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  • Persistence store in blackberry

    - by arunabha
    i am trying to save a simple string value "1".If i go back from one screen to another,its saving,but when i exit the app,and start again,i dont see that value being saved.I am implementing persistable interface.Can anyone suggest me where i am getting wrong import net.rim.device.api.util.Persistable; import net.rim.device.api.system.PersistentObject; import net.rim.device.api.system.PersistentStore; public class Persist implements Persistable { public static PersistentObject abc; public static String b; static { abc = PersistentStore.getPersistentObject(0xb92c8fe20b256b82L); } public static void data(){ synchronized (abc) { abc.setContents(1+""); abc.commit(); } } public static String getCurrQuestionNumber() { synchronized (abc) { System.out.println("new title is"+b); b= (String)abc.getContents(); System.out.println("title is"+b); return b; } } }

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  • Access Relationship Table in Grails

    - by WaZ
    Hi, I have the following domains classes: class Posts{ String Name String Country static hasMany = [tags:Tags] static constraints = { } } class Tags{ String Name static belongsTo = Posts static hasMany = [posts:Posts] static constraints = { } String toString() { "${TypeName}" } } Grails creates an another table in the database i.e. Posts_Tags. My requirement is: E.g. 1 post has 3 tags. So, in the Posts_Tags table there are 3 rows. How can I access the table Posts_Tags directly in my code so that I can manipulate the data or add some more fields to it.

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  • syntax error, unexpected '.', expecting ')'

    - by Jonathan
    Hi, I've got a problem when I'm calling a static var from another class. I get this pretty syntax error where php is unexpected the '.' Here is where I'm calling it : private $aLien = array( "menu1" => array("Accueil","statique/".Variable_init::$langue."/accueil.html",0,0), //This line "menu2" => array("Infos Pratiques","statique/".Variable_init::$langue."/info.html",0,0), "menu3" => array("Faire une réservation","statique/".Variable_init::$langue."/reserver.html",0,0), "menu4" => array("Pour Nous Joindre","statique/".Variable_init::$langue."/nousJoindre.html",0,0), "menu5" => array("Plan du site","statique/".Variable_init::$langue."/plansite.html",0,0) ); And here is my static var declaration from another class: class Variable_init implements iVariable_init{ public static $langue; public static $id_choix; public static $id_contenu;

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  • Is this a valid, lazy, thread-safe Singleton implementation for C#?

    - by Matthew
    I implemented a Singleton pattern like this: public sealed class MyClass { ... public static MyClass Instance { get { return SingletonHolder.instance; } } ... static class SingletonHolder { public static MyClass instance = new MyClass (); } } From Googling around for C# Singleton implementations, it doesn't seem like this is a common way to do things in C#. I found one similar implementation, but the SingletonHolder class wasn't static, and included an explicit (empty) static constructor. Is this a valid, lazy, thread-safe way to implement the Singleton pattern? Or is there something I'm missing?

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  • The ultimate c# file and directory utility library?

    - by Serge van den Oever
    I find myself writing file and directory utility functions all the time, and I was wondering if there is good file and directory library that already implements a more extensive set than available by default in System.IO. The kind of functions I'm looking for is things like: public static void GetTemporaryDirectory() { string tempDirectory = Path.Combine(Path.GetTempPath(), Path.GetRandomFileName()); Directory.CreateDirectory(tempDirectory); return tempDirectory; } public static void CreateEmptyFile(string filename) { File.Create(filename).Dispose(); } public static void CreateEmptyFile(string path, string filename) { File.Create(Path.Combine(path, filename)).Dispose(); } public static void CreateDirectory(string path) { Directory.CreateDirectory(path); } public static void CreateDirectory(string path, string childpath) { Directory.CreateDirectory(Path.Combine(path, childpath)); }

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  • INSERT SQL in Java

    - by Pierre
    Hello. I have a Java application and I want to use SQL database. I have a class for my connection : public class SQLConnection{ private static String url = "jdbc:postgresql://localhost:5432/table"; private static String user = "postgres"; private static String passwd = "toto"; private static Connection connect; public static Connection getInstance(){ if(connect == null){ try { connect = DriverManager.getConnection(url, user, passwd); } catch (SQLException e) { JOptionPane.showMessageDialog(null, e.getMessage(), "Connection Error", JOptionPane.ERROR_MESSAGE); } } return connect; } } And now, in another class I succeeded to print my values but when I attempt to insert a value nothing is happening ... Here's my code : try { Statement state = SQLConnection.getInstance().createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY); Statement state2 = SQLConnection.getInstance().createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE); state2.executeUpdate("INSERT INTO table(field1) VALUES (\"Value\")"); // Here's my problem ResultSet res = state.executeQuery("SELECT * FROM plateau");

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  • Is this method thread safe?

    - by user
    Are these methods getNewId() & fetchIdsInReserve() thread safe ? public final class IdManager { private static final int NO_OF_USERIDS_TO_KEEP_IN_RESERVE = 200; private static final AtomicInteger regstrdUserIdsCount_Cached = new AtomicInteger(100); private static int noOfUserIdsInReserveCurrently = 0; public static int getNewId(){ synchronized(IdManager.class){ if (noOfUserIdsInReserveCurrently <= 20) fetchIdsInReserve(); noOfUserIdsInReserveCurrently--; } return regstrdUserIdsCount_Cached.incrementAndGet(); } private static synchronized void fetchIdsInReserve(){ int reservedInDBTill = DBCountersReader.readCounterFromDB(....); // read column from DB if (noOfUserIdsInReserveCurrently + regstrdUserIdsCount_Cached.get() != reservedInDBTill) throw new Exception("Unreserved ids alloted by app before reserving from DB"); if (DBUpdater.incrementCounter(....)) //if write back to DB is successful noOfUserIdsInReserveCurrently += NO_OF_USERIDS_TO_KEEP_IN_RESERVE; } }

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  • How to create a new WCF/MVC/jQuery application from scratch

    - by pjohnson
    As a corporate developer by trade, I don't get much opportunity to create from-the-ground-up web sites; usually it's tweaks, fixes, and new functionality to existing sites. And with hobby sites, I often don't find the challenges I run into with enterprise systems; usually it's starting from Visual Studio's boilerplate project and adding whatever functionality I want to play around with, rarely deploying outside my own machine. So my experience creating a new enterprise-level site was a bit dated, and the technologies to do so have come a long way, and are much more ready to go out of the box. My intention with this post isn't so much to provide any groundbreaking insights, but to just tie together a lot of information in one place to make it easy to create a new site from scratch. Architecture One site I created earlier this year had an MVC 3 front end and a WCF 4-driven service layer. Using Visual Studio 2010, these project types are easy enough to add to a new solution. I created a third Class Library project to store common functionality the front end and services layers both needed to access, for example, the DataContract classes that the front end uses to call services in the service layer. By keeping DataContract classes in a separate project, I avoided the need for the front end to have an assembly/project reference directly to the services code, a bit cleaner and more flexible of an SOA implementation. Consuming the service Even by this point, VS has given you a lot. You have a working web site and a working service, neither of which do much but are great starting points. To wire up the front end and the services, I needed to create proxy classes and WCF client configuration information. I decided to use the SvcUtil.exe utility provided as part of the Windows SDK, which you should have installed if you installed VS. VS also provides an Add Service Reference command since the .NET 1.x ASMX days, which I've never really liked; it creates several .cs/.disco/etc. files, some of which contained hardcoded URL's, adding duplicate files (*1.cs, *2.cs, etc.) without doing a good job of cleaning up after itself. I've found SvcUtil much cleaner, as it outputs one C# file (containing several proxy classes) and a config file with settings, and it's easier to use to regenerate the proxy classes when the service changes, and to then maintain all your configuration in one place (your Web.config, instead of the Service Reference files). I provided it a reference to a copy of my common assembly so it doesn't try to recreate the data contract classes, had it use the type List<T> for collections, and modified the output files' names and .NET namespace, ending up with a command like: svcutil.exe /l:cs /o:MyService.cs /config:MyService.config /r:MySite.Common.dll /ct:System.Collections.Generic.List`1 /n:*,MySite.Web.ServiceProxies http://localhost:59999/MyService.svc I took the generated MyService.cs file and drop it in the web project, under a ServiceProxies folder, matching the namespace and keeping it separate from classes I coded manually. Integrating the config file took a little more work, but only needed to be done once as these settings didn't often change. A great thing Microsoft improved with WCF 4 is configuration; namely, you can use all the default settings and not have to specify them explicitly in your config file. Unfortunately, SvcUtil doesn't generate its config file this way. If you just copy & paste MyService.config's contents into your front end's Web.config, you'll copy a lot of settings you don't need, plus this will get unwieldy if you add more services in the future, each with its own custom binding. Really, as the only mandatory settings are the endpoint's ABC's (address, binding, and contract) you can get away with just this: <system.serviceModel>  <client>    <endpoint address="http://localhost:59999/MyService.svc" binding="wsHttpBinding" contract="MySite.Web.ServiceProxies.IMyService" />  </client></system.serviceModel> By default, the services project uses basicHttpBinding. As you can see, I switched it to wsHttpBinding, a more modern standard. Using something like netTcpBinding would probably be faster and more efficient since the client & service are both written in .NET, but it requires additional server setup and open ports, whereas switching to wsHttpBinding is much simpler. From an MVC controller action method, I instantiated the client, and invoked the method for my operation. As with any object that implements IDisposable, I wrapped it in C#'s using() statement, a tidy construct that ensures Dispose gets called no matter what, even if an exception occurs. Unfortunately there are problems with that, as WCF's ClientBase<TChannel> class doesn't implement Dispose according to Microsoft's own usage guidelines. I took an approach similar to Technology Toolbox's fix, except using partial classes instead of a wrapper class to extend the SvcUtil-generated proxy, making the fix more seamless from the controller's perspective, and theoretically, less code I have to change if and when Microsoft fixes this behavior. User interface The MVC 3 project template includes jQuery and some other common JavaScript libraries by default. I updated the ones I used to the latest versions using NuGet, available in VS via the Tools > Library Package Manager > Manage NuGet Packages for Solution... > Updates. I also used this dialog to remove packages I wasn't using. Given that it's smart enough to know the difference between the .js and .min.js files, I was hoping it would be smart enough to know which to include during build and publish operations, but this doesn't seem to be the case. I ended up using Cassette to perform the minification and bundling of my JavaScript and CSS files; ASP.NET 4.5 includes this functionality out of the box. The web client to web server link via jQuery was easy enough. In my JavaScript function, unobtrusively wired up to a button's click event, I called $.ajax, corresponding to an action method that returns a JsonResult, accomplished by passing my model class to the Controller.Json() method, which jQuery helpfully translates from JSON to a JavaScript object.$.ajax calls weren't perfectly straightforward. I tried using the simpler $.post method instead, but ran into trouble without specifying the contentType parameter, which $.post doesn't have. The url parameter is simple enough, though for flexibility in how the site is deployed, I used MVC's Url.Action method to get the URL, then sent this to JavaScript in a JavaScript string variable. If the request needed input data, I used the JSON.stringify function to convert a JavaScript object with the parameters into a JSON string, which MVC then parses into strongly-typed C# parameters. I also specified "json" for dataType, and "application/json; charset=utf-8" for contentType. For success and error, I provided my success and error handling functions, though success is a bit hairier. "Success" in this context indicates whether the HTTP request succeeds, not whether what you wanted the AJAX call to do on the web server was successful. For example, if you make an AJAX call to retrieve a piece of data, the success handler will be invoked for any 200 OK response, and the error handler will be invoked for failed requests, e.g. a 404 Not Found (if the server rejected the URL you provided in the url parameter) or 500 Internal Server Error (e.g. if your C# code threw an exception that wasn't caught). If an exception was caught and handled, or if the data requested wasn't found, this would likely go through the success handler, which would need to do further examination to verify it did in fact get back the data for which it asked. I discuss this more in the next section. Logging and exception handling At this point, I had a working application. If I ran into any errors or unexpected behavior, debugging was easy enough, but of course that's not an option on public web servers. Microsoft Enterprise Library 5.0 filled this gap nicely, with its Logging and Exception Handling functionality. First I installed Enterprise Library; NuGet as outlined above is probably the best way to do so. I needed a total of three assembly references--Microsoft.Practices.EnterpriseLibrary.ExceptionHandling, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Logging, and Microsoft.Practices.EnterpriseLibrary.Logging. VS links with the handy Enterprise Library 5.0 Configuration Console, accessible by right-clicking your Web.config and choosing Edit Enterprise Library V5 Configuration. In this console, under Logging Settings, I set up a Rolling Flat File Trace Listener to write to log files but not let them get too large, using a Text Formatter with a simpler template than that provided by default. Logging to a different (or additional) destination is easy enough, but a flat file suited my needs. At this point, I verified it wrote as expected by calling the Microsoft.Practices.EnterpriseLibrary.Logging.Logger.Write method from my C# code. With those settings verified, I went on to wire up Exception Handling with Logging. Back in the EntLib Configuration Console, under Exception Handling, I used a LoggingExceptionHandler, setting its Logging Category to the category I already had configured in the Logging Settings. Then, from code (e.g. a controller's OnException method, or any action method's catch block), I called the Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicy.HandleException method, providing the exception and the exception policy name I had configured in the Exception Handling Settings. Before I got this configured correctly, when I tried it out, nothing was logged. In working with .NET, I'm used to seeing an exception if something doesn't work or isn't set up correctly, but instead working with these EntLib modules reminds me more of JavaScript (before the "use strict" v5 days)--it just does nothing and leaves you to figure out why, I presume due in part to the listener pattern Microsoft followed with the Enterprise Library. First, I verified logging worked on its own. Then, verifying/correcting where each piece wires up to the next resolved my problem. Your C# code calls into the Exception Handling module, referencing the policy you pass the HandleException method; that policy's configuration contains a LoggingExceptionHandler that references a logCategory; that logCategory should be added in the loggingConfiguration's categorySources section; that category references a listener; that listener should be added in the loggingConfiguration's listeners section, which specifies the name of the log file. One final note on error handling, as the proper way to handle WCF and MVC errors is a whole other very lengthy discussion. For AJAX calls to MVC action methods, depending on your configuration, an exception thrown here will result in ASP.NET'S Yellow Screen Of Death being sent back as a response, which is at best unnecessarily and uselessly verbose, and at worst a security risk as the internals of your application are exposed to potential hackers. I mitigated this by overriding my controller's OnException method, passing the exception off to the Exception Handling module as above. I created an ErrorModel class with as few properties as possible (e.g. an Error string), sending as little information to the client as possible, to both maximize bandwidth and mitigate risk. I then return an ErrorModel in JSON format for AJAX requests: if (filterContext.HttpContext.Request.IsAjaxRequest()){    filterContext.Result = Json(new ErrorModel(...));    filterContext.ExceptionHandled = true;} My $.ajax calls from the browser get a valid 200 OK response and go into the success handler. Before assuming everything is OK, I check if it's an ErrorModel or a model containing what I requested. If it's an ErrorModel, or null, I pass it to my error handler. If the client needs to handle different errors differently, ErrorModel can contain a flag, error code, string, etc. to differentiate, but again, sending as little information back as possible is ideal. Summary As any experienced ASP.NET developer knows, this is a far cry from where ASP.NET started when I began working with it 11 years ago. WCF services are far more powerful than ASMX ones, MVC is in many ways cleaner and certainly more unit test-friendly than Web Forms (if you don't consider the code/markup commingling you're doing again), the Enterprise Library makes error handling and logging almost entirely configuration-driven, AJAX makes a responsive UI more feasible, and jQuery makes JavaScript coding much less painful. It doesn't take much work to get a functional, maintainable, flexible application, though having it actually do something useful is a whole other matter.

