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  • How to make smooth movements in OpenGL?

    - by thyrgle
    So this kind of on topic to my other OpenGL question (not my OpenGL ES question but OpenGL the desktop version). If you have someone press a key to move a square how do you make the square movement naturally and less jumpy but also at the same speed I have it now? This is my code for the glutKeyboardFunc() function: void handleKeypress(unsigned char key, int x, int y) { if (key == 'w') { for (int i = 0; i < 12; i++) { if (i == 1 || i == 7 || i == 10 || i == 4) { square[i] = square[i] + 1; } } glutPostRedisplay(); } if (key == 'd') { for (int i = 0; i < 12; i++) { if (i == 0 || i % 3 == 0) { square[i] = square[i] + 1; } } glutPostRedisplay(); } if (key == 's') { for (int i = 0; i < 12; i++) { if (i == 1 || i == 7 || i == 10 || i == 4) { square[i] = square[i] - 1; } } glutPostRedisplay(); } if (key == 'a') { for (int i = 0; i < 12; i++) { if (i == 0 || i % 3 == 0) { square[i] = square[i] - 1; } } glutPostRedisplay(); } } I'm sorry if this doesn't quite make sense I'll try to rephrase it in a better way if it doesn't make sense.

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  • method works fine, until it is called in a function, then UnboundLocalError

    - by user1776100
    I define a method called dist, to calculate the distance between two points which I does it correctly when directly using the method. However, when I get a function to call it to calculate the distance between two points, I get UnboundLocalError: local variable 'minkowski_distance' referenced before assignment edit sorry, I just realised, this function does work. However I have another method calling it that doesn't. I put the last method at the bottom This is the method: class MinkowskiDistance(Distance): def __init__(self, dist_funct_name_str = 'Minkowski distance', p=2): self.p = p def dist(self, obj_a, obj_b): distance_to_power_p=0 p=self.p for i in range(len(obj_a)): distance_to_power_p += abs((obj_a[i]-obj_b[i]))**(p) minkowski_distance = (distance_to_power_p)**(1/p) return minkowski_distance and this is the function: (it basically splits the tuples x and y into their number and string components and calculates the distance between the numeric part of x and y and then the distance between the string parts, then adds them. def total_dist(x, y, p=2, q=2): jacard = QGramDistance(q=q) minkowski = MinkowskiDistance(p=p) x_num = [] x_str = [] y_num = [] y_str = [] #I am spliting each vector into its numerical parts and its string parts so that the distances #of each part can be found, then summed together. for i in range(len(x)): if type(x[i]) == float or type(x[i]) == int: x_num.append(x[i]) y_num.append(y[i]) else: x_str.append(x[i]) y_str.append(y[i]) num_dist = minkowski.dist(x_num,y_num) str_dist = I find using some more steps #I am simply adding the two types of distance to get the total distance: return num_dist + str_dist class NearestNeighbourClustering(Clustering): def __init__(self, data_file, clust_algo_name_str='', strip_header = "no", remove = -1): self.data_file= data_file self.header_strip = strip_header self.remove_column = remove def run_clustering(self, max_dist, p=2, q=2): K = {} #dictionary of clusters data_points = self.read_data_file() K[0]=[data_points[0]] k=0 #I added the first point in the data to the 0th cluster #k = number of clusters minus 1 n = len(data_points) for i in range(1,n): data_point_in_a_cluster = "no" for c in range(k+1): distances_from_i = [total_dist(data_points[i],K[c][j], p=p, q=q) for j in range(len(K[c]))] d = min(distances_from_i) if d <= max_dist: K[c].append(data_points[i]) data_point_in_a_cluster = "yes" if data_point_in_a_cluster == "no": k += 1 K[k]=[data_points[i]] return K

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  • Calling a constructor from method within the same class

