instance caging - Page 85

Alpha interpolation in a pixel shader

- by c4sh

How does the interpolation in a fragment shader work when it comes to the alpha parameter? I'm programming a shader with SharpDX, DirectX11. My idea is to interpolate 2 3d points of a segment, so that I'll have the position interpolated in between in the pixel shader. But I want to know what happens with the alpha parameter when that position is blocked by another polygon. For instance, if alpha is 1.0 at the left end of my segment and 0.0 at the other one. What is the value of alpha in the middle, 0.5? Or does it depend on the visibility at that point (meaning it could be, for instance, 1.0 OR 0.0 depending on if that part of the segment is hidden by a poolygon?

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Creating a JSONP Formatter for ASP.NET Web API

- by Rick Strahl

Out of the box ASP.NET WebAPI does not include a JSONP formatter, but it's actually very easy to create a custom formatter that implements this functionality. JSONP is one way to allow Browser based JavaScript client applications to bypass cross-site scripting limitations and serve data from the non-current Web server. AJAX in Web Applications uses the XmlHttp object which by default doesn't allow access to remote domains. There are number of ways around this limitation <script> tag loading and JSONP is one of the easiest and semi-official ways that you can do this. JSONP works by combining JSON data and wrapping it into a function call that is executed when the JSONP data is returned. If you use a tool like jQUery it's extremely easy to access JSONP content. Imagine that you have a URL like this: http://RemoteDomain/aspnetWebApi/albums which on an HTTP GET serves some data - in this case an array of record albums. This URL is always directly accessible from an AJAX request if the URL is on the same domain as the parent request. However, if that URL lives on a separate server it won't be easily accessible to an AJAX request. Now, if the server can serve up JSONP this data can be accessed cross domain from a browser client. Using jQuery it's really easy to retrieve the same data with JSONP:function getAlbums() { $.getJSON("http://remotedomain/aspnetWebApi/albums?callback=?",null, function (albums) { alert(albums.length); }); } The resulting callback the same as if the call was to a local server when the data is returned. jQuery deserializes the data and feeds it into the method. Here the array is received and I simply echo back the number of items returned. From here your app is ready to use the data as needed. This all works fine - as long as the server can serve the data with JSONP. What does JSONP look like? JSONP is a pretty simple 'protocol'. All it does is wrap a JSON response with a JavaScript function call. The above result from the JSONP call looks like this:Query17103401925975181569_1333408916499( [{"Id":"34043957","AlbumName":"Dirty Deeds Done Dirt Cheap",…},{…}] ) The way JSONP works is that the client (jQuery in this case) sends of the request, receives the response and evals it. The eval basically executes the function and deserializes the JSON inside of the function. It's actually a little more complex for the framework that does this, but that's the gist of what happens. JSONP works by executing the code that gets returned from the JSONP call. JSONP and ASP.NET Web API As mentioned previously, JSONP support is not natively in the box with ASP.NET Web API. But it's pretty easy to create and plug-in a custom formatter that provides this functionality. The following code is based on Christian Weyers example but has been updated to the latest Web API CodePlex bits, which changes the implementation a bit due to the way dependent objects are exposed differently in the latest builds. Here's the code: using System; using System.IO; using System.Net; using System.Net.Http.Formatting; using System.Net.Http.Headers; using System.Threading.Tasks; using System.Web; using System.Net.Http; namespace Westwind.Web.WebApi { /// <summary> /// Handles JsonP requests when requests are fired with /// text/javascript or application/json and contain /// a callback= (configurable) query string parameter /// /// Based on Christian Weyers implementation /// https://github.com/thinktecture/Thinktecture.Web.Http/blob/master/Thinktecture.Web.Http/Formatters/JsonpFormatter.cs /// </summary> public class JsonpFormatter : JsonMediaTypeFormatter { public JsonpFormatter() { SupportedMediaTypes.Add(new MediaTypeHeaderValue("application/json")); SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/javascript")); //MediaTypeMappings.Add(new UriPathExtensionMapping("jsonp", "application/json")); JsonpParameterName = "callback"; } /// <summary> /// Name of the query string parameter to look for /// the jsonp function name /// </summary> public string JsonpParameterName {get; set; } /// <summary> /// Captured name of the Jsonp function that the JSON call /// is wrapped in. Set in GetPerRequestFormatter Instance /// </summary> private string JsonpCallbackFunction; public override bool CanWriteType(Type type) { return true; } /// <summary> /// Override this method to capture the Request object /// and look for the query string parameter and /// create a new instance of this formatter. /// /// This is the only place in a formatter where the /// Request object is available. /// </summary> /// <param name="type"></param> /// <param name="request"></param> /// <param name="mediaType"></param> /// <returns></returns> public override MediaTypeFormatter GetPerRequestFormatterInstance(Type type, HttpRequestMessage request, MediaTypeHeaderValue mediaType) { var formatter = new JsonpFormatter() { JsonpCallbackFunction = GetJsonCallbackFunction(request) }; return formatter; } /// <summary> /// Override to wrap existing JSON result with the /// JSONP function call /// </summary> /// <param name="type"></param> /// <param name="value"></param> /// <param name="stream"></param> /// <param name="contentHeaders"></param> /// <param name="transportContext"></param> /// <returns></returns> public override Task WriteToStreamAsync(Type type, object value, Stream stream, HttpContentHeaders contentHeaders, TransportContext transportContext) { if (!string.IsNullOrEmpty(JsonpCallbackFunction)) { return Task.Factory.StartNew(() => { var writer = new StreamWriter(stream); writer.Write( JsonpCallbackFunction + "("); writer.Flush(); base.WriteToStreamAsync(type, value, stream, contentHeaders, transportContext).Wait(); writer.Write(")"); writer.Flush(); }); } else { return base.WriteToStreamAsync(type, value, stream, contentHeaders, transportContext); } } /// <summary> /// Retrieves the Jsonp Callback function /// from the query string /// </summary> /// <returns></returns> private string GetJsonCallbackFunction(HttpRequestMessage request) { if (request.Method != HttpMethod.Get) return null; var query = HttpUtility.ParseQueryString(request.RequestUri.Query); var queryVal = query[this.JsonpParameterName]; if (string.IsNullOrEmpty(queryVal)) return null; return queryVal; } } } Note again that this code will not work with the Beta bits of Web API - it works only with post beta bits from CodePlex and hopefully this will continue to work until RTM :-) This code is a bit different from Christians original code as the API has changed. The biggest change is that the Read/Write functions no longer receive a global context object that gives access to the Request and Response objects as the older bits did. Instead you now have to override the GetPerRequestFormatterInstance() method, which receives the Request as a parameter. You can capture the Request there, or use the request to pick up the values you need and store them on the formatter. Note that I also have to create a new instance of the formatter since I'm storing request specific state on the instance (information whether the callback= querystring is present) so I return a new instance of this formatter. Other than that the code should be straight forward: The code basically writes out the function pre- and post-amble and the defers to the base stream to retrieve the JSON to wrap the function call into. The code uses the Async APIs to write this data out (this will take some getting used to seeing all over the place for me). Hooking up the JsonpFormatter Once you've created a formatter, it has to be added to the request processing sequence by adding it to the formatter collection. Web API is configured via the static GlobalConfiguration object. protected void Application_Start(object sender, EventArgs e) { // Verb Routing RouteTable.Routes.MapHttpRoute( name: "AlbumsVerbs", routeTemplate: "albums/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumApi" } ); GlobalConfiguration .Configuration .Formatters .Insert(0, new Westwind.Web.WebApi.JsonpFormatter()); } That's all it takes. Note that I added the formatter at the top of the list of formatters, rather than adding it to the end which is required. The JSONP formatter needs to fire before any other JSON formatter since it relies on the JSON formatter to encode the actual JSON data. If you reverse the order the JSONP output never shows up. So, in general when adding new formatters also try to be aware of the order of the formatters as they are added. Resources JsonpFormatter Code on GitHub© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api 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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A few things I learned regarding Azure billing policies

- by Vincent Grondin

An hour of small computing time: 0,12$ per hour A Gig of storage in the cloud: 0,15$ per hour 1 Gig of relational database using Azure SQL: 9,99$ per month A Visual Studio Professional with MSDN Premium account: 2500$ per year Winning an MSDN Professional account that comes preloaded with 750 free hours of Azure per month: PRICELESS !!! But was it really free???? Hmmm… Let’s see..... Here's a few things I learned regarding Azure billing policies when I attended a promotional training at Microsoft last week... 1) An instance deployed in the cloud really means whatever you upload in there... it doesn't matter if it's in STAGING OR PRODUCTION!!!! Your MSDN account comes with 750 free hours of small computing time per month which should be enough hours per month for one instance of one application deployed in the cloud... So we're cool, the application you run in the cloud doesn't cost you a penny.... BUT the one that's in staging is still consuming time!!! So if you don’t want to end up having to pay 42$ at the end of the month on your credit card like this happened to a friend of mine, DELETE them staging applications once you’ve put them in production! This also applies to the instance count you can modify in the configuration file… So stop and think before you decide you want to spawn 50 of those hello world apps . 2) If you have an MSDN account, then you have the promotional 750 hours of Azure credits per month and can use the Azure credits to explore the Cloud! But be aware, this promotion ends in 8 months (maybe more like 7 now) and then you will most likely go back to the standard 250 hours of Azure credits. If you do not delete your applications by then, you’ll get billed for the extra hours, believe me… There is a switch that you can toggle and which will STOP your automatic enrollment after the promotion and prevent you from renewing the Azure Account automatically. Yes the default setting is to automatically renew your account and remember, you entered your credit card information in the registration process so, yes, you WILL be billed… Go disable that ASAP Log into your account, go to “Windows Azure Platform” then click the “Subscriptions” tab and on the right side, you’ll see a drop down with different “Actions” into it… Choose “Opt out of auto renew” and, NOW you’re safe… Still, this is a great offer by Microsoft and I think everyone that has a chance should play a bit with Azure to get to know this technology a bit more... Happy Cloud Computing All

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LinqToXML removing empty xmlns attributes & adding attributes like xmlns:xsi, xsi:schemaLocation

- by Rohit Gupta

Suppose you need to generate the following XML: 1: <GenevaLoader xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 2: xsi:schemaLocation="http://www.advent.com/SchemaRevLevel401/Geneva masterschema.xsd" 3: xmlns="http://www.advent.com/SchemaRevLevel401/Geneva"> 4: <PriceRecords> 5: <PriceRecord> 6: </PriceRecord> 7: </PriceRecords> 8: </GenevaLoader> Normally you would write the following C# code to accomplish this: 1: const string ns = "http://www.advent.com/SchemaRevLevel401/Geneva"; 2: XNamespace xnsp = ns; 3: XNamespace xsi = XNamespace.Get("http://www.w3.org/2001/XMLSchema-instance"); 4: 5: XElement root = new XElement( xnsp + "GenevaLoader", 6: new XAttribute(XNamespace.Xmlns + "xsi", xsi.NamespaceName), 7: new XAttribute( xsi + "schemaLocation", "http://www.advent.com/SchemaRevLevel401/Geneva masterschema.xsd")); 8: 9: XElement priceRecords = new XElement("PriceRecords"); 10: root.Add(priceRecords); 11: 12: for(int i = 0; i < 3; i++) 13: { 14: XElement price = new XElement("PriceRecord"); 15: priceRecords.Add(price); 16: } 17: 18: doc.Save("geneva.xml"); The problem with this approach is that it adds a additional empty xmlns arrtribute on the “PriceRecords” element, like so : 1: <GenevaLoader xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.advent.com/SchemaRevLevel401/Geneva masterschema.xsd" xmlns="http://www.advent.com/SchemaRevLevel401/Geneva"> 2: <PriceRecords xmlns=""> 3: <PriceRecord> 4: </PriceRecord> 5: </PriceRecords> 6: </GenevaLoader> The solution is to add the xmlns NameSpace in code to each child and grandchild elements of the root element like so : 1: XElement priceRecords = new XElement( xnsp + "PriceRecords"); 2: root.Add(priceRecords); 3: 4: for(int i = 0; i < 3; i++) 5: { 6: XElement price = new XElement(xnsp + "PriceRecord"); 7: priceRecords.Add(price); 8: }

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Static vs Singleton in C# (Difference between Singleton and Static)

- by Jalpesh P. Vadgama

Recently I have came across a question what is the difference between Static and Singleton classes. So I thought it will be a good idea to share blog post about it.Difference between Static and Singleton classes:A singleton classes allowed to create a only single instance or particular class. That instance can be treated as normal object. You can pass that object to a method as parameter or you can call the class method with that Singleton object. While static class can have only static methods and you can not pass static class as parameter.We can implement the interfaces with the Singleton class while we can not implement the interfaces with static classes.We can clone the object of Singleton classes we can not clone the object of static classes.Singleton objects stored on heap while static class stored in stack.more at my personal blog: dotnetjalps.com