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  • how to use 3D map Actionscript class in mxml file for display map.

    - by nemade-vipin
    hello friends, I have created the application in which I have to use 3D map Action Script class in mxml file to display a map in form. that is in tab navigator last tab. My ActionScript 3D map class is(FlyingDirections):- package src.SBTSCoreObject { import src.SBTSCoreObject.JSONDecoder; import com.google.maps.InfoWindowOptions; import com.google.maps.LatLng; import com.google.maps.LatLngBounds; import com.google.maps.Map3D; import com.google.maps.MapEvent; import com.google.maps.MapOptions; import com.google.maps.MapType; import com.google.maps.MapUtil; import com.google.maps.View; import com.google.maps.controls.NavigationControl; import com.google.maps.geom.Attitude; import com.google.maps.interfaces.IPolyline; import com.google.maps.overlays.Marker; import com.google.maps.overlays.MarkerOptions; import com.google.maps.services.Directions; import com.google.maps.services.DirectionsEvent; import com.google.maps.services.Route; import flash.display.Bitmap; import flash.display.DisplayObject; import flash.display.DisplayObjectContainer; import flash.display.Loader; import flash.display.LoaderInfo; import flash.display.Sprite; import flash.events.Event; import flash.events.IOErrorEvent; import flash.events.MouseEvent; import flash.events.TimerEvent; import flash.filters.DropShadowFilter; import flash.geom.Point; import flash.net.URLLoader; import flash.net.URLRequest; import flash.net.navigateToURL; import flash.text.TextField; import flash.text.TextFieldAutoSize; import flash.text.TextFormat; import flash.utils.Timer; import flash.utils.getTimer; public class FlyingDirections extends Map3D { /** * Panoramio home page. */ private static const PANORAMIO_HOME:String = "http://www.panoramio.com/"; /** * The icon for the car. */ [Embed("assets/car-icon-24px.png")] private static const Car:Class; /** * The Panoramio icon. */ [Embed("assets/iw_panoramio.png")] private static const PanoramioIcon:Class; /** * We animate a zoom in to the start the route before the car starts * to move. This constant sets the time in seconds over which this * zoom occurs. */ private static const LEAD_IN_DURATION:Number = 3; /** * Duration of the trip in seconds. */ private static const TRIP_DURATION:Number = 40; /** * Constants that define the geometry of the Panoramio image markers. */ private static const BORDER_T:Number = 3; private static const BORDER_L:Number = 10; private static const BORDER_R:Number = 10; private static const BORDER_B:Number = 3; private static const GAP_T:Number = 2; private static const GAP_B:Number = 1; private static const IMAGE_SCALE:Number = 1; /** * Trajectory that the camera follows over time. Each element is an object * containing properties used to generate parameter values for flyTo(..). * fraction = 0 corresponds to the start of the trip; fraction = 1 * correspondsto the end of the trip. */ private var FLY_TRAJECTORY:Array = [ { fraction: 0, zoom: 6, attitude: new Attitude(0, 0, 0) }, { fraction: 0.2, zoom: 8.5, attitude: new Attitude(30, 30, 0) }, { fraction: 0.5, zoom: 9, attitude: new Attitude(30, 40, 0) }, { fraction: 1, zoom: 8, attitude: new Attitude(50, 50, 0) }, { fraction: 1.1, zoom: 8, attitude: new Attitude(130, 50, 0) }, { fraction: 1.2, zoom: 8, attitude: new Attitude(220, 50, 0) }, ]; /** * Number of panaramio photos for which we load data. We&apos;ll select a * subset of these approximately evenly spaced along the route. */ private static const NUM_GEOTAGGED_PHOTOS:int = 50; /** * Number of panaramio photos that we actually show. */ private static const NUM_SHOWN_PHOTOS:int = 7; /** * Scaling between real trip time and animation time. */ private static const SCALE_TIME:Number = 0.001; /** * getTimer() value at the instant that we start the trip. If this is 0 then * we have not yet started the car moving. */ private var startTimer:int = 0; /** * The current route. */ private var route:Route; /** * The polyline for the route. */ private var polyline:IPolyline; /** * The car marker. */ private var marker:Marker; /** * The cumulative duration in seconds over each step in the route. * cumulativeStepDuration[0] is 0; cumulativeStepDuration[1] adds the * duration of step 0; cumulativeStepDuration[2] adds the duration * of step 1; etc. */ private var cumulativeStepDuration:/*Number*/Array = []; /** * The cumulative distance in metres over each vertex in the route polyline. * cumulativeVertexDistance[0] is 0; cumulativeVertexDistance[1] adds the * distance to vertex 1; cumulativeVertexDistance[2] adds the distance to * vertex 2; etc. */ private var cumulativeVertexDistance:Array; /** * Array of photos loaded from Panoramio. This array has the same format as * the &apos;photos&apos; property within the JSON returned by the Panoramio API * (see http://www.panoramio.com/api/), with additional properties added to * individual photo elements to hold the loader structures that fetch * the actual images. */ private var photos:Array = []; /** * Array of polyline vertices, where each element is in world coordinates. * Several computations can be faster if we can use world coordinates * instead of LatLng coordinates. */ private var worldPoly:/*Point*/Array; /** * Whether the start button has been pressed. */ private var startButtonPressed:Boolean = false; /** * Saved event from onDirectionsSuccess call. */ private var directionsSuccessEvent:DirectionsEvent = null; /** * Start button. */ private var startButton:Sprite; /** * Alpha value used for the Panoramio image markers. */ private var markerAlpha:Number = 0; /** * Index of the current driving direction step. Used to update the * info window content each time we progress to a new step. */ private var currentStepIndex:int = -1; /** * The fly directions map constructor. * * @constructor */ public function FlyingDirections() { key="ABQIAAAA7QUChpcnvnmXxsjC7s1fCxQGj0PqsCtxKvarsoS-iqLdqZSKfxTd7Xf-2rEc_PC9o8IsJde80Wnj4g"; super(); addEventListener(MapEvent.MAP_PREINITIALIZE, onMapPreinitialize); addEventListener(MapEvent.MAP_READY, onMapReady); } /** * Handles map preintialize. Initializes the map center and zoom level. * * @param event The map event. */ private function onMapPreinitialize(event:MapEvent):void { setInitOptions(new MapOptions({ center: new LatLng(-26.1, 135.1), zoom: 4, viewMode: View.VIEWMODE_PERSPECTIVE, mapType:MapType.PHYSICAL_MAP_TYPE })); } /** * Handles map ready and looks up directions. * * @param event The map event. */ private function onMapReady(event:MapEvent):void { enableScrollWheelZoom(); enableContinuousZoom(); addControl(new NavigationControl()); // The driving animation will be updated on every frame. addEventListener(Event.ENTER_FRAME, enterFrame); addStartButton(); // We start the directions loading now, so that we&apos;re ready to go when // the user hits the start button. var directions:Directions = new Directions(); directions.addEventListener( DirectionsEvent.DIRECTIONS_SUCCESS, onDirectionsSuccess); directions.addEventListener( DirectionsEvent.DIRECTIONS_FAILURE, onDirectionsFailure); directions.load("48 Pirrama Rd, Pyrmont, NSW to Byron Bay, NSW"); } /** * Adds a big blue start button. */ private function addStartButton():void { startButton = new Sprite(); startButton.buttonMode = true; startButton.addEventListener(MouseEvent.CLICK, onStartClick); startButton.graphics.beginFill(0x1871ce); startButton.graphics.drawRoundRect(0, 0, 150, 100, 10, 10); startButton.graphics.endFill(); var startField:TextField = new TextField(); startField.autoSize = TextFieldAutoSize.LEFT; startField.defaultTextFormat = new TextFormat("_sans", 20, 0xffffff, true); startField.text = "Start!"; startButton.addChild(startField); startField.x = 0.5 * (startButton.width - startField.width); startField.y = 0.5 * (startButton.height - startField.height); startButton.filters = [ new DropShadowFilter() ]; var container:DisplayObjectContainer = getDisplayObject() as DisplayObjectContainer; container.addChild(startButton); startButton.x = 0.5 * (container.width - startButton.width); startButton.y = 0.5 * (container.height - startButton.height); var panoField:TextField = new TextField(); panoField.autoSize = TextFieldAutoSize.LEFT; panoField.defaultTextFormat = new TextFormat("_sans", 11, 0x000000, true); panoField.text = "Photos provided by Panoramio are under the copyright of their owners."; container.addChild(panoField); panoField.x = container.width - panoField.width - 5; panoField.y = 5; } /** * Handles directions success. Starts flying the route if everything * is ready. * * @param event The directions event. */ private function onDirectionsSuccess(event:DirectionsEvent):void { directionsSuccessEvent = event; flyRouteIfReady(); } /** * Handles click on the start button. Starts flying the route if everything * is ready. */ private function onStartClick(event:MouseEvent):void { startButton.removeEventListener(MouseEvent.CLICK, onStartClick); var container:DisplayObjectContainer = getDisplayObject() as DisplayObjectContainer; container.removeChild(startButton); startButtonPressed = true; flyRouteIfReady(); } /** * If we have loaded the directions and the start button has been pressed * start flying the directions route. */ private function flyRouteIfReady():void { if (!directionsSuccessEvent || !startButtonPressed) { return; } var directions:Directions = directionsSuccessEvent.directions; // Extract the route. route = directions.getRoute(0); // Draws the polyline showing the route. polyline = directions.createPolyline(); addOverlay(directions.createPolyline()); // Creates a car marker that is moved along the route. var car:DisplayObject = new Car(); marker = new Marker(route.startGeocode.point, new MarkerOptions({ icon: car, iconOffset: new Point(-car.width / 2, -car.height) })); addOverlay(marker); transformPolyToWorld(); createCumulativeArrays(); // Load Panoramio data for the region covered by the route. loadPanoramioData(directions.bounds); var duration:Number = route.duration; // Start a timer that will trigger the car moving after the lead in time. var leadInTimer:Timer = new Timer(LEAD_IN_DURATION * 1000, 1); leadInTimer.addEventListener(TimerEvent.TIMER, onLeadInDone); leadInTimer.start(); var flyTime:Number = -LEAD_IN_DURATION; // Set up the camera flight trajectory. for each (var flyStep:Object in FLY_TRAJECTORY) { var time:Number = flyStep.fraction * duration; var center:LatLng = latLngAt(time); var scaledTime:Number = time * SCALE_TIME; var zoom:Number = flyStep.zoom; var attitude:Attitude = flyStep.attitude; var elapsed:Number = scaledTime - flyTime; flyTime = scaledTime; flyTo(center, zoom, attitude, elapsed); } } /** * Loads Panoramio data for the route bounds. We load data about more photos * than we need, then select a subset lying along the route. * @param bounds Bounds within which to fetch images. */ private function loadPanoramioData(bounds:LatLngBounds):void { var params:Object = { order: "popularity", set: "full", from: "0", to: NUM_GEOTAGGED_PHOTOS.toString(10), size: "small", minx: bounds.getWest(), miny: bounds.getSouth(), maxx: bounds.getEast(), maxy: bounds.getNorth() }; var loader:URLLoader = new URLLoader(); var request:URLRequest = new URLRequest( "http://www.panoramio.com/map/get_panoramas.php?" + paramsToString(params)); loader.addEventListener(Event.COMPLETE, onPanoramioDataLoaded); loader.addEventListener(IOErrorEvent.IO_ERROR, onPanoramioDataFailed); loader.load(request); } /** * Transforms the route polyline to world coordinates. */ private function transformPolyToWorld():void { var numVertices:int = polyline.getVertexCount(); worldPoly = new Array(numVertices); for (var i:int = 0; i < numVertices; ++i) { var vertex:LatLng = polyline.getVertex(i); worldPoly[i] = fromLatLngToPoint(vertex, 0); } } /** * Returns the time at which the route approaches closest to the * given point. * @param world Point in world coordinates. * @return Route time at which the closest approach occurs. */ private function getTimeOfClosestApproach(world:Point):Number { var minDistSqr:Number = Number.MAX_VALUE; var numVertices:int = worldPoly.length; var x:Number = world.x; var y:Number = world.y; var minVertex:int = 0; for (var i:int = 0; i < numVertices; ++i) { var dx:Number = worldPoly[i].x - x; var dy:Number = worldPoly[i].y - y; var distSqr:Number = dx * dx + dy * dy; if (distSqr < minDistSqr) { minDistSqr = distSqr; minVertex = i; } } return cumulativeVertexDistance[minVertex]; } /** * Returns the array index of the first element that compares greater than * the given value. * @param ordered Ordered array of elements. * @param value Value to use for comparison. * @return Array index of the first element that compares greater than * the given value. */ private function upperBound(ordered:Array, value:Number, first:int=0, last:int=-1):int { if (last < 0) { last = ordered.length; } var count:int = last - first; var index:int; while (count > 0) { var step:int = count >> 1; index = first + step; if (value >= ordered[index]) { first = index + 1; count -= step - 1; } else { count = step; } } return first; } /** * Selects up to a given number of photos approximately evenly spaced along * the route. * @param ordered Array of photos, each of which is an object with * a property &apos;closestTime&apos;. * @param number Number of photos to select. */ private function selectEvenlySpacedPhotos(ordered:Array, number:int):Array { var start:Number = cumulativeVertexDistance[0]; var end:Number = cumulativeVertexDistance[cumulativeVertexDistance.length - 2]; var closestTimes:Array = []; for each (var photo:Object in ordered) { closestTimes.push(photo.closestTime); } var selectedPhotos:Array = []; for (var i:int = 0; i < number; ++i) { var idealTime:Number = start + ((end - start) * (i + 0.5) / number); var index:int = upperBound(closestTimes, idealTime); if (index < 1) { index = 0; } else if (index >= ordered.length) { index = ordered.length - 1; } else { var errorToPrev:Number = Math.abs(idealTime - closestTimes[index - 1]); var errorToNext:Number = Math.abs(idealTime - closestTimes[index]); if (errorToPrev < errorToNext) { --index; } } selectedPhotos.push(ordered[index]); } return selectedPhotos; } /** * Handles completion of loading the Panoramio index data. Selects from the * returned photo indices a subset of those that lie along the route and * initiates load of each of these. * @param event Load completion event. */ private function onPanoramioDataLoaded(event:Event):void { var loader:URLLoader = event.target as URLLoader; var decoder:JSONDecoder = new JSONDecoder(loader.data as String); var allPhotos:Array = decoder.getValue().photos; for each (var photo:Object in allPhotos) { var latLng:LatLng = new LatLng(photo.latitude, photo.longitude); photo.closestTime = getTimeOfClosestApproach(fromLatLngToPoint(latLng, 0)); } allPhotos.sortOn("closestTime", Array.NUMERIC); photos = selectEvenlySpacedPhotos(allPhotos, NUM_SHOWN_PHOTOS); for each (photo in photos) { var photoLoader:Loader = new Loader(); // The images aren&apos;t on panoramio.com: we can&apos;t acquire pixel access // using "new LoaderContext(true)". photoLoader.load( new URLRequest(photo.photo_file_url)); photo.loader = photoLoader; // Save the loader info: we use this to find the original element when // the load completes. photo.loaderInfo = photoLoader.contentLoaderInfo; photoLoader.contentLoaderInfo.addEventListener( Event.COMPLETE, onPhotoLoaded); } } /** * Creates a MouseEvent listener function that will navigate to the given * URL in a new window. * @param url URL to which to navigate. */ private function createOnClickUrlOpener(url:String):Function { return function(event:MouseEvent):void { navigateToURL(new URLRequest(url)); }; } /** * Handles completion of loading an individual Panoramio image. * Adds a custom marker that displays the image. Initially this is made * invisible so that it can be faded in as needed. * @param event Load completion event. */ private function onPhotoLoaded(event:Event):void { var loaderInfo:LoaderInfo = event.target as LoaderInfo; // We need to find which photo element this image corresponds to. for each (var photo:Object in photos) { if (loaderInfo == photo.loaderInfo) { var imageMarker:Sprite = createImageMarker(photo.loader, photo.owner_name, photo.owner_url); var options:MarkerOptions = new MarkerOptions({ icon: imageMarker, hasShadow: true, iconAlignment: MarkerOptions.ALIGN_BOTTOM | MarkerOptions.ALIGN_LEFT }); var latLng:LatLng = new LatLng(photo.latitude, photo.longitude); var marker:Marker = new Marker(latLng, options); photo.marker = marker; addOverlay(marker); // A hack: we add the actual image after the overlay has been added, // which creates the shadow, so that the shadow is valid even if we // don&apos;t have security privileges to generate the shadow from the // image. marker.foreground.visible = false; marker.shadow.alpha = 0; var imageHolder:Sprite = new Sprite(); imageHolder.addChild(photo.loader); imageHolder.buttonMode = true; imageHolder.addEventListener( MouseEvent.CLICK, createOnClickUrlOpener(photo.photo_url)); imageMarker.addChild(imageHolder); return; } } trace("An image was loaded which could not be found in the photo array."); } /** * Creates a custom marker showing an image. */ private function createImageMarker(child:DisplayObject, ownerName:String, ownerUrl:String):Sprite { var content:Sprite = new Sprite(); var panoramioIcon:Bitmap = new PanoramioIcon(); var iconHolder:Sprite = new Sprite(); iconHolder.addChild(panoramioIcon); iconHolder.buttonMode = true; iconHolder.addEventListener(MouseEvent.CLICK, onPanoramioIconClick); panoramioIcon.x = BORDER_L; panoramioIcon.y = BORDER_T; content.addChild(iconHolder); // NOTE: we add the image as a child only after we&apos;ve added the marker // to the map. Currently the API requires this if it&apos;s to generate the // shadow for unprivileged content. // Shrink the image, so that it doesn&apos;t obcure too much screen space. // Ideally, we&apos;d subsample, but we don&apos;t have pixel level access. child.scaleX = IMAGE_SCALE; child.scaleY = IMAGE_SCALE; var imageW:Number = child.width; var imageH:Number = child.height; child.x = BORDER_L + 30; child.y = BORDER_T + iconHolder.height + GAP_T; var authorField:TextField = new TextField(); authorField.autoSize = TextFieldAutoSize.LEFT; authorField.defaultTextFormat = new TextFormat("_sans", 12); authorField.text = "author:"; content.addChild(authorField); authorField.x = BORDER_L; authorField.y = BORDER_T + iconHolder.height + GAP_T + imageH + GAP_B; var ownerField:TextField = new TextField(); ownerField.autoSize = TextFieldAutoSize.LEFT; var textFormat:TextFormat = new TextFormat("_sans", 14, 0x0e5f9a); ownerField.defaultTextFormat = textFormat; ownerField.htmlText = "<a href=\"" + ownerUrl + "\" target=\"_blank\">" + ownerName + "</a>"; content.addChild(ownerField); ownerField.x = BORDER_L + authorField.width; ownerField.y = BORDER_T + iconHolder.height + GAP_T + imageH + GAP_B; var totalW:Number = BORDER_L + Math.max(imageW, ownerField.width + authorField.width) + BORDER_R; var totalH:Number = BORDER_T + iconHolder.height + GAP_T + imageH + GAP_B + ownerField.height + BORDER_B; content.graphics.beginFill(0xffffff); content.graphics.drawRoundRect(0, 0, totalW, totalH, 10, 10); content.graphics.endFill(); var marker:Sprite = new Sprite(); marker.addChild(content); content.x = 30; content.y = 0; marker.graphics.lineStyle(); marker.graphics.beginFill(0xff0000); marker.graphics.drawCircle(0, totalH + 30, 3); marker.graphics.endFill(); marker.graphics.lineStyle(2, 0xffffff); marker.graphics.moveTo(30 + 10, totalH - 10); marker.graphics.lineTo(0, totalH + 30); return marker; } /** * Handles click on the Panoramio icon. */ private function onPanoramioIconClick(event:MouseEvent):void { navigateToURL(new URLRequest(PANORAMIO_HOME)); } /** * Handles failure of a Panoramio image load. */ private function onPanoramioDataFailed(event:IOErrorEvent):void { trace("Load of image failed: " + event); } /** * Returns a string containing cgi query parameters. * @param Associative array mapping query parameter key to value. * @return String containing cgi query parameters. */ private static function paramsToString(params:Object):String { var result:String = ""; var separator:String = ""; for (var key:String in params) { result += separator + encodeURIComponent(key) + "=" + encodeURIComponent(params[key]); separator = "&"; } return result; } /** * Called once the lead-in flight is done. Starts the car driving along * the route and starts a timer to begin fade in of the Panoramio * images in 1.5 seconds. */ private function onLeadInDone(event:Event):void { // Set startTimer non-zero so that the car starts to move. startTimer = getTimer(); // Start a timer that will fade in the Panoramio images. var fadeInTimer:Timer = new Timer(1500, 1); fadeInTimer.addEventListener(TimerEvent.TIMER, onFadeInTimer); fadeInTimer.start(); } /** * Handles the fade in timer&apos;s TIMER event. Sets markerAlpha above zero * which causes the frame enter handler to fade in the markers. */ private function onFadeInTimer(event:Event):void { markerAlpha = 0.01; } /** * The end time of the flight. */ private function get endTime():Number { if (!cumulativeStepDuration || cumulativeStepDuration.length == 0) { return startTimer; } return startTimer + cumulativeStepDuration[cumulativeStepDuration.length - 1]; } /** * Creates the cumulative arrays, cumulativeStepDuration and * cumulativeVertexDistance. */ private function createCumulativeArrays():void { cumulativeStepDuration = new Array(route.numSteps + 1); cumulativeVertexDistance = new Array(polyline.getVertexCount() + 1); var polylineTotal:Number = 0; var total:Number = 0; var numVertices:int = polyline.getVertexCount(); for (var stepIndex:int = 0; stepIndex < route.numSteps; ++stepIndex) { cumulativeStepDuration[stepIndex] = total; total += route.getStep(stepIndex).duration; var startVertex:int = stepIndex >= 0 ? route.getStep(stepIndex).polylineIndex : 0; var endVertex:int = stepIndex < (route.numSteps - 1) ? route.getStep(stepIndex + 1).polylineIndex : numVertices; var duration:Number = route.getStep(stepIndex).duration; var stepVertices:int = endVertex - startVertex; var latLng:LatLng = polyline.getVertex(startVertex); for (var vertex:int = startVertex; vertex < endVertex; ++vertex) { cumulativeVertexDistance[vertex] = polylineTotal; if (vertex < numVertices - 1) { var nextLatLng:LatLng = polyline.getVertex(vertex + 1); polylineTotal += nextLatLng.distanceFrom(latLng); } latLng = nextLatLng; } } cumulativeStepDuration[stepIndex] = total; } /** * Opens the info window above the car icon that details the given * step of the driving directions. * @param stepIndex Index of the current step. */ private function openInfoForStep(stepIndex:int):void { // Sets the content of the info window. var content:String; if (stepIndex >= route.numSteps) { content = "<b>" + route.endGeocode.address + "</b>" + "<br /><br />" + route.summaryHtml; } else { content = "<b>" + stepIndex + ".</b> " + route.getStep(stepIndex).descriptionHtml; } marker.openInfoWindow(new InfoWindowOptions({ contentHTML: content })); } /** * Displays the driving directions step appropriate for the given time. * Opens the info window showing the step instructions each time we * progress to a new step. * @param time Time for which to display the step. */ private function displayStepAt(time:Number):void { var stepIndex:int = upperBound(cumulativeStepDuration, time) - 1; var minStepIndex:int = 0; var maxStepIndex:int = route.numSteps - 1; if (stepIndex >= 0 && stepIndex <= maxStepIndex && currentStepIndex != stepIndex) { openInfoForStep(stepIndex); currentStepIndex = stepIndex; } } /** * Returns the LatLng at which the car should be positioned at the given * time. * @param time Time for which LatLng should be found. * @return LatLng. */ private function latLngAt(time:Number):LatLng { var stepIndex:int = upperBound(cumulativeStepDuration, time) - 1; var minStepIndex:int = 0; var maxStepIndex:int = route.numSteps - 1; if (stepIndex < minStepIndex) { return route.startGeocode.point; } else if (stepIndex > maxStepIndex) { return route.endGeocode.point; } var stepStart:Number = cumulativeStepDuration[stepIndex]; var stepEnd:Number = cumulativeStepDuration[stepIndex + 1]; var stepFraction:Number = (time - stepStart) / (stepEnd - stepStart); var startVertex:int = route.getStep(stepIndex).polylineIndex; var endVertex:int = (stepIndex + 1) < route.numSteps ? route.getStep(stepIndex + 1).polylineIndex : polyline.getVertexCount(); var stepVertices:int = endVertex - startVertex; var stepLeng

