regard. The second case is Winnipeg Livestock Sales Ltd. v. Plewman. Desmond Plewman is an auctioneer, and worked at Winnipeg Livestock Sales. Part of his employment agreement was that he could not work for a competitor for 18 months if he left the company. Well, he left, and took up an important role in a competing company. The case went to court and as with Lyons v. Multari, the initial judge found in favour of the plaintiffs. Also as in the first case, that was overturned on appeal. Again, read through the transcript of the decision, but consider section [28]: In other words, even though Plewman has a great deal of skill as an auctioneer, Winnipeg Livestock has no proprietary interest in his professional skill and experience, even if they were acquired during his time working for Winnipeg Livestock.  Thus, Winnipeg Livestock has the burden of establishing that it has a legitimate proprietary interest requiring protection.  On this key question there is little evidence before the Court.  The record discloses that part of Plewman’s job was to “mingle with the … crowd” and to telephone customers and prospective customers about future prospects for the sale of livestock.  It may seem reasonable to assume that Winnipeg Livestock has a legitimate proprietary interest in its customer connections; but there is no evidence to indicate that there is any significant degree of “customer loyalty” in the business, as opposed to customers making choices based on other considerations such as cost, availability and the like. So are there any incidents where a non-compete can actually be valid? Yes, and these are considered “exceptional” cases, meaning that the situation meets certain circumstances. Michael Carabash has a great blog series discussing the above mentioned cases as well as the difference between a non-compete and non-solicit agreement. He talks about the exceptional criteria: In summary, the authorities reveal that the following circumstances will generally be relevant in determining whether a case is an “exceptional” one so that a general non-competition clause will be found to be reasonable: - The length of service with the employer. - The amount of personal service to clients. - Whether the employee dealt with clients exclusively, or on a sustained or     recurring basis. - Whether the knowledge about the client which the employee gained was of a   confidential nature, or involved an intimate knowledge of the client’s   particular needs, preferences or idiosyncrasies. - Whether the nature of the employee’s work meant that the employee had   influence over clients in the sense that the clients relied upon the employee’s   advice, or trusted the employee. - If competition by the employee has already occurred, whether there is   evidence that clients have switched their custom to him, especially without   direct solicitation. - The nature of the business with respect to whether personal knowledge of   the clients’ confidential matters is required. - The nature of the business with respect to the strength of customer loyalty,   how clients are “won” and kept, and whether the clientele is a recurring one. - The community involved and whether there were clientele yet to be exploited   by anyone. I close this blog post with a final quote, one from Zvulony & Co’s blog post on this subject. Again, all of this is not official legal advice, but I think we can see what all these sources are pointing towards. To answer my earlier question, there’s no teeth behind the threat of the bite. In light of this list, and the decisions in Lyons and Orlan, it is reasonably certain that in most employment situations a non-competition clause will be ineffective in protecting an employer from a departing employee who wishes to compete in the same business. The Courts have been relatively consistent in their position that if a non-solicitation clause can protect an employer’s interests, then a non-competition clause is probably unreasonable. Employers (or their solicitors) should avoid the inclination to draft restrictive covenants in broad, catch-all language. Or in other words, when drafting a restrictive covenant – take only what you need! D

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• Connection Reset on MySQL query

  - by sunwukung

  OK, I'm flummoxed. I'm trying to execute a query on a database (locally) and I keep getting a connection reset error. I've been using the method below in a generic DAO class to build a query string and pass to Zend_Db API. public function insert($params) { $loop = false; $keys = $values = ''; foreach($params as $k => $v){ if($loop == true){ $keys .= ','; $values .= ','; } $keys .= $this->db->quoteIdentifier($k); $values .= $this->db->quote($v); $loop = true; } $sql = "INSERT INTO " . $this->table_name . " ($keys) VALUES ($values)"; //formatResult returns an array of info regarding the status and any result sets of the query //I've commented that method call out anyway, so I don't think it's that try { $this->db->query($sql); return $this->formatResult(array( true, 'New record inserted into: '.$this->table_name )); }catch(PDOException $e) { return $this->formatResult($e); } } So far, this has worked fine - the errors have been occurring since we generated new tables to record user input. The insert string looks like this: INSERT INTO tablename(`id`,`title`,`summary`,`description`,`keywords`,`type_id`,`categories`) VALUES ('5539','Sample Title','Sample content',' \'Lorem ipsum dolor sit amet, consectetur adipiscing elit. In et pellentesque mauris. Curabitur hendrerit, leo id ultrices pellentesque, est purus mattis ligula, vitae imperdiet neque ligula bibendum sapien. Curabitur aliquet nisi et odio pharetra tincidunt. Phasellus sed iaculis nisl. Fusce commodo mauris et purus vehicula dictum. Nulla feugiat molestie accumsan. Donec fermentum libero in risus tempus elementum aliquam et magna. Fusce vitae sem metus. Aenean commodo pharetra risus, nec pellentesque augue ullamcorper nec. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Nullam vel elit libero. Vestibulum in turpis nunc.\'','this,is,a,sample,array',1,'category title') You'll probably notice the big chunk of whitespace before the Lorem Ipsum string. The description field is being populated from a TinyMCE textarea - I'm guessing it's chucking in some line returns, so I've tried stripping those out. However, even if I disable the TinyMCE field, the reset error still occurs. The next port of call was checking the limits on the table, since it seems to insert if the length of "description" is around the 300 mark (it varies between 310 - 330). The field limit is set to VARCHAR(1500) and the validation on this field won't allow anything past bigger than 1200 with HTML, 800 without. The real kicker is that if I take this sql string and execute it via the command line, it works fine - so I can't for the life of me figure out what's wrong. So, in a nutshell, I'm stumped. Any ideas?

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• Strange WCF Error - IIS hosted - context being aborted

  - by RandomNoob

  I have a WCF service that does some document conversions and returns the document to the caller. When developing locally on my local dev server, the service is hosted on ASP.NET Development server, a console application invokes the operation and executes within seconds. When I host the service in IIS via a .svc file, two of the documents work correctly, the third one bombs out, it begins to construct the word document using the OpenXml Sdk, but then just dies. I think this has something to do with IIS, but I cannot put my finger on it. There are a total of three types of documents I generate. In a nutshell this is how it works SQL 2005 DB/IBM DB2 - WCF Service written by other developer to expose data. This service only has one endpoint using basicHttpBinding My Service invokes his service, gets the relevant data, uses the Open Xml Sdk to generate a Microsoft Word Document, saves it on a server and returns the path to the user. The word documents are no bigger than 100KB. I am also using basicHttpBinding although I have tried wsHttpBinding with the same results. What is amazing is how fast it is locally, and even more that two of the documents generate just fine, its the third document type that refuses to work. To the error message: An error occured while receiving the HTTP Response to http://myservername.mydomain.inc/MyService/Service.Svc. This could be due to the service endpoint binding not using the HTTP Protocol. This could also be due to an HTTP request context being aborted by the server (possibly due to the server shutting down). See server logs for more details. I have spent the last 2 days trying to figure out what is going on, I have tried everything, including changing the maxReceivedMessageSize, maxBufferSize, maxBufferPoolSize, etc etc to large values, I even included: <httpRuntime maxRequestLength="2097151" executionTimeout="120"/> To see maybe if IIS was choking because of that. Programatically the service does nothing special, it just constructs the word documents from the data using the Open Xml Sdk and like I said, locally all 3 documents work when invoked via a console app running locally on the asp.net dev server, i.e. http://localhost:3332/myService.svc When I host it on IIS and I try to get a Windows Forms application to invoke it, I get the error. I know you will ask for logs, so yes I have logging enabled on my Host. And there is no error in the logs, I am logging everything. Basically I invoke two service operations written by another developer. MyOperation calls - HisOperation1 and then HisOperation2, both of those calls give me complex types. I am going to look at his code tomorrow, because he is using LINQ2SQL and there may be some funny business going on there. He is using a variety of collections etc, but the fact that I can run the exact same document, lets call it "Document 3" within seconds when the service is being hosted locally on ASP WebDev Server is what is most odd, why would it run on scaled down Cassini and blow up on IIS? From the log it seems, after calling HisOperation1 and HisOperation2 the service just goes into la-la land dies, there is a application pool (w3wp.exe) error in the Windows Event Log. Faulting application w3wp.exe, version 6.0.3790.1830, stamp 42435be1, faulting module kernel32.dll, version 5.2.3790.3311, stamp 49c5225e, debug? 0, fault address 0x00015dfa. It's classified as .NET 2.0 Runtime error. Any help is appreciated, the lack of sleep is getting to me. Help me Obi-Wan Kenobi, you're my only hope.

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• Problem with XML Deserialization C#

  - by alex

  I am having trouble with XML deserialization. In a nutshell - I have 2 classes: SMSMessage SMSSendingResponse I call an API that takes a bunch of parameters (represented by SMSMessage class) It returns an XML response. The response looks like this: <?xml version="1.0" encoding="utf-8"?> <data> <status>1</status> <message>OK</message> <results> <result> <account>12345</account> <to>012345678</to> <from>054321</from> <message>Testing</message> <flash></flash> <replace></replace> <report></report> <concat></concat> <id>f8d3eea1cbf6771a4bb02af3fb15253e</id> </result> </results> </data> Here is the SMSMessage class (with the xml serialization attributes so far) using System.Xml.Serialization; namespace XMLSerializationHelp { [XmlRoot("results")] public class SMSMessage { public string To { get { return Result.To; } } public string From { get { return Result.From; } } public string Message { get { return Result.Message; } } [XmlElement("result")] public Result Result { get; set; } } } Here is SMSMessageSendingResponse: using System.Xml.Serialization; namespace XMLSerializationHelp { [XmlRoot("data")] public class SMSSendingResponse { //should come from the results/result/account element. in our example "12345" public string AccountNumber { get { return SMSMessage.Result.AccountNumber; } } //should come from the "status" xml element [XmlElement("status")] public string Status { get; set; } //should come from the "message" xml element (in our example - "OK") [XmlElement("message")] public string Message { get; set; } //should come from the "id" xml element (in our example - "f8d3eea1cbf6771a4bb02af3fb15253e") public string ResponseID { get { return SMSMessage.Result.ResponseID; } } //should be created from the results/result element - ignore flash, replace, report and concat elements for now. [XmlElement("results")] public SMSMessage SMSMessage { get; set; } } } Here is the other class (Result) - I want to get rid of this, so only the 2 previously mentioned classes remain using System.Xml.Serialization; namespace XMLSerializationHelp { [XmlRoot("result")] public class Result { [XmlElement("account")] public string AccountNumber{ get; set; } [XmlElement("to")] public string To { get; set; } [XmlElement("from")] public string From { get; set; } [XmlElement("message")] public string Message { get; set; } [XmlElement("id")] public string ResponseID { get; set; } } } I don't want SMSMessage to be aware of the SMSSendingResponse - as this will be handled by a different part of my application

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• How to create a Facebook-App style notifications custom table?

  - by Tim Büthe

  I want to add a custom table to my iPhone app, that should look and work like the one used in the facebook app showing the notifications. It should contain rows with links in it. The text should be black, while the tap-able parts should appear blue. As a already figured out, labels only have one font, color and so on and you can't mix styles within it, I would have to use different components. The tab-able text parts maybe UIButtons with custom style without any border. I tried different approches to build the custom cell. I used Interface Builder, to layout components, but since the different parts have variable lengths they overlaid each other. I also tried to add instances of UIButton and UILabel as a subview to the cell's contentView as descibed in Apple's tutorial. The problem with this is that: The position and size of the components is fix and set when they get created using "initWithFrame:...". My code in "tableView:cellForRowAtIndexPath:" looks like this: UIButton *usernameButton; UILabel *mainLabel, *secondLabel; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { // cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease]; cell = [[[UITableViewCell alloc] initWithFrame:CGRectMake(0.0, 0.0, 220.0, 60.0) reuseIdentifier:CellIdentifier] autorelease]; [cell setBackgroundColor: [UIColor yellowColor]]; usernameButton = [[[UIButton alloc] initWithFrame:CGRectMake(0.0, 0.0, 220.0, 15.0)] autorelease]; usernameButton.tag = USERNAME_BUTTON_TAG; // ... format, font etc. usernameButton.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleHeight; [cell.contentView addSubview:usernameButton]; mainLabel = [[[UILabel alloc] initWithFrame:CGRectMake(0.0, 20.0, 220.0, 15.0)] autorelease]; mainLabel.tag = MAINLABEL_TAG; // ... format, font etc. mainLabel.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleHeight; [cell.contentView addSubview:mainLabel]; secondLabel = [[[UILabel alloc] initWithFrame:CGRectMake(0.0, 40.0, 220.0, 15.0)] autorelease]; secondLabel.tag = SECONDLABEL_TAG; // ... format, font etc. secondLabel.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleHeight; [cell.contentView addSubview:secondLabel]; } else { usernameButton = (UIButton *) [cell.contentView viewWithTag:USERNAME_BUTTON_TAG]; mainLabel = (UILabel *)[cell.contentView viewWithTag:MAINLABEL_TAG]; secondLabel = (UILabel *)[cell.contentView viewWithTag:SECONDLABEL_TAG]; } usernameButton.titleLabel.text = @"Peter"; mainLabel.text = @"sent you a message: ..."; secondLabel.text = @"11 minutes ago"; return cell; In a nutshell, I want to add the labels and buttons without a fix position or size, the buttons clickable and the cell height should automatically set according to the content. Here is an example of the cell's content: Peter sent you a message: "Hello! What are you doing?" Peter should be click/tab-able and his message, which has a variable length, should be italic and wrapped if necessary.

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• Pluralsight Meet the Author Podcast on Structuring JavaScript Code

  - by dwahlin

  I had the opportunity to talk with Fritz Onion from Pluralsight about one of my recent courses titled Structuring JavaScript Code for one of their Meet the Author podcasts. We talked about why JavaScript patterns are important for building more re-useable and maintainable apps, pros and cons of different patterns, and how to go about picking a pattern as a project is started. The course provides a solid walk-through of converting what I call “Function Spaghetti Code” into more modular code that’s easier to maintain, more re-useable, and less susceptible to naming conflicts. Patterns covered in the course include the Prototype Pattern, Revealing Module Pattern, and Revealing Prototype Pattern along with several other tips and techniques that can be used. Meet the Author:  Dan Wahlin on Structuring JavaScript Code   The transcript from the podcast is shown below: [Fritz]  Hello, this is Fritz Onion with another Pluralsight author interview. Today we’re talking with Dan Wahlin about his new course, Structuring JavaScript Code. Hi, Dan, it’s good to have you with us today. [Dan]  Thanks for having me, Fritz. [Fritz]  So, Dan, your new course, which came out in December of 2011 called Structuring JavaScript Code, goes into several patterns of usage in JavaScript as well as ways of organizing your code and what struck me about it was all the different techniques you described for encapsulating your code. I was wondering if you could give us just a little insight into what your motivation was for creating this course and sort of why you decided to write it and record it. [Dan]  Sure. So, I got started with JavaScript back in the mid 90s. In fact, back in the days when browsers that most people haven’t heard of were out and we had JavaScript but it wasn’t great. I was on a project in the late 90s that was heavy, heavy JavaScript and we pretty much did what I call in the course function spaghetti code where you just have function after function, there’s no rhyme or reason to how those functions are structured, they just kind of flow and it’s a little bit hard to do maintenance on it, you really don’t get a lot of reuse as far as from an object perspective. And so coming from an object-oriented background in JAVA and C#, I wanted to put something together that highlighted kind of the new way if you will of writing JavaScript because most people start out just writing functions and there’s nothing with that, it works, but it’s definitely not a real reusable solution. So the course is really all about how to move from just kind of function after function after function to the world of more encapsulated code and more reusable and hopefully better maintenance in the process. [Fritz]  So I am sure a lot of people have had similar experiences with their JavaScript code and will be looking forward to seeing what types of patterns you’ve put forth. Now, a couple I noticed in your course one is you start off with the prototype pattern. Do you want to describe sort of what problem that solves and how you go about using it within JavaScript? [Dan]  Sure. So, the patterns that are covered such as the prototype pattern and the revealing module pattern just as two examples, you know, show these kind of three things that I harp on throughout the course of encapsulation, better maintenance, reuse, those types of things. The prototype pattern specifically though has a couple kind of pros over some of the other patterns and that is the ability to extend your code without touching source code and what I mean by that is let’s say you’re writing a library that you know either other teammates or other people just out there on the Internet in general are going to be using. With the prototype pattern, you can actually write your code in such a way that we’re leveraging the JavaScript property and by doing that now you can extend my code that I wrote without touching my source code script or you can even override my code and perform some new functionality. Again, without touching my code.  And so you get kind of the benefit of the almost like inheritance or overriding in object oriented languages with this prototype pattern and it makes it kind of attractive that way definitely from a maintenance standpoint because, you know, you don’t want to modify a script I wrote because I might roll out version 2 and now you’d have to track where you change things and it gets a little tricky. So with this you just override those pieces or extend them and get that functionality and that’s kind of some of the benefits that that pattern offers out of the box. [Fritz]  And then the revealing module pattern, how does that differ from the prototype pattern and what problem does that solve differently? [Dan]  Yeah, so the prototype pattern and there’s another one that’s kind of really closely lined with revealing module pattern called the revealing prototype pattern and it also uses the prototype key word but it’s very similar to the one you just asked about the revealing module pattern. [Fritz]  Okay. [Dan]  This is a really popular one out there. In fact, we did a project for Microsoft that was very, very heavy JavaScript. It was an HMTL5 jQuery type app and we use this pattern for most of the structure if you will for the JavaScript code and what it does in a nutshell is allows you to get that encapsulation so you have really a single function wrapper that wraps all your other child functions but it gives you the ability to do public versus private members and this is kind of a sort of debate out there on the web. Some people feel that all JavaScript code should just be directly accessible and others kind of like to be able to hide their, truly their private stuff and a lot of people do that. You just put an underscore in front of your field or your variable name or your function name and that kind of is the defacto way to say hey, this is private. With the revealing module pattern you can do the equivalent of what objective oriented languages do and actually have private members that you literally can’t get to as an external consumer of the JavaScript code and then you can expose only those members that you want to be public. Now, you don’t get the benefit though of the prototype feature, which is I can’t easily extend the revealing module pattern type code if you don’t like something I’m doing, chances are you’re probably going to have to tweak my code to fix that because we’re not leveraging prototyping but in situations where you’re writing apps that are very specific to a given target app, you know, it’s not a library, it’s not going to be used in other apps all over the place, it’s a pattern I actually like a lot, it’s very simple to get going and then if you do like that public/private feature, it’s available to you. [Fritz]  Yeah, that’s interesting. So it’s almost, you can either go private by convention just by using a standard naming convention or you can actually enforce it by using the prototype pattern. [Dan]  Yeah, that’s exactly right. [Fritz]  So one of the things that I know I run across in JavaScript and I’m curious to get your take on is we do have all these different techniques of encapsulation and each one is really quite different when you’re using closures versus simply, you know, referencing member variables and adding them to your objects that the syntax changes with each pattern and the usage changes. So what would you recommend for people starting out in a brand new JavaScript project? Should they all sort of decide beforehand on what patterns they’re going to stick to or do you change it based on what part of the library you’re working on? I know that’s one of the points of confusion in this space. [Dan]  Yeah, it’s a great question. In fact, I just had a company ask me about that. So which one do I pick and, of course, there’s not one answer fits all. [Fritz]  Right. [Dan]  So it really depends what you just said is absolutely in my opinion correct, which is I think as a, especially if you’re on a team or even if you’re just an individual a team of one, you should go through and pick out which pattern for this particular project you think is best. Now if it were me, here’s kind of the way I think of it. If I were writing a let’s say base library that several web apps are going to use or even one, but I know that there’s going to be some pieces that I’m not really sure on right now as I’m writing I and I know people might want to hook in that and have some better extension points, then I would look at either the prototype pattern or the revealing prototype. Now, really just a real quick summation between the two the revealing prototype also gives you that public/private stuff like the revealing module pattern does whereas the prototype pattern does not but both of the prototype patterns do give you the benefit of that extension or that hook capability. So, if I were writing a library that I need people to override things or I’m not even sure what I need them to override, I want them to have that option, I’d probably pick a prototype, one of the prototype patterns. If I’m writing some code that is very unique to the app and it’s kind of a one off for this app which is what I think a lot of people are kind of in that mode as writing custom apps for customers, then my personal preference is the revealing module pattern you could always go with the module pattern as well which is very close but I think the revealing module patterns a little bit cleaner and we go through that in the course and explain kind of the syntax there and the differences. [Fritz]  Great, that makes a lot of sense. [Fritz]  I appreciate you taking the time, Dan, and I hope everyone takes a chance to look at your course and sort of make these decisions for themselves in their next JavaScript project. Dan’s course is, Structuring JavaScript Code and it’s available now in the Pluralsight Library. So, thank you very much, Dan. [Dan]  Thanks for having me again.