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Demystifying Silverlight Dependency Properties

- by dwahlin

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

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In Which We Demystify A Few Docupresentment Settings And Learn the Ethos of the Author

- by Andy Little

It's no secret that Docupresentment (part of the Oracle Documaker suite) is powerful tool for integrating on-demand and interactive applications for publishing with the Oracle Documaker framework. It's also no secret there are are many details with respect to the configuration of Docupresentment that can elude even the most erudite of of techies. To be sure, Docupresentment will work for you right out of the box, and in most cases will suit your needs without toying with a configuration file. But, where's the adventure in that? With this inaugural post to That's The Way, I'm going to introduce myself, and what my aim is with this blog. If you didn't figure it out already by checking out my profile, my name is Andy and I've been with Oracle (nee Skywire Software nee Docucorp nee Formmaker) since the formative years of 1998. Strangely, it doesn't seem that long ago, but it's certainly a lifetime in the age of technology. I recall running a BBS from my parent's basement on a 1200 baud modem, and the trepidation and sweaty-palmed excitement of upgrading to the power and speed of 2400 baud! Fine, I'll admit that perhaps I'm inflating the experience a bit, but I was kid! This is the stuff of War Games and King's Quest I and the demise of TI-99 4/A. Exciting times. So fast-forward a bit and I'm 12 years into a career in the world of document automation and publishing working for the best (IMHO) software company on the planet. With That's The Way I hope to shed a little light and peek under the covers of some of the more interesting aspects of implementations involving the tech space within the Oracle Insurance Global Business Unit (IGBU), which includes Oracle Documaker, Rating & Underwriting, and Policy Administration to name a few. I may delve off course a bit, and you'll likely get a dose of humor (at least in my mind) but I hope you'll glean at least a tidbit of usefulness with each post. Feel free to comment as I'm a fairly conversant guy and happy to talk -- it's stopping the talking that's the hard part... So, back to our regularly-scheduled post, already in progress. By this time you've visited Oracle's E-Delivery site and acquired your properly-licensed version of Oracle Documaker. Wait -- you didn't find it? Understandable -- navigating the voluminous download library within Oracle can be a daunting task. It's pretty simple once you’ve done it a few times. Login to the e-delivery site, and accept the license terms and restrictions. Then, you’ll be able to select the Oracle Insurance Applications product pack and your appropriate platform. Click Go and you’ll see a list of applicable products, and you’ll click on Oracle Documaker Media Pack (as I went to press with this article the version is 11.4): Finally, click the Download button next to Docupresentment (again, version at press time is 2.2 p5). This should give you a ZIP file that contains the installation packages for the Docupresentment Server and Client, cryptically named IDSServer22P05W32.exe and IDSClient22P05W32.exe. At this time, I’d like to take a little detour and explain that the world of Oracle, like most technical companies, is rife with acronyms. One of the reasons Skywire Software was a appealing to Oracle was our use of many acronyms, including the occasional use of multiple acronyms with the same meaning. I apologize in advance and will try to point these out along the way. Here’s your first sticky note to go along with that: IDS = Internet Document Server = Docupresentment Once you’ve completed the installation, you’ll have a shiny new Docupresentment server and client, and if you installed the default location it will be living in c:\docserv. Unix users, I’m one of you! You’ll find it by default in ~/docupresentment/docserv. Forging onward with the meat of this post is learning about some special configuration options. By now you’ve read the documentation included with the download (specifically ids_book.pdf) which goes into some detail of the rubric of the configuration file and in fact there’s even a handy utility that provides an interface to the configuration file (see Running IDSConfig in the documentation). But who wants to deal with a configuration utility when we have the tools and technology to edit the file <gasp> by hand! I shall now proceed with the standard Information Technology Under the Hood Disclaimer: Please remember to back up any files before you make changes. I am not responsible for any havoc you may wreak! Go to your installation directory, and locate your docserv.xml file. Open it in your favorite XML editor. I happen to be fond of Notepad++ with the XML Tools plugin. Almost immediately you will behold the splendor of the configuration file. Just take a moment and let that sink in. Ok – moving on. If you reviewed the documentation you know that inside the root <configuration> node there are multiple <section> nodes, each containing a specific group of settings. Let’s take a look at <section name=”DocumentServer”>: There are a few entries I’d like to discuss. First, <entry name=”StartCommand”>. This should be pretty self-explanatory; it’s the name of the executable that’s run when you fire up Docupresentment. Immediately following that is <entry name=”StartArguments”> and as you might imagine these are the arguments passed to the executable. A few things to point out: The –Dids.configuration=docserv.xml parameter specifies the name of your configuration file. The –Dlogging.configuration=logconf.xml parameter specifies the name of your logging configuration file (this uses log4j so bone up on that before you delve here). The -Djava.endorsed.dirs=lib/endorsed parameter specifies the path where 3rd party Java libraries can be located for use with Docupresentment. More on that in another post. The <entry name=”Instances”> allows you to specify the number of instances of Docupresentment that will be started. By default this is two, and generally two instances per CPU is adequate, however you will always need to perform load testing to determine the sweet spot based on your hardware and types of transactions. You may have many, many more instances than 2. Time for a sidebar on instances. An instance is nothing more than a separate process of Docupresentment. The Docupresentment service that you fire up with docserver.bat or docserver.sh actually starts a watchdog process, which is then responsible for starting up the actual Docupresentment processes. Each of these act independently from one another, so if one crashes, it does not affect any others. In the case of a crashed process, the watchdog will start up another instance so the number of configured instances are always running. Bottom line: instance = Docupresentment process. And now, finally, to the settings which gave me pause on an not-too-long-ago implementation! Docupresentment includes a feature that watches configuration files (such as docserv.xml and logconf.xml) and will automatically restart its instances to load the changes. You can configure the time that Docupresentment waits to check these files using the setting <entry name=”FileWatchTimeMillis”>. By default the number is 12000ms, or 12 seconds. You can save yourself a few CPU cycles by extending this time, or by disabling the check altogether by setting the value to 0. This may or may not be appropriate for your environment; if you have 100% uptime requirements then you probably don’t want to bring down an entire set of processes just to accept a new configuration value, so it’s best to leave this somewhere between 12 seconds to a few minutes. Another point to keep in mind: if you are using Documaker real-time processing under Docupresentment the Master Resource Library (MRL) files and INI options are cached, and if you need to affect a change, you’ll have to “restart” Docupresentment. Touching the docserv.xml file is an easy way to do this (other methods including using the RSS request, but that’s another post). The next item up: <entry name=”FilePurgeTimeSeconds”>. You may already know that the Docupresentment system can generate many temporary files based on certain request types that are processed through the system. What you may not know is how those files are cleaned up. There are many rules in Docupresentment that cause the creation of temporary files. When these files are created, Docupresentment writes an entry into a properties file called the file cache. This file contains the name, creation date, and expiration time of each temporary file created by each instance of Docupresentment. Periodically Docupresentment will check the file cache to determine if there are files that are past the expiration time, not unlike that block of cheese festering away in the back of my refrigerator. However, unlike my ‘fridge cleaning tendencies, Docupresentment is quick to remove files that are past their expiration time. You, my friend, have the power to control how often Docupresentment inspects the file cache. Simply set the value for <entry name=”FilePurgeTimeSeconds”> to the number of seconds appropriate for your requirements and you’re set. Note that file purging happens on a separate thread from normal request processing, so this shouldn’t interfere with response times unless the CPU happens to be really taxed at the point of cache processing. Finally, after all of this, we get to the final setting I’m going to address in this post: <entry name=”FilePurgeList”>. The default is “filecache.properties”. This establishes the root name for the Docupresentment file cache that I mentioned previously. Docupresentment creates a separate cache file for each instance based on this setting. If you have two instances, you’ll see two files created: filecache.properties.1 and filecache.properties.2. Feel free to open these up and check them out. I hope you’ve enjoyed this first foray into the configuration file of Docupresentment. If you did enjoy it, feel free to drop a comment, I welcome feedback. If you have ideas for other posts you’d like to see, please do let me know. You can reach me at [email protected]. ‘Til next time! ###

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Subterranean IL: Filter exception handlers

- by Simon Cooper

Filter handlers are the second type of exception handler that aren't accessible from C#. Unlike the other handler types, which have defined conditions for when the handlers execute, filter lets you use custom logic to determine whether the handler should be run. However, similar to a catch block, the filter block does not get run if control flow exits the block without throwing an exception. Introducing filter blocks An example of a filter block in IL is the following: .try { // try block } filter { // filter block endfilter }{ // filter handler } or, in v1 syntax, TryStart: // try block TryEnd: FilterStart: // filter block HandlerStart: // filter handler HandlerEnd: .try TryStart to TryEnd filter FilterStart handler HandlerStart to HandlerEnd In the v1 syntax there is no end label specified for the filter block. This is because the filter block must come immediately before the filter handler; the end of the filter block is the start of the filter handler. The filter block indicates to the CLR whether the filter handler should be executed using a boolean value on the stack when the endfilter instruction is run; true/non-zero if it is to be executed, false/zero if it isn't. At the start of the filter block, and the corresponding filter handler, a reference to the exception thrown is pushed onto the stack as a raw object (you have to manually cast to System.Exception). The allowed IL inside a filter block is tightly controlled; you aren't allowed branches outside the block, rethrow instructions, and other exception handling clauses. You can, however, use call and callvirt instructions to call other methods. Filter block logic To demonstrate filter block logic, in this example I'm filtering on whether there's a particular key in the Data dictionary of the thrown exception: .try { // try block } filter { // Filter starts with exception object on stack // C# code: ((Exception)e).Data.Contains("MyExceptionDataKey") // only execute handler if Contains returns true castclass [mscorlib]System.Exception callvirt instance class [mscorlib]System.Collections.IDictionary [mscorlib]System.Exception::get_Data() ldstr "MyExceptionDataKey" callvirt instance bool [mscorlib]System.Collections.IDictionary::Contains(object) endfilter }{ // filter handler // Also starts off with exception object on stack callvirt instance string [mscorlib]System.Object::ToString() call void [mscorlib]System.Console::WriteLine(string) } Conclusion Filter exception handlers are another exception handler type that isn't accessible from C#, however, just like fault handlers, the behaviour can be replicated using a normal catch block: try { // try block } catch (Exception e) { if (!FilterLogic(e)) throw; // handler logic } So, it's not that great a loss, but it's still annoying that this functionality isn't directly accessible. Well, every feature starts off with minus 100 points, so it's understandable why something like this didn't make it into the C# compiler ahead of a different feature.

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Juju Zookeeper & Provisioning Agent Not Deployed