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  • OBIEE 11.1.1 - User Interface (UI) Performance Is Slow With Internet Explorer 8

    - by Ahmed A
    The OBIEE 11g UI is performance is slow in IE 8 and faster in Firefox.  For VPN or WAN users, it takes long time to display links on Dashboards via IE 8. Cause is IE 8 generates many HTTP 304 return calls and this caused the 11g UI slower when compared to the Mozilla FireFox browser. To resolve this issue, you can implement HTTP compression and caching. This is a best practice.Why use Web Server Compression / Caching for OBIEE? Bandwidth Savings: Enabling HTTP compression can have a dramatic improvement on the latency of responses. By compressing static files and dynamic application responses, it will significantly reduce the remote (high latency) user response time. Improves request/response latency: Caching makes it possible to suppress the payload of the HTTP reply using the 304 status code.  Minimizing round trips over the Web to re-validate cached items can make a huge difference in browser page load times. This screen shot depicts the flow and where the compression and decompression occurs: Solution: a. How to Enable HTTP Caching / Compression in Oracle HTTP Server (OHS) 11.1.1.x 1. To implement HTTP compression / caching, install and configure Oracle HTTP Server (OHS) 11.1.1.x for the bi_serverN Managed Servers (refer to "OBIEE Enterprise Deployment Guide for Oracle Business Intelligence" document for details). 2. On the OHS machine, open the file HTTP Server configuration file (httpd.conf) for editing. This file is located in the OHS installation directory.For example: ORACLE_HOME/Oracle_WT1/instances/instance1/config/OHS/ohs13. In httpd.conf file, verify that the following directives are included and not commented out: LoadModule expires_module "${ORACLE_HOME}/ohs/modules/mod_expires.soLoadModule deflate_module "${ORACLE_HOME}/ohs/modules/mod_deflate.so 4. Add the following lines in httpd.conf file below the directive LoadModule section and restart the OHS: Note: For the Windows platform, you will need to enclose any paths in double quotes ("), for example:Alias "/analytics ORACLE_HOME/bifoundation/web/app"<Directory "ORACLE_HOME/bifoundation/web/app"> Alias /analytics ORACLE_HOME/bifoundation/web/app#Pls replace the ORACLE_HOME with your actual BI ORACLE_HOME path<Directory ORACLE_HOME/bifoundation/web/app>#We don't generate proper cross server ETags so disable themFileETag noneSetOutputFilter DEFLATE# Don't compress imagesSetEnvIfNoCase Request_URI \.(?:gif|jpe?g|png)$ no-gzip dont-vary<FilesMatch "\.(gif|jpeg|png|js|x-javascript|javascript|css)$">#Enable future expiry of static filesExpiresActive onExpiresDefault "access plus 1 week"     #1 week, this will stops the HTTP304 calls i.e. generated by IE 8Header set Cache-Control "max-age=604800"</FilesMatch>DirectoryIndex default.jsp</Directory>#Restrict access to WEB-INF<Location /analytics/WEB-INF>Order Allow,DenyDeny from all</Location> Note: Make sure you replace above placeholder "ORACLE_HOME" to your correct path for BI ORACLE_HOME.For example: my BI Oracle Home path is /Oracle/BIEE11g/Oracle_BI1/bifoundation/web/app Important Notes: Above caching rules restricted to static files found inside the /analytics directory(/web/app). This approach is safer instead of setting static file caching globally. In some customer environments you may not get 100% performance gains in IE 8.0 browser. So in that case you need to extend caching rules to other directories with static files content. If OHS is installed on separate dedicated machine, make sure static files in your BI ORACLE_HOME (../Oracle_BI1/bifoundation/web/app) is accessible to the OHS instance. The following screen shot summarizes the before and after results and improvements after enabling compression and caching:

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  • Enhanced Dynamic Filtering

    - by Ricardo Peres
    Remember my last post on dynamic filtering? Well, this time I'm extending the code in order to allow two levels of querying: Match type, represented by the following options: public enum MatchType { StartsWith = 0, Contains = 1 } And word match: public enum WordMatch { AnyWord = 0, AllWords = 1, ExactPhrase = 2 } You can combine the two levels in order to achieve the following combinations: MatchType.StartsWith + WordMatch.AnyWord Matches any record that starts with any of the words specified MatchType.StartsWith + WordMatch.AllWords Not available: does not make sense, throws an exception MatchType.StartsWith + WordMatch.ExactPhrase Matches any record that starts with the exact specified phrase MatchType.Contains + WordMatch.AnyWord Matches any record that contains any of the specified words MatchType.Contains + WordMatch.AllWords Matches any record that contains all of the specified words MatchType.Contains + WordMatch.ExactPhrase Matches any record that contains the exact specified phrase Here is the code: public static IList Search(IQueryable query, Type entityType, String dataTextField, String phrase, MatchType matchType, WordMatch wordMatch, Int32 maxCount) { String [] terms = phrase.Split(' ').Distinct().ToArray(); StringBuilder result = new StringBuilder(); PropertyInfo displayProperty = entityType.GetProperty(dataTextField); IList searchList = null; MethodInfo orderByMethod = typeof(Queryable).GetMethods(BindingFlags.Public | BindingFlags.Static).Where(m = m.Name == "OrderBy").ToArray() [ 0 ].MakeGenericMethod(entityType, displayProperty.PropertyType); MethodInfo takeMethod = typeof(Queryable).GetMethod("Take", BindingFlags.Public | BindingFlags.Static).MakeGenericMethod(entityType); MethodInfo whereMethod = typeof(Queryable).GetMethods(BindingFlags.Public | BindingFlags.Static).Where(m = m.Name == "Where").ToArray() [ 0 ].MakeGenericMethod(entityType); MethodInfo distinctMethod = typeof(Queryable).GetMethods(BindingFlags.Public | BindingFlags.Static).Where(m = m.Name == "Distinct" && m.GetParameters().Length == 1).Single().MakeGenericMethod(entityType); MethodInfo toListMethod = typeof(Enumerable).GetMethod("ToList", BindingFlags.Static | BindingFlags.Public).MakeGenericMethod(entityType); MethodInfo matchMethod = typeof(String).GetMethod ( (matchType == MatchType.StartsWith) ? "StartsWith" : "Contains", new Type [] { typeof(String) } ); MemberExpression member = Expression.MakeMemberAccess ( Expression.Parameter(entityType, "n"), displayProperty ); MethodCallExpression call = null; LambdaExpression where = null; LambdaExpression orderBy = Expression.Lambda ( member, member.Expression as ParameterExpression ); switch (matchType) { case MatchType.StartsWith: switch (wordMatch) { case WordMatch.AnyWord: call = Expression.Call ( member, matchMethod, Expression.Constant(terms [ 0 ]) ); where = Expression.Lambda ( call, member.Expression as ParameterExpression ); for (Int32 i = 1; i ()); where = Expression.Lambda ( Expression.Or ( where.Body, exp ), where.Parameters.ToArray() ); } break; case WordMatch.ExactPhrase: call = Expression.Call ( member, matchMethod, Expression.Constant(phrase) ); where = Expression.Lambda ( call, member.Expression as ParameterExpression ); break; case WordMatch.AllWords: throw (new Exception("The match type StartsWith is not supported with word match AllWords")); } break; case MatchType.Contains: switch (wordMatch) { case WordMatch.AnyWord: call = Expression.Call ( member, matchMethod, Expression.Constant(terms [ 0 ]) ); where = Expression.Lambda ( call, member.Expression as ParameterExpression ); for (Int32 i = 1; i ()); where = Expression.Lambda ( Expression.Or ( where.Body, exp ), where.Parameters.ToArray() ); } break; case WordMatch.ExactPhrase: call = Expression.Call ( member, matchMethod, Expression.Constant(phrase) ); where = Expression.Lambda ( call, member.Expression as ParameterExpression ); break; case WordMatch.AllWords: call = Expression.Call ( member, matchMethod, Expression.Constant(terms [ 0 ]) ); where = Expression.Lambda ( call, member.Expression as ParameterExpression ); for (Int32 i = 1; i ()); where = Expression.Lambda ( Expression.AndAlso ( where.Body, exp ), where.Parameters.ToArray() ); } break; } break; } query = orderByMethod.Invoke(null, new Object [] { query, orderBy }) as IQueryable; query = whereMethod.Invoke(null, new Object [] { query, where }) as IQueryable; if (maxCount != 0) { query = takeMethod.Invoke(null, new Object [] { query, maxCount }) as IQueryable; } searchList = toListMethod.Invoke(null, new Object [] { query }) as IList; return (searchList); } And this is how you'd use it: IQueryable query = ctx.MyEntities; IList list = Search(query, typeof(MyEntity), "Name", "Ricardo Peres", MatchType.Contains, WordMatch.ExactPhrase, 10 /*0 for all*/); SyntaxHighlighter.config.clipboardSwf = 'http://alexgorbatchev.com/pub/sh/2.0.320/scripts/clipboard.swf'; SyntaxHighlighter.brushes.CSharp.aliases = ['c#', 'c-sharp', 'csharp']; SyntaxHighlighter.all();

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  • Sharing Bandwidth and Prioritizing Realtime Traffic via HTB, Which Scenario Works Better?

    - by Mecki
    I would like to add some kind of traffic management to our Internet line. After reading a lot of documentation, I think HFSC is too complicated for me (I don't understand all the curves stuff, I'm afraid I will never get it right), CBQ is not recommend, and basically HTB is the way to go for most people. Our internal network has three "segments" and I'd like to share bandwidth more or less equally between those (at least in the beginning). Further I must prioritize traffic according to at least three kinds of traffic (realtime traffic, standard traffic, and bulk traffic). The bandwidth sharing is not as important as the fact that realtime traffic should always be treated as premium traffic whenever possible, but of course no other traffic class may starve either. The question is, what makes more sense and also guarantees better realtime throughput: Creating one class per segment, each having the same rate (priority doesn't matter for classes that are no leaves according to HTB developer) and each of these classes has three sub-classes (leaves) for the 3 priority levels (with different priorities and different rates). Having one class per priority level on top, each having a different rate (again priority won't matter) and each having 3 sub-classes, one per segment, whereas all 3 in the realtime class have highest prio, lowest prio in the bulk class, and so on. I'll try to make this more clear with the following ASCII art image: Case 1: root --+--> Segment A | +--> High Prio | +--> Normal Prio | +--> Low Prio | +--> Segment B | +--> High Prio | +--> Normal Prio | +--> Low Prio | +--> Segment C +--> High Prio +--> Normal Prio +--> Low Prio Case 2: root --+--> High Prio | +--> Segment A | +--> Segment B | +--> Segment C | +--> Normal Prio | +--> Segment A | +--> Segment B | +--> Segment C | +--> Low Prio +--> Segment A +--> Segment B +--> Segment C Case 1 Seems like the way most people would do it, but unless I don't read the HTB implementation details correctly, Case 2 may offer better prioritizing. The HTB manual says, that if a class has hit its rate, it may borrow from its parent and when borrowing, classes with higher priority always get bandwidth offered first. However, it also says that classes having bandwidth available on a lower tree-level are always preferred to those on a higher tree level, regardless of priority. Let's assume the following situation: Segment C is not sending any traffic. Segment A is only sending realtime traffic, as fast as it can (enough to saturate the link alone) and Segment B is only sending bulk traffic, as fast as it can (again, enough to saturate the full link alone). What will happen? Case 1: Segment A-High Prio and Segment B-Low Prio both have packets to send, since A-High Prio has the higher priority, it will always be scheduled first, till it hits its rate. Now it tries to borrow from Segment A, but since Segment A is on a higher level and Segment B-Low Prio has not yet hit its rate, this class is now served first, till it also hits the rate and wants to borrow from Segment B. Once both have hit their rates, both are on the same level again and now Segment A-High Prio is going to win again, until it hits the rate of Segment A. Now it tries to borrow from root (which has plenty of traffic spare, as Segment C is not using any of its guaranteed traffic), but again, it has to wait for Segment B-Low Prio to also reach the root level. Once that happens, priority is taken into account again and this time Segment A-High Prio will get all the bandwidth left over from Segment C. Case 2: High Prio-Segment A and Low Prio-Segment B both have packets to send, again High Prio-Segment A is going to win as it has the higher priority. Once it hits its rate, it tries to borrow from High Prio, which has bandwidth spare, but being on a higher level, it has to wait for Low Prio-Segment B again to also hit its rate. Once both have hit their rate and both have to borrow, High Prio-Segment A will win again until it hits the rate of the High Prio class. Once that happens, it tries to borrow from root, which has again plenty of bandwidth left (all bandwidth of Normal Prio is unused at the moment), but it has to wait again until Low Prio-Segment B hits the rate limit of the Low Prio class and also tries to borrow from root. Finally both classes try to borrow from root, priority is taken into account, and High Prio-Segment A gets all bandwidth root has left over. Both cases seem sub-optimal, as either way realtime traffic sometimes has to wait for bulk traffic, even though there is plenty of bandwidth left it could borrow. However, in case 2 it seems like the realtime traffic has to wait less than in case 1, since it only has to wait till the bulk traffic rate is hit, which is most likely less than the rate of a whole segment (and in case 1 that is the rate it has to wait for). Or am I totally wrong here? I thought about even simpler setups, using a priority qdisc. But priority queues have the big problem that they cause starvation if they are not somehow limited. Starvation is not acceptable. Of course one can put a TBF (Token Bucket Filter) into each priority class to limit the rate and thus avoid starvation, but when doing so, a single priority class cannot saturate the link on its own any longer, even if all other priority classes are empty, the TBF will prevent that from happening. And this is also sub-optimal, since why wouldn't a class get 100% of the line's bandwidth if no other class needs any of it at the moment? Any comments or ideas regarding this setup? It seems so hard to do using standard tc qdiscs. As a programmer it was such an easy task if I could simply write my own scheduler (which I'm not allowed to do).