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• E-Business Suite Technology Sessions at OAUG Collaborate 12

  - by Max Arderius

  Members of our E-Business Suite Applications Technology Group will be at the OAUG Collaborate 12 conference at the Mandalay Bay Convention Center in Las Vegas, Nevada on April 22 to 26, 2012.  Please drop by any of our sessions to hear the latest news and meet up with us. Speaker Sessions Session 9675Planning Your Oracle E-Business Suite Upgrade from Release 11i to 12.1 and BeyondAnne Carlson, Senior Director, Applications Technology Group, OracleSunday, April 22, 2:00 pm - 3:00 pmLocation: Jasmine B Attend this session to hear the latest Oracle E-Business Suite Release 12.1 upgrade planning tips gleaned from customers who have already performed the upgrade. Youll get specific, cross-product advice on how to decide your project's scope, understand the factors that affect your project's duration, develop a robust testing strategy, leverage Oracle Support resources, and more. In a nutshell, this session tells you things you need to know before embarking upon your Release 12.1 upgrade project. Session 9401Minimizing Oracle E-Business Suite Maintenance DowntimesElke Phelps, Principal Product Manager, Applications Technology Group, OracleKevin Hudson, Sr. Director, Applications Technology Group, OracleSunday, April 22, 2:10 pm - 3:10 pmLocation: South Seas EThis session starts with an architecture review of Oracle E-Business Suite fundamentals and then moves to a practical view of the different tools and approaches for downtimes. Topics include patching shortcuts, merging patches, distributing worker processes across multiple servers, running ADPatch in no-interactive mode, staged APPL_TOPs, shared file systems, deferring system-wide database tasks, avoiding resource bottlenecks etc... This session also describes the online patching capabilities coming in Release 12.2. Session 9368Oracle E-Business Suite Technology: Latest Features and RoadmapLisa Parekh, Vice President, Applications Technology Group, Oracle Sunday, April 22, 4:30 pm - 5:30 pmLocation: South Seas EThis session provides an overview of Oracle E-Business Suite technology strategy, the capabilities and associated business benefits of recent releases, as well as a review of the product roadmap. As a cornerstone session for Oracle E-Business Suite technology, come hear about the latest usability enhancements, systems administration and configuration management tools, security-related updates, and tools and options for extending, customizing, and integrating the Oracle E-Business Suite with other applications. Session 10709Oracle E-Business Suite Applications Strategy and General Manager UpdateCliff Godwin, Sr. VP, Application Development, OracleMonday, April 23, 2:30 pm - 3:30 pmLocation: Mandalay Bay DIn this session, hear from Oracle E-Business Suite General Manager Cliff Godwin as he delivers an update on the Oracle E-Business Suite product line. The session covers the value delivered by the current release of Oracle E-Business Suite applications, the momentum, and how Oracle E-Business Suite applications integrate into Oracle’s overall applications strategy. You will come away with an understanding of the value Oracle E-Business Suite applications deliver now and in the future. Session 9398How to Reduce TCO Using Oracle Application Management Suite for Oracle E-Business SuiteAngelo Rosado, Principal Product Manager, Applications Technology Group, OracleKenneth Baxter, Principal Product Strategy Manager, Management Pack Fusion Middleware Management, OracleTuesday, April 24, 8:00 am - 9:00 amLocation: Breakers GThis session covers the methods and tools you can use to gain insights into your end users, troubleshoot performance problems, define service-level objectives, and proactively monitor your end-to-end Oracle E-Business Suite environment to meet your availability and performance targets. Come hear how you can manage, diagnose, and monitor the Oracle E-Business Suite environment from a single console by using Oracle Enterprise Manager together with the Oracle Application Management Suite for Oracle E-Business Suite. Session 9370 Coexistence of Oracle E-Business Suite and Oracle Fusion Applications: Platform Perspective Nadia Bendjedou, Senior Director, Product Strategy, Oracle Tuesday, April 24, 2:00 pm - 3:00 pm Location: South Seas E Join us at this session if you are wondering which tools to integrate your data, your processes and your User Interface. Or what tools to customize and extend your screens and reports (OAF, Forms, ADF, Oracle Reports, BI etc....), what tools to secure, protect and manage your Oracle E-Business Suite etc... Or simply if you are looking for a technical roadmap for your Oracle E-Business Suite infrastructure to CO-EXIST with the rest of your enterprise applications including Oracle Fusion Applications. Session 9375 Oracle E-Business Suite Directions: Deployment and System AdministrationMax Arderius, Manager, Applications Development Group, OracleTuesday, April 24, 4:30 pm - 5:30 pmLocation: Breakers GWhat's coming in the next major version of Oracle E-Business Suite 12? This session covers the latest technology stack, including the use of Oracle WebLogic Server and Oracle Database 11g Release 2. Topics include an architectural overview, installation and upgrade options, new configuration options, and new tools for hot-cloning and automated "lights out" cloning. Learn about how online patching will reduce your database patching downtimes to the time it takes to bounce your database server.Session 9369Oracle E-Business Suite Technology Certification Primer and RoadmapSteven Chan, Sr. Director, Applications Technology Group, Oracle Wednesday, April 25, 8:15 am - 9:15 amLocation: South Seas FThis Oracle Development session summarizes the latest certifications and roadmap for the Oracle E-Business Suite technology stack, including database releases/options, Java, Oracle Forms, Oracle Containers for J2EE, desktop OS, browsers, JRE releases, Office/OpenOffice, development and Web authoring tools, user authentication and management, BI, security options, clouds, Oracle VM etc.... It also covers the most-commonly-asked questions about technology stack component support dates and upgrade implications. Session 9407The Latest Oracle E-Business Suite Release User Interface and Usability EnhancementsGustavo Jimenez, Sr. Manager, Applications Technology Group, Oracle Wednesday, April 25, 1:00 pm - 2:00 pmLocation: South Seas GIn this session, developers will get a detailed look at new features designed to enhance usability, offer more capabilities for personalization and extensions, and support the development and use of dashboards and Web services. Topics include rich new UI capabilities such as new home page features, Navigator and Favorites pull-down menus, Oracle ADF task flows etc.... In addition, we will cover the personalization/extensibility enhancements, business layer extensions, Oracle ADF integration and much more. Session 9374Best Practices for Oracle E-Business Suite Performance Tuning and Upgrade OptimizationIsam Alyousfi, Senior Director, Applications Performance, OracleUdayan Parvate, Director, Release Engineering, Quality and Release Management, Oracle Thursday, April 26, 8:30 am - 9:30 amLocation: South Seas FThis presentation will offer tips and techniques on tuning all the layers of the Oracle E-Business Suite stack including the various tiers of the Oracle E-Business Suite environment. You will learn about tuning Oracle Forms, Concurrent Manager, Apache, and Oracle Discoverer. Track down memory leaks and other issues on the Java and Java Virtual Machine layers. The session also covers Oracle E-Business Suite product-level tuning, including Oracle Workflow, Oracle Order Management, Oracle Payroll, and other modules.Session 9412 Oracle E-Business Suite 12.1 Desktop Integration: Beyond Oracle Applications Desktop IntegratorGustavo Jimenez, Sr. Manager, Applications Technology Group, OracleThursday, April 26, 8:30 am - 9:30 amLocation: Breakers GThis session describes the new expanded functionality in Oracle Web Applications Desktop Integrator, Oracle Report Manager, and dedicated integrators. You have more options for desktop integration now, not fewer. Topics include an overview of prepackaged solutions for integrating Oracle E-Business Suite with desktop applications such as Microsoft Excel, Word, and Projects. The session also discusses how you can use the Desktop Integration Framework feature to create your own integrators quickly and easily.Session 9533 Upgrading your Customizations to Oracle E-Business Suite Release 12.1Sara Woodhull, Principal Product Manager, Applications Technology Group, Oracle Thursday, April 26, 11:00 am - 12:00 pmLocation: South Seas FHave you personalized Forms or OA Framework screens? Have you used mod_plsql or Applications Express to tailor your Release 11i functionality? Have you extended or customized your Release 11i environment using other tools? This session will help you understand customization scenarios, use cases, tools, and technologies for ensuring that your Oracle E-Business Suite Release 12.1 environment fits your users' needs closely and that any future customizations will be easy to upgrade. Special Interest Groups (SIG) Session 10535OAUG Database SIG- Part IMichael Brown, Colibri Limited Company Sunday, April 22, 3:20 pm - 4:20 pmLocation: South Seas FThis is the annual meeting of the Database SIG at Collaborate. The call for candidates for the chair will be closed at the meeting. Plans include a speaker from Oracle and a presentation on applications performance. The details of the meeting will be posted on http://www.dbsig.com. Guest Presentation: Oracle E-Business Suite Database PerformanceIsam Alyousfi, Senior Director, Applications Performance, Oracle Session 10720OAUG EBS Applications Technology SIG- Part ISrini Chaval, Cummins Monday, April 23, 2:30 pm - 3:30 pmLocation: South Seas F Guest Presentation:Oracle E-Business Suite Technology Certification RoadmapSteven Chan, Sr. Director, Applications Technology Group, Oracle Session 10510OAUG EBS Applications Technology SIG- Part IISrini Chaval, CumminsMonday, April 23, 3:45 pm - 4:45 pmLocation: South Seas F Guest Presentation:Oracle E-Business Suite 12.2 Online Patching Kevin Hudson, Sr. Director, Applications Technology Group, Oracle Session 10522 OAUG Upgrade SIG- Part IISandra Vucinic, VLAD Group, Inc. Wednesday, April 25, 3:00 pm - 4:00 pmLocation: South Seas FUpgrade SIG will host a business meeting followed by panel (Q&A) related to EBS Upgrade topics and Oracle presentation. Guest Presentation:Upgrading E-Business Suite Amrita Mehrok, Director, Financials Product Strategy, Oracle Nadia Bendjedou, Senior Director, Product Strategy, Oracle Session 10722OAUG Upgrade SIG- Part IISandra Vucinic, VLAD Group, Inc. Wednesday, April 25, 4:15 pm - 5:15 pmLocation: South Seas FUpgrade SIG will host a business meeting followed by panel (Q&A) related to EBS Upgrade topics and Oracle presentation. Guest Presentation:Tuning the Oracle E-Business Suite Upgrade Isam Alyousfi, Senior Director, Applications Performance, Oracle Panels Session 9360Oracle E-Business Suite Cloning PanelSandra Vucinic, VLAD Group, Inc. Guest Speaker: Max Arderius, Manager, Applications Technology Group, OracleWednesday, April 25, 9:30 am - 10:30 amLocation: South Seas FThis panel will discuss differences between available release 11i, R12 and R12.1 cloning methods. Advantages and disadvantages of each cloning method will be discussed in depth. This panel of experienced database administrators will lead a discussion focusing on the questions such as “which cloning method is best to use in your particular environment”. Attendees will gain practical knowledge, tips and tricks to assist with cloning of Oracle E-Business Suite release 11i, R12 and R12.1 environments. Session 10022Oracle Applications Tuning PanelMark Farnham, Rightsizing, Inc.Guest Speaker: Isam Alyousfi, Senior Director, Applications Performance, OracleThursday, April 26, 09:45 am - 10:45 amLocation: South Seas FThis applications performance panel session, sponsored by the OAUG Database SIG, provides a Q&A forum focused on helping you address your Oracle Applications (Oracle E-Business Suite and Oracle's PeopleSoft Enterprise and Siebel applications) performance- and scalability-related issues. The panel comprises several well-known Oracle Applications performance experts. Topic areas include Oracle Database; the network; and the applications tier, including patching and upgrade performance. For complete listing of all speaker sessions and other activities, please visit the OAUG Collaborate Web Site.

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

  - by Rick Strahl

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

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• C# Neural Networks with Encog

  - by JoshReuben

  Neural Networks ·       I recently read a book Introduction to Neural Networks for C# , by Jeff Heaton. http://www.amazon.com/Introduction-Neural-Networks-C-2nd/dp/1604390093/ref=sr_1_2?ie=UTF8&s=books&qid=1296821004&sr=8-2-spell. Not the 1st ANN book I've perused, but a nice revision.   ·       Artificial Neural Networks (ANNs) are a mechanism of machine learning – see http://en.wikipedia.org/wiki/Artificial_neural_network , http://en.wikipedia.org/wiki/Category:Machine_learning ·       Problems Not Suited to a Neural Network Solution- Programs that are easily written out as flowcharts consisting of well-defined steps, program logic that is unlikely to change, problems in which you must know exactly how the solution was derived. ·       Problems Suited to a Neural Network – pattern recognition, classification, series prediction, and data mining. Pattern recognition - network attempts to determine if the input data matches a pattern that it has been trained to recognize. Classification - take input samples and classify them into fuzzy groups. ·       As far as machine learning approaches go, I thing SVMs are superior (see http://en.wikipedia.org/wiki/Support_vector_machine ) - a neural network has certain disadvantages in comparison: an ANN can be overtrained, different training sets can produce non-deterministic weights and it is not possible to discern the underlying decision function of an ANN from its weight matrix – they are black box. ·       In this post, I'm not going to go into internals (believe me I know them). An autoassociative network (e.g. a Hopfield network) will echo back a pattern if it is recognized. ·       Under the hood, there is very little maths. In a nutshell - Some simple matrix operations occur during training: the input array is processed (normalized into bipolar values of 1, -1) - transposed from input column vector into a row vector, these are subject to matrix multiplication and then subtraction of the identity matrix to get a contribution matrix. The dot product is taken against the weight matrix to yield a boolean match result. For backpropogation training, a derivative function is required. In learning, hill climbing mechanisms such as Genetic Algorithms and Simulated Annealing are used to escape local minima. For unsupervised training, such as found in Self Organizing Maps used for OCR, Hebbs rule is applied. ·       The purpose of this post is not to mire you in technical and conceptual details, but to show you how to leverage neural networks via an abstraction API - Encog   Encog ·       Encog is a neural network API ·       Links to Encog: http://www.encog.org , http://www.heatonresearch.com/encog, http://www.heatonresearch.com/forum ·       Encog requires .Net 3.5 or higher – there is also a Silverlight version. Third-Party Libraries – log4net and nunit. ·       Encog supports feedforward, recurrent, self-organizing maps, radial basis function and Hopfield neural networks. ·       Encog neural networks, and related data, can be stored in .EG XML files. ·       Encog Workbench allows you to edit, train and visualize neural networks. The Encog Workbench can generate code. Synapses and layers ·       the primary building blocks - Almost every neural network will have, at a minimum, an input and output layer. In some cases, the same layer will function as both input and output layer. ·       To adapt a problem to a neural network, you must determine how to feed the problem into the input layer of a neural network, and receive the solution through the output layer of a neural network. ·       The Input Layer - For each input neuron, one double value is stored. An array is passed as input to a layer. Encog uses the interface INeuralData to hold these arrays. The class BasicNeuralData implements the INeuralData interface. Once the neural network processes the input, an INeuralData based class will be returned from the neural network's output layer. ·       convert a double array into an INeuralData object : INeuralData data = new BasicNeuralData(= new double[10]); ·       the Output Layer- The neural network outputs an array of doubles, wraped in a class based on the INeuralData interface. ·        The real power of a neural network comes from its pattern recognition capabilities. The neural network should be able to produce the desired output even if the input has been slightly distorted. ·       Hidden Layers– optional. between the input and output layers. very much a “black box”. If the structure of the hidden layer is too simple it may not learn the problem. If the structure is too complex, it will learn the problem but will be very slow to train and execute. Some neural networks have no hidden layers. The input layer may be directly connected to the output layer. Further, some neural networks have only a single layer. A single layer neural network has the single layer self-connected. ·       connections, called synapses, contain individual weight matrixes. These values are changed as the neural network learns. Constructing a Neural Network ·       the XOR operator is a frequent “first example” -the “Hello World” application for neural networks. ·       The XOR Operator- only returns true when both inputs differ. 0 XOR 0 = 0 1 XOR 0 = 1 0 XOR 1 = 1 1 XOR 1 = 0 ·       Structuring a Neural Network for XOR  - two inputs to the XOR operator and one output. ·       input: 0.0,0.0 1.0,0.0 0.0,1.0 1.0,1.0 ·       Expected output: 0.0 1.0 1.0 0.0 ·       A Perceptron - a simple feedforward neural network to learn the XOR operator. ·       Because the XOR operator has two inputs and one output, the neural network will follow suit. Additionally, the neural network will have a single hidden layer, with two neurons to help process the data. The choice for 2 neurons in the hidden layer is arbitrary, and often comes down to trial and error. ·       Neuron Diagram for the XOR Network ·       ·       The Encog workbench displays neural networks on a layer-by-layer basis. ·       Encog Layer Diagram for the XOR Network:   ·       Create a BasicNetwork - Three layers are added to this network. the FinalizeStructure method must be called to inform the network that no more layers are to be added. The call to Reset randomizes the weights in the connections between these layers. var network = new BasicNetwork(); network.AddLayer(new BasicLayer(2)); network.AddLayer(new BasicLayer(2)); network.AddLayer(new BasicLayer(1)); network.Structure.FinalizeStructure(); network.Reset(); ·       Neural networks frequently start with a random weight matrix. This provides a starting point for the training methods. These random values will be tested and refined into an acceptable solution. However, sometimes the initial random values are too far off. Sometimes it may be necessary to reset the weights again, if training is ineffective. These weights make up the long-term memory of the neural network. Additionally, some layers have threshold values that also contribute to the long-term memory of the neural network. Some neural networks also contain context layers, which give the neural network a short-term memory as well. The neural network learns by modifying these weight and threshold values. ·       Now that the neural network has been created, it must be trained. Training a Neural Network ·       construct a INeuralDataSet object - contains the input array and the expected output array (of corresponding range). Even though there is only one output value, we must still use a two-dimensional array to represent the output. public static double[][] XOR_INPUT ={ new double[2] { 0.0, 0.0 }, new double[2] { 1.0, 0.0 }, new double[2] { 0.0, 1.0 }, new double[2] { 1.0, 1.0 } };   public static double[][] XOR_IDEAL = { new double[1] { 0.0 }, new double[1] { 1.0 }, new double[1] { 1.0 }, new double[1] { 0.0 } };   INeuralDataSet trainingSet = new BasicNeuralDataSet(XOR_INPUT, XOR_IDEAL); ·       Training is the process where the neural network's weights are adjusted to better produce the expected output. Training will continue for many iterations, until the error rate of the network is below an acceptable level. Encog supports many different types of training. Resilient Propagation (RPROP) - general-purpose training algorithm. All training classes implement the ITrain interface. The RPROP algorithm is implemented by the ResilientPropagation class. Training the neural network involves calling the Iteration method on the ITrain class until the error is below a specific value. The code loops through as many iterations, or epochs, as it takes to get the error rate for the neural network to be below 1%. Once the neural network has been trained, it is ready for use. ITrain train = new ResilientPropagation(network, trainingSet);   for (int epoch=0; epoch < 10000; epoch++) { train.Iteration(); Debug.Print("Epoch #" + epoch + " Error:" + train.Error); if (train.Error > 0.01) break; } Executing a Neural Network ·       Call the Compute method on the BasicNetwork class. Console.WriteLine("Neural Network Results:"); foreach (INeuralDataPair pair in trainingSet) { INeuralData output = network.Compute(pair.Input); Console.WriteLine(pair.Input[0] + "," + pair.Input[1] + ", actual=" + output[0] + ",ideal=" + pair.Ideal[0]); } ·       The Compute method accepts an INeuralData class and also returns a INeuralData object. Neural Network Results: 0.0,0.0, actual=0.002782538818034049,ideal=0.0 1.0,0.0, actual=0.9903741937121177,ideal=1.0 0.0,1.0, actual=0.9836807956566187,ideal=1.0 1.0,1.0, actual=0.0011646072586172778,ideal=0.0 ·       the network has not been trained to give the exact results. This is normal. Because the network was trained to 1% error, each of the results will also be within generally 1% of the expected value.