- by Keith Tobin

I am using juju with the openstack provider, i expected that when i bootstrap that zookeeper and provisioning agent would get deployed on the bootstrap vm in openstack. This dose not seem to be the case. the bootstrap vm gets deployed but it seems that nothing gets deployed to the VM. See logs below, I may be missing something, also how is it possible to log on the bootstrap vm. Could I manual deploy, if so what do I need to do. Juju Bootstrap commend root@cinder01:/home/cinder# juju -v bootstrap 2012-10-12 03:21:20,976 DEBUG Initializing juju bootstrap runtime 2012-10-12 03:21:20,982 WARNING Verification of xxxxS certificates is disabled for this environment. Set 'ssl-hostname-verification' to ensure secure communication. 2012-10-12 03:21:20,982 DEBUG openstack: using auth-mode 'userpass' with xxxx:xxxxxx.10:35357/v2.0/ 2012-10-12 03:21:21,064 DEBUG openstack: authenticated til u'2012-10-13T08:21:13Z' 2012-10-12 03:21:21,064 DEBUG openstack: GET 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors' 2012-10-12 03:21:21,091 DEBUG openstack: 200 '{"flavors": [{"id": "3", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/3", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/3", "rel": "bookmark"}], "name": "m1.medium"}, {"id": "4", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/4", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/4", "rel": "bookmark"}], "name": "m1.large"}, {"id": "1", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/1", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/1", "rel": "bookmark"}], "name": "m1.tiny"}, {"id": "5", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/5", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/5", "rel": "bookmark"}], "name": "m1.xlarge"}, {"id": "2", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/2", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/2", "rel": "bookmark"}], "name": "m1.small"}]}' 2012-10-12 03:21:21,091 INFO Bootstrapping environment 'openstack' (origin: ppa type: openstack)... 2012-10-12 03:21:21,091 DEBUG access object-store @ xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/provider-state 2012-10-12 03:21:21,092 DEBUG openstack: GET 'xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/provider-state' 2012-10-12 03:21:21,165 DEBUG openstack: 200 '{}\n' 2012-10-12 03:21:21,165 DEBUG Verifying writable storage 2012-10-12 03:21:21,165 DEBUG access object-store @ xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/bootstrap-verify 2012-10-12 03:21:21,166 DEBUG openstack: PUT 'xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/bootstrap-verify' 2012-10-12 03:21:21,251 DEBUG openstack: 201 '201 Created\n\n\n\n ' 2012-10-12 03:21:21,251 DEBUG Launching juju bootstrap instance. 2012-10-12 03:21:21,271 DEBUG access object-store @ xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/juju_master_id 2012-10-12 03:21:21,273 DEBUG access compute @ xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/os-security-groups 2012-10-12 03:21:21,273 DEBUG openstack: GET 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/os-security-groups' 2012-10-12 03:21:21,321 DEBUG openstack: 200 '{"security_groups": [{"rules": [{"from_port": -1, "group": {}, "ip_protocol": "icmp", "to_port": -1, "parent_group_id": 1, "ip_range": {"cidr": "0.0.0.0/0"}, "id": 7}, {"from_port": 22, "group": {}, "ip_protocol": "tcp", "to_port": 22, "parent_group_id": 1, "ip_range": {"cidr": "0.0.0.0/0"}, "id": 38}], "tenant_id": "d5f52673953f49e595279e89ddde979d", "id": 1, "name": "default", "description": "default"}]}' 2012-10-12 03:21:21,322 DEBUG Creating juju security group juju-openstack 2012-10-12 03:21:21,322 DEBUG openstack: POST 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/os-security-groups' 2012-10-12 03:21:21,401 DEBUG openstack: 200 '{"security_group": {"rules": [], "tenant_id": "d5f52673953f49e595279e89ddde979d", "id": 48, "name": "juju-openstack", "description": "juju group for openstack"}}' 2012-10-12 03:21:21,401 DEBUG openstack: POST 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/os-security-group-rules' 2012-10-12 03:21:21,504 DEBUG openstack: 200 '{"security_group_rule": {"from_port": 22, "group": {}, "ip_protocol": "tcp", "to_port": 22, "parent_group_id": 48, "ip_range": {"cidr": "0.0.0.0/0"}, "id": 54}}' 2012-10-12 03:21:21,504 DEBUG openstack: POST 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/os-security-group-rules' 2012-10-12 03:21:21,647 DEBUG openstack: 200 '{"security_group_rule": {"from_port": 1, "group": {"tenant_id": "d5f52673953f49e595279e89ddde979d", "name": "juju-openstack"}, "ip_protocol": "tcp", "to_port": 65535, "parent_group_id": 48, "ip_range": {}, "id": 55}}' 2012-10-12 03:21:21,647 DEBUG openstack: POST 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/os-security-group-rules' 2012-10-12 03:21:21,791 DEBUG openstack: 200 '{"security_group_rule": {"from_port": 1, "group": {"tenant_id": "d5f52673953f49e595279e89ddde979d", "name": "juju-openstack"}, "ip_protocol": "udp", "to_port": 65535, "parent_group_id": 48, "ip_range": {}, "id": 56}}' 2012-10-12 03:21:21,792 DEBUG Creating machine security group juju-openstack-0 2012-10-12 03:21:21,792 DEBUG openstack: POST 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/os-security-groups' 2012-10-12 03:21:21,871 DEBUG openstack: 200 '{"security_group": {"rules": [], "tenant_id": "d5f52673953f49e595279e89ddde979d", "id": 49, "name": "juju-openstack-0", "description": "juju group for openstack machine 0"}}' 2012-10-12 03:21:21,871 DEBUG access compute @ xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/detail 2012-10-12 03:21:21,871 DEBUG openstack: GET 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/detail' 2012-10-12 03:21:21,906 DEBUG openstack: 200 '{"flavors": [{"vcpus": 2, "disk": 10, "name": "m1.medium", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/3", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/3", "rel": "bookmark"}], "rxtx_factor": 1.0, "OS-FLV-EXT-DATA:ephemeral": 40, "ram": 4096, "id": "3", "swap": ""}, {"vcpus": 4, "disk": 10, "name": "m1.large", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/4", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/4", "rel": "bookmark"}], "rxtx_factor": 1.0, "OS-FLV-EXT-DATA:ephemeral": 80, "ram": 8192, "id": "4", "swap": ""}, {"vcpus": 1, "disk": 0, "name": "m1.tiny", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/1", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/1", "rel": "bookmark"}], "rxtx_factor": 1.0, "OS-FLV-EXT-DATA:ephemeral": 0, "ram": 512, "id": "1", "swap": ""}, {"vcpus": 8, "disk": 10, "name": "m1.xlarge", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/5", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/5", "rel": "bookmark"}], "rxtx_factor": 1.0, "OS-FLV-EXT-DATA:ephemeral": 160, "ram": 16384, "id": "5", "swap": ""}, {"vcpus": 1, "disk": 10, "name": "m1.small", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/2", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/2", "rel": "bookmark"}], "rxtx_factor": 1.0, "OS-FLV-EXT-DATA:ephemeral": 20, "ram": 2048, "id": "2", "swap": ""}]}' 2012-10-12 03:21:21,907 DEBUG access compute @ xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers 2012-10-12 03:21:21,907 DEBUG openstack: POST 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers' 2012-10-12 03:21:22,284 DEBUG openstack: 202 '{"server": {"OS-DCF:diskConfig": "MANUAL", "id": "a598b402-8678-4447-baeb-59255409a023", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023", "rel": "bookmark"}], "adminPass": "SuFp48cZzdo4"}}' 2012-10-12 03:21:22,284 DEBUG access object-store @ xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/juju_master_id 2012-10-12 03:21:22,285 DEBUG openstack: PUT 'xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/juju_master_id' 2012-10-12 03:21:22,375 DEBUG openstack: 201 '201 Created\n\n\n\n ' 2012-10-12 03:21:27,379 DEBUG Waited for 5 seconds for networking on server u'a598b402-8678-4447-baeb-59255409a023' 2012-10-12 03:21:27,380 DEBUG access compute @ xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023 2012-10-12 03:21:27,380 DEBUG openstack: GET 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023' 2012-10-12 03:21:27,556 DEBUG openstack: 200 '{"server": {"OS-EXT-STS:task_state": "networking", "addresses": {"private": [{"version": 4, "addr": "10.0.0.8"}]}, "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023", "rel": "bookmark"}], "image": {"id": "5bf60467-0136-4471-9818-e13ade75a0a1", "links": [{"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/images/5bf60467-0136-4471-9818-e13ade75a0a1", "rel": "bookmark"}]}, "OS-EXT-STS:vm_state": "building", "OS-EXT-SRV-ATTR:instance_name": "instance-00000060", "flavor": {"id": "1", "links": [{"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/1", "rel": "bookmark"}]}, "id": "a598b402-8678-4447-baeb-59255409a023", "user_id": "01610f73d0fb4922aefff09f2627e50c", "OS-DCF:diskConfig": "MANUAL", "accessIPv4": "", "accessIPv6": "", "progress": 0, "OS-EXT-STS:power_state": 0, "config_drive": "", "status": "BUILD", "updated": "2012-10-12T08:21:23Z", "hostId": "1cdb25708fb8e464d83a69fe4a024dcd5a80baf24a82ec28f9d9f866", "OS-EXT-SRV-ATTR:host": "nova01", "key_name": "", "OS-EXT-SRV-ATTR:hypervisor_hostname": null, "name": "juju openstack instance 0", "created": "2012-10-12T08:21:22Z", "tenant_id": "d5f52673953f49e595279e89ddde979d", "metadata": {}}}' 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 2012-10-12 03:21:27,557 DEBUG access compute @ xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/os-floating-ips 2012-10-12 03:21:27,557 DEBUG openstack: GET 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/os-floating-ips' 2012-10-12 03:21:27,815 DEBUG openstack: 200 '{"floating_ips": [{"instance_id": "a0e0df11-91c0-4801-95b3-62d910d729e9", "ip": "xxxx.35", "fixed_ip": "10.0.0.5", "id": 447, "pool": "nova"}, {"instance_id": "b84f1a42-7192-415e-8650-ebb1aa56e97f", "ip": "xxxx.36", "fixed_ip": "10.0.0.6", "id": 448, "pool": "nova"}, {"instance_id": null, "ip": "xxxx.37", "fixed_ip": null, "id": 449, "pool": "nova"}, {"instance_id": null, "ip": "xxxx.38", "fixed_ip": null, "id": 450, "pool": "nova"}, {"instance_id": null, "ip": "xxxx.39", "fixed_ip": null, "id": 451, "pool": "nova"}, {"instance_id": null, "ip": "xxxx.40", "fixed_ip": null, "id": 452, "pool": "nova"}, {"instance_id": null, "ip": "xxxx.41", "fixed_ip": null, "id": 453, "pool": "nova"}]}' 2012-10-12 03:21:27,815 DEBUG access compute @ xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023/action 2012-10-12 03:21:27,816 DEBUG openstack: POST 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023/action' 2012-10-12 03:21:28,356 DEBUG openstack: 202 '' 2012-10-12 03:21:28,356 DEBUG access object-store @ xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/provider-state 2012-10-12 03:21:28,357 DEBUG openstack: PUT 'xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/provider-state' 2012-10-12 03:21:28,446 DEBUG openstack: 201 '201 Created\n\n\n\n ' 2012-10-12 03:21:28,446 INFO 'bootstrap' command finished successfully Juju Status Command root@cinder01:/home/cinder# juju -v status 2012-10-12 03:23:28,314 DEBUG Initializing juju status runtime 2012-10-12 03:23:28,320 WARNING Verification of xxxxS certificates is disabled for this environment. Set 'ssl-hostname-verification' to ensure secure communication. 2012-10-12 03:23:28,320 DEBUG openstack: using auth-mode 'userpass' with xxxx:xxxxxx.10:35357/v2.0/ 2012-10-12 03:23:28,320 INFO Connecting to environment... 2012-10-12 03:23:28,403 DEBUG openstack: authenticated til u'2012-10-13T08:23:20Z' 2012-10-12 03:23:28,403 DEBUG access object-store @ xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/provider-state 2012-10-12 03:23:28,403 DEBUG openstack: GET 'xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/provider-state' 2012-10-12 03:23:35,480 DEBUG openstack: 200 'zookeeper-instances: [a598b402-8678-4447-baeb-59255409a023]\n' 2012-10-12 03:23:35,480 DEBUG access compute @ xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023 2012-10-12 03:23:35,480 DEBUG openstack: GET 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023' 2012-10-12 03:23:35,662 DEBUG openstack: 200 '{"server": {"OS-EXT-STS:task_state": null, "addresses": {"private": [{"version": 4, "addr": "10.0.0.8"}, {"version": 4, "addr": "xxxx.37"}]}, "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023", "rel": "bookmark"}], "image": {"id": "5bf60467-0136-4471-9818-e13ade75a0a1", "links": [{"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/images/5bf60467-0136-4471-9818-e13ade75a0a1", "rel": "bookmark"}]}, "OS-EXT-STS:vm_state": "active", "OS-EXT-SRV-ATTR:instance_name": "instance-00000060", "flavor": {"id": "1", "links": [{"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/1", "rel": "bookmark"}]}, "id": "a598b402-8678-4447-baeb-59255409a023", "user_id": "01610f73d0fb4922aefff09f2627e50c", "OS-DCF:diskConfig": "MANUAL", "accessIPv4": "", "accessIPv6": "", "progress": 0, "OS-EXT-STS:power_state": 1, "config_drive": "", "status": "ACTIVE", "updated": "2012-10-12T08:21:40Z", "hostId": "1cdb25708fb8e464d83a69fe4a024dcd5a80baf24a82ec28f9d9f866", "OS-EXT-SRV-ATTR:host": "nova01", "key_name": "", "OS-EXT-SRV-ATTR:hypervisor_hostname": null, "name": "juju openstack instance 0", "created": "2012-10-12T08:21:22Z", "tenant_id": "d5f52673953f49e595279e89ddde979d", "metadata": {}}}' 2012-10-12 03:23:35,663 DEBUG Connecting to environment using xxxx.37... 2012-10-12 03:23:35,663 DEBUG Spawning SSH process with remote_user="ubuntu" remote_host="xxxx.37" remote_port="2181" local_port="45859". 2012-10-12 03:23:36,173:4355(0x7fd581973700):ZOO_INFO@log_env@658: Client environment:zookeeper.version=zookeeper C client 3.3.5 2012-10-12 03:23:36,173:4355(0x7fd581973700):ZOO_INFO@log_env@662: Client environment:host.name=cinder01 2012-10-12 03:23:36,174:4355(0x7fd581973700):ZOO_INFO@log_env@669: Client environment:os.name=Linux 2012-10-12 03:23:36,174:4355(0x7fd581973700):ZOO_INFO@log_env@670: Client environment:os.arch=3.2.0-23-generic 2012-10-12 03:23:36,174:4355(0x7fd581973700):ZOO_INFO@log_env@671: Client environment:os.version=#36-Ubuntu SMP Tue Apr 10 20:39:51 UTC 2012 2012-10-12 03:23:36,174:4355(0x7fd581973700):ZOO_INFO@log_env@679: Client environment:user.name=cinder 2012-10-12 03:23:36,174:4355(0x7fd581973700):ZOO_INFO@log_env@687: Client environment:user.home=/root 2012-10-12 03:23:36,175:4355(0x7fd581973700):ZOO_INFO@log_env@699: Client environment:user.dir=/home/cinder 2012-10-12 03:23:36,175:4355(0x7fd581973700):ZOO_INFO@zookeeper_init@727: Initiating client connection, host=localhost:45859 sessionTimeout=10000 watcher=0x7fd57f9146b0 sessionId=0 sessionPasswd= context=0x2c1dab0 flags=0 2012-10-12 03:23:36,175:4355(0x7fd577fff700):ZOO_ERROR@handle_socket_error_msg@1579: Socket [127.0.0.1:45859] zk retcode=-4, errno=111(Connection refused): server refused to accept the client 2012-10-12 03:23:39,512:4355(0x7fd577fff700):ZOO_ERROR@handle_socket_error_msg@1579: Socket [127.0.0.1:45859] zk retcode=-4, errno=111(Connection refused): server refused to accept the client 2012-10-12 03:23:42,848:4355(0x7fd577fff700):ZOO_ERROR@handle_socket_error_msg@1579: Socket [127.0.0.1:45859] zk retcode=-4, errno=111(Connection refused): server refused to accept the client ^Croot@cinder01:/home/cinder#