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  • Thoughts on C# Extension Methods

    - by Damon
    I'm not a huge fan of extension methods.  When they first came out, I remember seeing a method on an object that was fairly useful, but when I went to use it another piece of code that method wasn't available.  Turns out it was an extension method and I hadn't included the appropriate assembly and imports statement in my code to use it.  I remember being a bit confused at first about how the heck that could happen (hey, extension methods were new, cut me some slack) and it took a bit of time to track down exactly what it was that I needed to include to get that method back.  I just imagined a new developer trying to figure out why a method was missing and fruitlessly searching on MSDN for a method that didn't exist and it just didn't sit well with me. I am of the opinion that if you have an object, then you shouldn't have to include additional assemblies to get additional instance level methods out of that object.  That opinion applies to namespaces as well - I do not like it when the contents of a namespace are split out into multiple assemblies.  I prefer to have static utility classes instead of extension methods to keep things nicely packaged into a cohesive unit.  It also makes it abundantly clear where utility methods are used in code.  I will concede, however, that it can make code a bit more verbose and lengthy.  There is always a trade-off. Some people harp on extension methods because it breaks the tenants of object oriented development and allows you to add methods to sealed classes.  Whatever.  Extension methods are just utility methods that you can tack onto an object after the fact.  Extension methods do not give you any more access to an object than the developer of that object allows, so I say that those who cry OO foul on extension methods really don't have much of an argument on which to stand.  In fact, I have to concede that my dislike of them is really more about style than anything of great substance. One interesting thing that I found regarding extension methods is that you can call them on null objects. Take a look at this extension method: namespace ExtensionMethods {   public static class StringUtility   {     public static int WordCount(this string str)     {       if(str == null) return 0;       return str.Split(new char[] { ' ', '.', '?' },         StringSplitOptions.RemoveEmptyEntries).Length;     }   }   } Notice that the extension method checks to see if the incoming string parameter is null.  I was worried that the runtime would perform a check on the object instance to make sure it was not null before calling an extension method, but that is apparently not the case.  So, if you call the following code it runs just fine. string s = null; int words = s.WordCount(); I am a big fan of things working, but this seems to go against everything I've come to know about instance level methods.  However, an extension method is really a static method masquerading as an instance-level method, so I suppose it would be far more frustrating if it failed since there is really no reason it shouldn't succeed. Although I'm not a fan of extension methods, I will say that if you ever find yourself at an impasse with a die-hard fan of either the utility class or extension method approach, then there is a common ground.  Extension methods are defined in static classes, and you call them from those static classes as well as directly from the objects they extend.  So if you build your utility classes using extension methods, then you can have it your way and they can have it theirs. 

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  • Is a university education really worth it for a good programmer?

    - by Jon Purdy
    The title says it all, but here's the personal side of it: I've been doing design and programming for about as long as I can remember. If there's a programming problem, I can figure it out. (Though admittedly StackOverflow has allowed me to skip the figuring out and get straight to the doing in many instances.) I've made games, esoteric programming languages, and widgets and gizmos galore. I'm currently working on a general-purpose programming language. There's nothing I do better than programming. However, I'm just as passionate about design. Thus when I felt leaving high school that my design skills were lacking, I decided to attend university for New Media Design and Imaging, a digital design-related major. For a year, I diligently studied art and programmed in my free time. As the next year progressed, however, I was obligated to take fewer art and design classes and more technical classes. The trouble was of course that these classes were geared toward non-technical students, and were far beneath my skill level at the time. No amount of petitioning could overcome the institution's reluctance to allow me to test out of such classes, and the major offered no promise for any greater challenge in the future, so I took the extreme route: I switched into the technical equivalent of the major, New Media Interactive Development. A lot of my credits moved over into the new major, but many didn't. It would have been infeasible to switch to a more rigorous technical major such as Computer Science, and having tutored Computer Science students at every level here, I doubt I would be exposed to anything that I haven't already or won't eventually find out on my own, since I'm so involved in the field. I'm now on track to graduate perhaps a year later than I had planned, which puts a significant financial strain on my family and my future self. My schedule continues to be bogged down with classes that are wholly unnecessary for me to take. I'm being re-introduced to subjects that I've covered a thousand times over, simply because I've always been interested in it all. And though I succeed in avoiding the cynical and immature tactic of failing to complete work out of some undeserved sense of superiority, I'm becoming increasingly disillusioned by the lack of intellectual stimulation. Further, my school requires students to complete a number of quarters of co-op work experience proportional to their major. My original major required two quarters, but my current requires three, delaying my graduation even more. To top it all off, college is putting a severe strain on my relationship with my very close partner of a few years, so I've searched diligently for co-op jobs in my area, alas to no avail. I'm now in my third year, and approaching that point past which I can no longer handle this. Either I keep my head down, get a degree no matter what it takes, and try to get a job with a company that will pay me enough to do what I love that I can eventually pay off my loans; or I cut my losses now, move wherever there is work, and in six months start paying off what debt I've accumulated thus far. So the real question is: is a university education really more than just a formality? It's a big decision, and one I can't make lightly. I think this is the appropriate venue for this kind of question, and I hope it sticks around for the sake of others who might someday find themselves in similar situations. My heartfelt thanks for reading, and in advance for your help.

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  • Remote Desktop (Vino-Server) connects but display doesn't work?

    - by kmassada
    Ubuntu comes default with vino-server, I can remote into my machine, and connect to it, however, the display inside my remote client, is a mirror of my own desktop. I tried using one monitor, thinking that's what is the issue but still won't work. (vino-server:3608): EggSMClient-CRITICAL **: egg_sm_client_set_mode: assertion `global_client == NULL || global_client_mode == EGG_SM_CLIENT_MODE_DISABLED' failed 25/07/2012 12:23:58 PM Autoprobing TCP port in (all) network interface 25/07/2012 12:23:58 PM Listening IPv6://[::]:5900 25/07/2012 12:23:58 PM Listening IPv4://0.0.0.0:5900 25/07/2012 12:23:58 PM Autoprobing selected port 5900 25/07/2012 12:23:58 PM Advertising security type: 'TLS' (18) 25/07/2012 12:23:58 PM Re-binding socket to listen for VNC connections on TCP port 5900 in (all) interface 25/07/2012 12:23:58 PM Listening IPv6://[::]:5900 25/07/2012 12:23:58 PM Listening IPv4://0.0.0.0:5900 25/07/2012 12:23:58 PM Clearing securityTypes 25/07/2012 12:23:58 PM Advertising security type: 'TLS' (18) 25/07/2012 12:23:58 PM Clearing securityTypes 25/07/2012 12:23:58 PM Advertising security type: 'TLS' (18) 25/07/2012 12:23:58 PM Advertising authentication type: 'No Authentication' (1) 25/07/2012 12:23:58 PM Re-binding socket to listen for VNC connections on TCP port 5900 in (all) interface 25/07/2012 12:23:58 PM Listening IPv6://[::]:5900 25/07/2012 12:23:58 PM Listening IPv4://0.0.0.0:5900 25/07/2012 12:23:58 PM Clearing securityTypes 25/07/2012 12:23:58 PM Clearing authTypes 25/07/2012 12:23:58 PM Advertising security type: 'TLS' (18) 25/07/2012 12:23:58 PM Advertising authentication type: 'VNC Authentication' (2) 25/07/2012 12:23:58 PM Clearing securityTypes 25/07/2012 12:23:58 PM Clearing authTypes 25/07/2012 12:23:58 PM Advertising security type: 'TLS' (18) 25/07/2012 12:23:58 PM Advertising authentication type: 'VNC Authentication' (2) 25/07/2012 12:23:58 PM Advertising security type: 'VNC Authentication' (2) (vino-server:3608): LIBDBUSMENU-GLIB-WARNING **: Trying to remove a child that doesn't believe we're it's parent. (vino-server:3608): LIBDBUSMENU-GLIB-WARNING **: Trying to remove a child that doesn't believe we're it's parent. 25/07/2012 12:24:16 PM [IPv4] Got connection from client static-XXXX.bltmmd.fios.verizon.net 25/07/2012 12:24:16 PM other clients: 25/07/2012 12:24:29 PM Client Protocol Version 3.7 25/07/2012 12:24:29 PM Advertising security type 18 25/07/2012 12:24:29 PM Advertising security type 2 25/07/2012 12:24:30 PM Client returned security type 18 25/07/2012 12:24:30 PM Advertising authentication type 2 25/07/2012 12:24:30 PM Client returned authentication type 2 25/07/2012 12:24:37 PM rfbProcessClientNormalMessage: ignoring unknown encoding type -258 25/07/2012 12:24:37 PM Enabling NewFBSize protocol extension for client static-XXXX.bltmmd.fios.verizon.net 25/07/2012 12:24:37 PM rfbProcessClientNormalMessage: ignoring unknown encoding type 1464686185 25/07/2012 12:24:37 PM rfbProcessClientNormalMessage: ignoring unknown encoding type -259 25/07/2012 12:24:37 PM rfbProcessClientNormalMessage: ignoring unknown encoding type -257 (vino-server:3608): LIBDBUSMENU-GLIB-WARNING **: Trying to remove a child that doesn't believe we're it's parent. 25/07/2012 12:24:55 PM Client static-XXXX.bltmmd.fios.verizon.net gone 25/07/2012 12:24:55 PM Statistics: 25/07/2012 12:24:55 PM key events received 0, pointer events 80 25/07/2012 12:24:55 PM framebuffer updates 43, rectangles 152, bytes 292401 25/07/2012 12:24:55 PM tight rectangles 152, bytes 292401 25/07/2012 12:24:55 PM raw bytes equivalent 11621332, compression ratio 39.744502 25/07/2012 12:25:21 PM [IPv4] Got connection from client static-XXXX.bltmmd.fios.verizon.net 25/07/2012 12:25:21 PM other clients: 25/07/2012 12:25:28 PM Client Protocol Version 3.7 25/07/2012 12:25:28 PM Advertising security type 18 25/07/2012 12:25:28 PM Advertising security type 2 25/07/2012 12:25:28 PM Client returned security type 18 25/07/2012 12:25:29 PM Advertising authentication type 2 25/07/2012 12:25:29 PM Client returned authentication type 2 25/07/2012 12:25:37 PM rfbProcessClientNormalMessage: ignoring unknown encoding type -258 25/07/2012 12:25:37 PM Enabling NewFBSize protocol extension for client static-XXXX.bltmmd.fios.verizon.net 25/07/2012 12:25:37 PM rfbProcessClientNormalMessage: ignoring unknown encoding type 1464686185 25/07/2012 12:25:37 PM rfbProcessClientNormalMessage: ignoring unknown encoding type -259 25/07/2012 12:25:37 PM rfbProcessClientNormalMessage: ignoring unknown encoding type -257 (vino-server:3608): LIBDBUSMENU-GLIB-WARNING **: Trying to remove a child that doesn't believe we're it's parent. 25/07/2012 12:25:47 PM Client static-XXXX.bltmmd.fios.verizon.net gone 25/07/2012 12:25:47 PM Statistics: 25/07/2012 12:25:47 PM key events received 0, pointer events 7283 25/07/2012 12:25:47 PM framebuffer updates 27, rectangles 82, bytes 113354 25/07/2012 12:25:47 PM tight rectangles 82, bytes 113354 25/07/2012 12:25:47 PM raw bytes equivalent 5831432, compression ratio 51.444431 couple of things I notice, the following error occurs over and over again. the menu error seems to be caused by ubuntu, similar problems occur http://trac.wxwidgets.org/ticket/14292, (vino-server:3608): LIBDBUSMENU-GLIB-WARNING **: Trying to remove a child that doesn't believe we're it's parent. the second one also seem to be a display related issue, can't seem to figure out a solution. I really rather try to fix this issue than have to use the other vnc clients most suggest. (vino-server:3608): EggSMClient-CRITICAL **: egg_sm_client_set_mode: assertion `global_client == NULL || global_client_mode == EGG_SM_CLIENT_MODE_DISABLED' failed