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• C#/.NET Little Wonders: The EventHandler and EventHandler&lt;TEventArgs&gt; delegates

  - by James Michael Hare

  Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. In the last two weeks, we examined the Action family of delegates (and delegates in general), and the Func family of delegates and how they can be used to support generic, reusable algorithms and classes. So this week, we are going to look at a handy pair of delegates that can be used to eliminate the need for defining custom delegates when creating events: the EventHandler and EventHandler<TEventArgs> delegates. Events and delegates Before we begin, let’s quickly consider events in .NET.  According to the MSDN: An event in C# is a way for a class to provide notifications to clients of that class when some interesting thing happens to an object. So, basically, you can create an event in a type so that users of that type can subscribe to notifications of things of interest.  How is this different than some of the delegate programming that we talked about in the last two weeks?  Well, you can think of an event as a special access modifier on a delegate.  Some differences between the two are: Events are a special access case of delegates They behave much like delegates instances inside the type they are declared in, but outside of that type they can only be (un)subscribed to. Events can specify add/remove behavior explicitly If you want to do additional work when someone subscribes or unsubscribes to an event, you can specify the add and remove actions explicitly. Events have access modifiers, but these only specify the access level of those who can (un)subscribe A public event, for example, means anyone can (un)subscribe, but it does not mean that anyone can raise (invoke) the event directly.  Events can only be raised by the type that contains them In contrast, if a delegate is visible, it can be invoked outside of the object (not even in a sub-class!). Events tend to be for notifications only, and should be treated as optional Semantically speaking, events typically don’t perform work on the the class directly, but tend to just notify subscribers when something of note occurs. My basic rule-of-thumb is that if you are just wanting to notify any listeners (who may or may not care) that something has happened, use an event.  However, if you want the caller to provide some function to perform to direct the class about how it should perform work, make it a delegate. Declaring events using custom delegates To declare an event in a type, we simply use the event keyword and specify its delegate type.  For example, let’s say you wanted to create a new TimeOfDayTimer that triggers at a given time of the day (as opposed to on an interval).  We could write something like this: 1: public delegate void TimeOfDayHandler(object source, ElapsedEventArgs e); 2:  3: // A timer that will fire at time of day each day. 4: public class TimeOfDayTimer : IDisposable 5: { 6: // Event that is triggered at time of day. 7: public event TimeOfDayHandler Elapsed; 8:  9: // ... 10: } The first thing to note is that the event is a delegate type, which tells us what types of methods may subscribe to it.  The second thing to note is the signature of the event handler delegate, according to the MSDN: The standard signature of an event handler delegate defines a method that does not return a value, whose first parameter is of type Object and refers to the instance that raises the event, and whose second parameter is derived from type EventArgs and holds the event data. If the event does not generate event data, the second parameter is simply an instance of EventArgs. Otherwise, the second parameter is a custom type derived from EventArgs and supplies any fields or properties needed to hold the event data. So, in a nutshell, the event handler delegates should return void and take two parameters: An object reference to the object that raised the event. An EventArgs (or a subclass of EventArgs) reference to event specific information. Even if your event has no additional information to provide, you are still expected to provide an EventArgs instance.  In this case, feel free to pass the EventArgs.Empty singleton instead of creating new instances of EventArgs (to avoid generating unneeded memory garbage). The EventHandler delegate Because many events have no additional information to pass, and thus do not require custom EventArgs, the signature of the delegates for subscribing to these events is typically: 1: // always takes an object and an EventArgs reference 2: public delegate void EventHandler(object sender, EventArgs e) It would be insane to recreate this delegate for every class that had a basic event with no additional event data, so there already exists a delegate for you called EventHandler that has this very definition!  Feel free to use it to define any events which supply no additional event information: 1: public class Cache 2: { 3: // event that is raised whenever the cache performs a cleanup 4: public event EventHandler OnCleanup; 5:  6: // ... 7: } This will handle any event with the standard EventArgs (no additional information).  But what of events that do need to supply additional information?  Does that mean we’re out of luck for subclasses of EventArgs?  That’s where the generic for of EventHandler comes into play… The generic EventHandler<TEventArgs> delegate Starting with the introduction of generics in .NET 2.0, we have a generic delegate called EventHandler<TEventArgs>.  Its signature is as follows: 1: public delegate void EventHandler<TEventArgs>(object sender, TEventArgs e) 2: where TEventArgs : EventArgs This is similar to EventHandler except it has been made generic to support the more general case.  Thus, it will work for any delegate where the first argument is an object (the sender) and the second argument is a class derived from EventArgs (the event data). For example, let’s say we wanted to create a message receiver, and we wanted it to have a few events such as OnConnected that will tell us when a connection is established (probably with no additional information) and OnMessageReceived that will tell us when a new message arrives (probably with a string for the new message text). So for OnMessageReceived, our MessageReceivedEventArgs might look like this: 1: public sealed class MessageReceivedEventArgs : EventArgs 2: { 3: public string Message { get; set; } 4: } And since OnConnected needs no event argument type defined, our class might look something like this: 1: public class MessageReceiver 2: { 3: // event that is called when the receiver connects with sender 4: public event EventHandler OnConnected; 5:  6: // event that is called when a new message is received. 7: public event EventHandler<MessageReceivedEventArgs> OnMessageReceived; 8:  9: // ... 10: } Notice, nowhere did we have to define a delegate to fit our event definition, the EventHandler and generic EventHandler<TEventArgs> delegates fit almost anything we’d need to do with events. Sidebar: Thread-safety and raising an event When the time comes to raise an event, we should always check to make sure there are subscribers, and then only raise the event if anyone is subscribed.  This is important because if no one is subscribed to the event, then the instance will be null and we will get a NullReferenceException if we attempt to raise the event. 1: // This protects against NullReferenceException... or does it? 2: if (OnMessageReceived != null) 3: { 4: OnMessageReceived(this, new MessageReceivedEventArgs(aMessage)); 5: } The above code seems to handle the null reference if no one is subscribed, but there’s a problem if this is being used in multi-threaded environments.  For example, assume we have thread A which is about to raise the event, and it checks and clears the null check and is about to raise the event.  However, before it can do that thread B unsubscribes to the event, which sets the delegate to null.  Now, when thread A attempts to raise the event, this causes the NullReferenceException that we were hoping to avoid! To counter this, the simplest best-practice method is to copy the event (just a multicast delegate) to a temporary local variable just before we raise it.  Since we are inside the class where this event is being raised, we can copy it to a local variable like this, and it will protect us from multi-threading since multicast delegates are immutable and assignments are atomic: 1: // always make copy of the event multi-cast delegate before checking 2: // for null to avoid race-condition between the null-check and raising it. 3: var handler = OnMessageReceived; 4: 5: if (handler != null) 6: { 7: handler(this, new MessageReceivedEventArgs(aMessage)); 8: } The very slight trade-off is that it’s possible a class may get an event after it unsubscribes in a multi-threaded environment, but this is a small risk and classes should be prepared for this possibility anyway.  For a more detailed discussion on this, check out this excellent Eric Lippert blog post on Events and Races. Summary Generic delegates give us a lot of power to make generic algorithms and classes, and the EventHandler delegate family gives us the flexibility to create events easily, without needing to redefine delegates over and over.  Use them whenever you need to define events with or without specialized EventArgs.   Tweet Technorati Tags: .NET, C#, CSharp, Little Wonders, Generics, Delegates, EventHandler

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• How I understood monads, part 1/2: sleepless and self-loathing in Seattle

  - by Bertrand Le Roy

  For some time now, I had been noticing some interest for monads, mostly in the form of unintelligible (to me) blog posts and comments saying “oh, yeah, that’s a monad” about random stuff as if it were absolutely obvious and if I didn’t know what they were talking about, I was probably an uneducated idiot, ignorant about the simplest and most fundamental concepts of functional programming. Fair enough, I am pretty much exactly that. Being the kind of guy who can spend eight years in college just to understand a few interesting concepts about the universe, I had to check it out and try to understand monads so that I too can say “oh, yeah, that’s a monad”. Man, was I hit hard in the face with the limitations of my own abstract thinking abilities. All the articles I could find about the subject seemed to be vaguely understandable at first but very quickly overloaded the very few concept slots I have available in my brain. They also seemed to be consistently using arcane notation that I was entirely unfamiliar with. It finally all clicked together one Friday afternoon during the team’s beer symposium when Louis was patient enough to break it down for me in a language I could understand (C#). I don’t know if being intoxicated helped. Feel free to read this with or without a drink in hand. So here it is in a nutshell: a monad allows you to manipulate stuff in interesting ways. Oh, OK, you might say. Yeah. Exactly. Let’s start with a trivial case: public static class Trivial { public static TResult Execute<T, TResult>( this T argument, Func<T, TResult> operation) { return operation(argument); } } This is not a monad. I removed most concepts here to start with something very simple. There is only one concept here: the idea of executing an operation on an object. This is of course trivial and it would actually be simpler to just apply that operation directly on the object. But please bear with me, this is our first baby step. Here’s how you use that thing: "some string" .Execute(s => s + " processed by trivial proto-monad.") .Execute(s => s + " And it's chainable!"); What we’re doing here is analogous to having an assembly chain in a factory: you can feed it raw material (the string here) and a number of machines that each implement a step in the manufacturing process and you can start building stuff. The Trivial class here represents the empty assembly chain, the conveyor belt if you will, but it doesn’t care what kind of raw material gets in, what gets out or what each machine is doing. It is pure process. A real monad will need a couple of additional concepts. Let’s say the conveyor belt needs the material to be processed to be contained in standardized boxes, just so that it can safely and efficiently be transported from machine to machine or so that tracking information can be attached to it. Each machine knows how to treat raw material or partly processed material, but it doesn’t know how to treat the boxes so the conveyor belt will have to extract the material from the box before feeding it into each machine, and it will have to box it back afterwards. This conveyor belt with boxes is essentially what a monad is. It has one method to box stuff, one to extract stuff from its box and one to feed stuff into a machine. So let’s reformulate the previous example but this time with the boxes, which will do nothing for the moment except containing stuff. public class Identity<T> { public Identity(T value) { Value = value; } public T Value { get; private set;} public static Identity<T> Unit(T value) { return new Identity<T>(value); } public static Identity<U> Bind<U>( Identity<T> argument, Func<T, Identity<U>> operation) { return operation(argument.Value); } } Now this is a true to the definition Monad, including the weird naming of the methods. It is the simplest monad, called the identity monad and of course it does nothing useful. Here’s how you use it: Identity<string>.Bind( Identity<string>.Unit("some string"), s => Identity<string>.Unit( s + " was processed by identity monad.")).Value That of course is seriously ugly. Note that the operation is responsible for re-boxing its result. That is a part of strict monads that I don’t quite get and I’ll take the liberty to lift that strange constraint in the next examples. To make this more readable and easier to use, let’s build a few extension methods: public static class IdentityExtensions { public static Identity<T> ToIdentity<T>(this T value) { return new Identity<T>(value); } public static Identity<U> Bind<T, U>( this Identity<T> argument, Func<T, U> operation) { return operation(argument.Value).ToIdentity(); } } With those, we can rewrite our code as follows: "some string".ToIdentity() .Bind(s => s + " was processed by monad extensions.") .Bind(s => s + " And it's chainable...") .Value; This is considerably simpler but still retains the qualities of a monad. But it is still pointless. Let’s look at a more useful example, the state monad, which is basically a monad where the boxes have a label. It’s useful to perform operations on arbitrary objects that have been enriched with an attached state object. public class Stateful<TValue, TState> { public Stateful(TValue value, TState state) { Value = value; State = state; } public TValue Value { get; private set; } public TState State { get; set; } } public static class StateExtensions { public static Stateful<TValue, TState> ToStateful<TValue, TState>( this TValue value, TState state) { return new Stateful<TValue, TState>(value, state); } public static Stateful<TResult, TState> Execute<TValue, TState, TResult>( this Stateful<TValue, TState> argument, Func<TValue, TResult> operation) { return operation(argument.Value) .ToStateful(argument.State); } } You can get a stateful version of any object by calling the ToStateful extension method, passing the state object in. You can then execute ordinary operations on the values while retaining the state: var statefulInt = 3.ToStateful("This is the state"); var processedStatefulInt = statefulInt .Execute(i => ++i) .Execute(i => i * 10) .Execute(i => i + 2); Console.WriteLine("Value: {0}; state: {1}", processedStatefulInt.Value, processedStatefulInt.State); This monad differs from the identity by enriching the boxes. There is another way to give value to the monad, which is to enrich the processing. An example of that is the writer monad, which can be typically used to log the operations that are being performed by the monad. Of course, the richest monads enrich both the boxes and the processing. That’s all for today. I hope with this you won’t have to go through the same process that I did to understand monads and that you haven’t gone into concept overload like I did. Next time, we’ll examine some examples that you already know but we will shine the monadic light, hopefully illuminating them in a whole new way. Realizing that this pattern is actually in many places but mostly unnoticed is what will enable the truly casual “oh, yes, that’s a monad” comments. Here’s the code for this article: http://weblogs.asp.net/blogs/bleroy/Samples/Monads.zip The Wikipedia article on monads: http://en.wikipedia.org/wiki/Monads_in_functional_programming This article was invaluable for me in understanding how to express the canonical monads in C# (interesting Linq stuff in there): http://blogs.msdn.com/b/wesdyer/archive/2008/01/11/the-marvels-of-monads.aspx

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• C#/.NET &ndash; Finding an Item&rsquo;s Index in IEnumerable&lt;T&gt;