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Don’t Program by Fear, Question Everything

- by João Angelo

Perusing some code base I’ve recently came across with a code comment that I would like to share. It was something like this: class Animal { public Animal() { this.Id = Guid.NewGuid(); } public Guid Id { get; private set; } } class Cat : Animal { public Cat() : base() // Always call base since it's not always done automatically { } } Note: All class names were changed to protect the innocent. To clear any possible doubts the C# specification explicitly states that: If an instance constructor has no constructor initializer, a constructor initializer of the form base() is implicitly provided. Thus, an instance constructor declaration of the form C(...) {...} is exactly equivalent to C(...): base() {...} So in conclusion it’s clearly an incorrect comment but what I find alarming is how a comment like that gets into a code base and survives the test of time. Not to forget what it can do to someone who is making a jump from other technologies to C# and reads stuff like that.

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JMS Step 5 - How to Create an 11g BPEL Process Which Reads a Message Based on an XML Schema from a JMS Queue

- by John-Brown.Evans

JMS Step 5 - How to Create an 11g BPEL Process Which Reads a Message Based on an XML Schema from a JMS Queue .jblist{list-style-type:disc;margin:0;padding:0;padding-left:0pt;margin-left:36pt} ol{margin:0;padding:0} .c12_5{vertical-align:top;width:468pt;border-style:solid;background-color:#f3f3f3;border-color:#000000;border-width:1pt;padding:5pt 5pt 5pt 5pt} .c8_5{vertical-align:top;border-style:solid;border-color:#000000;border-width:1pt;padding:5pt 5pt 0pt 5pt} .c10_5{vertical-align:top;width:207pt;border-style:solid;border-color:#000000;border-width:1pt;padding:5pt 5pt 5pt 5pt} .c14_5{vertical-align:top;border-style:solid;border-color:#000000;border-width:1pt;padding:0pt 5pt 0pt 5pt} .c21_5{background-color:#ffffff} .c18_5{color:#1155cc;text-decoration:underline} .c16_5{color:#666666;font-size:12pt} .c5_5{background-color:#f3f3f3;font-weight:bold} .c19_5{color:inherit;text-decoration:inherit} .c3_5{height:11pt;text-align:center} .c11_5{font-weight:bold} .c20_5{background-color:#00ff00} .c6_5{font-style:italic} .c4_5{height:11pt} .c17_5{background-color:#ffff00} .c0_5{direction:ltr} .c7_5{font-family:"Courier New"} .c2_5{border-collapse:collapse} .c1_5{line-height:1.0} .c13_5{background-color:#f3f3f3} .c15_5{height:0pt} .c9_5{text-align:center} .title{padding-top:24pt;line-height:1.15;text-align:left;color:#000000;font-size:36pt;font-family:"Arial";font-weight:bold;padding-bottom:6pt} .subtitle{padding-top:18pt;line-height:1.15;text-align:left;color:#666666;font-style:italic;font-size:24pt;font-family:"Georgia";padding-bottom:4pt} li{color:#000000;font-size:10pt;font-family:"Arial"} p{color:#000000;font-size:10pt;margin:0;font-family:"Arial"} h1{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:24pt;font-family:"Arial";font-weight:normal} h2{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:18pt;font-family:"Arial";font-weight:normal} h3{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:14pt;font-family:"Arial";font-weight:normal} h4{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:12pt;font-family:"Arial";font-weight:normal} h5{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:11pt;font-family:"Arial";font-weight:normal} h6{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:10pt;font-family:"Arial";font-weight:normal} Welcome to another post in the series of blogs which demonstrates how to use JMS queues in a SOA context. The previous posts were: JMS Step 1 - How to Create a Simple JMS Queue in Weblogic Server 11g JMS Step 2 - Using the QueueSend.java Sample Program to Send a Message to a JMS Queue JMS Step 3 - Using the QueueReceive.java Sample Program to Read a Message from a JMS Queue JMS Step 4 - How to Create an 11g BPEL Process Which Writes a Message Based on an XML Schema to a JMS Queue Today we will create a BPEL process which will read (dequeue) the message from the JMS queue, which we enqueued in the last example. The JMS adapter will dequeue the full XML payload from the queue. 1. Recap and Prerequisites In the previous examples, we created a JMS Queue, a Connection Factory and a Connection Pool in the WebLogic Server Console. Then we designed and deployed a BPEL composite, which took a simple XML payload and enqueued it to the JMS queue. In this example, we will read that same message from the queue, using a JMS adapter and a BPEL process. As many of the configuration steps required to read from that queue were done in the previous samples, this one will concentrate on the new steps. A summary of the required objects is listed below. To find out how to create them please see the previous samples. They also include instructions on how to verify the objects are set up correctly. WebLogic Server Objects Object Name Type JNDI Name TestConnectionFactory Connection Factory jms/TestConnectionFactory TestJMSQueue JMS Queue jms/TestJMSQueue eis/wls/TestQueue Connection Pool eis/wls/TestQueue Schema XSD File The following XSD file is used for the message format. It was created in the previous example and will be copied to the new process. stringPayload.xsd <?xml version="1.0" encoding="windows-1252" ?> <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://www.example.org" targetNamespace="http://www.example.org" elementFormDefault="qualified"> <xsd:element name="exampleElement" type="xsd:string"> </xsd:element> </xsd:schema> JMS Message After executing the previous samples, the following XML message should be in the JMS queue located at jms/TestJMSQueue: <?xml version="1.0" encoding="UTF-8" ?><exampleElement xmlns="http://www.example.org">Test Message</exampleElement> JDeveloper Connection You will need a valid Application Server Connection in JDeveloper pointing to the SOA server which the process will be deployed to. 2. Create a BPEL Composite with a JMS Adapter Partner Link In the previous example, we created a composite in JDeveloper called JmsAdapterWriteSchema. In this one, we will create a new composite called JmsAdapterReadSchema. There are probably many ways of incorporating a JMS adapter into a SOA composite for incoming messages. One way is design the process in such a way that the adapter polls for new messages and when it dequeues one, initiates a SOA or BPEL instance. This is possibly the most common use case. Other use cases include mid-flow adapters, which are activated from within the BPEL process. In this example we will use a polling adapter, because it is the most simple to set up and demonstrate. But it has one disadvantage as a demonstrative model. When a polling adapter is active, it will dequeue all messages as soon as they reach the queue. This makes it difficult to monitor messages we are writing to the queue, because they will disappear from the queue as soon as they have been enqueued. To work around this, we will shut down the composite after deploying it and restart it as required. (Another solution for this would be to pause the consumption for the queue and resume consumption again if needed. This can be done in the WLS console JMS-Modules -> queue -> Control -> Consumption -> Pause/Resume.) We will model the composite as a one-way incoming process. Usually, a BPEL process will do something useful with the message after receiving it, such as passing it to a database or file adapter, a human workflow or external web service. But we only want to demonstrate how to dequeue a JMS message using BPEL and a JMS adapter, so we won’t complicate the design with further activities. However, we do want to be able to verify that we have read the message correctly, so the BPEL process will include a small piece of embedded java code, which will print the message to standard output, so we can view it in the SOA server’s log file. Alternatively, you can view the instance in the Enterprise Manager and verify the message. The following steps are all executed in JDeveloper. Create the project in the same JDeveloper application used for the previous examples or create a new one. Create a SOA Project Create a new project and choose SOA Tier > SOA Project as its type. Name it JmsAdapterReadSchema. When prompted for the composite type, choose Empty Composite. Create a JMS Adapter Partner Link In the composite editor, drag a JMS adapter over from the Component Palette to the left-hand swim lane, under Exposed Services. This will start the JMS Adapter Configuration Wizard. Use the following entries: Service Name: JmsAdapterRead Oracle Enterprise Messaging Service (OEMS): Oracle WebLogic JMS AppServer Connection: Use an application server connection pointing to the WebLogic server on which the JMS queue and connection factory mentioned under Prerequisites above are located. Adapter Interface > Interface: Define from operation and schema (specified later) Operation Type: Consume Message Operation Name: Consume_message Consume Operation Parameters Destination Name: Press the Browse button, select Destination Type: Queues, then press Search. Wait for the list to populate, then select the entry for TestJMSQueue , which is the queue created in a previous example. JNDI Name: The JNDI name to use for the JMS connection. As in the previous example, this is probably the most common source of error. This is the JNDI name of the JMS adapter’s connection pool created in the WebLogic Server and which points to the connection factory. JDeveloper does not verify the value entered here. If you enter a wrong value, the JMS adapter won’t find the queue and you will get an error message at runtime, which is very difficult to trace. In our example, this is the value eis/wls/TestQueue . (See the earlier step on how to create a JMS Adapter Connection Pool in WebLogic Server for details.) Messages/Message SchemaURL: We will use the XSD file created during the previous example, in the JmsAdapterWriteSchema project to define the format for the incoming message payload and, at the same time, demonstrate how to import an existing XSD file into a JDeveloper project. Press the magnifying glass icon to search for schema files. In the Type Chooser, press the Import Schema File button. Select the magnifying glass next to URL to search for schema files. Navigate to the location of the JmsAdapterWriteSchema project > xsd and select the stringPayload.xsd file. Check the “Copy to Project” checkbox, press OK and confirm the following Localize Files popup. Now that the XSD file has been copied to the local project, it can be selected from the project’s schema files. Expand Project Schema Files > stringPayload.xsd and select exampleElement: string . Press Next and Finish, which will complete the JMS Adapter configuration.Save the project. Create a BPEL Component Drag a BPEL Process from the Component Palette (Service Components) to the Components section of the composite designer. Name it JmsAdapterReadSchema and select Template: Define Service Later and press OK. Wire the JMS Adapter to the BPEL Component Now wire the JMS adapter to the BPEL process, by dragging the arrow from the adapter to the BPEL process. A Transaction Properties popup will be displayed. Set the delivery mode to async.persist. This completes the steps at the composite level. 3 . Complete the BPEL Process Design Invoke the BPEL Flow via the JMS Adapter Open the BPEL component by double-clicking it in the design view of the composite.xml, or open it from the project navigator by selecting the JmsAdapterReadSchema.bpel file. This will display the BPEL process in the design view. You should see the JmsAdapterRead partner link in the left-hand swim lane. Drag a Receive activity onto the BPEL flow diagram, then drag a wire (left-hand yellow arrow) from it to the JMS adapter. This will open the Receive activity editor. Auto-generate the variable by pressing the green “+” button and check the “Create Instance” checkbox. This will result in a BPEL instance being created when a new JMS message is received. At this point it would actually be OK to compile and deploy the composite and it would pick up any messages from the JMS queue. In fact, you can do that to test it, if you like. But it is very rudimentary and would not be doing anything useful with the message. Also, you could only verify the actual message payload by looking at the instance’s flow in the Enterprise Manager. There are various other possibilities; we could pass the message to another web service, write it to a file using a file adapter or to a database via a database adapter etc. But these will all introduce unnecessary complications to our sample. So, to keep it simple, we will add a small piece of Java code to the BPEL process which will write the payload to standard output. This will be written to the server’s log file, which will be easy to monitor. Add a Java Embedding Activity First get the full name of the process’s input variable, as this will be needed for the Java code. Go to the Structure pane and expand Variables > Process > Variables. Then expand the input variable, for example, "Receive1_Consume_Message_InputVariable > body > ns2:exampleElement”, and note variable’s name and path, if they are different from this one. Drag a Java Embedding activity from the Component Palette (Oracle Extensions) to the BPEL flow, after the Receive activity, then open it to edit. Delete the example code and replace it with the following, replacing the variable parts with those in your sample, if necessary.: System.out.println("JmsAdapterReadSchema process picked up a message"); oracle.xml.parser.v2.XMLElement inputPayload = (oracle.xml.parser.v2.XMLElement)getVariableData( "Receive1_Consume_Message_InputVariable", "body", "/ns2:exampleElement"); String inputString = inputPayload.getFirstChild().getNodeValue(); System.out.println("Input String is " + inputPayload.getFirstChild().getNodeValue()); Tip. If you are not sure of the exact syntax of the input variable, create an Assign activity in the BPEL process and copy the variable to another, temporary one. Then check the syntax created by the BPEL designer. This completes the BPEL process design in JDeveloper. Save, compile and deploy the process to the SOA server. 3. Test the Composite Shut Down the JmsAdapterReadSchema Composite After deploying the JmsAdapterReadSchema composite to the SOA server it is automatically activated. If there are already any messages in the queue, the adapter will begin polling them. To ease the testing process, we will deactivate the process first Log in to the Enterprise Manager (Fusion Middleware Control) and navigate to SOA > soa-infra (soa_server1) > default (or wherever you deployed your composite to) and click on JmsAdapterReadSchema [1.0] . Press the Shut Down button to disable the composite and confirm the following popup. Monitor Messages in the JMS Queue In a separate browser window, log in to the WebLogic Server Console and navigate to Services > Messaging > JMS Modules > TestJMSModule > TestJMSQueue > Monitoring. This is the location of the JMS queue we created in an earlier sample (see the prerequisites section of this sample). Check whether there are any messages already in the queue. If so, you can dequeue them using the QueueReceive Java program created in an earlier sample. This will ensure that the queue is empty and doesn’t contain any messages in the wrong format, which would cause the JmsAdapterReadSchema to fail. Send a Test Message In the Enterprise Manager, navigate to the JmsAdapterWriteSchema created earlier, press Test and send a test message, for example “Message from JmsAdapterWriteSchema”. Confirm that the message was written correctly to the queue by verifying it via the queue monitor in the WLS Console. Monitor the SOA Server’s Output A program deployed on the SOA server will write its standard output to the terminal window in which the server was started, unless this has been redirected to somewhere else, for example to a file. If it has not been redirected, go to the terminal session in which the server was started, otherwise open and monitor the file to which it was redirected. Re-Enable the JmsAdapterReadSchema Composite In the Enterprise Manager, navigate to the JmsAdapterReadSchema composite again and press Start Up to re-enable it. This should cause the JMS adapter to dequeue the test message and the following output should be written to the server’s standard output: JmsAdapterReadSchema process picked up a message. Input String is Message from JmsAdapterWriteSchema Note that you can also monitor the payload received by the process, by navigating to the the JmsAdapterReadSchema’s Instances tab in the Enterprise Manager. Then select the latest instance and view the flow of the BPEL component. The Receive activity will contain and display the dequeued message too. 4 . Troubleshooting This sample demonstrates how to dequeue an XML JMS message using a BPEL process and no additional functionality. For example, it doesn’t contain any error handling. Therefore, any errors in the payload will result in exceptions being written to the log file or standard output. If you get any errors related to the payload, such as Message handle error ... ORABPEL-09500 ... XPath expression failed to execute. An error occurs while processing the XPath expression; the expression is /ns2:exampleElement. ... etc. check that the variable used in the Java embedding part of the process was entered correctly. Possibly follow the tip mentioned in previous section. If this doesn’t help, you can delete the Java embedding part and simply verify the message via the flow diagram in the Enterprise Manager. Or use a different method, such as writing it to a file via a file adapter. This concludes this example. In the next post, we will begin with an AQ JMS example, which uses JMS to write to an Advanced Queue stored in the database. Best regards John-Brown Evans Oracle Technology Proactive Support Delivery