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  • jtreg update, December 2012

    - by jjg
    There is a new version of jtreg available. The primary new feature is support for tests that have been written for use with TestNG, the popular open source testing framework. TestNG is supported by a variety of tools and plugins, which means that it is now possible to develop tests for OpenJDK using those tools, while still retaining the ability to have the tests be part of the OpenJDK test suite, and run with a single test harness, jtreg. jtreg can be downloaded from the OpenJDK jtreg page: http://openjdk.java.net/jtreg. TestNG support jtreg supports both single TestNG tests, which can be freely intermixed with other types of jtreg tests, and groups of TestNG tests. A single TestNG test class can be compiled and run by providing a test description using the new action tag: @run testng classname The test will be executed by using org.testng.TestNG. No main method is required. A group of TestNG tests organized in a standard package hierarchy can also be compiled and run by jtreg. Any such group must be identified by specifying the root directory of the package hierarchy. You can either do this in the top level TEST.ROOT file, or in a TEST.properties file in any subdirectory enclosing the group of tests. In either case, add a line to the file of the form: TestNG.dirs = dir ... Directories beginning with '/' are evaluated relative to the root directory of the test suite; otherwise they are evaluated relative to the directory containing the declaring file. In particular, note that you can simply use "TestNG.dirs = ." in a TEST.properties file in the root directory of the test group's package hierarchy. No additional test descriptions are necessary, but test descriptions containing information tags, such as @bug, @summary, etc are permitted. All the Java source files in the group will be compiled if necessary, before any of the tests in the group are run. The selected tests within the group will be run, one at a time, using org.testng.TestNG. Library classes The specification for the @library tag has been extended so that any paths beginning with '/' will be evaluated relative to the root directory of the test suite. In addition, some bugs have been fixed that prevented sharing the compiled versions of library classes between tests in different directories. Note: This has uncovered some issues in tests that use a combination of @build and @library tags, such that some tests may fail unexpectedly with ClassNotFoundException. The workaround for now is to ensure that library classes are listed before the test classes in any @build tags. To specify one or more library directories for a group of TestNG tests, add a line of the following form to the TEST.properties file in the root directory of the group's package hierarchy: lib.dirs = dir ... As before, directories beginning with '/' are evaluated relative to the root directory of the test suite; otherwise they are evaluated relative to the directory containing the declaring file. The libraries will be available to all classes in the group; you cannot specify different libraries for different tests within the group. Coming soon ... From this point on, jtreg development will be using the new jtreg repository in the OpenJDK code-tools project. There is a new email alias jtreg-dev at openjdk.java.net for discussions about jtreg development. The existing alias jtreg-use at openjdk.java.net will continue to be available for questions about using jtreg. For more information ... An updated version of the jtreg Tag Language Specification is being prepared, and will be made available when it is ready. In the meantime, you can find more information about the support for TestNG by executing the following command: $ jtreg -onlinehelp TestNG For more information on TestNG itself, visit testng.org.

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  • How should I plan the inheritance structure for my game?

    - by Eric Thoma
    I am trying to write a platform shooter in C++ with a really good class structure for robustness. The game itself is secondary; it is the learning process of writing it that is primary. I am implementing an inheritance tree for all of the objects in my game, but I find myself unsure on some decisions. One specific issue that it bugging me is this: I have an Actor that is simply defined as anything in the game world. Under Actor is Character. Both of these classes are abstract. Under Character is the Philosopher, who is the main character that the user commands. Also under Character is NPC, which uses an AI module with stock routines for friendly, enemy and (maybe) neutral alignments. So under NPC I want to have three subclasses: FriendlyNPC, EnemyNPC and NeutralNPC. These classes are not abstract, and will often be subclassed in order to make different types of NPC's, like Engineer, Scientist and the most evil Programmer. Still, if I want to implement a generic NPC named Kevin, it would nice to be able to put him in without making a new class for him. I could just instantiate a FriendlyNPC and pass some values for the AI machine and for the dialogue; that would be ideal. But what if Kevin is the one benevolent Programmer in the whole world? Now we must make a class for him (but what should it be called?). Now we have a character that should inherit from Programmer (as Kevin has all the same abilities but just uses the friendly AI functions) but also should inherit from FriendlyNPC. Programmer and FriendlyNPC branched away from each other on the inheritance tree, so inheriting from both of them would have conflicts, because some of the same functions have been implemented in different ways on the two of them. 1) Is there a better way to order these classes to avoid these conflicts? Having three subclasses; Friendly, Enemy and Neutral; from each type of NPC; Engineer, Scientist, and Programmer; would amount to a huge number of classes. I would share specific implementation details, but I am writing the game slowly, piece by piece, and so I haven't implemented past Character yet. 2) Is there a place where I can learn these programming paradigms? I am already trying to take advantage of some good design patterns, like MVC architecture and Mediator objects. The whole point of this project is to write something in good style. It is difficult to tell what should become a subclass and what should become a state (i.e. Friendly boolean v. Friendly class). Having many states slows down code with if statements and makes classes long and unwieldy. On the other hand, having a class for everything isn't practical. 3) Are there good rules of thumb or resources to learn more about this? 4) Finally, where does templating come in to this? How should I coordinate templates into my class structure? I have never actually taken advantage of templating honestly, but I hear that it increases modularity, which means good code.

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  • Would this be a good web application architecture?

    - by Gustav Bertram
    My problem Our MVC based framework does not allow us to cache only part of our output. Ideally we want to cahce static and semi-static bits, and run dynamic bits. In addition, we need to consider data caching that reacts to database changes. My idea The concept I came up with was to represent a page as a tree of XML fragment objects. (I say XML, but I mean XHTML). Some of the fragments are dynamic, and can pull their data directly from models or other sources, but most of the fragments are static scaffolding. If a subtree of fragments is completely static, then I imagine that they could unfold into pure XML that would then be cached as the text representation of their parent element. This process would ideally continue until we are left with a root element that contains all of the static XML, and has a couple of dynamic XML fragments that are resolved and attached to the relevant nodes of the XML tree just before the page is displayed. In addition to separating content into dynamic and static fragments, some fragments could be dynamic and cached. A simple expiry time which propagates up through the XML fragment tree would indicate that a specific fragment should periodically be refreshed. A newspaper section or front page does not need to be updated each second. Minutes or sometimes even longer is sufficient. Other fragments would be dynamic and uncached. Typically too many articles are viewed for them to be cached - the cache would overflow. Some individual articles may be cached if they are extremely popular. Functional notes The folding mechanism could be to be smart enough to judge when it would be more profitable to fold a dynamic cached fragment and propagate the expiry date to the parent fragment, or to keep it separate and simple attach to the XML tree when resolving the page. If some dynamic cached fragments are associated to database objects through mechanisms like a globally unique content id, then changes to the database could trigger changes to the output cache. If fragments store the identifiers of parent fragments, then they could trigger a refolding process that would then include the updated data. A set of pure XML with an ordered array of fragment objects (that each store the identifying information of the node to which they should be attached), can be resolved in a fairly simple way by walking the XML tree, and merging the data from the fragments. Because it is not necessary to parse and construct the entire tree in memory before attaching nodes, processing should be fairly fast. The identifiers of each fragment would be a combination of relevant identity data and the type of fragment object. Cached parent fragments would contain references to these identifiers, in order to then either pull them from the fragment cache, or to run their code. The controller's responsibility is reduced to making changes to the database, and telling the root XML fragment object to render itself. The Question My question has two parts: Is this a good design? Are there any obvious flaws I'm missing? Has somebody else thought of this before? References? Is there an existing alternative that I should consider? A cool templating engine maybe?

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  • Is this Hybrid of Interface / Composition kosher?

    - by paul
    I'm working on a project in which I'm considering using a hybrid of interfaces and composition as a single thing. What I mean by this is having a contain*ee* class be used as a front for functionality implemented in a contain*er* class, where the container exposes the containee as a public property. Example (pseudocode): class Visibility(lambda doShow, lambda doHide, lambda isVisible) public method Show() {...} public method Hide() {...} public property IsVisible public event Shown public event Hidden class SomeClassWithVisibility private member visibility = new Visibility(doShow, doHide, isVisible) public property Visibility with get() = visibility private method doShow() {...} private method doHide() {...} private method isVisible() {...} There are three reasons I'm considering this: The language in which I'm working (F#) has some annoyances w.r.t. implementing interfaces the way I need to (unless I'm missing something) and this will help avoid a lot of boilerplate code. The containee classes could really be considered properties of the container class(es); i.e. there seems to be a fairly strong has-a relationship. The containee classes will likely implement code which would have been pretty much the same when implemented in all the container classes, so why not do it once in one place? In the above example, this would include managing and emitting the Shown/Hidden events. Does anyone see any isseus with this Composiface/Intersition method, or know of a better way? EDIT 2012.07.26 - It seems a little background information is warranted: Where I work, we have a bunch of application front-ends that have limited access to system resources -- they need access to these resources to fully function. To remedy this we have a back-end application that can access the needed resources, with which the front-ends can communicate. (There is an API written for the front-ends for accessing back-end functionality as though it were part of the front-end.) The back-end program is out of date and its functionality is incomplete. It has made the transition from company to company a couple of times and we can't even compile it anymore. So I'm trying to rewrite it in my spare time. I'm trying to update things to make a nice(r) interface/API for the front-ends (while allowing for backwards compatibility with older front-ends), hopefully something full of OOPy goodness. The thing is, I don't want to write the front-end API after I've written pretty much the same code in F# for implementing the back-end; so, what I'm planning on doing is applying attributes to classes/methods/properties that I would like to have code for in the API then generate this code from the F# assembly using reflection. The method outlined in this question is a possible alternative I'm considering instead of implementing straight interfaces on the classes in F# because they're kind of a bear: In order to access something of an interface that has been implemented in a class, you have to explicitly cast an instance of that class to the interface type. This would make things painful when getting calls from the front-ends. If you don't want to have to do this, you have to call out all of the interface's methods/properties again in the class, outside of the interface implementation (which is separate from regular class members), and call the implementation's members. This is basically repeating the same code, which is what I'm trying to avoid!

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  • Dynamically load and call delegates based on source data

    - by makerofthings7
    Assume I have a stream of records that need to have some computation. Records will have a combination of these functions run Sum, Aggregate, Sum over the last 90 seconds, or ignore. A data record looks like this: Date;Data;ID Question Assuming that ID is an int of some kind, and that int corresponds to a matrix of some delegates to run, how should I use C# to dynamically build that launch map? I'm sure this idea exists... it is used in Windows Forms which has many delegates/events, most of which will never actually be invoked in a real application. The sample below includes a few delegates I want to run (sum, count, and print) but I don't know how to make the quantity of delegates fire based on the source data. (say print the evens, and sum the odds in this sample) using System; using System.Threading; using System.Collections.Generic; internal static class TestThreadpool { delegate int TestDelegate(int parameter); private static void Main() { try { // this approach works is void is returned. //ThreadPool.QueueUserWorkItem(new WaitCallback(PrintOut), "Hello"); int c = 0; int w = 0; ThreadPool.GetMaxThreads(out w, out c); bool rrr =ThreadPool.SetMinThreads(w, c); Console.WriteLine(rrr); // perhaps the above needs time to set up6 Thread.Sleep(1000); DateTime ttt = DateTime.UtcNow; TestDelegate d = new TestDelegate(PrintOut); List<IAsyncResult> arDict = new List<IAsyncResult>(); int count = 1000000; for (int i = 0; i < count; i++) { IAsyncResult ar = d.BeginInvoke(i, new AsyncCallback(Callback), d); arDict.Add(ar); } for (int i = 0; i < count; i++) { int result = d.EndInvoke(arDict[i]); } // Give the callback time to execute - otherwise the app // may terminate before it is called //Thread.Sleep(1000); var res = DateTime.UtcNow - ttt; Console.WriteLine("Main program done----- Total time --> " + res.TotalMilliseconds); } catch (Exception e) { Console.WriteLine(e); } Console.ReadKey(true); } static int PrintOut(int parameter) { // Console.WriteLine(Thread.CurrentThread.ManagedThreadId + " Delegate PRINTOUT waited and printed this:"+parameter); var tmp = parameter * parameter; return tmp; } static int Sum(int parameter) { Thread.Sleep(5000); // Pretend to do some math... maybe save a summary to disk on a separate thread return parameter; } static int Count(int parameter) { Thread.Sleep(5000); // Pretend to do some math... maybe save a summary to disk on a separate thread return parameter; } static void Callback(IAsyncResult ar) { TestDelegate d = (TestDelegate)ar.AsyncState; //Console.WriteLine("Callback is delayed and returned") ;//d.EndInvoke(ar)); } }