  - by James Michael Hare

  Sorry for the long blogging hiatus.  First it was, of course, the holidays hustle and bustle, then my brother and his wife gave birth to their son, so I’ve been away from my blogging for two weeks. Background: Finding an item’s index in List<T> is easy… Many times in our day to day programming activities, we want to find the index of an item in a collection.  Now, if we have a List<T> and we’re looking for the item itself this is trivial: 1: // assume have a list of ints: 2: var list = new List<int> { 1, 13, 42, 64, 121, 77, 5, 99, 132 }; 3:  4: // can find the exact item using IndexOf() 5: var pos = list.IndexOf(64); This will return the position of the item if it’s found, or –1 if not.  It’s easy to see how this works for primitive types where equality is well defined.  For complex types, however, it will attempt to compare them using EqualityComparer<T>.Default which, in a nutshell, relies on the object’s Equals() method. So what if we want to search for a condition instead of equality?  That’s also easy in a List<T> with the FindIndex() method: 1: // assume have a list of ints: 2: var list = new List<int> { 1, 13, 42, 64, 121, 77, 5, 99, 132 }; 3:  4: // finds index of first even number or -1 if not found. 5: var pos = list.FindIndex(i => i % 2 == 0);   Problem: Finding an item’s index in IEnumerable<T> is not so easy... This is all well and good for lists, but what if we want to do the same thing for IEnumerable<T>?  A collection of IEnumerable<T> has no indexing, so there’s no direct method to find an item’s index.  LINQ, as powerful as it is, gives us many tools to get us this information, but not in one step.  As with almost any problem involving collections, there are several ways to accomplish the same goal.  And once again as with almost any problem involving collections, the choice of the solution somewhat depends on the situation. So let’s look at a few possible alternatives.  I’m going to express each of these as extension methods for simplicity and consistency. Solution: The TakeWhile() and Count() combo One of the things you can do is to perform a TakeWhile() on the list as long as your find condition is not true, and then do a Count() of the items it took.  The only downside to this method is that if the item is not in the list, the index will be the full Count() of items, and not –1.  So if you don’t know the size of the list beforehand, this can be confusing. 1: // a collection of extra extension methods off IEnumerable<T> 2: public static class EnumerableExtensions 3: { 4: // Finds an item in the collection, similar to List<T>.FindIndex() 5: public static int FindIndex<T>(this IEnumerable<T> list, Predicate<T> finder) 6: { 7: // note if item not found, result is length and not -1! 8: return list.TakeWhile(i => !finder(i)).Count(); 9: } 10: } Personally, I don’t like switching the paradigm of not found away from –1, so this is one of my least favorites.  Solution: Select with index Many people don’t realize that there is an alternative form of the LINQ Select() method that will provide you an index of the item being selected: 1: list.Select( (item,index) => do something here with the item and/or index... ) This can come in handy, but must be treated with care.  This is because the index provided is only as pertains to the result of previous operations (if any).  For example: 1: // assume have a list of ints: 2: var list = new List<int> { 1, 13, 42, 64, 121, 77, 5, 99, 132 }; 3:  4: // you'd hope this would give you the indexes of the even numbers 5: // which would be 2, 3, 8, but in reality it gives you 0, 1, 2 6: list.Where(item => item % 2 == 0).Select((item,index) => index); The reason the example gives you the collection { 0, 1, 2 } is because the where clause passes over any items that are odd, and therefore only the even items are given to the select and only they are given indexes. Conversely, we can’t select the index and then test the item in a Where() clause, because then the Where() clause would be operating on the index and not the item! So, what we have to do is to select the item and index and put them together in an anonymous type.  It looks ugly, but it works: 1: // extensions defined on IEnumerable<T> 2: public static class EnumerableExtensions 3: { 4: // finds an item in a collection, similar to List<T>.FindIndex() 5: public static int FindIndex<T>(this IEnumerable<T> list, Predicate<T> finder) 6: { 7: // if you don't name the anonymous properties they are the variable names 8: return list.Select((item, index) => new { item, index }) 9: .Where(p => finder(p.item)) 10: .Select(p => p.index + 1) 11: .FirstOrDefault() - 1; 12: } 13: }     So let’s look at this, because i know it’s convoluted: First Select() joins the items and their indexes into an anonymous type. Where() filters that list to only the ones matching the predicate. Second Select() picks the index of the matches and adds 1 – this is to distinguish between not found and first item. FirstOrDefault() returns the first item found from the previous clauses or default (zero) if not found. Subtract one so that not found (zero) will be –1, and first item (one) will be zero. The bad thing is, this is ugly as hell and creates anonymous objects for each item tested until it finds the match.  This concerns me a bit but we’ll defer judgment until compare the relative performances below. Solution: Convert ToList() and use FindIndex() This solution is easy enough.  We know any IEnumerable<T> can be converted to List<T> using the LINQ extension method ToList(), so we can easily convert the collection to a list and then just use the FindIndex() method baked into List<T>. 1: // a collection of extension methods for IEnumerable<T> 2: public static class EnumerableExtensions 3: { 4: // find the index of an item in the collection similar to List<T>.FindIndex() 5: public static int FindIndex<T>(this IEnumerable<T> list, Predicate<T> finder) 6: { 7: return list.ToList().FindIndex(finder); 8: } 9: } This solution is simplicity itself!  It is very concise and elegant and you need not worry about anyone misinterpreting what it’s trying to do (as opposed to the more convoluted LINQ methods above). But the main thing I’m concerned about here is the performance hit to allocate the List<T> in the ToList() call, but once again we’ll explore that in a second. Solution: Roll your own FindIndex() for IEnumerable<T> Of course, you can always roll your own FindIndex() method for IEnumerable<T>.  It would be a very simple for loop which scans for the item and counts as it goes.  There’s many ways to do this, but one such way might look like: 1: // extension methods for IEnumerable<T> 2: public static class EnumerableExtensions 3: { 4: // Finds an item matching a predicate in the enumeration, much like List<T>.FindIndex() 5: public static int FindIndex<T>(this IEnumerable<T> list, Predicate<T> finder) 6: { 7: int index = 0; 8: foreach (var item in list) 9: { 10: if (finder(item)) 11: { 12: return index; 13: } 14:  15: index++; 16: } 17:  18: return -1; 19: } 20: } Well, it’s not quite simplicity, and those less familiar with LINQ may prefer it since it doesn’t include all of the lambdas and behind the scenes iterators that come with deferred execution.  But does having this long, blown out method really gain us much in performance? Comparison of Proposed Solutions So we’ve now seen four solutions, let’s analyze their collective performance.  I took each of the four methods described above and run them over 100,000 iterations of lists of size 10, 100, 1000, and 10000 and here’s the performance results.  Then I looked for targets at the begining of the list (best case), middle of the list (the average case) and not in the list (worst case as must scan all of the list). Each of the times below is the average time in milliseconds for one execution as computer over the 100,000 iterations: Searches Matching First Item (Best Case)   10 100 1000 10000 TakeWhile 0.0003 0.0003 0.0003 0.0003 Select 0.0005 0.0005 0.0005 0.0005 ToList 0.0002 0.0003 0.0013 0.0121 Manual 0.0001 0.0001 0.0001 0.0001   Searches Matching Middle Item (Average Case)   10 100 1000 10000 TakeWhile 0.0004 0.0020 0.0191 0.1889 Select 0.0008 0.0042 0.0387 0.3802 ToList 0.0002 0.0007 0.0057 0.0562 Manual 0.0002 0.0013 0.0129 0.1255   Searches Where Not Found (Worst Case)   10 100 1000 10000 TakeWhile 0.0006 0.0039 0.0381 0.3770 Select 0.0012 0.0081 0.0758 0.7583 ToList 0.0002 0.0012 0.0100 0.0996 Manual 0.0003 0.0026 0.0253 0.2514   Notice something interesting here, you’d think the “roll your own” loop would be the most efficient, but it only wins when the item is first (or very close to it) regardless of list size.  In almost all other cases though and in particular the average case and worst case, the ToList()/FindIndex() combo wins for performance, even though it is creating some temporary memory to hold the List<T>.  If you examine the algorithm, the reason why is most likely because once it’s in a ToList() form, internally FindIndex() scans the internal array which is much more efficient to iterate over.  Thus, it takes a one time performance hit (not including any GC impact) to create the List<T> but after that the performance is much better. Summary If you’re concerned about too many throw-away objects, you can always roll your own FindIndex() method, but for sheer simplicity and overall performance, using the ToList()/FindIndex() combo performs best on nearly all list sizes in the average and worst cases.    Technorati Tags: C#,.NET,Litte Wonders,BlackRabbitCoder,Software,LINQ,List

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• The Art of Productivity

  - by dwahlin

  Getting things done has always been a challenge regardless of gender, age, race, skill, or job position. No matter how hard some people try, they end up procrastinating tasks until the last minute. Some people simply focus better when they know they’re out of time and can’t procrastinate any longer. How many times have you put off working on a term paper in school until the very last minute? With only a few hours left your mental energy and focus seem to kick in to high gear especially as you realize that you either get the paper done now or risk failing. It’s amazing how a little pressure can turn into a motivator and allow our minds to focus on a given task. Some people seem to specialize in procrastinating just about everything they do while others tend to be the “doers” who get a lot done and ultimately rise up the ladder at work. What’s the difference between these types of people? Is it pure laziness or are other factors at play? I think that some people are certainly more motivated than others, but I also think a lot of it is based on the process that “doers” tend to follow - whether knowingly or unknowingly. While I’ve certainly fought battles with procrastination, I’ve always had a knack for being able to get a lot done in a relatively short amount of time. I think a lot of my “get it done” attitude goes back to the the strong work ethic my parents instilled in me at a young age. I remember my dad saying, “You need to learn to work hard!” when I was around 5 years old. I remember that moment specifically because I was on a tractor with him the first time I heard it while he was trying to move some large rocks into a pile. The tractor was big but so were the rocks and my dad had to balance the tractor perfectly so that it didn’t tip forward too far. It was challenging work and somewhat tedious but my dad finished the task and taught me a few important lessons along the way including persistence, the importance of having a skill, and getting the job done right without skimping along the way. In this post I’m going to list a few of the techniques and processes I follow that I hope may be beneficial to others. I blogged about the general concept back in 2009 but thought I’d share some updated information and lessons learned since then. Most of the ideas that follow came from learning and refining my daily work process over the years. However, since most of the ideas are common sense (at least in my opinion), I suspect they can be found in other productivity processes that are out there. Let’s start off with one of the most important yet simple tips: Start Each Day with a List. Start Each Day with a List What are you planning to get done today? Do you keep track of everything in your head or rely on your calendar? While most of us think that we’re pretty good at managing “to do” lists strictly in our head you might be surprised at how affective writing out lists can be. By writing out tasks you’re forced to focus on the most important tasks to accomplish that day, commit yourself to those tasks, and have an easy way to track what was supposed to get done and what actually got done. Start every morning by making a list of specific tasks that you want to accomplish throughout the day. I’ll even go so far as to fill in times when I’d like to work on tasks if I have a lot of meetings or other events tying up my calendar on a given day. I’m not a big fan of using paper since I type a lot faster than I write (plus I write like a 3rd grader according to my wife), so I use the Sticky Notes feature available in Windows. Here’s an example of yesterday’s sticky note: What do you add to your list? That’s the subject of the next tip. Focus on Small Tasks It’s no secret that focusing on small, manageable tasks is more effective than trying to focus on large and more vague tasks. When you make your list each morning only add tasks that you can accomplish within a given time period. For example, if I only have 30 minutes blocked out to work on an article I don’t list “Write Article”. If I do that I’ll end up wasting 30 minutes stressing about how I’m going to get the article done in 30 minutes and ultimately get nothing done. Instead, I’ll list something like “Write Introductory Paragraphs for Article”. The next day I may add, “Write first section of article” or something that’s small and manageable – something I’m confident that I can get done. You’ll find that once you’ve knocked out several smaller tasks it’s easy to continue completing others since you want to keep the momentum going. In addition to keeping my tasks focused and small, I also make a conscious effort to limit my list to 4 or 5 tasks initially. I’ve found that if I list more than 5 tasks I feel a bit overwhelmed which hurts my productivity. It’s easy to add additional tasks as you complete others and you get the added benefit of that confidence boost of knowing that you’re being productive and getting things done as you remove tasks and add others. Getting Started is the Hardest (Yet Easiest) Part I’ve always found that getting started is the hardest part and one of the biggest contributors to procrastination. Getting started working on tasks is a lot like getting a large rock pushed to the bottom of a hill. It’s difficult to get the rock rolling at first, but once you manage to get it rocking some it’s really easy to get it rolling on its way to the bottom. As an example, I’ve written 100s of articles for technical magazines over the years and have really struggled with the initial introductory paragraphs. Keep in mind that these are the paragraphs that don’t really add that much value (in my opinion anyway). They introduce the reader to the subject matter and nothing more. What a waste of time for me to sit there stressing about how to start the article. On more than one occasion I’ve spent more than an hour trying to come up with 2-3 paragraphs of text.  Talk about a productivity killer! Whether you’re struggling with a writing task, some code for a project, an email, or other tasks, jumping in without thinking too much is the best way to get started I’ve found. I’m not saying that you shouldn’t have an overall plan when jumping into a task, but on some occasions you’ll find that if you simply jump into the task and stop worrying about doing everything perfectly that things will flow more smoothly. For my introductory paragraph problem I give myself 5 minutes to write out some general concepts about what I know the article will cover and then spend another 10-15 minutes going back and refining that information. That way I actually have some ideas to work with rather than a blank sheet of paper. If I still find myself struggling I’ll write the rest of the article first and then circle back to the introductory paragraphs once I’m done. To sum this tip up: Jump into a task without thinking too hard about it. It’s better to to get the rock at the top of the hill rocking some than doing nothing at all. You can always go back and refine your work.   Learn a Productivity Technique and Stick to It There are a lot of different productivity programs and seminars out there being sold by companies. I’ve always laughed at how much money people spend on some of these motivational programs/seminars because I think that being productive isn’t that hard if you create a re-useable set of steps and processes to follow. That’s not to say that some of these programs/seminars aren’t worth the money of course because I know they’ve definitely benefited some people that have a hard time getting things done and staying focused. One of the best productivity techniques I’ve ever learned is called the “Pomodoro Technique” and it’s completely free. This technique is an extremely simple way to manage your time without having to remember a bunch of steps, color coding mechanisms, or other processes. The technique was originally developed by Francesco Cirillo in the 80s and can be implemented with a simple timer. In a nutshell here’s how the technique works: Pick a task to work on Set the timer to 25 minutes and work on the task Once the timer rings record your time Take a 5 minute break Repeat the process Here’s why the technique works well for me: It forces me to focus on a single task for 25 minutes. In the past I had no time goal in mind and just worked aimlessly on a task until I got interrupted or bored. 25 minutes is a small enough chunk of time for me to stay focused. Any distractions that may come up have to wait until after the timer goes off. If the distraction is really important then I stop the timer and record my time up to that point. When the timer is running I act as if I only have 25 minutes total for the task (like you’re down to the last 25 minutes before turning in your term paper….frantically working to get it done) which helps me stay focused and turns into a “beat the clock” type of game. It’s actually kind of fun if you treat it that way and really helps me focus on a the task at hand. I automatically know how much time I’m spending on a given task (more on this later) by using this technique. I know that I have 5 minutes after each pomodoro (the 25 minute sprint) to waste on anything I’d like including visiting a website, stepping away from the computer, etc. which also helps me stay focused when the 25 minute timer is counting down. I use this technique so much that I decided to build a program for Windows 8 called Pomodoro Focus (I plan to blog about how it was built in a later post). It’s a Windows Store application that allows people to track tasks, productive time spent on tasks, interruption time experienced while working on a given task, and the number of pomodoros completed. If a time estimate is given when the task is initially created, Pomodoro Focus will also show the task completion percentage. I like it because it allows me to track my tasks, time spent on tasks (very useful in the consulting world), and even how much time I wasted on tasks (pressing the pause button while working on a task starts the interruption timer). I recently added a new feature that charts productive and interruption time for tasks since I wanted to see how productive I was from week to week and month to month. A few screenshots from the Pomodoro Focus app are shown next, I had a lot of fun building it and use it myself to as I work on tasks.   There are certainly many other productivity techniques and processes out there (and a slew of books describing them), but the Pomodoro Technique has been the simplest and most effective technique I’ve ever come across for staying focused and getting things done.   Persistence is Key Getting things done is great but one of the biggest lessons I’ve learned in life is that persistence is key especially when you’re trying to get something done that at times seems insurmountable. Small tasks ultimately lead to larger tasks getting accomplished, however, it’s not all roses along the way as some of the smaller tasks may come with their own share of bumps and bruises that lead to discouragement about the end goal and whether or not it is worth achieving at all. I’ve been on several long-term projects over my career as a software developer (I have one personal project going right now that fits well here) and found that repeating, “Persistence is the key!” over and over to myself really helps. Not every project turns out to be successful, but if you don’t show persistence through the hard times you’ll never know if you succeeded or not. Likewise, if you don’t persistently stick to the process of creating a daily list, follow a productivity process, etc. then the odds of consistently staying productive aren’t good.   Track Your Time How much time do you actually spend working on various tasks? If you don’t currently track time spent answering emails, on phone calls, and working on various tasks then you might be surprised to find out that a task that you thought was going to take you 30 minutes ultimately ended up taking 2 hours. If you don’t track the time you spend working on tasks how can you expect to learn from your mistakes, optimize your time better, and become more productive? That’s another reason why I like the Pomodoro Technique – it makes it easy to stay focused on tasks while also tracking how much time I’m working on a given task.   Eliminate Distractions I blogged about this final tip several years ago but wanted to bring it up again. If you want to be productive (and ultimately successful at whatever you’re doing) then you can’t waste a lot of time playing games or on Twitter, Facebook, or other time sucking websites. If you see an article you’re interested in that has no relation at all to the tasks you’re trying to accomplish then bookmark it and read it when you have some spare time (such as during a pomodoro break). Fighting the temptation to check your friends’ status updates on Facebook? Resist the urge and realize how much those types of activities are hurting your productivity and taking away from your focus. I’ll admit that eliminating distractions is still tough for me personally and something I have to constantly battle. But, I’ve made a conscious decision to cut back on my visits and updates to Facebook, Twitter, Google+ and other sites. Sure, my Klout score has suffered as a result lately, but does anyone actually care about those types of scores aside from your online “friends” (few of whom you’ve actually met in person)? :-) Ultimately it comes down to self-discipline and how badly you want to be productive and successful in your career, life goals, hobbies, or whatever you’re working on. Rather than having your homepage take you to a time wasting news site, game site, social site, picture site, or others, how about adding something like the following as your homepage? Every time your browser opens you’ll see a personal message which helps keep you on the right track. You can download my ubber-sophisticated homepage here if interested. Summary Is there a single set of steps that if followed can ultimately lead to productivity? I don’t think so since one size has never fit all. Every person is different, works in their own unique way, and has their own set of motivators, distractions, and more. While I certainly don’t consider myself to be an expert on the subject of productivity, I do think that if you learn what steps work best for you and gradually refine them over time that you can come up with a personal productivity process that can serve you well. Productivity is definitely an “art” that anyone can learn with a little practice and persistence. You’ve seen some of the steps that I personally like to follow and I hope you find some of them useful in boosting your productivity. If you have others you use please leave a comment. I’m always looking for ways to improve.