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state: pending & public-address: null :: Juju setup on local machine

- by Danny Kopping

I've setup Juju on a local VM inside VMWare running on Mac OSX. Everything seems to be working fine, except when I deployed MySQL & WordPress from the examples, I get the following when I run juju status: danny@ubuntu:~$ juju status machines: 0: dns-name: localhost instance-id: local instance-state: running state: down services: mysql: charm: local:oneiric/mysql-11 relations: db: wordpress units: mysql/0: machine: 0 public-address: 192.168.122.107 relations: db: state: up state: started wordpress: charm: local:oneiric/wordpress-31 exposed: true relations: db: mysql units: wordpress/0: machine: 0 open-ports: [] public-address: null relations: {} state: pending state: pending and public-address: null Can't find any documentation relating to this issue. Any help very much appreciated - wonderful idea for a project!

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System Variables, Stored Procedures or Functions for Meta Data

- by BuckWoody

Whenever you want to know something about SQL Server’s configuration, whether that’s the Instance itself or a database, you have a few options. If you want to know “dynamic” data, such as how much memory or CPU is consumed or what a particular query is doing, you should be using the Dynamic Management Views (DMVs) that you can read about here: http://msdn.microsoft.com/en-us/library/ms188754.aspx But if you’re looking for how much memory is installed on the server, the version of the Instance, the drive letters of the backups and so on, you have other choices. The first of these are system variables. You access these with a SELECT statement, and they are useful when you need a discrete value for use, say in another query or to put into a table. You can read more about those here: http://msdn.microsoft.com/en-us/library/ms173823.aspx You also have a few stored procedures you can use. These often bring back a lot more data, pre-formatted for the screen. You access these with the EXECUTE syntax. It is a bit more difficult to take the data they return and get a single value or place the results in another table, but it is possible. You can read more about those here: http://msdn.microsoft.com/en-us/library/ms187961.aspx Yet another option is to use a system function, which you access with a SELECT statement, which also brings back a discrete value that you can use in a test or to place in another table. You can read about those here: http://msdn.microsoft.com/en-us/library/ms187812.aspx By the way, many of these constructs simply query from tables in the master or msdb databases for the Instance or the system tables in a user database. You can get much of the information there as well, and there are even system views in each database to show you the meta-data dealing with structure – more on that here: http://msdn.microsoft.com/en-us/library/ms186778.aspx Some of these choices are the only way to get at a certain piece of data. But others overlap – you can use one or the other, they both come back with the same data. So, like many Microsoft products, you have multiple ways to do the same thing. And that’s OK – just research what each is used for and how it’s intended to be used, and you’ll be able to select (pun intended) the right choice. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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GlassFish Clustering with DCOM on Windows

- by ByronNevins

DCOM - Distributed COM, a Microsoft protocol for communicating with Windows machines. Why use DCOM? In GlassFish 3.1 SSH is used as the standard way to run commands on remote nodes for clustering. It is very difficult for users to get SSH configured properly on Windows. SSH does not come with Windows so we have to depend on third party tools. And then the user is forced to install and configure these tools -- which can be tricky. DCOM is available on all supported platforms. It is built-in to Windows. The idea is to use DCOM to communicate with remote Windows nodes. This has the huge advantage that the user has to do minimal, if any, configuration on the Windows nodes. Implementation HighlightsTwo open Source Libraries have been added to GlassFish: Jcifs – a SAMBA implementation in Java J-interop – A Java implementation for making DCOM calls to remote Windows computers. Note that any supported platform can use DCOM to work with Windows nodes -- not just Windows.E.g. you can have a Linux DAS work with Windows remote instances.All existing SSH commands now have a corresponding DCOM command – except for setup-ssh which isn’t needed for DCOM. validate-dcom is an all new command. New DCOM Commands create-node-dcom delete-node-dcom install-node-dcom list-nodes-dcom ping-node-dcom uninstall-node-dcom update-node-dcom validate-dcom setup-local-dcom (This is only available via Update Center for GlassFish 3.1.2) These commands are in-place in the trunk (4.0). And in the branch (3.1.2) Windows Configuration Challenges There are an infinite number of possible configurations of Windows if you look at it as a combination of main release, service-pack, special drivers, software, configuration etc. Later versions of Windows err on the side of tightening security be default. This means that the Windows host may need to have configuration changes made.These configuration changes mostly need to be made by the user. setup-local-dcom will assist you in making required changes to the Windows Registry. See the reference blogs for details. The validate-dcom Command validate-dcom is a crucial command. It should be run before any other commands. If it does not run successfully then there is no point in running other commands.The validate-dcom command must be used from a DAS machine to test a different Windows machine. If validate-dcom runs successfully you can be confident that all the DCOM commands will work. Conversely, the opposite is also true: If validate-dcom fails, then no DCOM commands will work. What validate-dcom does Verify that the remote host is not the local machine. Resolves the remote host name Checks that the remote DCOM port is being listened on (135, 139) Checks that the remote host’s File Sharing is enabled (port 445) It copies a file (a script) to the remote host to verify that SAMBA is working and authorization is correct It runs a script that it copied on-the-fly to the remote host. Tips and Tricks The bread and butter commands that use DCOM are existing commands like create-instance, start-instance etc. All of the commands that have dcom in their name are for dealing with the actual nodes. The way the software works is to call asadmin.bat on the remote machine and run a command. This means that you can track these commands easily on the remote machine with the usual tools. E.g. using AS_LOGFILE, looking at log files, etc. It’s easy to attach a debugger to the remote asadmin process, “just in time”, if necessary. How to debug the remote commands:Edit the asadmin.bat file that is in the glassfish/bin folder. Use glassfish/lib/nadmin.bat in GlassFish 4.0+Add these options to the java call:-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=1234 Now if you run, say start-instance on DAS, you can attach your debugger, at your leisure, to the remote machines port 1234. It will be running start-local-instance and patiently waiting for you to attach.

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Ways to ensure unique instances of a class?

- by Peanut

I'm looking for different ways to ensure that each instance of a given class is a uniquely identifiable instance. For example, I have a Name class with the field name. Once I have a Name object with name initialised to John Smith I don't want to be able to instantiate a different Name object also with the name as John Smith, or if instantiation does take place I want a reference to the orginal object to be passed back rather than a new object. I'm aware that one way of doing this is to have a static factory that holds a Map of all the current Name objects and the factory checks that an object with John Smith as the name doesn't already exist before passing back a reference to a Name object. Another way I could think of off the top of my head is having a static Map in the Name class and when the constructor is called throwing an exception if the value passed in for name is already in use in another object, however I'm aware throwing exceptions in a constructor is generally a bad idea. Are there other ways of achieving this?

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Solaris: What comes next?