    - by Nathan
    I'm new to java and I'm learning about creating object classes. One of my homework assignment requires that I call the constructor at least once within a method of the same object class. I'm getting an error that says The method DoubleMatrix(double[][]) is undefined for the type DoubleMatrix Here's my constructor: public DoubleMatrix(double[][] tempArray) { // Declaration int flag = 0; int cnt; // Statement // check to see if doubArray isn't null and has more than 0 rows if(tempArray == null || tempArray.length < 0) { flag++; } // check to see if each row has the same length if(flag == 0) { for(cnt = 0; cnt <= tempArray.length - 1 || flag != 1; cnt++) { if(tempArray[cnt + 1].length != tempArray[0].length) { flag++; } } } else if(flag == 1) { makeDoubMatrix(1, 1);// call makeDoubMatrix method } }// end constructor 2 Here's the method where I try and call the constructor: public double[][] addMatrix(double[][] tempDoub) { // Declaration double[][] newMatrix; int rCnt, cCnt; //Statement // checking to see if both are of same dimension if(doubMatrix.length == tempDoub.length && doubMatrix[0].length == tempDoub[0].length) { newMatrix = new double[doubMatrix.length][doubMatrix[0].length]; // for loop to add matrix to a new one for(rCnt = 0; rCnt <= doubMatrix.length; rCnt++) { for(cCnt = 0; cCnt <= doubMatrix.length; cCnt++) { newMatrix[rCnt][cCnt] = doubMatrix[rCnt][cCnt] + tempDoub[rCnt][cCnt]; } } } else { newMatrix = new double[0][0]; DoubleMatrix(newMatrix) } return newMatrix; }// end addMatrix method Can someone point me to the right direction and explain why I'm getting an error?

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  • saveOrUpdate(Object) method of Hibernate

    - by Vikram
    when i use saveOrUpdate(Object) method of Hibernate. How can I know that row is updated or new row added into table??? Return type of method saveOrUpdate(Object) is void, so am not able to find out the result after calling this method. kindly help me.

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  • Are very short or abbreviated method/function names that don't use full words bad practice or a matter of style.

    - by Alb
    Is there nowadays any case for brevity over clarity with method names? Tonight I came across the Python method repr() which seems like a bad name for a method to me. It's not an English word. It apparently is an abbreviation of 'representation' and even if you can deduce that, it still doesn't tell you what the method does. A good method name is subjective to a certain degree, but I had assumed that modern best practices agreed that names should be at least full words and descriptive enough to reveal enough about the method that you would easily find one when looking for it. Method names made from words help let your code read like English. repr() seems to have no advantages as a name other than being short and IDE auto-complete makes this a non-issue. An additional reason given in an answer is that python names are brief so that you can do many things on one line. Surely the better way is to just extract the many things to their own function, and repeat until lines are not too long. Are these just a hangover from the unix way of doing things? Commands with names like ls, rm, ps and du (if you could call those names) were hard to find and hard to remember. I know that the everyday usage of commands such as these is different than methods in code so the matter of whether those are bad names is a different matter.

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  • Are short abbreviated method/function names that don't use full words bad practice or a matter of style?

    - by Alb
    Is there nowadays any case for brevity over clarity with method names? Tonight I came across the Python method repr() which seems like a bad name for a method to me. It's not an English word. It apparently is an abbreviation of 'representation' and even if you can deduce that, it still doesn't tell you what the method does. A good method name is subjective to a certain degree, but I had assumed that modern best practices agreed that names should be at least full words and descriptive enough to reveal enough about the method that you would easily find one when looking for it. Method names made from words help let your code read like English. repr() seems to have no advantages as a name other than being short and IDE auto-complete makes this a non-issue. An additional reason given in an answer is that python names are brief so that you can do many things on one line. Surely the better way is to just extract the many things to their own function, and repeat until lines are not too long. Are these just a hangover from the unix way of doing things? Commands with names like ls, rm, ps and du (if you could call those names) were hard to find and hard to remember. I know that the everyday usage of commands such as these is different than methods in code so the matter of whether those are bad names is a different matter.

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  • BAD ARCHIVE MIRROR using PXE BOOT method

    - by omkar
    i m trying to automatically install UBUNTU on a client PC by using the method of PXE BOOT method....my Objectives are below:- i m following the steps given in this link installation using PXE BOOT INSTALL 1:-the server will have a KICKSTART config file which contains the parameters for the OS installation and the files which are required for the OS installations. 2:-the client will have to detect this configuration along with the setup files and complete the installation without any input from the user. In my server i have installed DHCP3-server,Apache2 and TFTP for helping me with the installation. i have nearly achieved my first objective,i m able to boot my client using the files stored in the server,but during the installation stage it is asking me to "CHOOSE A MIRROR of UBUNTU ARCHIVE".i gave the server's IP address and the path in the server where the files are located but then too its giving me error "BAD ARCHIVE MIRROR". so is it possible that instead of downloading all the files from the internet and storing them on my disk , can i use the files which comes with the UBUNTU-CD, and how to store this files in what format (should i zip them ) on the disk. secondly i am also generating the ks.cfg which i wanted to give to the client for automatic installation of the OS ,so how should the configuration file be given to the installation process.