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• CodePlex Daily Summary for Sunday, October 27, 2013

  CodePlex Daily Summary for Sunday, October 27, 2013Popular ReleasesASP.net MVC Awesome - jQuery Ajax Helpers: 3.5.3 (mvc5): version 3.5.3 - support for mvc5 version 3.5.2 - fix for setting single value to multivalue controls - datepicker min max date offset fix - html encoding for keys fix - enable Column.ClientFormatFunc to be a function call that will return a function version 3.5.1 ========================== - fixed html attributes rendering - fixed loading animation rendering - css improvements version 3.5 ========================== - autosize for all popups ( can be turned off by calling in js...Media Companion: Media Companion MC3.585b: IMDB plot scraping Fixed. New* Movie - Rename Folder using Movie Set, option to move ignored articles to end of Movie Set, only for folder renaming. Fixed* Media Companion - Fixed if using profiles, config files would blown up in size due to some settings duplicating. * Ignore Article of An was cutting of last character of movie title. * If Rescraping title, sort title changed depending on 'Move article to end of Sort Title' setting. * Movie - If changing Poster source order, list would beco...MoreTerra (Terraria World Viewer): MoreTerra 1.11.4: Release 1.11.4 =========== = Compatibility = =========== Updated to add the new tiles/walls in 1.2.1Gac Library -- C++ Utilities for GPU Accelerated GUI and Script: Gaclib 0.5.5.0: Gaclib.zip contains the following content GacUIDemo Demo solution and projects Public Source GacUI library Document HTML document. Please start at reference_gacui.html Content Necessary CSS/JPG files for document. Improvements to the previous release Add 1 demos Editor.Toolstrip.Document Added new features GuiDocumentViewer and GuiDocumentLabel is editable like an RichTextEdit control.BlackJumboDog: Ver5.9.7: 2013.10.24 Ver5.9.7 (1)FTP???????、２?????????????shift-jis????????????? (2)????HTTP????、???????POST??????????????????Fluent Validation for .NET: 5.0: If you find FluentValidation useful, please consider making a donation. Donate to FluentValidation Changes in this release: Display name is now lazily-loaded by default (as a result, localization via DisplayAttribute now works correctly) Added WebApi integration (contributed by dmorganb) Support for MVC 5 (package names are FluentValidation.Mvc5 and FluentValidation.Mvc5-signed) Remove support for partial trustAdder: Adder 1.0: First and I hope last version.TFS Workspaces Cleaner: TFS Workspaces Cleaner v1.0.5045: This is v1.0 of TFS Workspaces Cleaner, a tool that deletes Team Foundation Server workspaces that have not been accessed in a number of days, along with their files locally on disk.Config Transformation Tool: Config Transformation Tool v1.5: [+] Add encoding parameter to specify default encoding. [!] Default encoding has been changed to utf8 (Unicode before). [b] If you use set of parameters where last of parameter uses quotes - tool trims last quote, which changes parameter value. [b] If 'indent' was specified, but not 'indentchars' - tool fails with ArgumentNullException. [b] If verbose flag is not specified tool does not output any error logs to console.CtrlAltStudio Viewer: CtrlAltStudio Viewer 1.1.0.34322 Alpha 4: This experimental release of the CtrlAltStudio Viewer includes the following significant features: Oculus Rift support. Stereoscopic 3D display support. Based on Firestorm viewer 4.4.2 codebase. For more details, see the release notes linked to below. Release notes: http://ctrlaltstudio.com/viewer/release-notes/1-1-0-34322-alpha-4 Support info: http://ctrlaltstudio.com/viewer/support Privacy policy: http://ctrlaltstudio.com/viewer/privacy Disclaimer: This software is not provided or sup...VsTortoise - a TortoiseSVN add-in for Microsoft Visual Studio: VsTortoise Build 32 Beta: Note: This release does not work with custom VsTortoise toolbars. These get removed every time when you shutdown Visual Studio. (#7940) This release has been tested with Visual Studio 2008, 2010, 2012 and 2013, using TortoiseSVN 1.6, 1.7 and 1.8. It should also still work with Visual Studio 2005, but I couldn't find anyone to test it in VS2005. Build 32 (beta) changelogNew: Added Visual Studio 2013 support New: Added Visual Studio 2012 support New: Added SVN 1.8 support New: Added 'Ch...ABCat: ABCat v.2.0.1a: ?????????? ???????? ? ?????????? ?????? ???? ??? Win7. ????????? ?????? ????????? ?? ???????. ????? ?????, ???? ????? ???????? ????????? ?????????? ????????? "?? ??????? ????? ???????????? ?????????? ??????...", ?? ?????????? ??????? ? ?????????? ?????? Microsoft SQL Ce ?? ????????? ??????: http://www.microsoft.com/en-us/download/details.aspx?id=17876. ???????? ?????? x64 ??? x86 ? ??????????? ?? ?????? ???????????? ???????. ??? ??????? ????????? ?? ?????????? ?????? Entity Framework, ? ???? ...patterns & practices: Data Access Guidance: Data Access Guidance 2013: This is the 2013 release of Data Access Guidance. The documentation for this RI is also available on MSDN: Data Access for Highly-Scalable Solutions: Using SQL, NoSQL, and Polyglot Persistence: http://msdn.microsoft.com/en-us/library/dn271399.aspxLINQ to Twitter: LINQ to Twitter v2.1.10: Supports .NET 3.5, .NET 4.0, .NET 4.5, Silverlight 4.0, Windows Phone 7.1, Windows Phone 8, Client Profile, Windows 8, and Windows Azure. 100% Twitter API coverage. Also supports Twitter API v1.1! Also on NuGet.TerrariViewer: TerrariViewer v7.2 [Terraria Inventory Editor]: Added "Check for Update" button Hopefully fixed Windows XP issue You can now backspace in Item stack fieldsSimple Injector: Simple Injector v2.3.6: This patch releases fixes one bug concerning resolving open generic types that contain nested generic type arguments. Nested generic types were handled incorrectly in certain cases. This affects RegisterOpenGeneric and RegisterDecorator. (work item 20332)Virtual Wifi Hotspot for Windows 7 & 8: Virtual Router Plus 2.6.0: Virtual Router Plus 2.6.0Fast YouTube Downloader: Fast YouTube Downloader 2.3.0: Fast YouTube DownloaderMagick.NET: Magick.NET 6.8.7.101: Magick.NET linked with ImageMagick 6.8.7.1. Breaking changes: - Renamed Matrix classes: MatrixColor = ColorMatrix and MatrixConvolve = ConvolveMatrix. - Renamed Depth method with Channels parameter to BitDepth and changed the other method into a property.VidCoder: 1.5.9 Beta: Added Rip DVD and Rip Blu-ray AutoPlay actions for Windows: now you can have VidCoder start up and scan a disc when you insert it. Go to Start -> AutoPlay to set it up. Added error message for Windows XP users rather than letting it crash. Removed "quality" preset from list for QSV as it currently doesn't offer much improvement. Changed installer to ignore version number when copying files over. Should reduce the chances of a bug from me forgetting to increment a version number. Fixed ...New ProjectsC# In A Nutshell: TestDNN (DotNetNuke) Farsi - ?? ?? ?? (??? ?? ????) ?????: ?????? ????? ?????? ??? ?? ?? ?? ?? (??? ?? ????).examquestions: This is a uni projectFishing in Grenada Website: This project is to show progress in developing a Community Site for the Web Application Development Course at the University of Hertfordshire.HashTag Enterprise Library Logging Application Block Extensions: This library allows development teams using EntLib to deliver consistent log messages by using greatly simplified methods for writing messages to Logging Block.Ivion OS: Ivion OS adalah sistem operasi asli buatan anak Indonesia yang ditulis dengan bahasa Assembly.MVC4 Samples: You can easily develope an application in MVC Framework by the code samples provided by Microsoft Requirements:VS 2012My Journal Tracker - a DayOne Snapshot Client for Microsoft Windows: write your DayOne journal (a iOS and Mac OSX journal app) on your Windows PC. Make nice snapshots and view your journal on your iPad.Nigerian food lovers: This site attends to the needs of people who love Nigerian food. It brings them together and helps them answer basic questions.Online Radio 3.1: Software for listening online radio streams.OpenAntrag: Über das Portal OpenAntrag können Bürger über Fraktionen oder Einzelabgeordnete der Piratenpartei ihre Ideen und Wünsche einbringen. ORI_T1_2013_2: ORI, UFSCar, Dicionario, Tesauro, Hash, TabelaPiGest: Gestionale Open Source per piccole imprese.The Barter Website: The aim is to create a Web 2.0 Page which will allow it´s users to share goods they don´t need anymore in exchange for goods they currently need.Web Scripting - Assignment 1 - Simple Addition Project: Assignment 1 - Initial web 2.0 site idea and Subversion * Module - Web Application Development * University of HertfordshireWinPath Manager: The program is a utility to help users to perform the edits the window path variable and auto shorten it .

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• Optimistic non-locking copy of InnoDB .frm files

  - by jothir

  MySQL Enterprise Backup(MEB) does hot backup of innodb data and log files. Till MEB 3.6.1, the user backs up the only innodb tables in a 3 step process: STEP 1. Take backup using --only-innodb option STEP 2. Temporarily make the table read only by executing “FLUSH TABLES WITH READ LOCK” MEB 3.7.0 has an enhancement to innodb file copying. The .frm files gets copied along with the hot backup done for innodb files. I would like to make the blog a little interactive by explaining the feature as answers: 1. What are these .frm files? The files containing the metadata, such as the table definition, of a MySQL table. For backups, the full set of .frm files are always required along with the backup data, to be able to restore tables that are altered or dropped after the backup. 2. Can the .frm files not be copied by MEB itself? --only-innodb-with-frm is the new option introduced in MEB 3.7.1 to do a copy of .frm files without locking the tables during backup operation itself. This is to reduce the pain of manually copying the .frm files. The option is intended for backups where you can ensure that no ALTER TABLE, CREATE TABLE, DROP TABLE, or other DDL statements modify the .frm files for InnoDB tables during the backup operation. 3. How is data consistency ensured? MEB does validation of the .frm files after copying by comparing with the server directory to see if the timestamps of any of the .frm files is greater than the saved system time (check .frm time).  This change in timestamp of the .frm files will show if a table is altered during the process of backup. The total number of frm files in the server directory is also verified against the copied contents. If the number of .frm files is less compared to server directory, it shows that table/tables have been dropped during the process of backup. If the number of .frm files is more compared to server directory, it shows that new table/tables have been created during backup operation. 4. How does MEB handle data inconsistency? MEB copies the .frm files through several iterations,  does the validation and throws a WARNING if there is any inconsistency found in .frm files at the end of backup operation. This means the user is warned of some DDL operations that had occurred during backup operation, and has to manually copy the .frm files or do a backup again. 5. What is the option and explain its usage? The option introduced is --only-innodb-with-frm which does optimistic copy of .frm files without locking. This can be used when the user wants to backup only innodb tables along with .frm files. The option can take one of the 2 values: all | related. --only-innodb-with-frm=all does copy of all .frm files of all innodb tables. --only-innodb-with-frm=related works in conjunction with --include option.This is to allow partial backup of .frm files corresponding to the tables specified in --include. Let me show the usage with example output: ./mysqlbackup -uroot --backup-dir=/logs/backupWithFrmAll --only-innodb-with-frm=all backup MySQL Enterprise Backup version 3.7.1 [2012/06/05] Copyright (c) 2003, 2012, Oracle and/or its affiliates. All Rights Reserved. INFO: Starting with following command line ... ./mysqlbackup -uroot --backup-dir=/logs/backupWithFrmAll        --only-innodb-with-frm=all backup INFO: Got some server configuration information from running server. IMPORTANT: Please check that mysqlbackup run completes successfully.            At the end of a successful 'backup' run mysqlbackup            prints "mysqlbackup completed OK!". --------------------------------------------------------------------                       Server Repository Options: --------------------------------------------------------------------  datadir                          =  /mysql/trydb/  innodb_data_home_dir             =    innodb_data_file_path            =  ibdata1:10M:autoextend  innodb_log_group_home_dir        =  /mysql/trydb/  innodb_log_files_in_group        =  2  innodb_log_file_size             =  5242880 --------------------------------------------------------------------                       Backup Config Options: --------------------------------------------------------------------  datadir                          =  /logs/backupWithFrmAll/datadir  innodb_data_home_dir             =  /logs/backupWithFrmAll/datadir  innodb_data_file_path            =  ibdata1:10M:autoextend  innodb_log_group_home_dir        =  /logs/backupWithFrmAll/datadir  innodb_log_files_in_group        =  2  innodb_log_file_size             =  5242880 mysqlbackup: INFO: Unique generated backup id for this is 13451979804504860 mysqlbackup: INFO: Uses posix_fadvise() for performance optimization. mysqlbackup: INFO: System tablespace file format is Antelope. mysqlbackup: INFO: Found checkpoint at lsn 1656792. mysqlbackup: INFO: Starting log scan from lsn 1656320. 120817 15:36:22 mysqlbackup: INFO: Copying log... 120817 15:36:22 mysqlbackup: INFO: Log copied, lsn 1656792.          We wait 1 second before starting copying the data files... 120817 15:36:23 mysqlbackup: INFO: Copying /mysql/trydb/ibdata1 (Antelope file format). 120817 15:36:23 mysqlbackup: INFO: Copying /mysql/trydb/innodb1/table2.ibd (Antelope file format). 120817 15:36:23 mysqlbackup: INFO: Copying /mysql/trydb/innodb1/table3.ibd (Antelope file format). 120817 15:36:23 mysqlbackup: INFO: Copying /mysql/trydb/innodb1/table1.ibd (Antelope file format). mysqlbackup: INFO: Opening backup source directory '/mysql/trydb/' 120817 15:36:23 mysqlbackup: INFO: Starting to backup .frm files in the subdirectories of /mysql/trydb/ mysqlbackup: INFO: Copying innodb data and logs during final stage ... mysqlbackup: INFO: A copied database page was modified at 1656792.          (This is the highest lsn found on page)          Scanned log up to lsn 1656792.          Was able to parse the log up to lsn 1656792.          Maximum page number for a log record 0 mysqlbackup: INFO: Copying non-innodb files took 2.000 seconds 120817 15:36:25 mysqlbackup: INFO: Full backup completed! mysqlbackup: INFO: Backup created in directory '/logs/backupWithFrmAll' -------------------------------------------------------------   Parameters Summary          -------------------------------------------------------------   Start LSN                  : 1656320   End LSN                    : 1656792 ------------------------------------------------------------- mysqlbackup completed OK! bash$ ls /logs/backupWithFrmAll/datadir/innodb1/ table1.frm  table1.ibd  table2.frm  table2.ibd  table3.frm  table3.ibd Here the backup directory contains all the .frm files of all the innodb tables. ./mysqlbackup -uroot --backup-dir=/logs/backupWithFrm --include="innodb1.table3.*" --only-innodb-with-frm=related backup MySQL Enterprise Backup version 3.7.1 [2012/06/05] Copyright (c) 2003, 2012, Oracle and/or its affiliates. All Rights Reserved. INFO: Starting with following command line ... ./mysqlbackup -uroot --backup-dir=/logs/backup371frm        --include=innodb1.table3.* --only-innodb-with-frm=related backup INFO: Got some server configuration information from running server. IMPORTANT: Please check that mysqlbackup run completes successfully.            At the end of a successful 'backup' run mysqlbackup            prints "mysqlbackup completed OK!". --------------------------------------------------------------------                       Server Repository Options: --------------------------------------------------------------------  datadir                          = /mysql/trydb/  innodb_data_home_dir             =    innodb_data_file_path            =  ibdata1:10M:autoextend  innodb_log_group_home_dir        =  /mysql/trydb  innodb_log_files_in_group        =  2  innodb_log_file_size             =  5242880 --------------------------------------------------------------------                       Backup Config Options: --------------------------------------------------------------------  datadir                          =  /logs/backupWithFrm/datadir  innodb_data_home_dir             =  /logs/backupWithFrm/datadir  innodb_data_file_path            =  ibdata1:10M:autoextend  innodb_log_group_home_dir        =  /logs/backupWithFrm/datadir  innodb_log_files_in_group        =  2  innodb_log_file_size             =  5242880 mysqlbackup: INFO: Unique generated backup id for this is 13451973458118162 mysqlbackup: INFO: Uses posix_fadvise() for performance optimization. mysqlbackup: INFO: The --include option specified: innodb1.table3.* mysqlbackup: INFO: System tablespace file format is Antelope. mysqlbackup: INFO: Found checkpoint at lsn 1656792. mysqlbackup: INFO: Starting log scan from lsn 1656320. 120817 15:25:47 mysqlbackup: INFO: Copying log... 120817 15:25:47 mysqlbackup: INFO: Log copied, lsn 1656792.          We wait 1 second before starting copying the data files... 120817 15:25:48 mysqlbackup: INFO: Copying /mysql/trydbibdata1 (Antelope file format). 120817 15:25:49 mysqlbackup: INFO: Copying /mysql/trydbinnodb1/table3.ibd (Antelope file format). mysqlbackup: INFO: Opening backup source directory '/mysql/trydb' 120817 15:25:49 mysqlbackup: INFO: Starting to backup .frm files in the subdirectories of /mysql/trydb mysqlbackup: INFO: Copying innodb data and logs during final stage ... mysqlbackup: INFO: A copied database page was modified at 1656792.          (This is the highest lsn found on page)          Scanned log up to lsn 1656792.          Was able to parse the log up to lsn 1656792.          Maximum page number for a log record 0 mysqlbackup: INFO: Copying non-innodb files took 2.000 seconds 120817 15:25:51 mysqlbackup: INFO: Full backup completed! mysqlbackup: INFO: Backup created in directory '/logs/backupWithFrm' -------------------------------------------------------------   Parameters Summary          -------------------------------------------------------------   Start LSN                  : 1656320   End LSN                    : 1656792 ------------------------------------------------------------- mysqlbackup completed OK! bash$ ls /logs/backupWithFrm/datadir/innodb1/ table3.frm table3.ibd Thus the backup directory contains only the .frm file matching the innodb table name specified in --include option. In a nutshell, we present our great new option --only-innodb-with-frm which is a true hot InnoDB-only backup with .frm files, but with an additional check, if any DDL happened during the backup. If a DDL has happened, the DBA can decide if to repeat the backup, or to live with the potential inconsistency. This is the ideal solution for users that have all their "real" data in InnoDB and seldom change their schemas. You may also like: http://dev.mysql.com/doc/mysql-enterprise-backup/3.7/en/backup-partial-options.html   STEP 3. Manually copy the .frm files of innodb tables to the destination directory where backup is stored.