- by alanc

As you probably know by now, a few months ago, we released Solaris 11 after years of development. That of course means we now need to figure out what comes next - if Solaris 11 is “The First Cloud OS”, then what do we need to make future releases of Solaris be, to be modern and competitive when they're released? So we've been having planning and brainstorming meetings, and I've captured some notes here from just one of those we held a couple weeks ago with a number of the Silicon Valley based engineers. Now before someone sees an idea here and calls their product rep wanting to know what's up, please be warned what follows are rough ideas, and as I'll discuss later, none of them have any committment, schedule, working code, or even plan for integration in any possible future product at this time. (Please don't make me force you to read the full Oracle future product disclaimer here, you should know it by heart already from the front of every Oracle product slide deck.) To start with, we did some background research, looking at ideas from other Oracle groups, and competitive OS'es. We examined what was hot in the technology arena and where the interesting startups were heading. We then looked at Solaris to see where we could apply those ideas. Making Network Admins into Socially Networking Admins We all know an admin who has grumbled about being the only one stuck late at work to fix a problem on the server, or having to work the weekend alone to do scheduled maintenance. But admins are humans (at least most are), and crave companionship and community with their fellow humans. And even when they're alone in the server room, they're never far from a network connection, allowing access to the wide world of wonders on the Internet. Our solution here is not building a new social network - there's enough of those already, and Oracle even has its own Oracle Mix social network already. What we proposed is integrating Solaris features to help engage our system admins with these social networks, building community and bringing them recognition in the workplace, using achievement recognition systems as found in many popular gaming platforms. For instance, if you had a Facebook account, and a group of admin friends there, you could register it with our Social Network Utility For Facebook, and then your friends might see: Alan earned the achievement Critically Patched (April 2012) for patching all his servers. Matt is only at 50% - encourage him to complete this achievement today! To avoid any undue risk of advertising who has unpatched servers that are easier targets for hackers to break into, this information would be tightly protected via Facebook's world-renowned privacy settings to avoid it falling into the wrong hands. A related form of gamification we considered was replacing simple certfications with role-playing-game-style Experience Levels. Instead of just knowing an admin passed a test establishing a given level of competency, these would provide recruiters with a more detailed level of how much real-world experience an admin has. Achievements such as the one above would feed into it, but larger numbers of experience points would be gained by tougher or more critical tasks - such as recovering a down system, or migrating a service to a new platform. (As long as it was an Oracle platform of course - migrating to an HP or IBM platform would cause the admin to lose points with us.) Unfortunately, we couldn't figure out a good way to prevent (if you will) “gaming” the system. For instance, a disgruntled admin might decide to start ignoring warnings from FMA that a part is beginning to fail or skip preventative maintenance, in the hopes that they'd cause a catastrophic failure to earn more points for bolstering their resume as they look for a job elsewhere, and not worrying about the effect on your business of a mission critical server going down. More Z's for ZFS Our suggested new feature for ZFS was inspired by the worlds most successful Z-startup of all time: Zynga. Using the Social Network Utility For Facebook described above, we'd tie it in with ZFS monitoring to help you out when you find yourself in a jam needing more disk space than you have, and can't wait a month to get a purchase order through channels to buy more. Instead with the click of a button you could post to your group: Alan can't find any space in his server farm! Can you help? Friends could loan you some space on their connected servers for a few weeks, knowing that you'd return the favor when needed. ZFS would create a new filesystem for your use on their system, and securely share it with your system using Kerberized NFS. If none of your friends have space, then you could buy temporary use space in small increments at affordable rates right there in Facebook, using your Facebook credits, and then file an expense report later, after the urgent need has passed. Universal Single Sign On One thing all the engineers agreed on was that we still had far too many "Single" sign ons to deal with in our daily work. On the web, every web site used to have its own password database, forcing us to hope we could remember what login name was still available on each site when we signed up, and which unique password we came up with to avoid having to disclose our other passwords to a new site. In recent years, the web services world has finally been reducing the number of logins we have to manage, with many services allowing you to login using your identity from Google, Twitter or Facebook. So we proposed following their lead, introducing PAM modules for web services - no more would you have to type in whatever login name IT assigned and try to remember the password you chose the last time password aging forced you to change it - you'd simply choose which web service you wanted to authenticate against, and would login to your Solaris account upon reciept of a cookie from their identity service. Pinning notes to the cloud We also all noted that we all have our own pile of notes we keep in our daily work - in text files in our home directory, in notebooks we carry around, on white boards in offices and common areas, on sticky notes on our monitors, or on scraps of paper pinned to our bulletin boards. The contents of the notes vary, some are things just for us, some are useful for our groups, some we would share with the world. For instance, when our group moved to a new building a couple years ago, we had a white board in the hallway listing all the NIS & DNS servers, subnets, and other network configuration information we needed to set up our Solaris machines after the move. Similarly, as Solaris 11 was finishing and we were all learning the new network configuration commands, we shared notes in wikis and e-mails with our fellow engineers. Users may also remember one of the popular features of Sun's old BigAdmin site was a section for sharing scripts and tips such as these. Meanwhile, the online "pin board" at Pinterest is taking the web by storm. So we thought, why not mash those up to solve this problem? We proposed a new BigAddPin site where users could “pin” notes, command snippets, configuration information, and so on. For instance, once they had worked out the ideal Automated Installation manifest for their app server, they could pin it up to share with the rest of their group, or choose to make it public as an example for the world. Localized data, such as our group's notes on the servers for our subnet, could be shared only to users connecting from that subnet. And notes that they didn't want others to see at all could be marked private, such as the list of phone numbers to call for late night pizza delivery to the machine room, the birthdays and anniversaries they can never remember but would be sleeping on the couch if they forgot, or the list of automatically generated completely random, impossible to remember root passwords to all their servers. For greater integration with Solaris, we'd put support right into the command shells — redirect output to a pinned note, set your path to include pinned notes as scripts you can run, or bring up your recent shell history and pin a set of commands to save for the next time you need to remember how to do that operation. Location service for Solaris servers A longer term plan would involve convincing the hardware design groups to put GPS locators with wireless transmitters in future server designs. This would help both admins and service personnel trying to find servers in todays massive data centers, and could feed into location presence apps to help show potential customers that while they may not see many Solaris machines on the desktop any more, they are all around. For instance, while walking down Wall Street it might show “There are over 2000 Solaris computers in this block.” [Note: this proposal was made before the recent media coverage of a location service aggregrator app with less noble intentions, and in hindsight, we failed to consider what happens when such data similarly falls into the wrong hands. We certainly wouldn't want our app to be misinterpreted as “There are over $20 million dollars of SPARC servers in this building, waiting for you to steal them.” so it's probably best it was rejected.] Harnessing the power of the GPU for Security Most modern OS'es make use of the widespread availability of high powered GPU hardware in today's computers, with desktop environments requiring 3-D graphics acceleration, whether in Ubuntu Unity, GNOME Shell on Fedora, or Aero Glass on Windows, but we haven't yet made Solaris fully take advantage of this, beyond our basic offering of Compiz on the desktop. Meanwhile, more businesses are interested in increasing security by using biometric authentication, but must also comply with laws in many countries preventing discrimination against employees with physical limations such as missing eyes or fingers, not to mention the lost productivity when employees can't login due to tinted contacts throwing off a retina scan or a paper cut changing their fingerprint appearance until it heals. Fortunately, the two groups considering these problems put their heads together and found a common solution, using 3D technology to enable authentication using the one body part all users are guaranteed to have - pam_phrenology.so, a new PAM module that uses an array USB attached web cams (or just one if the user is willing to spin their chair during login) to take pictures of the users head from all angles, create a 3D model and compare it to the one in the authentication database. While Mythbusters has shown how easy it can be to fool common fingerprint scanners, we have not yet seen any evidence that people can impersonate the shape of another user's cranium, no matter how long they spend beating their head against the wall to reshape it. This could possibly be extended to group users, using modern versions of some of the older phrenological studies, such as giving all users with long grey beards access to the System Architect role, or automatically placing users with pointy spikes in their hair into an easy use mode. Unfortunately, there are still some unsolved technical challenges we haven't figured out how to overcome. Currently, a visit to the hair salon causes your existing authentication to expire, and some users have found that shaving their heads is the only way to avoid bad hair days becoming bad login days. Reaction to these ideas After gathering all our notes on these ideas from the engineering brainstorming meeting, we took them in to present to our management. Unfortunately, most of their reaction cannot be printed here, and they chose not to accept any of these ideas as they were, but they did have some feedback for us to consider as they sent us back to the drawing board. They strongly suggested our ideas would be better presented if we weren't trying to decipher ink blotches that had been smeared by the condensation when we put our pint glasses on the napkins we were taking notes on, and to that end let us know they would not be approving any more engineering offsites in Irish themed pubs on the Friday of a Saint Patrick's Day weekend. (Hopefully they mean that situation specifically and aren't going to deny the funding for travel to this year's X.Org Developer's Conference just because it happens to be in Bavaria and ending on the Friday of the weekend Oktoberfest starts.) They recommended our research techniques could be improved over just sitting around reading blogs and checking our Facebook, Twitter, and Pinterest accounts, such as considering input from alternate viewpoints on topics such as gamification. They also mentioned that Oracle hadn't fully adopted some of Sun's common practices and we might have to try harder to get those to be accepted now that we are one unified company. So as I said at the beginning, don't pester your sales rep just yet for any of these, since they didn't get approved, but if you have better ideas, pass them on and maybe they'll get into our next batch of planning.

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A few questions about integrating AudioKinetic Wwise and Unity

- by SaldaVonSchwartz

I'm new to Wwise and to using it with Unity, and though I have gotten the integration to work, I'm still dealing with some loose ends and have a few questions: (I'm on Unity 4.3 as of now but I think it shouldn't make any difference) The base path: The Wwise documentation implies you set this in the AkGlobalSoundEngineInitializer basePath public ivar, which is exposed to the editor. However, I found that this variable is not really used. Instead, the path is hardcoded to /Audio/GeneratedSoundBanks in AkBankPath. I had to modify both scripts to actually look in the path that I set in the editor property. What's the deal with this? Just sloppyness or am I missing something? Also about paths: since I'm on Mac, I'm using Unity natively under OS X and in tadem, the Wwise authoring tool via VMWare and I share the OS X Unity project folder so I can generate the soundbanks into the assets folder. However, the authoring tool (downloaded the latest one for Windows) doesn't automatically generate any "platform-specific" subfolders for my wwise files. That is, again, the Unity integration scripts assume the path to be /Audio/GeneratedSoundBanks/<my-platform>/ which in my case would be Mac (I set the authoring tool to generate for Mac). The documentation says wwise will automatically generate the platform-specific folders but it just dumps all the stuff in GeneratedSoundBanks. Am I missing some setting? cause right now I just manually create the /Mac folder. The C# methods AkSoundEngine.PostEvent and AkSoundEngine.LoadBank for instance, have a few overloads, including ones where I can refer to the soundbanks or events by their ID. However, if I try to use these, for instance: AkSoundEngine.LoadBank(, AkSoundEngine.AK_DEFAULT_POOL_ID) where the int I got from the .h header, I get Ak_Fail. If I use the overloads that reference the objects by string name then it works. What gives? Converting the ID header to C#: The integration comes with a C# script that seems to fork a process to call Python in turn to covert the C++ header into a C# script. This always fails unless I manually execute the Python script myself from outside Unity. Might be a permissions thing, but has anyone experienced this? The Profiler: I set up the Unity player to run in the background and am using the "Profile" version of the plugin. However, when I start the Unity OS X standalone app, the profiler in VMWare does not see it. This I'm thinking might just be that I'm trying to see a running instance of the sound engine inside an OS X binary from a Windows virtual machine. But I'm just wondering if anyone has gotten the Windows profiler to see an OS X Unity binary. Different versions of the integration plugin: It's not clear to me from the documentation whether I have to manually (or write a script to do it) remove the "Profile" version and install the "Release" version when I'm going to do a Release build or if I should install both version in Unity and it'll select the right one. Thanks!

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Can't specify window's class in CCSM's Place Windows

- by Anto

Following this method, I wanted to "place" some of my windows on specific viewports. For instance, I want Xchat to always start on my top right viewport (x=2, y=1). But after I have set everything up and clicked the "Close" button to validate it (I don't have any other action button, like "OK" or "Apply"), the only thing that get saved up are the viewport X and Y coordinates. The window class (in my case class=Xchat) remains empty. This bug only occurs in the "Windows with fixed viewport" section; it works well in the "Windows with fixed placement mode", for instance. How can I solve or circumvent this issue ?

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ResponseStatusLine protocol violation