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  • Using LDAP as auth method for git repositories

    - by Lenni
    I want to convince my boss that we should be using git for version control. He says, that it absolutely must authenticate users through our central LDAP server. I looked at the various solutions (gitweb, gitorious ... ) and couln't really find a definitive answer about whether they support LDAP authentication. The only solution I could find a little info on was a Apache+mod_ldap setting. But that would mean that the user authenticating on LDAP wouldn't necessarily be the same as the actual git user, right? (Not that this is a huge problem, but just something which would bug me.) So, what's the best way to authenticate git users via LDAP?

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  • What does "fully supported" mean in context of Radeon Opensource Video Driver?

    - by stevecoh1
    UPDATE: This is not a request for support of my specific issue. Details of that issue are here: How to recover from bad upgrade to 13.04 (Unity very slow) . I have "solved" that issue, for the time being anyway, by loading alternative lighter weight desktops. This question was opened specifically to question the meaning of the documentation at https://help.ubuntu.com/community/RadeonDriver . END OF UPDATE There it is, in Black and White: https://help.ubuntu.com/community/RadeonDriver Fully Supported All these Radeon(HD) cards and derivatives have good 3D acceleration support. This is not an exhaustive list: ... RV610/RV630 Radeon HD 2400/2600/2700/4200/4225/4250 Yet in my case (the HD2400) this proves to be manifestly untrue, at least if "Fully Supported" means sufficient to run Unity in Ubuntu 13.04. It runs all the applications I can launch under Unity, but Unity itself is unbearably slow. It's quite striking really. Click on the "Dash" - go get a cup of coffee. Type a key in the Unity search box, wait five seconds for it to appear. Type Alt-tab and wait five seconds for the screen to finish painting. None of these issues appear outside of Unity components. As you all know, there are complaints about slow performance all over the Internet about Unity. Shouldn't this page somehow address this issue? Especially if "fully supported" doesn't mean sufficiently to run the default modern Ubuntu release. What does "fully supported" mean?

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  • - (void)alertViewCancel:(UIAlertView *)alertView is not called

    - by Sean
    Hi all I've got the problem that the UIAlertViewDelegate method - (void)alertViewCancel:(UIAlertView *)alertView is not called when I cancel a AlertView with it's cancel button. Weird is that the delegate method - (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex works perfectly. Does anyone have an idea? Thanks in advance Sean

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  • python3: removing several chars from a string with a long chain of .replace().replace().replace()

    - by MadSc13ntist
    I found this example on stack overflow. I understand it, but seems like a bit much for such a simple method concept... removing several chars from a string. import string exclude = set(string.punctuation) s = ''.join(ch for ch in s if ch not in exclude) is there a builtin string method in python 3.1 to do something to the tune of: s = "a,b,c,d,e,f,g,h,i" s = s.strip([",", "d", "h"]) instead of: s = s.replace(",", "").replace("d", "").replace("h", "")

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  • Ruby - How to remove a setter on an object

    - by Markus Orrelly
    Given a class like this: class B class << self attr_accessor :var end end Suppose I can't modify the original source code of class B. How might I go about removing the setter on the class variable var? I've tried using something like B.send("unset_method", "var="), but that doesn't work (nor does remove_method, or overwriting that method with a var= method that doesn't do anything). Any ideas?

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  • How to implement callback methods inside classes (PHP)

    - by sombe
    I need to use a class callback method on an array inside another method (the callback function belongs to the class). class Database { public function escape_string_for_db($string){ return mysql_real_escape_string($string); } public function escape_all_array($array){ return array_filter($array,"$this->escape_string_for_db"); } } Is this the right way to go about that? (I mean, in terms of the second parameter passed to array_filter)

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  • Overriding jQuery plugin methods, as default and for single instances

    - by Kilgore2k
    Hi, The basic question is: How do I perform a basic override of a plugin method without editing the original plugin file? Is it possible to create an override for a specific instance: Example: An rtf plugin uses: $('selector').wysiwyg('setContent',newContent); In order to display the rtf text as readonly I would like for the same method to be applied to a div instead of the body of the IFRAME I would like to overwrite the original 'setContent' with my own code, just for this one element. Thanks

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  • Overloading methods in C#

    - by Craig Johnston
    Is there a way to simplify the process of adding an overloaded method in C# using VS2005? In VB6, I would have just added an Optional parameter the function, but in C# do I have to have to type out a whole new method with this new parameter?