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• treeview binding wpf cannot bind nested property in a class

  - by devnet247

  Hi all New to wpf and therefore struggling a bit. I am putting together a quick demo before we go for the full implementation I have a treeview on the left with Continent Country City structure when a user select the city it should populate some textboxes in a tabcontrol on the right hand side I made it sort of work but cannot make it work with composite objects. In a nutshell can you spot what is wrong with my zaml or code. Why is not binding to a my CityDetails.ClubsCount or CityDetails.PubsCount? What I am building is based on http://www.codeproject.com/KB/WPF/TreeViewWithViewModel.aspx Thanks a lot for any suggestions or reply DataModel public class City { public City(string cityName) { CityName = cityName; } public string CityName { get; set; } public string Population { get; set; } public string Area { get; set; } public CityDetails CityDetailsInfo { get; set; } } public class CityDetails { public CityDetails(int pubsCount,int clubsCount) { PubsCount = pubsCount; ClubsCount = clubsCount; } public int ClubsCount { get; set; } public int PubsCount { get; set; } } ViewModel public class CityViewModel : TreeViewItemViewModel { private City _city; private RelayCommand _testCommand; public CityViewModel(City city, CountryViewModel countryViewModel):base(countryViewModel,false) { _city = city; } public string CityName { get { return _city.CityName; } } public string Area { get { return _city.Area; } } public string Population { get { return _city.Population; } } public City City { get { return _city; } set { _city = value; } } public CityDetails CityDetailsInfo { get { return _city.CityDetailsInfo; } set { _city.CityDetailsInfo = value; } } } XAML <DockPanel> <DockPanel LastChildFill="True"> <Label DockPanel.Dock="top" Content="Title " HorizontalAlignment="Center"></Label> <StatusBar DockPanel.Dock="Bottom"> <StatusBarItem Content="Status Bar" ></StatusBarItem> </StatusBar> <Grid DockPanel.Dock="Top"> <Grid.ColumnDefinitions> <ColumnDefinition/> <ColumnDefinition Width="Auto"/> <ColumnDefinition Width="2*"/> </Grid.ColumnDefinitions> <TreeView Name="tree" ItemsSource="{Binding Continents}"> <TreeView.ItemContainerStyle> <Style TargetType="{x:Type TreeViewItem}"> <Setter Property="IsExpanded" Value="{Binding IsExpanded,Mode=TwoWay}"/> <Setter Property="IsSelected" Value="{Binding IsSelected,Mode=TwoWay}"/> <Setter Property="FontWeight" Value="Normal"/> <Style.Triggers> <Trigger Property="IsSelected" Value="True"> <Setter Property="FontWeight" Value="Bold"></Setter> </Trigger> </Style.Triggers> </Style> </TreeView.ItemContainerStyle> <TreeView.Resources> <HierarchicalDataTemplate DataType="{x:Type ViewModels:ContinentViewModel}" ItemsSource="{Binding Children}"> <StackPanel Orientation="Horizontal"> <Image Width="16" Height="16" Margin="3,0" Source="Images\Continent.png"/> <TextBlock Text="{Binding ContinentName}"/> </StackPanel> </HierarchicalDataTemplate> <HierarchicalDataTemplate DataType="{x:Type ViewModels:CountryViewModel}" ItemsSource="{Binding Children}"> <StackPanel Orientation="Horizontal"> <Image Width="16" Height="16" Margin="3,0" Source="Images\Country.png"/> <TextBlock Text="{Binding CountryName}"/> </StackPanel> </HierarchicalDataTemplate> <DataTemplate DataType="{x:Type ViewModels:CityViewModel}" > <StackPanel Orientation="Horizontal"> <Image Width="16" Height="16" Margin="3,0" Source="Images\City.png"/> <TextBlock Text="{Binding CityName}"/> </StackPanel> </DataTemplate> </TreeView.Resources> </TreeView> <GridSplitter Grid.Row="0" Grid.Column="1" Background="LightGray" Width="5" HorizontalAlignment="Stretch" VerticalAlignment="Stretch"/> <Grid Grid.Column="2" Margin="5" > <TabControl> <TabItem Header="Details" DataContext="{Binding Path=SelectedItem.City, ElementName=tree, Mode=OneWay}"> <StackPanel > <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding CityName}"/> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding Area}"/> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding Population}"/> <!-- DONT WORK WHY--> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding SelectedItem.CityDetailsInfo.ClubsCount}"/> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding SelectedItem.CityDetailsInfo.PubsCount}"/> </StackPanel> </TabItem> </TabControl> </Grid> </Grid> </DockPanel> </DockPanel>

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• Build Environment setup - Using .net, java, hudson, and ruby - Could really use a critique

  - by Jeff D

  I'm trying to figure out the best way to stitch together a fast, repeatable, unbreakable build process for the following environment. I've got a plan for how to do it, but I'd really appreciate a critique. (I'd also appreciate some sample code, but more on that later) Ecosystem - Logical: Website - asp.net MVC 2, .net 3.5, Visual Studio 2010. IIS 6, Facebook iframe application application. This website/facebook app uses a few services. An internal search api, an internal read/write api, facebook, and an IP geolocation service. More details on these below Internal search api - .net, restful, built using old school .ashx handlers. The api uses lucene, and a sql server database behind the scenes. My project won't touch the lucene code, but does potentially touch the database and the web services. internal read/write api - java, restful, running on Tomcat Facebook web services A mocking site that emulates the internal read/write api, and parts of the facebook api Hudson - Runs unit tests on checkin, and creates some installers that behave inconsistently. Ecosystem - Physical: All of these machines can talk to one another, except for Hudson. Hudson can't see any of the target machines. So code must be pulled, rather than pushed. (Security thing) 1. Web Server - Holds the website, and the read/write api. (The api itself writes to a replicated sql server environment). 2. Search Server - Houses the search api. 3. Hudson Server - Does not have permissions to push to any environment. They have to pull. 4. Lucene Server 5. Database Server Problem I've been trying to set this site up to run in a stress environment, but the number of setup steps, the amount of time it takes to update a component, the black-box nature of the current installers, and the time it takes to generate data into the test system is absolutely destroying my productivity. I tweak one setting, have to redeploy, restart in a certain order, resetup some of the settings, and rebuild test data. Errors result in headscratching, and then basically starting over. Very bad. This problem is complicated further by my stress testing. I need to be able to turn on and off different external components, so that I can effectively determine the scalability of each piece. I've got strategies in place for how to do that for each dependency, but it further complicates my setup strategy, because now each component has 2 options. A mock version, or a real version. Configurations everywhere must be updated accordingly. Goals Fast - I want to drop this from a 20 minute exercise when things go perfectly, to a 3 minute one Stupid simple - I want to tell the environment what to do with as few commands as possible, and not have to remember how to stitch the environments together Repeatable - I want the script to be idempotent. Kind of a corollary to the Stupid Simple thing. The Plan So Far Here's what I've come up with so far, and what I've come looking for feedback on: Use VisualStudio's new web.config transformations to permit easily altering configs based on envrionment. This solution isn't really sufficient though. I will leave web.config set up to let the site run locally, but when deploying elsewhere, I have as many as 6 different possible outputs for the stress environment alone (because of the mocks of the various dependencies), let alone the settings for prod, QA, and dev. Each of these would then require it's own setup, or a setup that would then post-process the configs. So I'm currently leaning toward just having the dev version, and a version that converts key configuration values into a ruby string interpolation syntax. ({#VAR_NAME} kinda thing) Create a ruby script for each server that is essentially a bootstrapping script. That is to say, it will do nothing but load the ruby code that does the 'real' work from hudson/subversion, so that the script's functionality can evolve with the application, making it easy to build the site at any point in time by reference the appropriate version of the script. So in a nutshell, this script loads another script, and runs it. The 'real' ruby script will then accept commandline parameters that describe how the environment should look. From there, 1 configuration file can be used, and ruby will download the current installers, run them, post-process the configs, restart IIS/Tomcat, and kick off any data setup code that is needed. So that's it. I'm in a real time crunch to get this site stress-tested, so any feedback that you think could abbreviate the time this might take would be appreciated. That includes a shameless request for sample ruby code. I've not gotten too much further than puts "Hello World". :-) Just guidance would be helpful. Is this something that Rake would be useful for? How would you recommend I write tests for this animal? (I use interfaces and automocking frameworks to mock out things like http requests in .net. With ducktyping, it seems that this might be easier, but I don't know how to tell my code to use a fake duck in test, but a real one in practice) Thanks all. Sorry for such such a long-winded, open-ended question.

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• Convert XML namespace prefixes with C#?

  - by jrista

  I have run into an exasperating problem getting a Java service client to communicate successfully with a WCF service. I have overcome many hurdles, and I believe that this is my last one. The problem boils down to how Java Axis + WSS4J seem to handle xml namespaces. The Java platform seem to be very rigid in what they expect for xml namespace prefixes, and as such, do not understand the WCF reply messages. My problem in a nutshell is as follows. I have an xml response similar to the following from my WCF service: <s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" xmlns:a="http://www.w3.org/2005/08/addressing" xmlns:u="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd"> <s:Header> <a:Action s:mustUnderstand="1" u:Id="_3">http://tempuri.org/IProcessor/DoProcessingResponse</a:Action> <h:CorrelationID xmlns:h="http://tempuri.org/">1234</h:CorrelationID> <a:RelatesTo u:Id="_4">uuid:40f800a0-9613-4f4a-96c5-b9fd98085deb</a:RelatesTo> <o:Security s:mustUnderstand="1" xmlns:o="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd"> <!-- WS-Security header stuff --> </o:Security> </s:Header> <s:Body u:Id="_1"> <e:EncryptedData Id="_2" Type="http://www.w3.org/2001/04/xmlenc#Content" xmlns:e="http://www.w3.org/2001/04/xmlenc#"> <e:EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#aes128-cbc"/> <e:CipherData> <e:CipherValue>NfA6XunmyLlT2ucA+5QneoawHm+imcaCltDAJC1mRZOSxoB6YGpDLY1FyVykPbPGDoFGUESLsmvvbD62sNnRrgE+AuKPo+1CD3DF4LfurRcEv9A50ba9V+ViqlrhydhK</e:CipherValue> </e:CipherData> </e:EncryptedData> </s:Body> </s:Envelope> This response uses simple one-character namespace prefixes for most things, such as 's' for SOAP Envelope, 'a' for WS-Addressing, 'o' for 'WS-Security', etc. The Java client, namely WSS4J, seems to expect the following: <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:wsa="http://www.w3.org/2005/08/addressing" xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd"> <soap:Header> <wsa:Action soap:mustUnderstand="1" wsu:Id="_3">http://tempuri.org/IProcessor/DoProcessingResponse</wsa:Action> <h:CorrelationID xmlns:h="http://tempuri.org/">1234</h:CorrelationID> <wsa:RelatesTo wsu:Id="_4">uuid:40f800a0-9613-4f4a-96c5-b9fd98085deb</a:RelatesTo> <wsse:Security soap:mustUnderstand="1" xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd"> <!-- WS-Security header stuff --> </wsse:Security> </soap:Header> <soap:Body u:Id="_1"> <xenc:EncryptedData Id="_2" Type="http://www.w3.org/2001/04/xmlenc#Content" xmlns:xenc="http://www.w3.org/2001/04/xmlenc#"> <xenc:EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#aes128-cbc"/> <xenc:CipherData> <xenc:CipherValue>NfA6XunmyLlT2ucA+5QneoawHm+imcaCltDAJC1mRZOSxoB6YGpDLY1FyVykPbPGDoFGUESLsmvvbD62sNnRrgE+AuKPo+1CD3DF4LfurRcEv9A50ba9V+ViqlrhydhK</xenc:CipherValue> </xenc:CipherData> </xenc:EncryptedData> </soap:Body> </soap:Envelope> Upon receipt of my response message, the Java client and WSS4J seem to want to look up elements by their own internal xml aliases, such as 'wsa' for WS-Addressing, and 'wsse' for WS-Security Extensions. Since neither of those namespaces are present in the actual response xml, exceptions are thrown. I am wondering if there is any simple way to transform an xml document from one set of namespaces to another set using C#, .NET, and the System.Xml namespace. I've poked around with XmlNamespaceManager a bit, but it does not seem to fully support what I need...or at least, I have been unable to find any really useful examples, and am not fully sure how it works. I am trying to avoid having to write some heavy-duty process to handle this manually myself, as I do not want to drastically impact the performance of our services when called by a Java Axis/WSS4J client.

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• E-Business Suite Technology Sessions at OpenWorld 2012