- by Tom Hines

I parse/scrape a few web page every now and then and recently ran across an error that stated: "The server committed a protocol violation. Section=ResponseStatusLine". After a few web searches, I found a couple of suggestions – one of which said the problem could be fixed by changing the HttpWebRequest ProtocolVersion to 1.0 with the command: 1: HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(strURI); 2: req.ProtocolVersion = HttpVersion.Version10; …but that did not work in my particular case. What DID work was the next suggestion I found that suggested the use of the setting: “useUnsafeHeaderParsing” either in the app.config file or programmatically. If added to the app.config, it would be: 1:  2: <system.net> 3: <settings> 4: <httpWebRequest useUnsafeHeaderParsing ="true"/> 5: </settings> 6: </system.net> If done programmatically, it would look like this: C++: 1: // UUHP_CPP.h 2: #pragma once 3: using namespace System; 4: using namespace System::Reflection; 5: 6: namespace UUHP_CPP 7: { 8: public ref class CUUHP_CPP 9: { 10: public: 11: static bool UseUnsafeHeaderParsing(String^% strError) 12: { 13: Assembly^ assembly = Assembly::GetAssembly(System::Net::Configuration::SettingsSection::typeid); //__typeof 14: if (nullptr==assembly) 15: { 16: strError = "Could not access Assembly"; 17: return false; 18: } 19: 20: Type^ type = assembly->GetType("System.Net.Configuration.SettingsSectionInternal"); 21: if (nullptr==type) 22: { 23: strError = "Could not access internal settings"; 24: return false; 25: } 26: 27: Object^ obj = type->InvokeMember("Section", 28: BindingFlags::Static | BindingFlags::GetProperty | BindingFlags::NonPublic, 29: nullptr, nullptr, gcnew array<Object^,1>(0)); 30: 31: if(nullptr == obj) 32: { 33: strError = "Could not invoke Section member"; 34: return false; 35: } 36: 37: FieldInfo^ fi = type->GetField("useUnsafeHeaderParsing", BindingFlags::NonPublic | BindingFlags::Instance); 38: if(nullptr == fi) 39: { 40: strError = "Could not access useUnsafeHeaderParsing field"; 41: return false; 42: } 43: 44: if (!(bool)fi->GetValue(obj)) 45: { 46: fi->SetValue(obj, true); 47: } 48: 49: return true; 50: } 51: }; 52: } C# (CSharp): 1: using System; 2: using System.Reflection; 3: 4: namespace UUHP_CS 5: { 6: public class CUUHP_CS 7: { 8: public static bool UseUnsafeHeaderParsing(ref string strError) 9: { 10: Assembly assembly = Assembly.GetAssembly(typeof(System.Net.Configuration.SettingsSection)); 11: if (null == assembly) 12: { 13: strError = "Could not access Assembly"; 14: return false; 15: } 16: 17: Type type = assembly.GetType("System.Net.Configuration.SettingsSectionInternal"); 18: if (null == type) 19: { 20: strError = "Could not access internal settings"; 21: return false; 22: } 23: 24: object obj = type.InvokeMember("Section", 25: BindingFlags.Static | BindingFlags.GetProperty | BindingFlags.NonPublic, 26: null, null, new object[] { }); 27: 28: if (null == obj) 29: { 30: strError = "Could not invoke Section member"; 31: return false; 32: } 33: 34: // If it's not already set, set it. 35: FieldInfo fi = type.GetField("useUnsafeHeaderParsing", BindingFlags.NonPublic | BindingFlags.Instance); 36: if (null == fi) 37: { 38: strError = "Could not access useUnsafeHeaderParsing field"; 39: return false; 40: } 41: 42: if (!Convert.ToBoolean(fi.GetValue(obj))) 43: { 44: fi.SetValue(obj, true); 45: } 46: 47: return true; 48: } 49: } 50: } F# (FSharp): 1: namespace UUHP_FS 2: open System 3: open System.Reflection 4: module CUUHP_FS = 5: let UseUnsafeHeaderParsing(strError : byref<string>) : bool = 6: // 7: let assembly : Assembly = Assembly.GetAssembly(typeof<System.Net.Configuration.SettingsSection>) 8: if (null = assembly) then 9: strError <- "Could not access Assembly" 10: false 11: else 12: 13: let myType : Type = assembly.GetType("System.Net.Configuration.SettingsSectionInternal") 14: if (null = myType) then 15: strError <- "Could not access internal settings" 16: false 17: else 18: 19: let obj : Object = myType.InvokeMember("Section", BindingFlags.Static ||| BindingFlags.GetProperty ||| BindingFlags.NonPublic, null, null, Array.zeroCreate 0) 20: if (null = obj) then 21: strError <- "Could not invoke Section member" 22: false 23: else 24: 25: // If it's not already set, set it. 26: let fi : FieldInfo = myType.GetField("useUnsafeHeaderParsing", BindingFlags.NonPublic ||| BindingFlags.Instance) 27: if(null = fi) then 28: strError <- "Could not access useUnsafeHeaderParsing field" 29: false 30: else 31: 32: if (not(Convert.ToBoolean(fi.GetValue(obj)))) then 33: fi.SetValue(obj, true) 34: 35: // Now return true 36: true VB (Visual Basic): 1: Option Explicit On 2: Option Strict On 3: Imports System 4: Imports System.Reflection 5: 6: Public Class CUUHP_VB 7: Public Shared Function UseUnsafeHeaderParsing(ByRef strError As String) As Boolean 8: 9: Dim assembly As [Assembly] 10: assembly = [assembly].GetAssembly(GetType(System.Net.Configuration.SettingsSection)) 11: 12: If (assembly Is Nothing) Then 13: strError = "Could not access Assembly" 14: Return False 15: End If 16: 17: Dim type As Type 18: type = [assembly].GetType("System.Net.Configuration.SettingsSectionInternal") 19: If (type Is Nothing) Then 20: strError = "Could not access internal settings" 21: Return False 22: End If 23: 24: Dim obj As Object 25: obj = [type].InvokeMember("Section", _ 26: BindingFlags.Static Or BindingFlags.GetProperty Or BindingFlags.NonPublic, _ 27: Nothing, Nothing, New [Object]() {}) 28: 29: If (obj Is Nothing) Then 30: strError = "Could not invoke Section member" 31: Return False 32: End If 33: 34: ' If it's not already set, set it. 35: Dim fi As FieldInfo 36: fi = [type].GetField("useUnsafeHeaderParsing", BindingFlags.NonPublic Or BindingFlags.Instance) 37: If (fi Is Nothing) Then 38: strError = "Could not access useUnsafeHeaderParsing field" 39: Return False 40: End If 41: 42: If (Not Convert.ToBoolean(fi.GetValue(obj))) Then 43: fi.SetValue(obj, True) 44: End If 45: 46: Return True 47: End Function 48: End Class Technorati Tags: C++,CPP,VB,Visual Basic,F#,FSharp,C#,CSharp,ResponseStatusLine,protocol violation

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C#/.NET Little Wonders: The Generic Func 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. Back in one of my three original “Little Wonders” Trilogy of posts, I had listed generic delegates as one of the Little Wonders of .NET. Later, someone posted a comment saying said that they would love more detail on the generic delegates and their uses, since my original entry just scratched the surface of them. Last week, I began our look at some of the handy generic delegates built into .NET with a description of delegates in general, and the Action family of delegates. For this week, I’ll launch into a look at the Func family of generic delegates and how they can be used to support generic, reusable algorithms and classes. Quick Delegate Recap Delegates are similar to function pointers in C++ in that they allow you to store a reference to a method. They can store references to either static or instance methods, and can actually be used to chain several methods together in one delegate. Delegates are very type-safe and can be satisfied with any standard method, anonymous method, or a lambda expression. They can also be null as well (refers to no method), so care should be taken to make sure that the delegate is not null before you invoke it. Delegates are defined using the keyword delegate, where the delegate’s type name is placed where you would typically place the method name: 1: // This delegate matches any method that takes string, returns nothing 2: public delegate void Log(string message); This delegate defines a delegate type named Log that can be used to store references to any method(s) that satisfies its signature (whether instance, static, lambda expression, etc.). Delegate instances then can be assigned zero (null) or more methods using the operator = which replaces the existing delegate chain, or by using the operator += which adds a method to the end of a delegate chain: 1: // creates a delegate instance named currentLogger defaulted to Console.WriteLine (static method) 2: Log currentLogger = Console.Out.WriteLine; 3: 4: // invokes the delegate, which writes to the console out 5: currentLogger("Hi Standard Out!"); 6: 7: // append a delegate to Console.Error.WriteLine to go to std error 8: currentLogger += Console.Error.WriteLine; 9: 10: // invokes the delegate chain and writes message to std out and std err 11: currentLogger("Hi Standard Out and Error!"); While delegates give us a lot of power, it can be cumbersome to re-create fairly standard delegate definitions repeatedly, for this purpose the generic delegates were introduced in various stages in .NET. These support various method types with particular signatures. Note: a caveat with generic delegates is that while they can support multiple parameters, they do not match methods that contains ref or out parameters. If you want to a delegate to represent methods that takes ref or out parameters, you will need to create a custom delegate. We’ve got the Func… delegates Just like it’s cousin, the Action delegate family, the Func delegate family gives us a lot of power to use generic delegates to make classes and algorithms more generic. Using them keeps us from having to define a new delegate type when need to make a class or algorithm generic. Remember that the point of the Action delegate family was to be able to perform an “action” on an item, with no return results. Thus Action delegates can be used to represent most methods that take 0 to 16 arguments but return void. You can assign a method The Func delegate family was introduced in .NET 3.5 with the advent of LINQ, and gives us the power to define a function that can be called on 0 to 16 arguments and returns a result. Thus, the main difference between Action and Func, from a delegate perspective, is that Actions return nothing, but Funcs return a result. The Func family of delegates have signatures as follows: Func<TResult> – matches a method that takes no arguments, and returns value of type TResult. Func<T, TResult> – matches a method that takes an argument of type T, and returns value of type TResult. Func<T1, T2, TResult> – matches a method that takes arguments of type T1 and T2, and returns value of type TResult. Func<T1, T2, …, TResult> – and so on up to 16 arguments, and returns value of type TResult. These are handy because they quickly allow you to be able to specify that a method or class you design will perform a function to produce a result as long as the method you specify meets the signature. For example, let’s say you were designing a generic aggregator, and you wanted to allow the user to define how the values will be aggregated into the result (i.e. Sum, Min, Max, etc…). To do this, we would ask the user of our class to pass in a method that would take the current total, the next value, and produce a new total. A class like this could look like: 1: public sealed class Aggregator<TValue, TResult> 2: { 3: // holds method that takes previous result, combines with next value, creates new result 4: private Func<TResult, TValue, TResult> _aggregationMethod; 5: 6: // gets or sets the current result of aggregation 7: public TResult Result { get; private set; } 8: 9: // construct the aggregator given the method to use to aggregate values 10: public Aggregator(Func<TResult, TValue, TResult> aggregationMethod = null) 11: { 12: if (aggregationMethod == null) throw new ArgumentNullException("aggregationMethod"); 13: 14: _aggregationMethod = aggregationMethod; 15: } 16: 17: // method to add next value 18: public void Aggregate(TValue nextValue) 19: { 20: // performs the aggregation method function on the current result and next and sets to current result 21: Result = _aggregationMethod(Result, nextValue); 22: } 23: } Of course, LINQ already has an Aggregate extension method, but that works on a sequence of IEnumerable<T>, whereas this is designed to work more with aggregating single results over time (such as keeping track of a max response time for a service). We could then use this generic aggregator to find the sum of a series of values over time, or the max of a series of values over time (among other things): 1: // creates an aggregator that adds the next to the total to sum the values 2: var sumAggregator = new Aggregator<int, int>((total, next) => total + next); 3: 4: // creates an aggregator (using static method) that returns the max of previous result and next 5: var maxAggregator = new Aggregator<int, int>(Math.Max); So, if we were timing the response time of a web method every time it was called, we could pass that response time to both of these aggregators to get an idea of the total time spent in that web method, and the max time spent in any one call to the web method: 1: // total will be 13 and max 13 2: int responseTime = 13; 3: sumAggregator.Aggregate(responseTime); 4: maxAggregator.Aggregate(responseTime); 5: 6: // total will be 20 and max still 13 7: responseTime = 7; 8: sumAggregator.Aggregate(responseTime); 9: maxAggregator.Aggregate(responseTime); 10: 11: // total will be 40 and max now 20 12: responseTime = 20; 13: sumAggregator.Aggregate(responseTime); 14: maxAggregator.Aggregate(responseTime); The Func delegate family is useful for making generic algorithms and classes, and in particular allows the caller of the method or user of the class to specify a function to be performed in order to generate a result. What is the result of a Func delegate chain? If you remember, we said earlier that you can assign multiple methods to a delegate by using the += operator to chain them. So how does this affect delegates such as Func that return a value, when applied to something like the code below? 1: Func<int, int, int> combo = null; 2: 3: // What if we wanted to aggregate the sum and max together? 4: combo += (total, next) => total + next; 5: combo += Math.Max; 6: 7: // what is the result? 8: var comboAggregator = new Aggregator<int, int>(combo); Well, in .NET if you chain multiple methods in a delegate, they will all get invoked, but the result of the delegate is the result of the last method invoked in the chain. Thus, this aggregator would always result in the Math.Max() result. The other chained method (the sum) gets executed first, but it’s result is thrown away: 1: // result is 13 2: int responseTime = 13; 3: comboAggregator.Aggregate(responseTime); 4: 5: // result is still 13 6: responseTime = 7; 7: comboAggregator.Aggregate(responseTime); 8: 9: // result is now 20 10: responseTime = 20; 11: comboAggregator.Aggregate(responseTime); So remember, you can chain multiple Func (or other delegates that return values) together, but if you do so you will only get the last executed result. Func delegates and co-variance/contra-variance in .NET 4.0 Just like the Action delegate, as of .NET 4.0, the Func delegate family is contra-variant on its arguments. In addition, it is co-variant on its return type. To support this, in .NET 4.0 the signatures of the Func delegates changed to: Func<out TResult> – matches a method that takes no arguments, and returns value of type TResult (or a more derived type). Func<in T, out TResult> – matches a method that takes an argument of type T (or a less derived type), and returns value of type TResult(or a more derived type). Func<in T1, in T2, out TResult> – matches a method that takes arguments of type T1 and T2 (or less derived types), and returns value of type TResult (or a more derived type). Func<in T1, in T2, …, out TResult> – and so on up to 16 arguments, and returns value of type TResult (or a more derived type). Notice the addition of the in and out keywords before each of the generic type placeholders. As we saw last week, the in keyword is used to specify that a generic type can be contra-variant -- it can match the given type or a type that is less derived. However, the out keyword, is used to specify that a generic type can be co-variant -- it can match the given type or a type that is more derived. On contra-variance, if you are saying you need an function that will accept a string, you can just as easily give it an function that accepts an object. In other words, if you say “give me an function that will process dogs”, I could pass you a method that will process any animal, because all dogs are animals. On the co-variance side, if you are saying you need a function that returns an object, you can just as easily pass it a function that returns a string because any string returned from the given method can be accepted by a delegate expecting an object result, since string is more derived. Once again, in other words, if you say “give me a method that creates an animal”, I can pass you a method that will create a dog, because all dogs are animals. It really all makes sense, you can pass a more specific thing to a less specific parameter, and you can return a more specific thing as a less specific result. In other words, pay attention to the direction the item travels (parameters go in, results come out). Keeping that in mind, you can always pass more specific things in and return more specific things out. For example, in the code below, we have a method that takes a Func<object> to generate an object, but we can pass it a Func<string> because the return type of object can obviously accept a return value of string as well: 1: // since Func<object> is co-variant, this will access Func<string>, etc... 2: public static string Sequence(int count, Func<object> generator) 3: { 4: var builder = new StringBuilder(); 5: 6: for (int i=0; i<count; i++) 7: { 8: object value = generator(); 9: builder.Append(value); 10: } 11: 12: return builder.ToString(); 13: } Even though the method above takes a Func<object>, we can pass a Func<string> because the TResult type placeholder is co-variant and accepts types that are more derived as well: 1: // delegate that's typed to return string. 2: Func<string> stringGenerator = () => DateTime.Now.ToString(); 3: 4: // This will work in .NET 4.0, but not in previous versions 5: Sequence(100, stringGenerator); Previous versions of .NET implemented some forms of co-variance and contra-variance before, but .NET 4.0 goes one step further and allows you to pass or assign an Func<A, BResult> to a Func<Y, ZResult> as long as A is less derived (or same) as Y, and BResult is more derived (or same) as ZResult. Sidebar: The Func and the Predicate A method that takes one argument and returns a bool is generally thought of as a predicate. Predicates are used to examine an item and determine whether that item satisfies a particular condition. Predicates are typically unary, but you may also have binary and other predicates as well. Predicates are often used to filter results, such as in the LINQ Where() extension method: 1: var numbers = new[] { 1, 2, 4, 13, 8, 10, 27 }; 2: 3: // call Where() using a predicate which determines if the number is even 4: var evens = numbers.Where(num => num % 2 == 0); As of .NET 3.5, predicates are typically represented as Func<T, bool> where T is the type of the item to examine. Previous to .NET 3.5, there was a Predicate<T> type that tended to be used (which we’ll discuss next week) and is still supported, but most developers recommend using Func<T, bool> now, as it prevents confusion with overloads that accept unary predicates and binary predicates, etc.: 1: // this seems more confusing as an overload set, because of Predicate vs Func 2: public static SomeMethod(Predicate<int> unaryPredicate) { } 3: public static SomeMethod(Func<int, int, bool> binaryPredicate) { } 4: 5: // this seems more consistent as an overload set, since just uses Func 6: public static SomeMethod(Func<int, bool> unaryPredicate) { } 7: public static SomeMethod(Func<int, int, bool> binaryPredicate) { } Also, even though Predicate<T> and Func<T, bool> match the same signatures, they are separate types! Thus you cannot assign a Predicate<T> instance to a Func<T, bool> instance and vice versa: 1: // the same method, lambda expression, etc can be assigned to both 2: Predicate<int> isEven = i => (i % 2) == 0; 3: Func<int, bool> alsoIsEven = i => (i % 2) == 0; 4: 5: // but the delegate instances cannot be directly assigned, strongly typed! 6: // ERROR: cannot convert type... 7: isEven = alsoIsEven; 8: 9: // however, you can assign by wrapping in a new instance: 10: isEven = new Predicate<int>(alsoIsEven); 11: alsoIsEven = new Func<int, bool>(isEven); So, the general advice that seems to come from most developers is that Predicate<T> is still supported, but we should use Func<T, bool> for consistency in .NET 3.5 and above. Sidebar: Func as a Generator for Unit Testing One area of difficulty in unit testing can be unit testing code that is based on time of day. We’d still want to unit test our code to make sure the logic is accurate, but we don’t want the results of our unit tests to be dependent on the time they are run. One way (of many) around this is to create an internal generator that will produce the “current” time of day. This would default to returning result from DateTime.Now (or some other method), but we could inject specific times for our unit testing. Generators are typically methods that return (generate) a value for use in a class/method. For example, say we are creating a CacheItem<T> class that represents an item in the cache, and we want to make sure the item shows as expired if the age is more than 30 seconds. Such a class could look like: 1: // responsible for maintaining an item of type T in the cache 2: public sealed class CacheItem<T> 3: { 4: // helper method that returns the current time 5: private static Func<DateTime> _timeGenerator = () => DateTime.Now; 6: 7: // allows internal access to the time generator 8: internal static Func<DateTime> TimeGenerator 9: { 10: get { return _timeGenerator; } 11: set { _timeGenerator = value; } 12: } 13: 14: // time the item was cached 15: public DateTime CachedTime { get; private set; } 16: 17: // the item cached 18: public T Value { get; private set; } 19: 20: // item is expired if older than 30 seconds 21: public bool IsExpired 22: { 23: get { return _timeGenerator() - CachedTime > TimeSpan.FromSeconds(30.0); } 24: } 25: 26: // creates the new cached item, setting cached time to "current" time 27: public CacheItem(T value) 28: { 29: Value = value; 30: CachedTime = _timeGenerator(); 31: } 32: } Then, we can use this construct to unit test our CacheItem<T> without any time dependencies: 1: var baseTime = DateTime.Now; 2: 3: // start with current time stored above (so doesn't drift) 4: CacheItem<int>.TimeGenerator = () => baseTime; 5: 6: var target = new CacheItem<int>(13); 7: 8: // now add 15 seconds, should still be non-expired 9: CacheItem<int>.TimeGenerator = () => baseTime.AddSeconds(15); 10: 11: Assert.IsFalse(target.IsExpired); 12: 13: // now add 31 seconds, should now be expired 14: CacheItem<int>.TimeGenerator = () => baseTime.AddSeconds(31); 15: 16: Assert.IsTrue(target.IsExpired); Now we can unit test for 1 second before, 1 second after, 1 millisecond before, 1 day after, etc. Func delegates can be a handy tool for this type of value generation to support more testable code. Summary Generic delegates give us a lot of power to make truly generic algorithms and classes. The Func family of delegates is a great way to be able to specify functions to calculate a result based on 0-16 arguments. Stay tuned in the weeks that follow for other generic delegates in the .NET Framework! Tweet Technorati Tags: .NET, C#, CSharp, Little Wonders, Generics, Func, Delegates