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  • C# Dev Challenge Part 1 of n &ndash; Beginner Edition

    - by mbcrump
    I developed this challenge to test one’s knowledge of C Sharp. I am planning on creating several challenges with different skill sets, so don’t get mad if this challenge doesn’t well challenge you... I noticed that most people like short quizzes so this one only contains 5 questions. All of the challenges are clear and concise of what I am asking you to do. No smoke and mirrors here, meaning that none of the code has syntax errors. The purpose of this exercise is to test several OOP concepts and see how much of the C# language you really know. Question #1 – Lets start off Easy… Will the following code snippet compile successfully? What does this question test? - Can this compile without a namespace? Do you have to have an entry point of “static void Main()”? class Test { static int Main() { System.Console.WriteLine("Developer Challenge"); return 0; } } Answer (select text in box below): Yes, it will compile successfully. Question #2 – What is the value of the Console.WriteLine statements? What does this question test? – Do I understand reference types/value types? If a variable is declared with the @ symbol and its not a reserved keyword does the application compile successfully? using System; internal struct MyStruct { public int Value; } internal class MyClass { public int Value; } class Test { static void Main() { MyStruct @struct1 = new MyStruct(); MyStruct @struct2 = @struct1; @struct2.Value = 100; MyClass @ref1 = new MyClass(); MyClass @ref2 = @ref1; @ref2.Value = 100; Console.WriteLine("Value Type: {0} {1}", @struct1.Value, @struct2.Value); Console.WriteLine("Reference Type: {0} {1}", @ref1.Value, @ref2.Value); } } Answer (select text in box below): Value Type: 0 100 Reference Type: 100 100 Question #3 – What is the value of the Console.WriteLine statements? What does this question test? – Can 2 objects reference the same point in memory? using System; class Test { static void Main() { string s1 = "Testing2"; string t1 = s1; Console.WriteLine(s1 == t1); Console.WriteLine((object)s1 == (object)t1); } } Answer (select text in box below): True True Question #4 – What is the value of the Console.WriteLine statements? What does this question test? – How does the “Stack” work – LIFO or FIFO?   using System; using System.Collections; class Test { static void Main() { Stack a = new Stack(5); a.Push("1"); a.Push("2"); a.Push("3"); a.Push("4"); a.Push("5"); foreach (var o in a) { Console.WriteLine(o); } } } Answer (select text in box below): 5 4 3 2 1 Question #5 – What is the value of the Console.WriteLine statements? What does this question test? – Array and General Looping Knowledge. using System; namespace ConsoleApplication5 { class Program { static void Main(string[] args) { int[] J_LIST = new int[5] { 1, 2, 3, 4, 5 }; int K = 10; int L = 5; foreach (var J in J_LIST) { K = K - J; L = K + 2 * J; Console.WriteLine("J = {0, 5} K = {1, 5} L = {2, 5}", J, K, L); } Console.ReadLine(); } } } Answer (select text in box below): J = 1 K = 9 L = 11 J = 2 K = 7 L = 11 J = 3 K = 4 L = 10 J = 4 K = 0 L = 8 J = 5 K = -5 L = 5 Stay Tuned for more challenges!

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  • InternalsVisibleTo attribute and security vulnerability

    - by Sergey Litvinov
    I found one issue with InternalsVisibleTo attribute usage. The idea of InternalsVisibleTo attribute to allow some other assemblies to use internal classes\methods of this assembly. To make it work you need sign your assemblies. So, if other assemblies isn't specified in main assembly and if they have incorrect public key, then they can't use Internal members. But the issue in Reflection Emit type generation. For example, we have CorpLibrary1 assembly and it has such class: public class TestApi { internal virtual void DoSomething() { Console.WriteLine("Base DoSomething"); } public void DoApiTest() { // some internal logic // ... // call internal method DoSomething(); } } This assembly is marked with such attribute to allow another CorpLibrary2 to make inheritor for that TestAPI and override behaviour of DoSomething method. [assembly: InternalsVisibleTo("CorpLibrary2, PublicKey=0024000004800000940000000602000000240000525341310004000001000100434D9C5E1F9055BF7970B0C106AAA447271ECE0F8FC56F6AF3A906353F0B848A8346DC13C42A6530B4ED2E6CB8A1E56278E664E61C0D633A6F58643A7B8448CB0B15E31218FB8FE17F63906D3BF7E20B9D1A9F7B1C8CD11877C0AF079D454C21F24D5A85A8765395E5CC5252F0BE85CFEB65896EC69FCC75201E09795AAA07D0")] The issue is that I'm able to override this internal DoSomething method and break class logic. My steps to do it: Generate new assembly in runtime via AssemblyBuilder Get AssemblyName from CorpLibrary1 and copy PublikKey to new assembly Generate new assembly that will inherit TestApi class As PublicKey and name of generated assembly is the same as in InternalsVisibleTo, then we can generate new DoSomething method that will override internal method in TestAPI assembly Then we have another assembly that isn't related to this CorpLibrary1 and can't use internal members. We have such test code in it: class Program { static void Main(string[] args) { var builder = new FakeBuilder(InjectBadCode, "DoSomething", true); TestApi fakeType = builder.CreateFake(); fakeType.DoApiTest(); // it will display: // Inject bad code // Base DoSomething Console.ReadLine(); } public static void InjectBadCode() { Console.WriteLine("Inject bad code"); } } And this FakeBuilder class has such code: /// /// Builder that will generate inheritor for specified assembly and will overload specified internal virtual method /// /// Target type public class FakeBuilder { private readonly Action _callback; private readonly Type _targetType; private readonly string _targetMethodName; private readonly string _slotName; private readonly bool _callBaseMethod; public FakeBuilder(Action callback, string targetMethodName, bool callBaseMethod) { int randomId = new Random((int)DateTime.Now.Ticks).Next(); _slotName = string.Format("FakeSlot_{0}", randomId); _callback = callback; _targetType = typeof(TFakeType); _targetMethodName = targetMethodName; _callBaseMethod = callBaseMethod; } public TFakeType CreateFake() { // as CorpLibrary1 can't use code from unreferences assemblies, we need to store this Action somewhere. // And Thread is not bad place for that. It's not the best place as it won't work in multithread application, but it's just a sample LocalDataStoreSlot slot = Thread.AllocateNamedDataSlot(_slotName); Thread.SetData(slot, _callback); // then we generate new assembly with the same nameand public key as target assembly trusts by InternalsVisibleTo attribute var newTypeName = _targetType.Name + "Fake"; var targetAssembly = Assembly.GetAssembly(_targetType); AssemblyName an = new AssemblyName(); an.Name = GetFakeAssemblyName(targetAssembly); // copying public key to new generated assembly var assemblyName = targetAssembly.GetName(); an.SetPublicKey(assemblyName.GetPublicKey()); an.SetPublicKeyToken(assemblyName.GetPublicKeyToken()); AssemblyBuilder assemblyBuilder = Thread.GetDomain().DefineDynamicAssembly(an, AssemblyBuilderAccess.RunAndSave); ModuleBuilder moduleBuilder = assemblyBuilder.DefineDynamicModule(assemblyBuilder.GetName().Name, true); // create inheritor for specified type TypeBuilder typeBuilder = moduleBuilder.DefineType(newTypeName, TypeAttributes.Public | TypeAttributes.Class, _targetType); // LambdaExpression.CompileToMethod can be used only with static methods, so we need to create another method that will call our Inject method // we can do the same via ILGenerator, but expression trees are more easy to use MethodInfo methodInfo = CreateMethodInfo(moduleBuilder); MethodBuilder methodBuilder = typeBuilder.DefineMethod(_targetMethodName, MethodAttributes.Public | MethodAttributes.Virtual); ILGenerator ilGenerator = methodBuilder.GetILGenerator(); // call our static method that will call inject method ilGenerator.EmitCall(OpCodes.Call, methodInfo, null); // in case if we need, then we put call to base method if (_callBaseMethod) { var baseMethodInfo = _targetType.GetMethod(_targetMethodName, BindingFlags.NonPublic | BindingFlags.Instance); // place this to stack ilGenerator.Emit(OpCodes.Ldarg_0); // call the base method ilGenerator.EmitCall(OpCodes.Call, baseMethodInfo, new Type[0]); // return ilGenerator.Emit(OpCodes.Ret); } // generate type, create it and return to caller Type cheatType = typeBuilder.CreateType(); object type = Activator.CreateInstance(cheatType); return (TFakeType)type; } /// /// Get name of assembly from InternalsVisibleTo AssemblyName /// private static string GetFakeAssemblyName(Assembly assembly) { var internalsVisibleAttr = assembly.GetCustomAttributes(typeof(InternalsVisibleToAttribute), true).FirstOrDefault() as InternalsVisibleToAttribute; if (internalsVisibleAttr == null) { throw new InvalidOperationException("Assembly hasn't InternalVisibleTo attribute"); } var ind = internalsVisibleAttr.AssemblyName.IndexOf(","); var name = internalsVisibleAttr.AssemblyName.Substring(0, ind); return name; } /// /// Generate such code: /// ((Action)Thread.GetData(Thread.GetNamedDataSlot(_slotName))).Invoke(); /// private LambdaExpression MakeStaticExpressionMethod() { var allocateMethod = typeof(Thread).GetMethod("GetNamedDataSlot", BindingFlags.Static | BindingFlags.Public); var getDataMethod = typeof(Thread).GetMethod("GetData", BindingFlags.Static | BindingFlags.Public); var call = Expression.Call(allocateMethod, Expression.Constant(_slotName)); var getCall = Expression.Call(getDataMethod, call); var convCall = Expression.Convert(getCall, typeof(Action)); var invokExpr = Expression.Invoke(convCall); var lambda = Expression.Lambda(invokExpr); return lambda; } /// /// Generate static class with one static function that will execute Action from Thread NamedDataSlot /// private MethodInfo CreateMethodInfo(ModuleBuilder moduleBuilder) { var methodName = "_StaticTestMethod_" + _slotName; var className = "_StaticClass_" + _slotName; TypeBuilder typeBuilder = moduleBuilder.DefineType(className, TypeAttributes.Public | TypeAttributes.Class); MethodBuilder methodBuilder = typeBuilder.DefineMethod(methodName, MethodAttributes.Static | MethodAttributes.Public); LambdaExpression expression = MakeStaticExpressionMethod(); expression.CompileToMethod(methodBuilder); var type = typeBuilder.CreateType(); return type.GetMethod(methodName, BindingFlags.Static | BindingFlags.Public); } } remarks about sample: as we need to execute code from another assembly, CorpLibrary1 hasn't access to it, so we need to store this delegate somewhere. Just for testing I stored it in Thread NamedDataSlot. It won't work in multithreaded applications, but it's just a sample. I know that we use Reflection to get private\internal members of any class, but within reflection we can't override them. But this issue is allows anyone to override internal class\method if that assembly has InternalsVisibleTo attribute. I tested it on .Net 3.5\4 and it works for both of them. How does it possible to just copy PublicKey without private key and use it in runtime? The whole sample can be found there - https://github.com/sergey-litvinov/Tests_InternalsVisibleTo UPDATE1: That test code in Program and FakeBuilder classes hasn't access to key.sn file and that library isn't signed, so it hasn't public key at all. It just copying it from CorpLibrary1 by using Reflection.Emit

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  • Combining MVVM Light Toolkit and Unity 2.0