  - by Max Arderius

  Oracle OpenWorld 2012 is almost here! We're looking forward to updating you on our products, strategy, and roadmaps. This year, the E-Business Suite Applications Technology Group (ATG) will participate in 25 speaker sessions, two Meet the Experts round-table discussions, five demoground booths and seven Special Interest Group meetings as guest speakers. We hope to see you at our sessions.  Please join us to hear the latest news and connect with senior ATG development staff. Here's a downloadable listing of all Applications Technology Group-related sessions with times and locations: FOCUS ON Oracle E-Business Suite - Applications Tools and Technology (PDF) General Sessions GEN8474 - Oracle E-Business Suite - Strategy, Update, and RoadmapCliff Godwin, SVP, Oracle Monday, Oct 1, 12:15 PM - 1:15 PM - Moscone West 2002/2004 In this session, hear Oracle E-Business Suite General Manager Cliff Godwin deliver an update on the Oracle E-Business Suite product line. This session covers the value delivered by the current release of Oracle E-Business Suite, the momentum, and how Oracle E-Business Suite applications integrate into Oracle’s overall applications strategy. You’ll come away with an understanding of the value Oracle E-Business Suite applications deliver now and will deliver in the future. GEN9173 - Optimize and Extend Oracle Applications - The Path to Oracle Fusion ApplicationsNadia Bendjedou, Oracle; Corre Curtice, Bhavish Madurai (CSC) Tuesday, Oct 2, 10:15 AM - 11:15 AM - Moscone West 3002/3004 One of the main objectives of this session is to help organizations build their IT roadmap for the next five years and be aligned with the Oracle Applications strategy in general and the Oracle Fusion Applications strategy in particular. Come hear about some of the common sense, practical steps you can take to optimize the performance of your Oracle Applications today and prepare your path to Oracle Fusion Applications for when your organization is ready to embrace them. Each step you take in adopting Oracle Fusion technology gets you partway to Oracle Fusion Applications. Conference Sessions CON9024 - Oracle E-Business Suite Technology: Latest Features and Roadmap Lisa Parekh, Oracle Monday, Oct 1, 10:45 AM - 11:45 AM - Moscone West 2016 This Oracle development session provides a comprehensive overview of Oracle’s product strategy for Oracle E-Business Suite technology, the capabilities and associated business benefits of recent releases, and a review of capabilities on the product roadmap. This is the cornerstone session for the Oracle E-Business Suite technology stack. Come hear about the latest new usability enhancements of the user interface; systems administration and configuration management tools; security-related updates; and tools and options for extending, customizing, and integrating Oracle E-Business Suite with other applications. CON9021 - Oracle E-Business Suite Future Directions: Deployment and System AdministrationMax Arderius, Oracle Monday, Oct 1, 3:15 PM - 4:15 PM - Moscone West 2016  What’s coming in the next major version of Oracle E-Business Suite 12? This Oracle Development session covers the latest technology stack, including the use of Oracle WebLogic Server (Oracle Fusion Middleware 11g) and Oracle Database 11g Release 2 (11.2). Topics include an architectural overview of the latest updates, installation and upgrade options, new configuration options, and new tools for hot cloning and automated “lights-out” cloning. Come learn how online patching (based on the Oracle Database 11g Release 2 Edition-Based Redefinition feature) will reduce your database patching downtimes to however long it takes to bounce your database server. CON9017 - Desktop Integration in Oracle E-Business Suite 12.1 Padmaprabodh Ambale, Gustavo Jimenez, Oracle Monday, Oct 1, 4:45 PM - 5:45 PM - Moscone West 2016 This presentation covers the latest functional enhancements in Oracle Web Applications Desktop Integrator and Oracle Report Manager, enhanced Microsoft Office support, and greater support for building custom desktop integration solutions. The session also presents tips and tricks for upgrading from Oracle Applications Desktop Integrator to Oracle Web Applications Desktop Integrator and Oracle Report Manager. CON9023 - Oracle E-Business Suite Technology Certification Primer and Roadmap Steven Chan, Oracle Tuesday, Oct 2, 10:15 AM - 11:15 AM - Moscone West 2016  Is your Oracle E-Business Suite technology stack up to date? Are you taking advantage of all the latest options and capabilities? This Oracle development session summarizes the latest certifications and roadmap for the Oracle E-Business Suite technology stack, including elements such as database releases and options, Java, Oracle Forms, Oracle Containers for J2EE, desktop operating systems, browsers, JRE releases, development and Web authoring tools, user authentication and management, business intelligence, Oracle Application Management Packs, security options, clouds, Oracle VM, and virtualization. The session also covers the most commonly asked questions about tech stack component support dates and upgrade implications. CON9028 - Minimizing Oracle E-Business Suite Maintenance DowntimesSantiago Bastidas, Elke Phelps, Oracle Tuesday, Oct 2, 11:45 AM - 12:45 PM - Moscone West 2016 This Oracle development session features a survey of the best techniques sysadmins can use to minimize patching downtimes. It starts with an architectural-level review of Oracle E-Business Suite fundamentals and then moves to a practical view of the various tools and approaches for downtimes. Topics include patching shortcuts, merging patches, distributing worker processes across multiple servers, running ADPatch in noninteractive mode, staged APPL_TOPs, shared file systems, deferring systemwide database tasks, avoiding resource bottlenecks, and more. An added bonus: hear about the upcoming Oracle E-Business Suite 12 online patching capabilities based on the groundbreaking Oracle Database 11g Release 2 Edition-Based Redefinition feature. CON9116 - Extending the Use of Oracle E-Business Suite with the Oracle Endeca PlatformOsama Elkady, Muhannad Obeidat, Oracle Tuesday, Oct 2, 11:45 AM - 12:45 PM - Moscone West 2018 The Oracle Endeca platform includes a leading unstructured data correlation and analytics engine, together with a best-in class catalog search and guided navigation solution, to improve the productivity of all types of users in your enterprise. This development session focuses on the details behind the Oracle Endeca platform’s integration into Oracle E-Business Suite. It demonstrates how easily you can extend the use of the Oracle Endeca platform into other areas of Oracle E-Business Suite and how you can bring in your own data and build new Oracle Endeca applications for Oracle E-Business Suite. CON9005 - Oracle E-Business Suite Integration Best PracticesVeshaal Singh, Oracle, Jeffrey Hand, Zebra Technologies Tuesday, Oct 2, 1:15 PM - 2:15 PM - Moscone West 2018 Oracle is investing across applications and technologies to make the application integration experience easier for customers. Today Oracle has certified Oracle E-Business Suite on Oracle Fusion Middleware 11g and provides a comprehensive set of integration technologies. Learn about Oracle’s integration offering across data- and process-centric integrations. These technologies can be used to address various application integration challenges and styles. In this session, you will get an understanding of how, when, and where you can leverage Oracle’s integration technologies to connect end-to-end business processes across your enterprise, including your Oracle Applications portfolio.  CON9026 - Latest Oracle E-Business Suite 12.1 User Interface and Usability EnhancementsPadmaprabodh Ambale, Oracle Tuesday, Oct 2, 1:15 PM - 2:15 PM - Moscone West 2016 This Oracle development session details the latest UI enhancements to Oracle Application Framework in Oracle E-Business Suite 12.1. Developers will get a detailed look at new features to enhance usability, offer more capabilities for personalization and extensions, and support the development and use of dashboards and Web services. Topics include new rich UI capabilities such as new home page features, Navigator and Favorites pull-down menus, REST interface, embedded widgets for analytics content, Oracle Application Development Framework (Oracle ADF) task flows, third-party widgets, a look-ahead list of values, inline attachments, pop-ups, personalization and extensibility enhancements, business layer extensions, Oracle ADF integration, and mobile devices. CON8805 - Planning Your Oracle E-Business Suite Upgrade from 11i to Release 12.1 and BeyondAnne Carlson, Oracle Tuesday, Oct 2, 5:00 PM - 6:00 PM - Moscone West 3002/3004 Attend this session to hear the latest Oracle E-Business Suite 12.1 upgrade planning tips from Oracle’s support, consulting, development, and IT organizations. You’ll get specific cross-product advice on how to understand the factors that affect your project’s duration, decide on your project’s scope, develop a robust testing strategy, leverage Oracle Support resources, and more. In a nutshell, this session tells you things you need to know before embarking upon your Release 12.1 upgrade project. CON9053 - Advanced Management of Oracle E-Business Suite with Oracle Enterprise ManagerAngelo Rosado, Oracle Tuesday, Oct 2, 5:00 PM - 6:00 PM - Moscone West 2016 The task of managing and monitoring Oracle E-Business Suite environments can be very challenging. Oracle Enterprise Manager is the only product on the market that is designed to monitor and manage all the different technologies that constitute Oracle E-Business Suite applications, including end user, midtier, configuration, host, and database management—to name just a few. Customers that have implemented Oracle Enterprise Manager have experienced dramatic improvements in system visibility and diagnostic capability as well as administrator productivity. The purpose of this session is to highlight the key features and benefits of Oracle Enterprise Manager and Oracle Application Management Suite for Oracle E-Business Suite. CON8809 - Oracle E-Business Suite 12.1 Upgrade Best Practices: Technical InsightIsam Alyousfi, Udayan Parvate, Oracle Wednesday, Oct 3, 10:15 AM - 11:15 AM - Moscone West 3011 This session is ideal for organizations thinking about upgrading to Oracle E-Business Suite 12.1. It covers the fundamentals of upgrading to Release 12.1, including the technology stack components and supported upgrade paths. Hear from Oracle Development about the set of best practices for patching in general and executing the Release 12.1 technical upgrade, with special considerations for minimizing your downtime. Also get to know about relatively recent upgrade resources. CON9032 - Upgrading Your Customizations of Oracle E-Business Suite 12.1Sara Woodhull, Oracle Wednesday, Oct 3, 10:15 AM - 11:15 AM - Moscone West 2016 Have you personalized Oracle Forms or Oracle Application Framework screens in Oracle E-Business Suite? Have you used mod_plsql in Release 11i? Have you extended or customized your Release 11i environment with other tools? The technical options for upgrading these customizations as part of your Oracle E-Business Suite Release 12.1 upgrade can be bewildering. Come to this Oracle development session to learn about selecting the best upgrade approach for your existing customizations. The session will help you understand customization scenarios and use cases, tools, and technologies to ensure that your Oracle E-Business Suite Release 12.1 environment fits your users’ needs closely and that any future customizations will be easy to upgrade. CON9259 - Oracle E-Business Suite Internationalization and Multilingual FeaturesMaher Al-Nubani, Oracle Wednesday, Oct 3, 10:15 AM - 11:15 AM - Moscone West 2018 Oracle E-Business Suite supports more countries, languages, and regions than ever. Come to this Oracle development session to get an overview of internationalization features and capabilities and see new Release 12 features such as calendar support for Hijra and Thai, new group separators, lightweight multilingual support (MLS) setup, new character sets such as AL32UTF, newly supported languages, Mac certifications, Oracle iSetup support for moving MLS setups, new file export options for Unicode, new MLS number spelling options, and more. CON7188 - Mobile Apps for Oracle E-Business Suite with Oracle ADF Mobile and Oracle SOA SuiteSrikant Subramaniam, Joe Huang, Veshaal Singh, Oracle Wednesday, Oct 3, 10:15 AM - 11:15 AM - Moscone West 3001 Follow your mobile customers, employees, and partners with Oracle Fusion Middleware. See how native iPhone and iPad applications can easily be built for Oracle E-Business Suite with the new Oracle ADF Mobile and Oracle SOA Suite. Using Oracle ADF Mobile, developers can quickly develop native applications for Apple iOS and other mobile platforms. The Oracle SOA Suite/Oracle ADF Mobile combination can execute business transactions on Oracle E-Business Suite. This session includes a demo in which a mobile user approves a business transaction in Oracle E-Business Suite and a demo of the tools used to build a native on-device solution. These concepts for mobile applications also apply to other Oracle applications.CON9029 - Oracle E-Business Suite Directions: Slashing Downtimes with Online PatchingKevin Hudson, Oracle Wednesday, Oct 3, 11:45 AM - 12:45 PM - Moscone West 2016 Oracle E-Business Suite will soon include online patching (based on the Oracle Database 11g Release 2 Edition-Based Redefinition feature), which will reduce your database patching downtimes to however long it takes to bounce your database server. This Oracle development session details how online patching works, with special attention to what’s happening at a database object level when database patches are applied to an Oracle E-Business Suite environment that’s still running. Come learn about the operational and system management implications for minimizing maintenance downtimes when applying database patches with this new technology and the related impact on customizations you might have built on top of Oracle E-Business Suite. CON8806 - Upgrading to Oracle E-Business Suite 12.1: Technical and Functional PanelAndrew Katz, Komori America Corporation; Sandra Vucinic, VLAD Group, Inc. ;Srini Chavali, Cummins Inc.; Amrita Mehrok, Nadia Bendjedou, Anne Carlson Oracle Wednesday, Oct 3, 1:15 PM - 2:15 PM - Moscone West 2018 In this panel discussion, Oracle experts, customers, and partners share their experiences in upgrading to the latest release of Oracle E-Business Suite, Release 12.1. The panelists cover aspects of a typical Release 12 upgrade, technical (upgrading the technical infrastructure) as well as functional (upgrading to the new financial infrastructure). Hear directly from the experts who either develop the product or support, implement, or upgrade it, and find out how to apply their lessons learned to your organization. CON9027 - Personalize and Extend Oracle E-Business Suite Applications with Rich MashupsGustavo Jimenez, Padmaprabodh Ambale, Oracle Wednesday, Oct 3, 1:15 PM - 2:15 PM - Moscone West 2016 This session covers the use of several Oracle Fusion Middleware technologies to personalize and extend your existing Oracle E-Business Suite applications. The Oracle Fusion Middleware technologies covered include Oracle Application Development Framework (Oracle ADF), Oracle WebCenter, Oracle Endeca applications, and Oracle Business Intelligence Enterprise Edition with Oracle E-Business Suite Oracle Application Framework applications. CON9036 - Advanced Oracle E-Business Suite Architectures: Maximum Availability, Security, and MoreElke Phelps, Oracle Wednesday, Oct 3, 3:30 PM - 4:30 PM - Moscone West 2016 This session includes architecture diagrams and configuration instructions for building a maximum availability architecture (MAA) that will help you design a disaster recovery solution that fits the needs of your business. Database and application high-availability features it describes include Oracle Data Guard, Oracle Real Application Clusters (Oracle RAC), Oracle Active Data Guard, load-balancing Web and forms services, parallel concurrent processing, and the use of Oracle Exalogic and Oracle Exadata to provide a highly available environment. The session also covers the latest updates to systems management tools, AutoConfig, cloud computing, virtualization, and Oracle WebLogic Server and provides sneak previews of upcoming functionality. CON9047 - Efficiently Scaling Oracle E-Business Suite on Oracle Exadata and Oracle ExalogicIsam Alyousfi, Nishit Rao, Oracle Wednesday, Oct 3, 5:00 PM - 6:00 PM - Moscone West 2016 Oracle Exadata and Oracle Exalogic are designed from the ground up with optimizations in software and hardware to deliver superfast performance for mission-critical applications such as Oracle E-Business Suite. Oracle E-Business Suite applications run three to eight times as fast on the Oracle Exadata/Oracle Exalogic platform in standard benchmark tests. Besides performance, customers benefit from simplified support, enhanced manageability, and the ability to consolidate multiple Oracle E-Business Suite instances. Attend this session to understand best practices for Oracle E-Business Suite deployment on Oracle Exalogic and Oracle Exadata through customer case studies. Learn how adopting the Exa* platform increases efficiency, simplifies scaling, and boosts performance for peak loads. CON8716 - Web Services and SOA Integration Options for Oracle E-Business SuiteRekha Ayothi, Veshaal Singh, Oracle Thursday, Oct 4, 11:15 AM - 12:15 PM - Moscone West 2016 This Oracle development session provides a deep dive into a subset of the Web services and SOA-related integration options available to Oracle E-Business Suite systems integrators. It offers a technical look at Oracle E-Business Suite Integrated SOA Gateway, Oracle SOA Suite, Oracle Application Adapters for Data Integration for Oracle E-Business Suite, and other Web services options for integrating Oracle E-Business Suite with other applications. Systems integrators and developers will get an overview of the latest integration capabilities and technologies available out of the box with Oracle E-Business Suite and possibly a sneak preview of upcoming functionality and features. CON9030 - Recommendations for Oracle E-Business Suite Performance TuningIsam Alyousfi, Samer Barakat, Oracle Thursday, Oct 4, 11:15 AM - 12:15 PM - Moscone West 2018 Need to squeeze more performance out of your existing servers? This packed Oracle development session summarizes practical tips and lessons learned from performance-tuning and benchmarking the world’s largest Oracle E-Business Suite environments. Apps sysadmins will learn concrete tips and techniques for identifying and resolving performance bottlenecks on all layers, with special attention to application- and database-tier servers. Learn about tuning Oracle Forms, Oracle Concurrent Manager, Apache, and Oracle Discoverer. Track down memory leaks and other issues at the Java and JVM layers. The session also covers Oracle E-Business Suite product-level tuning, including Oracle Workflow, Oracle Order Management, Oracle Payroll, and other modules. CON3429 - Using Oracle ADF with Oracle E-Business Suite: The Full Integration ViewSiva Puthurkattil, Lake County; Juan Camilo Ruiz, Sara Woodhull, Oracle Thursday, Oct 4, 11:15 AM - 12:15 PM - Moscone West 3003 Oracle E-Business Suite delivers functionality for handling the core business of your organization. However, user requirements and new technologies are driving an emerging need to implement new types of user interfaces for these applications. This session provides an overview of how to use Oracle Application Development Framework (Oracle ADF) to deliver cutting-edge Web 2.0 and mobile rich user interfaces that front existing Oracle E-Business Suite processes, and it also explores all the existing types of integration between the two worlds. CON9020 - Integrating Oracle E-Business Suite with Oracle Identity Management SolutionsSunil Ghosh, Elke Phelps, Oracle Thursday, Oct 4, 12:45 PM - 1:45 PM - Moscone West 2016 Need to integrate Oracle E-Business Suite with Microsoft Windows Kerberos, Active Directory, CA Netegrity SiteMinder, or other third-party authentication systems? Want to understand your options when Oracle Premier Support for Oracle Single Sign-On ends in December 2011? This Oracle Development session covers the latest certified integrations with Oracle Access Manager 11g and Oracle Internet Directory 11g, which can be used individually or as bridges for integrating with third-party authentication solutions. The session presents an architectural overview of how Oracle Access Manager, its WebGate and AccessGate components, and Oracle Internet Directory work together, with implications for Oracle Discoverer, Oracle Portal, and other Oracle Fusion identity management products. CON9019 - Troubleshooting, Diagnosing, and Optimizing Oracle E-Business Suite TechnologyGustavo Jimenez, Oracle Thursday, Oct 4, 2:15 PM - 3:15 PM - Moscone West 2016 This session covers how you can proactively diagnose Oracle E-Business Suite applications, including extensions built with Oracle Fusion Middleware technologies such as Oracle Application Development Framework (Oracle ADF) and Oracle WebCenter to catch potential issues in the middle tier before they become more serious. Topics include debugging, logging infrastructure, warning signs, performance tuning, information required when logging service requests, general JVM optimization, and an overall picture of all the moving parts that make it possible for Oracle E-Business Suite to isolate and fix problems. Also learn how Oracle Diagnostics Framework will help prevent downtime caused by failures. CON9031 - The Top 10 Things You Can Do to Secure Your Oracle E-Business Suite InstanceEric Bing, Erik Graversen, Oracle Thursday, Oct 4, 2:15 PM - 3:15 PM - Moscone West 2018 Learn the top 10 things you can do to secure your applications and your sensitive data. This Oracle development session for system administrators and security professionals explores some of the most important and overlooked things you can do to secure your Oracle E-Business Suite instance. It also covers data masking and other mechanisms for protecting sensitive data. Special Interest Groups (SIG) Some of our most senior staff have been invited to participate on the following SIG meetings as guest speakers: SIG10525 - OAUG - Archive & Purge SIGBrian Bent - Pre-Sales Engineer, TierData, Inc. Sunday, Sep 30, 10:30 AM - 12:00 PM - Moscone West 3011 The Archive and Purge SIG is an organization in which users can share their experiences and solicit functional and technical advice on archiving and purging data in Oracle E-Business Suite. This session provides an opportunity for users to network and share best practices, tips, and tricks. Guest: Oracle E-Business Suite Database Performance, Archive & Purging - Q&A SessionIsam Alyousfi, Senior Director, Applications Performance, Oracle SIG10547 - OAUG - Oracle E-Business (EBS) Applications Technology SIGSrini Chavali - IT Director, Cummins Inc Sunday, Sep 30, 10:30 AM - 12:00 PM - Moscone West 3018 The general purpose of the EBS Applications Technology SIG is to inform and educate its members about current and future components of the tech stack as they relate to Oracle E-Business Suite. Attend this meeting for networking and education and to share best practices. Guest: Oracle E-Business Suite Technology Certification Roadmap - Presentation and Q&ASteven Chan, Sr. Director, Applications Technology Group, Oracle SIG10559 - OAUG - User Management SIGSusan Behn - VP of Oracle Delivery, Infosemantics, Inc. Sunday, Sep 30, 10:30 AM - 12:00 PM - Moscone West 3024 The E-Business Suite User Management SIG focuses on the components of user management that enable Oracle E-Business Suite users to define administrative functions and manage users’ access to functions and data based on roles within an organization—rather than the user’s individual identity—which is referred to as role-based access control (RBAC). This meeting includes an introduction to Oracle User Management that covers the Oracle User Management building blocks and presents an example of creating a security policy.Guest: Security and User Management - Q&A SessionEric Bing, Sr. Director, EBS Security, OracleSara Woodhull, Principal Product Manager, Applications Technology Group, Oracle SIG10515 - OAUG – Upgrade SIGBarbara Matthews - Consultant, On Call DBASandra Vucinic, VLAD Group, Inc. Sunday, Sep 30, 12:00 PM - 2:00 PM - Moscone West 3009 This Upgrade SIG session starts with a business meeting and then features a Q&A panel discussion on Oracle E-Business Suite upgrade topics. The session• Reviews Upgrade SIG goals and objectives• Provides answers, during the Q&A session, to questions related to Oracle E-Business Suite upgrades• Shares “real world” experiences, tips, and techniques for Oracle E-Business Suite upgrades to Release 12.1. Guest: Oracle E-Business Suite Upgrade - Q&A SessionAnne Carlson - Sr. Director, Oracle E-Business Suite Product Strategy, OracleUdayan Parvate - Director, EBS Release Engineering, OracleSuzana Ferrari, Sr. Principal Consultant, OracleIsam Alyousfi, Sr. Director, Applications Performance, Oracle SIG10552 - OAUG - Oracle E-Business Suite SIGDonna Rosentrater - Manager, Global Sourcing & Procurement Systems, TJX Sunday, Sep 30, 12:15 PM - 1:45 PM - Moscone West 3020 The E-Business Suite SIG, affiliated with OAUG, supports Oracle E-Business Suite users through networking, education, and sharing of best practices. This SIG meeting will feature a general discussion of Oracle E-Business Suite product strategies in Release 12 and migration to Oracle Fusion Applications. Guest: Oracle E-Business Suite - Q&A SessionJeanne Lowell, Vice President, EBS Product Strategy, OracleNadia Bendjedou, Sr. Director, Product Strategy, Oracle SIG10556 - OAUG - SysAdmin SIGRandy Giefer - Sr Systems and Security Architect, Solution Beacon, LLC Sunday, Sep 30, 12:15 PM - 1:45 PM - Moscone West 3022 The SysAdmin SIG provides a forum in which OAUG members and participants can share updates, tips, and successful practices relating to system administration in an Oracle applications environment. The SysAdmin SIG strives to enable system administrators to become more effective and efficient in their jobs by providing them with access to people and information that can increase their system administration knowledge and experience. Attend this meeting to network, share best practices, and benefit from educational content. Guest: Oracle E-Business Suite 12.2 Online Patching- Presentation and Q&AKevin Hudson, Sr. Director, Applications Technology Group, Oracle SIG10553 - OAUG - Database SIGMichael Brown - Senior DBA, COLIBRI LTD LC Sunday, Sep 30, 2:00 PM - 3:15 PM - Moscone West 3020 The OAUG Database SIG provides an opportunity for applications database administrators to learn from and share their experiences with supporting the various Oracle applications environments. This session will include a brief business meeting followed by a short presentation. It will end with an open discussion among the attendees about items of interest to those present. Guest: Oracle E-Business Suite Database Performance - Presentation and Q&AIsam Alyousfi, Sr. Director, Applications Performance, Oracle Meet the Experts We're planning two round-table discussions where you can review your questions with senior E-Business Suite ATG staff: MTE9648 - Meet the Experts for Oracle E-Business Suite: Planning Your Upgrade Jeanne Lowell - VP, EBS Product Strategy, Oracle John Abraham - Sr. Principal Product Manager, Oracle Nadia Bendjedou - Sr. Director - Product Strategy, Oracle Anne Carlson - Sr. Director, Applications Technology Group, Oracle Udayan Parvate - Director, EBS Release Engineering, Oracle Isam Alyousfi, Sr. Director, Applications Performance, Oracle Monday, Oct 1, 3:15 PM - 4:15 PM - Moscone West 2001A Don’t miss this Oracle Applications Meet the Experts session with experts who specialize in Oracle E-Business Suite upgrade best practices. This is the place where attendees can have informal and semistructured but open one-on-one discussions with Strategy and Development regarding Oracle Applications strategy and your specific business and IT strategy. The experts will be available to discuss the value of the latest releases and share insights into the best path for your enterprise, so come ready with your questions. Space is limited, so make sure you register. MTE9649 - Meet the Oracle E-Business Suite Tools and Technology Experts Lisa Parekh - Vice President, Technology Integration, Oracle Steven Chan - Sr. Director, Oracle Elke Phelps - Sr. Principal Product Manager, Applications Technology Group, Oracle Max Arderius - Manager, Applications Technology Group, Oracle Tuesday, Oct 2, 1:15 PM - 2:15 PM - Moscone West 2001A Don’t miss this Oracle Applications Meet the Experts session with experts who specialize in Oracle E-Business Suite technology. This is the place where attendees can have informal and semistructured but open one-on-one discussions with Strategy and Development regarding Oracle Applications strategy and your specific business and IT strategy. The experts will be available to discuss the value of the latest releases and share insights into the best path for your enterprise, so come ready with your questions. Space is limited, so make sure you register. Demos We have five booths in the exhibition demogrounds this year, where you can try ATG technologies firsthand and get your questions answered. Please stop by and meet our staff at the following locations: Advanced Architecture and Technology Stack for Oracle E-Business Suite (W-067) New User Productivity Capabilities in Oracle E-Business Suite (W-065) End-to-End Management of Oracle E-Business Suite (W-063) Oracle E-Business Suite 12.1 Technical Upgrade Best Practices (W-066) SOA-Based Integration for Oracle E-Business Suite (W-064)