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How to build a Singleton-like dependency injector replacement (Php)

- by Erparom

I know out there are a lot of excelent containers, even frameworks almost entirely DI based with good strong IoC classes. However, this doesn't help me to "define" a new pattern. (This is Php code but understandable to anyone) Supose we have: //Declares the singleton class bookSingleton { private $author; private static $bookInstance; private static $isLoaned = FALSE; //The private constructor private function __constructor() { $this->author = "Onecrappy Writer Ofcheap Novels"; } //Sets the global isLoaned state and also gets self instance public static function loanBook() { if (self::$isLoaned === FALSE) { //Book already taken, so return false return FALSE; } else { //Ok, not loaned, lets instantiate (if needed and loan) if (!isset(self::$bookInstance)) { self::$bookInstance = new BookSingleton(); } self::$isLoaned = TRUE; } } //Return loaned state to false, so another book reader can take the book public function returnBook() { $self::$isLoaned = FALSE; } public function getAuthor() { return $this->author; } } Then we get the singelton consumtion class: //Consumes the Singleton class BookBorrower() { private $borrowedBook; private $haveBookState; public function __construct() { this->haveBookState = FALSE; } //Use the singelton-pattern behavior public function borrowBook() { $this->borrowedBook = BookSingleton::loanBook(); //Check if was successfully borrowed if (!this->borrowedBook) { $this->haveBookState = FALSE; } else { $this->haveBookState = TRUE; } } public function returnBook() { $this->borrowedBook->returnBook(); $this->haveBookState = FALSE; } public function getBook() { if ($this->haveBookState) { return "The book is loaned, the author is" . $this->borrowedbook->getAuthor(); } else { return "I don't have the book, perhaps someone else took it"; } } } At last, we got a client, to test the behavior function __autoload($class) { require_once $class . '.php'; } function write ($whatever,$breaks) { for($break = 0;$break<$breaks;$break++) { $whatever .= "\n"; } echo nl2br($whatever); } write("Begin Singleton test", 2); $borrowerJuan = new BookBorrower(); $borrowerPedro = new BookBorrower(); write("Juan asks for the book", 1); $borrowerJuan->borrowBook(); write("Book Borrowed? ", 1); write($borrowerJuan->getAuthorAndTitle(),2); write("Pedro asks for the book", 1); $borrowerPedro->borrowBook(); write("Book Borrowed? ", 1); write($borrowerPedro->getAuthorAndTitle(),2); write("Juan returns the book", 1); $borrowerJuan->returnBook(); write("Returned Book Juan? ", 1); write($borrowerJuan->getAuthorAndTitle(),2); write("Pedro asks again for the book", 1); $borrowerPedro->borrowBook(); write("Book Borrowed? ", 1); write($borrowerPedro->getAuthorAndTitle(),2); This will end up in the expected behavior: Begin Singleton test Juan asks for the book Book Borrowed? The book is loaned, the author is = Onecrappy Writer Ofcheap Novels Pedro asks for the book Book Borrowed? I don't have the book, perhaps someone else took it Juan returns the book Returned Book Juan? I don't have the book, perhaps someone else took it Pedro asks again for the book Book Borrowed? The book is loaned, the author is = Onecrappy Writer Ofcheap Novels So I want to make a pattern based on the DI technique able to do exactly the same, but without singleton pattern. As far as I'm aware, I KNOW I must inject the book inside "borrowBook" function instead of taking a static instance: public function borrowBook(BookNonSingleton $book) { if (isset($this->borrowedBook) || $book->isLoaned()) { $this->haveBook = FALSE; return FALSE; } else { $this->borrowedBook = $book; $this->haveBook = TRUE; return TRUE; } } And at the client, just handle the book: $borrowerJuan = new BookBorrower(); $borrowerJuan-borrowBook(new NonSingletonBook()); Etc... and so far so good, BUT... Im taking the responsability of "single instance" to the borrower, instead of keeping that responsability inside the NonSingletonBook, that since it has not anymore a private constructor, can be instantiated as many times... making instances on each call. So, What does my NonSingletonBook class MUST be in order to never allow borrowers to have this same book twice? (aka) keep the single instance. Because the dependency injector part of the code (borrower) does not solve me this AT ALL. Is it needed the container with an "asShared" method builder with static behavior? No way to encapsulate this functionallity into the Book itself? "Hey Im a book and I shouldn't be instantiated more than once, I'm unique"

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Commands in Task-It - Part 2

Download Source Code NOTE: To run the source code provided you will need the recently released versions of Silverlight 4 and VisualStudio 2010, as well as WCF RIA Services. After downloading the source code be sure to set Commands2.Web as the StartUp Project and Default.aspx as the StartPage. In my last post, Commands in Task-It - Part 1, we looked at a very simple solution that demonstrated how a single command instance (SaveCommand) could be bound to two UI controls, a Button and a RadTreeViewItem. In this example we'll get more complex, binding a single command instance (MoveToCommand) will be bound to multiple RadMenuItems in a RadContextMenu that is tied to a RadGridView. This time we'll also set a separate CommandParameter on each RadMenuItem, so when the command is invoked, we will be able to use that parameter to determine what to do next. The user interface This screen ...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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LSP vs OCP / Liskov Substitution VS Open Close

- by Kolyunya

I am trying to understand the SOLID principles of OOP and I've come to the conclusion that LSP and OCP have some similarities (if not to say more). the open/closed principle states "software entities (classes, modules, functions, etc.) should be open for extension, but closed for modification". LSP in simple words states that any instance of Foo can be replaced with any instance of Bar which is derived from Foo and the program will work the same very way. I'm not a pro OOP programmer, but it seems to me that LSP is only possible if Bar, derived from Foo does not change anything in it but only extends it. That means that in particular program LSP is true only when OCP is true and OCP is true only if LSP is true. That means that they are equal. Correct me if I'm wrong. I really want to understand these ideas. Great thanks for an answer.

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Is it appropriate for a class to only be a collection of information with no logic?

- by qegal

Say I have a class Person that has instance variables age, weight, and height, and another class Fruit that has instance variables sugarContent and texture. The Person class has no methods save setters and getters, while the Fruit class has both setters and getters and logic methods like calculateSweetness. Is the Fruit class the type of class that is better practice than the Person class. What I mean by this is that the Person class seems like it doesn't have much purpose; it exists solely to organize data, while the Fruit class organizes data and actually contains methods for logic.

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Changes to File Store Provider in UCM PS3

- by Kevin Smith

In the recent PS3 release of UCM (11.1.1.4.0) there are some significant changes to the File Store Provider (FSP) configuration. For new PS3 installs (not upgrades from PS2) the FSP default storage rule includes a dispersion rule that will change the web-layout and vault paths by adding dispersion directories to the paths to limit the number of files in the vault and web-layout directories. What that means is that if you install a new PS3 UCM instance and migrate content in from a previous version of UCM the web URL will change. That is a critical problem for web sites and just general document management. See below for some details on the FSP configuration in PS3 and how you can change the default behavior. use the link below to read the rest of this post where I describe the issue in detaill and provide instructions for how to modify a PS3 instance to use the old format for the web-layout path.

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