    - by Alan Cordner
    This is more of a commentary than a question, though feedback would be nice. I have been tasked to create the user interface for a new project we are doing. We want to use WPF and I wanted to learn all of the modern UI design techniques available. Since I am fairly new to WPF I have been researching what is available. I think I have pretty much settled on using MVVM Light Toolkit (mainly because of its "Blendability" and the EventToCommand behavior!), but I wanted to incorporate IoC also. So, here is what I have come up with. I have modified the default ViewModelLocator class in a MVVM Light project to use a UnityContainer to handle dependency injections. Considering I didn't know what 90% of these terms meant 3 months ago, I think I'm on the right track. // Example of MVVM Light Toolkit ViewModelLocator class that implements Microsoft // Unity 2.0 Inversion of Control container to resolve ViewModel dependencies. using Microsoft.Practices.Unity; namespace MVVMLightUnityExample { public class ViewModelLocator { public static UnityContainer Container { get; set; } #region Constructors static ViewModelLocator() { if (Container == null) { Container = new UnityContainer(); // register all dependencies required by view models Container .RegisterType<IDialogService, ModalDialogService>(new ContainerControlledLifetimeManager()) .RegisterType<ILoggerService, LogFileService>(new ContainerControlledLifetimeManager()) ; } } /// <summary> /// Initializes a new instance of the ViewModelLocator class. /// </summary> public ViewModelLocator() { ////if (ViewModelBase.IsInDesignModeStatic) ////{ //// // Create design time view models ////} ////else ////{ //// // Create run time view models ////} CreateMain(); } #endregion #region MainViewModel private static MainViewModel _main; /// <summary> /// Gets the Main property. /// </summary> public static MainViewModel MainStatic { get { if (_main == null) { CreateMain(); } return _main; } } /// <summary> /// Gets the Main property. /// </summary> [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1822:MarkMembersAsStatic", Justification = "This non-static member is needed for data binding purposes.")] public MainViewModel Main { get { return MainStatic; } } /// <summary> /// Provides a deterministic way to delete the Main property. /// </summary> public static void ClearMain() { _main.Cleanup(); _main = null; } /// <summary> /// Provides a deterministic way to create the Main property. /// </summary> public static void CreateMain() { if (_main == null) { // allow Unity to resolve the view model and hold onto reference _main = Container.Resolve<MainViewModel>(); } } #endregion #region OrderViewModel // property to hold the order number (injected into OrderViewModel() constructor when resolved) public static string OrderToView { get; set; } /// <summary> /// Gets the OrderViewModel property. /// </summary> public static OrderViewModel OrderViewModelStatic { get { // allow Unity to resolve the view model // do not keep local reference to the instance resolved because we need a new instance // each time - the corresponding View is a UserControl that can be used multiple times // within a single window/view // pass current value of OrderToView parameter to constructor! return Container.Resolve<OrderViewModel>(new ParameterOverride("orderNumber", OrderToView)); } } /// <summary> /// Gets the OrderViewModel property. /// </summary> [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1822:MarkMembersAsStatic", Justification = "This non-static member is needed for data binding purposes.")] public OrderViewModel Order { get { return OrderViewModelStatic; } } #endregion /// <summary> /// Cleans up all the resources. /// </summary> public static void Cleanup() { ClearMain(); Container = null; } } } And the MainViewModel class showing dependency injection usage: using GalaSoft.MvvmLight; using Microsoft.Practices.Unity; namespace MVVMLightUnityExample { public class MainViewModel : ViewModelBase { private IDialogService _dialogs; private ILoggerService _logger; /// <summary> /// Initializes a new instance of the MainViewModel class. This default constructor calls the /// non-default constructor resolving the interfaces used by this view model. /// </summary> public MainViewModel() : this(ViewModelLocator.Container.Resolve<IDialogService>(), ViewModelLocator.Container.Resolve<ILoggerService>()) { if (IsInDesignMode) { // Code runs in Blend --> create design time data. } else { // Code runs "for real" } } /// <summary> /// Initializes a new instance of the MainViewModel class. /// Interfaces are automatically resolved by the IoC container. /// </summary> /// <param name="dialogs">Interface to dialog service</param> /// <param name="logger">Interface to logger service</param> public MainViewModel(IDialogService dialogs, ILoggerService logger) { _dialogs = dialogs; _logger = logger; if (IsInDesignMode) { // Code runs in Blend --> create design time data. _dialogs.ShowMessage("Running in design-time mode!", "Injection Constructor", DialogButton.OK, DialogImage.Information); _logger.WriteLine("Running in design-time mode!"); } else { // Code runs "for real" _dialogs.ShowMessage("Running in run-time mode!", "Injection Constructor", DialogButton.OK, DialogImage.Information); _logger.WriteLine("Running in run-time mode!"); } } public override void Cleanup() { // Clean up if needed _dialogs = null; _logger = null; base.Cleanup(); } } } And the OrderViewModel class: using GalaSoft.MvvmLight; using Microsoft.Practices.Unity; namespace MVVMLightUnityExample { /// <summary> /// This class contains properties that a View can data bind to. /// <para> /// Use the <strong>mvvminpc</strong> snippet to add bindable properties to this ViewModel. /// </para> /// <para> /// You can also use Blend to data bind with the tool's support. /// </para> /// <para> /// See http://www.galasoft.ch/mvvm/getstarted /// </para> /// </summary> public class OrderViewModel : ViewModelBase { private const string testOrderNumber = "123456"; private Order _order; /// <summary> /// Initializes a new instance of the OrderViewModel class. /// </summary> public OrderViewModel() : this(testOrderNumber) { } /// <summary> /// Initializes a new instance of the OrderViewModel class. /// </summary> public OrderViewModel(string orderNumber) { if (IsInDesignMode) { // Code runs in Blend --> create design time data. _order = new Order(orderNumber, "My Company", "Our Address"); } else { _order = GetOrder(orderNumber); } } public override void Cleanup() { // Clean own resources if needed _order = null; base.Cleanup(); } } } And the code that could be used to display an order view for a specific order: public void ShowOrder(string orderNumber) { // pass the order number to show to ViewModelLocator to be injected //into the constructor of the OrderViewModel instance ViewModelLocator.OrderToShow = orderNumber; View.OrderView orderView = new View.OrderView(); } These examples have been stripped down to show only the IoC ideas. It took a lot of trial and error, searching the internet for examples, and finding out that the Unity 2.0 documentation is lacking (at best) to come up with this solution. Let me know if you think it could be improved.

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  • Error with my Android Application httpGet

    - by Coombes
    Basically I'm getting a strange issue with my Android application, it's supposed to grab a JSON Array and print out some values, the class looks like this: ShowComedianActivity.class package com.example.connecttest; public class ShowComedianActivity extends Activity{ TextView name; TextView add; TextView email; TextView tel; String id; // Progress Dialog private ProgressDialog pDialog; //JSON Parser class JSONParser jsonParser = new JSONParser(); // Single Comedian url private static final String url_comedian_details = "http://86.9.71.17/connect/get_comedian_details.php"; // JSON Node names private static final String TAG_SUCCESS = "success"; private static final String TAG_COMEDIAN = "comedian"; private static final String TAG_ID = "id"; private static final String TAG_NAME = "name"; private static final String TAG_ADDRESS = "address"; private static final String TAG_EMAIL = "email"; private static final String TAG_TEL = "tel"; public void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.show_comedian); // Getting Comedian Details from intent Intent i = getIntent(); // Getting id from intent id = i.getStringExtra(TAG_ID); new GetComedianDetails().execute(); } class GetComedianDetails extends AsyncTask<String, String, String>{ protected void onPreExecute(){ super.onPreExecute(); pDialog = new ProgressDialog(ShowComedianActivity.this); pDialog.setMessage("Fetching Comedian details. Please wait..."); pDialog.setIndeterminate(false); pDialog.setCancelable(true); pDialog.show(); } @Override protected String doInBackground(String... params) { runOnUiThread(new Runnable(){ public void run(){ int success; try{ //Building parameters List<NameValuePair> params = new ArrayList<NameValuePair>(); params.add(new BasicNameValuePair("id",id)); // Getting comedian details via HTTP request // Uses a GET request JSONObject json = jsonParser.makeHttpRequest(url_comedian_details, "GET", params); // Check Log for json response Log.d("Single Comedian details", json.toString()); //JSON Success tag success = json.getInt(TAG_SUCCESS); if(success == 1){ // Succesfully received product details JSONArray comedianObj = json.getJSONArray(TAG_COMEDIAN); //JSON Array // get first comedian object from JSON Array JSONObject comedian = comedianObj.getJSONObject(0); // comedian with id found name = (TextView) findViewById(R.id.name); add = (TextView) findViewById(R.id.add); email = (TextView) findViewById(R.id.email); tel = (TextView) findViewById(R.id.tel); // Set text to details name.setText(comedian.getString(TAG_NAME)); add.setText(comedian.getString(TAG_ADDRESS)); email.setText(comedian.getString(TAG_EMAIL)); tel.setText(comedian.getString(TAG_TEL)); } } catch (JSONException e){ e.printStackTrace(); } } }); return null; } } } And my JSON Parser class looks like: package com.example.connecttest; public class JSONParser { static InputStream is = null; static JSONObject jObj = null; static String json = ""; // constructor public JSONParser() { } // function get json from url // by making HTTP POST or GET method public JSONObject makeHttpRequest(String url, String method, List<NameValuePair> params) { // Making HTTP request try { // check for request method if(method == "POST"){ // request method is POST // defaultHttpClient DefaultHttpClient httpClient = new DefaultHttpClient(); HttpPost httpPost = new HttpPost(url); httpPost.setEntity(new UrlEncodedFormEntity(params)); HttpResponse httpResponse = httpClient.execute(httpPost); HttpEntity httpEntity = httpResponse.getEntity(); is = httpEntity.getContent(); }else if(method == "GET"){ // request method is GET DefaultHttpClient httpClient = new DefaultHttpClient(); String paramString = URLEncodedUtils.format(params, "utf-8"); url += "?" + paramString; HttpGet httpGet = new HttpGet(url); HttpResponse httpResponse = httpClient.execute(httpGet); HttpEntity httpEntity = httpResponse.getEntity(); is = httpEntity.getContent(); } } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } try { BufferedReader reader = new BufferedReader(new InputStreamReader( is, "iso-8859-1"), 8); StringBuilder sb = new StringBuilder(); String line = null; while ((line = reader.readLine()) != null) { sb.append(line + "\n"); } is.close(); json = sb.toString(); } catch (Exception e) { Log.e("Buffer Error", "Error converting result " + e.toString()); } // try parse the string to a JSON object try { jObj = new JSONObject(json); } catch (JSONException e) { Log.e("JSON Parser", "Error parsing data " + e.toString()); } // return JSON String return jObj; } } Now when I run a debug it's querying the correct address with ?id=1 on the end of the URL, and when I navigate to that url I get the following JSON Array: {"success":1,"comedian":[{"id":"1","name":"Michael Coombes","address":"5 Trevethenick Road","email":"[email protected]","tel":"xxxxxxxxxxxx"}]} However my app just crashes, the log-cat report looks like this: 03-22 02:05:02.140: E/Trace(3776): error opening trace file: No such file or directory (2) 03-22 02:05:04.590: E/AndroidRuntime(3776): FATAL EXCEPTION: main 03-22 02:05:04.590: E/AndroidRuntime(3776): android.os.NetworkOnMainThreadException 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117) 03-22 02:05:04.590: E/AndroidRuntime(3776): at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84) 03-22 02:05:04.590: E/AndroidRuntime(3776): at libcore.io.IoBridge.connectErrno(IoBridge.java:127) 03-22 02:05:04.590: E/AndroidRuntime(3776): at libcore.io.IoBridge.connect(IoBridge.java:112) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.net.Socket.connect(Socket.java:842) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:144) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465) 03-22 02:05:04.590: E/AndroidRuntime(3776): at com.example.connecttest.JSONParser.makeHttpRequest(JSONParser.java:62) 03-22 02:05:04.590: E/AndroidRuntime(3776): at com.example.connecttest.ShowComedianActivity$GetComedianDetails$1.run(ShowComedianActivity.java:89) 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.os.Handler.handleCallback(Handler.java:615) 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.os.Handler.dispatchMessage(Handler.java:92) 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.os.Looper.loop(Looper.java:137) 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.app.ActivityThread.main(ActivityThread.java:4745) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.lang.reflect.Method.invokeNative(Native Method) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.lang.reflect.Method.invoke(Method.java:511) 03-22 02:05:04.590: E/AndroidRuntime(3776): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 03-22 02:05:04.590: E/AndroidRuntime(3776): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 03-22 02:05:04.590: E/AndroidRuntime(3776): at dalvik.system.NativeStart.main(Native Method) From this I'm guessing the error is in the jsonParser.makeHttpRequest however I can't for the life of me figure out what's going wrong and was hoping someone brighter than I could illuminate me.

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  • C# performance analysis- how to count CPU cycles?

    - by Lirik
    Is this a valid way to do performance analysis? I want to get nanosecond accuracy and determine the performance of typecasting: class PerformanceTest { static double last = 0.0; static List<object> numericGenericData = new List<object>(); static List<double> numericTypedData = new List<double>(); static void Main(string[] args) { double totalWithCasting = 0.0; double totalWithoutCasting = 0.0; for (double d = 0.0; d < 1000000.0; ++d) { numericGenericData.Add(d); numericTypedData.Add(d); } Stopwatch stopwatch = new Stopwatch(); for (int i = 0; i < 10; ++i) { stopwatch.Start(); testWithTypecasting(); stopwatch.Stop(); totalWithCasting += stopwatch.ElapsedTicks; stopwatch.Start(); testWithoutTypeCasting(); stopwatch.Stop(); totalWithoutCasting += stopwatch.ElapsedTicks; } Console.WriteLine("Avg with typecasting = {0}", (totalWithCasting/10)); Console.WriteLine("Avg without typecasting = {0}", (totalWithoutCasting/10)); Console.ReadKey(); } static void testWithTypecasting() { foreach (object o in numericGenericData) { last = ((double)o*(double)o)/200; } } static void testWithoutTypeCasting() { foreach (double d in numericTypedData) { last = (d * d)/200; } } } The output is: Avg with typecasting = 468872.3 Avg without typecasting = 501157.9 I'm a little suspicious... it looks like there is nearly no impact on the performance. Is casting really that cheap?

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