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• Creating STA COM compatible ASP.NET Applications

  - by Rick Strahl

  When building ASP.NET applications that interface with old school COM objects like those created with VB6 or Visual FoxPro (MTDLL), it's extremely important that the threads that are serving requests use Single Threaded Apartment Threading. STA is a COM built-in technology that allows essentially single threaded components to operate reliably in a multi-threaded environment. STA's guarantee that COM objects instantiated on a specific thread stay on that specific thread and any access to a COM object from another thread automatically marshals that thread to the STA thread. The end effect is that you can have multiple threads, but a COM object instance lives on a fixed never changing thread. ASP.NET by default uses MTA (multi-threaded apartment) threads which are truly free spinning threads that pay no heed to COM object marshaling. This is vastly more efficient than STA threading which has a bit of overhead in determining whether it's OK to run code on a given thread or whether some sort of thread/COM marshaling needs to occur. MTA COM components can be very efficient, but STA COM components in a multi-threaded environment always tend to have a fair amount of overhead. It's amazing how much COM Interop I still see today so while it seems really old school to be talking about this topic, it's actually quite apropos for me as I have many customers using legacy COM systems that need to interface with other .NET applications. In this post I'm consolidating some of the hacks I've used to integrate with various ASP.NET technologies when using STA COM Components. STA in ASP.NET Support for STA threading in the ASP.NET framework is fairly limited. Specifically only the original ASP.NET WebForms technology supports STA threading directly via its STA Page Handler implementation or what you might know as ASPCOMPAT mode. For WebForms running STA components is as easy as specifying the ASPCOMPAT attribute in the @Page tag:<%@ Page Language="C#" AspCompat="true" %> which runs the page in STA mode. Removing it runs in MTA mode. Simple. Unfortunately all other ASP.NET technologies built on top of the core ASP.NET engine do not support STA natively. So if you want to use STA COM components in MVC or with class ASMX Web Services, there's no automatic way like the ASPCOMPAT keyword available. So what happens when you run an STA COM component in an MTA application? In low volume environments - nothing much will happen. The COM objects will appear to work just fine as there are no simultaneous thread interactions and the COM component will happily run on a single thread or multiple single threads one at a time. So for testing running components in MTA environments may appear to work just fine. However as load increases and threads get re-used by ASP.NET COM objects will end up getting created on multiple different threads. This can result in crashes or hangs, or data corruption in the STA components which store their state in thread local storage on the STA thread. If threads overlap this global store can easily get corrupted which in turn causes problems. STA ensures that any COM object instance loaded always stays on the same thread it was instantiated on. What about COM+? COM+ is supposed to address the problem of STA in MTA applications by providing an abstraction with it's own thread pool manager for COM objects. It steps in to the COM instantiation pipeline and hands out COM instances from its own internally maintained STA Thread pool. This guarantees that the COM instantiation threads are STA threads if using STA components. COM+ works, but in my experience the technology is very, very slow for STA components. It adds a ton of overhead and reduces COM performance noticably in load tests in IIS. COM+ can make sense in some situations but for Web apps with STA components it falls short. In addition there's also the need to ensure that COM+ is set up and configured on the target machine and the fact that components have to be registered in COM+. COM+ also keeps components up at all times, so if a component needs to be replaced the COM+ package needs to be unloaded (same is true for IIS hosted components but it's more common to manage that). COM+ is an option for well established components, but native STA support tends to provide better performance and more consistent usability, IMHO. STA for non supporting ASP.NET Technologies As mentioned above only WebForms supports STA natively. However, by utilizing the WebForms ASP.NET Page handler internally it's actually possible to trick various other ASP.NET technologies and let them work with STA components. This is ugly but I've used each of these in various applications and I've had minimal problems making them work with FoxPro STA COM components which is about as dififcult as it gets for COM Interop in .NET. In this post I summarize several STA workarounds that enable you to use STA threading with these ASP.NET Technologies: ASMX Web Services ASP.NET MVC WCF Web Services ASP.NET Web API ASMX Web Services I start with classic ASP.NET ASMX Web Services because it's the easiest mechanism that allows for STA modification. It also clearly demonstrates how the WebForms STA Page Handler is the key technology to enable the various other solutions to create STA components. Essentially the way this works is to override the WebForms Page class and hijack it's init functionality for processing requests. Here's what this looks like for Web Services:namespace FoxProAspNet { public class WebServiceStaHandler : System.Web.UI.Page, IHttpAsyncHandler { protected override void OnInit(EventArgs e) { IHttpHandler handler = new WebServiceHandlerFactory().GetHandler( this.Context, this.Context.Request.HttpMethod, this.Context.Request.FilePath, this.Context.Request.PhysicalPath); handler.ProcessRequest(this.Context); this.Context.ApplicationInstance.CompleteRequest(); } public IAsyncResult BeginProcessRequest( HttpContext context, AsyncCallback cb, object extraData) { return this.AspCompatBeginProcessRequest(context, cb, extraData); } public void EndProcessRequest(IAsyncResult result) { this.AspCompatEndProcessRequest(result); } } public class AspCompatWebServiceStaHandlerWithSessionState : WebServiceStaHandler, IRequiresSessionState { } } This class overrides the ASP.NET WebForms Page class which has a little known AspCompatBeginProcessRequest() and AspCompatEndProcessRequest() method that is responsible for providing the WebForms ASPCOMPAT functionality. These methods handle routing requests to STA threads. Note there are two classes - one that includes session state and one that does not. If you plan on using ASP.NET Session state use the latter class, otherwise stick to the former. This maps to the EnableSessionState page setting in WebForms. This class simply hooks into this functionality by overriding the BeginProcessRequest and EndProcessRequest methods and always forcing it into the AspCompat methods. The way this works is that BeginProcessRequest() fires first to set up the threads and starts intializing the handler. As part of that process the OnInit() method is fired which is now already running on an STA thread. The code then creates an instance of the actual WebService handler factory and calls its ProcessRequest method to start executing which generates the Web Service result. Immediately after ProcessRequest the request is stopped with Application.CompletRequest() which ensures that the rest of the Page handler logic doesn't fire. This means that even though the fairly heavy Page class is overridden here, it doesn't end up executing any of its internal processing which makes this code fairly efficient. In a nutshell, we're highjacking the Page HttpHandler and forcing it to process the WebService process handler in the context of the AspCompat handler behavior. Hooking up the Handler Because the above is an HttpHandler implementation you need to hook up the custom handler and replace the standard ASMX handler. To do this you need to modify the web.config file (here for IIS 7 and IIS Express): <configuration> <system.webServer> <handlers> <remove name="WebServiceHandlerFactory-Integrated-4.0" /> <add name="Asmx STA Web Service Handler" path="*.asmx" verb="*" type="FoxProAspNet.WebServiceStaHandler" precondition="integrated"/> </handlers> </system.webServer> </configuration> (Note: The name for the WebServiceHandlerFactory-Integrated-4.0 might be slightly different depending on your server version. Check the IIS Handler configuration in the IIS Management Console for the exact name or simply remove the handler from the list there which will propagate to your web.config). For IIS 5 & 6 (Windows XP/2003) or the Visual Studio Web Server use:<configuration> <system.web> <httpHandlers> <remove path="*.asmx" verb="*" /> <add path="*.asmx" verb="*" type="FoxProAspNet.WebServiceStaHandler" /> </httpHandlers> </system.web></configuration> To test, create a new ASMX Web Service and create a method like this: [WebService(Namespace = "http://foxaspnet.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] public class FoxWebService : System.Web.Services.WebService { [WebMethod] public string HelloWorld() { return "Hello World. Threading mode is: " + System.Threading.Thread.CurrentThread.GetApartmentState(); } } Run this before you put in the web.config configuration changes and you should get: Hello World. Threading mode is: MTA Then put the handler mapping into Web.config and you should see: Hello World. Threading mode is: STA And you're on your way to using STA COM components. It's a hack but it works well! I've used this with several high volume Web Service installations with various customers and it's been fast and reliable. ASP.NET MVC ASP.NET MVC has quickly become the most popular ASP.NET technology, replacing WebForms for creating HTML output. MVC is more complex to get started with, but once you understand the basic structure of how requests flow through the MVC pipeline it's easy to use and amazingly flexible in manipulating HTML requests. In addition, MVC has great support for non-HTML output sources like JSON and XML, making it an excellent choice for AJAX requests without any additional tools. Unlike WebForms ASP.NET MVC doesn't support STA threads natively and so some trickery is needed to make it work with STA threads as well. MVC gets its handler implementation through custom route handlers using ASP.NET's built in routing semantics. To work in an STA handler requires working in the Page Handler as part of the Route Handler implementation. As with the Web Service handler the first step is to create a custom HttpHandler that can instantiate an MVC request pipeline properly:public class MvcStaThreadHttpAsyncHandler : Page, IHttpAsyncHandler, IRequiresSessionState { private RequestContext _requestContext; public MvcStaThreadHttpAsyncHandler(RequestContext requestContext) { if (requestContext == null) throw new ArgumentNullException("requestContext"); _requestContext = requestContext; } public IAsyncResult BeginProcessRequest(HttpContext context, AsyncCallback cb, object extraData) { return this.AspCompatBeginProcessRequest(context, cb, extraData); } protected override void OnInit(EventArgs e) { var controllerName = _requestContext.RouteData.GetRequiredString("controller"); var controllerFactory = ControllerBuilder.Current.GetControllerFactory(); var controller = controllerFactory.CreateController(_requestContext, controllerName); if (controller == null) throw new InvalidOperationException("Could not find controller: " + controllerName); try { controller.Execute(_requestContext); } finally { controllerFactory.ReleaseController(controller); } this.Context.ApplicationInstance.CompleteRequest(); } public void EndProcessRequest(IAsyncResult result) { this.AspCompatEndProcessRequest(result); } public override void ProcessRequest(HttpContext httpContext) { throw new NotSupportedException("STAThreadRouteHandler does not support ProcessRequest called (only BeginProcessRequest)"); } } This handler code figures out which controller to load and then executes the controller. MVC internally provides the information needed to route to the appropriate method and pass the right parameters. Like the Web Service handler the logic occurs in the OnInit() and performs all the processing in that part of the request. Next, we need a RouteHandler that can actually pick up this handler. Unlike the Web Service handler where we simply registered the handler, MVC requires a RouteHandler to pick up the handler. RouteHandlers look at the URL's path and based on that decide on what handler to invoke. The route handler is pretty simple - all it does is load our custom handler: public class MvcStaThreadRouteHandler : IRouteHandler { public IHttpHandler GetHttpHandler(RequestContext requestContext) { if (requestContext == null) throw new ArgumentNullException("requestContext"); return new MvcStaThreadHttpAsyncHandler(requestContext); } } At this point you can instantiate this route handler and force STA requests to MVC by specifying a route. The following sets up the ASP.NET Default Route:Route mvcRoute = new Route("{controller}/{action}/{id}", new RouteValueDictionary( new { controller = "Home", action = "Index", id = UrlParameter.Optional }), new MvcStaThreadRouteHandler()); RouteTable.Routes.Add(mvcRoute);   To make this code a little easier to work with and mimic the behavior of the routes.MapRoute() functionality extension method that MVC provides, here is an extension method for MapMvcStaRoute(): public static class RouteCollectionExtensions { public static void MapMvcStaRoute(this RouteCollection routeTable, string name, string url, object defaults = null) { Route mvcRoute = new Route(url, new RouteValueDictionary(defaults), new MvcStaThreadRouteHandler()); RouteTable.Routes.Add(mvcRoute); } } With this the syntax to add  route becomes a little easier and matches the MapRoute() method:RouteTable.Routes.MapMvcStaRoute( name: "Default", url: "{controller}/{action}/{id}", defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional } ); The nice thing about this route handler, STA Handler and extension method is that it's fully self contained. You can put all three into a single class file and stick it into your Web app, and then simply call MapMvcStaRoute() and it just works. Easy! To see whether this works create an MVC controller like this: public class ThreadTestController : Controller { public string ThreadingMode() { return Thread.CurrentThread.GetApartmentState().ToString(); } } Try this test both with only the MapRoute() hookup in the RouteConfiguration in which case you should get MTA as the value. Then change the MapRoute() call to MapMvcStaRoute() leaving all the parameters the same and re-run the request. You now should see STA as the result. You're on your way using STA COM components reliably in ASP.NET MVC. WCF Web Services running through IIS WCF Web Services provide a more robust and wider range of services for Web Services. You can use WCF over HTTP, TCP, and Pipes, and WCF services support WS* secure services. There are many features in WCF that go way beyond what ASMX can do. But it's also a bit more complex than ASMX. As a basic rule if you need to serve straight SOAP Services over HTTP I 'd recommend sticking with the simpler ASMX services especially if COM is involved. If you need WS* support or want to serve data over non-HTTP protocols then WCF makes more sense. WCF is not my forte but I found a solution from Scott Seely on his blog that describes the progress and that seems to work well. I'm copying his code below so this STA information is all in one place and quickly explain. Scott's code basically works by creating a custom OperationBehavior which can be specified via an [STAOperation] attribute on every method. Using his attribute you end up with a class (or Interface if you separate the contract and class) that looks like this: [ServiceContract] public class WcfService { [OperationContract] public string HelloWorldMta() { return Thread.CurrentThread.GetApartmentState().ToString(); } // Make sure you use this custom STAOperationBehavior // attribute to force STA operation of service methods [STAOperationBehavior] [OperationContract] public string HelloWorldSta() { return Thread.CurrentThread.GetApartmentState().ToString(); } } Pretty straight forward. The latter method returns STA while the former returns MTA. To make STA work every method needs to be marked up. The implementation consists of the attribute and OperationInvoker implementation. Here are the two classes required to make this work from Scott's post:public class STAOperationBehaviorAttribute : Attribute, IOperationBehavior { public void AddBindingParameters(OperationDescription operationDescription, System.ServiceModel.Channels.BindingParameterCollection bindingParameters) { } public void ApplyClientBehavior(OperationDescription operationDescription, System.ServiceModel.Dispatcher.ClientOperation clientOperation) { // If this is applied on the client, well, it just doesn’t make sense. // Don’t throw in case this attribute was applied on the contract // instead of the implementation. } public void ApplyDispatchBehavior(OperationDescription operationDescription, System.ServiceModel.Dispatcher.DispatchOperation dispatchOperation) { // Change the IOperationInvoker for this operation. dispatchOperation.Invoker = new STAOperationInvoker(dispatchOperation.Invoker); } public void Validate(OperationDescription operationDescription) { if (operationDescription.SyncMethod == null) { throw new InvalidOperationException("The STAOperationBehaviorAttribute " + "only works for synchronous method invocations."); } } } public class STAOperationInvoker : IOperationInvoker { IOperationInvoker _innerInvoker; public STAOperationInvoker(IOperationInvoker invoker) { _innerInvoker = invoker; } public object[] AllocateInputs() { return _innerInvoker.AllocateInputs(); } public object Invoke(object instance, object[] inputs, out object[] outputs) { // Create a new, STA thread object[] staOutputs = null; object retval = null; Thread thread = new Thread( delegate() { retval = _innerInvoker.Invoke(instance, inputs, out staOutputs); }); thread.SetApartmentState(ApartmentState.STA); thread.Start(); thread.Join(); outputs = staOutputs; return retval; } public IAsyncResult InvokeBegin(object instance, object[] inputs, AsyncCallback callback, object state) { // We don’t handle async… throw new NotImplementedException(); } public object InvokeEnd(object instance, out object[] outputs, IAsyncResult result) { // We don’t handle async… throw new NotImplementedException(); } public bool IsSynchronous { get { return true; } } } The key in this setup is the Invoker and the Invoke method which creates a new thread and then fires the request on this new thread. Because this approach creates a new thread for every request it's not super efficient. There's a bunch of overhead involved in creating the thread and throwing it away after each thread, but it'll work for low volume requests and insure each thread runs in STA mode. If better performance is required it would be useful to create a custom thread manager that can pool a number of STA threads and hand off threads as needed rather than creating new threads on every request. If your Web Service needs are simple and you need only to serve standard SOAP 1.x requests, I would recommend sticking with ASMX services. It's easier to set up and work with and for STA component use it'll be significantly better performing since ASP.NET manages the STA thread pool for you rather than firing new threads for each request. One nice thing about Scotts code is though that it works in any WCF environment including self hosting. It has no dependency on ASP.NET or WebForms for that matter. STA - If you must STA components are a  pain in the ass and thankfully there isn't too much stuff out there anymore that requires it. But when you need it and you need to access STA functionality from .NET at least there are a few options available to make it happen. Each of these solutions is a bit hacky, but they work - I've used all of them in production with good results with FoxPro components. I hope compiling all of these in one place here makes it STA consumption a little bit easier. I feel your pain :-) Resources Download STA Handler Code Examples Scott Seely's original STA WCF OperationBehavior Article© Rick Strahl, West Wind Technologies, 2005-2012Posted in FoxPro   ASP.NET  .NET  COM   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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