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  • How to implement callback functions inside classes (PHP)

    - by sombe
    I need to use a class callback method on an array inside another method (the callback function belongs to the class). class Database { public function escape_string_for_db($string){ return mysql_real_escape_string($string); } public function escape_all_array($array){ return array_filter($array,"$this->escape_string_for_db"); } } Is this the right way to go about that? (I mean, in terms of the second parameter passed to array_filter)

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  • Custom ASP.NET Routing to an HttpHandler

    - by Rick Strahl
    As of version 4.0 ASP.NET natively supports routing via the now built-in System.Web.Routing namespace. Routing features are automatically integrated into the HtttpRuntime via a few custom interfaces. New Web Forms Routing Support In ASP.NET 4.0 there are a host of improvements including routing support baked into Web Forms via a RouteData property available on the Page class and RouteCollection.MapPageRoute() route handler that makes it easy to route to Web forms. To map ASP.NET Page routes is as simple as setting up the routes with MapPageRoute:protected void Application_Start(object sender, EventArgs e) { RegisterRoutes(RouteTable.Routes); } void RegisterRoutes(RouteCollection routes) { routes.MapPageRoute("StockQuote", "StockQuote/{symbol}", "StockQuote.aspx"); routes.MapPageRoute("StockQuotes", "StockQuotes/{symbolList}", "StockQuotes.aspx"); } and then accessing the route data in the page you can then use the new Page class RouteData property to retrieve the dynamic route data information:public partial class StockQuote1 : System.Web.UI.Page { protected StockQuote Quote = null; protected void Page_Load(object sender, EventArgs e) { string symbol = RouteData.Values["symbol"] as string; StockServer server = new StockServer(); Quote = server.GetStockQuote(symbol); // display stock data in Page View } } Simple, quick and doesn’t require much explanation. If you’re using WebForms most of your routing needs should be served just fine by this simple mechanism. Kudos to the ASP.NET team for putting this in the box and making it easy! How Routing Works To handle Routing in ASP.NET involves these steps: Registering Routes Creating a custom RouteHandler to retrieve an HttpHandler Attaching RouteData to your HttpHandler Picking up Route Information in your Request code Registering routes makes ASP.NET aware of the Routes you want to handle via the static RouteTable.Routes collection. You basically add routes to this collection to let ASP.NET know which URL patterns it should watch for. You typically hook up routes off a RegisterRoutes method that fires in Application_Start as I did in the example above to ensure routes are added only once when the application first starts up. When you create a route, you pass in a RouteHandler instance which ASP.NET caches and reuses as routes are matched. Once registered ASP.NET monitors the routes and if a match is found just prior to the HttpHandler instantiation, ASP.NET uses the RouteHandler registered for the route and calls GetHandler() on it to retrieve an HttpHandler instance. The RouteHandler.GetHandler() method is responsible for creating an instance of an HttpHandler that is to handle the request and – if necessary – to assign any additional custom data to the handler. At minimum you probably want to pass the RouteData to the handler so the handler can identify the request based on the route data available. To do this you typically add  a RouteData property to your handler and then assign the property from the RouteHandlers request context. This is essentially how Page.RouteData comes into being and this approach should work well for any custom handler implementation that requires RouteData. It’s a shame that ASP.NET doesn’t have a top level intrinsic object that’s accessible off the HttpContext object to provide route data more generically, but since RouteData is directly tied to HttpHandlers and not all handlers support it it might cause some confusion of when it’s actually available. Bottom line is that if you want to hold on to RouteData you have to assign it to a custom property of the handler or else pass it to the handler via Context.Items[] object that can be retrieved on an as needed basis. It’s important to understand that routing is hooked up via RouteHandlers that are responsible for loading HttpHandler instances. RouteHandlers are invoked for every request that matches a route and through this RouteHandler instance the Handler gains access to the current RouteData. Because of this logic it’s important to understand that Routing is really tied to HttpHandlers and not available prior to handler instantiation, which is pretty late in the HttpRuntime’s request pipeline. IOW, Routing works with Handlers but not with earlier in the pipeline within Modules. Specifically ASP.NET calls RouteHandler.GetHandler() from the PostResolveRequestCache HttpRuntime pipeline event. Here’s the call stack at the beginning of the GetHandler() call: which fires just before handler resolution. Non-Page Routing – You need to build custom RouteHandlers If you need to route to a custom Http Handler or other non-Page (and non-MVC) endpoint in the HttpRuntime, there is no generic mapping support available. You need to create a custom RouteHandler that can manage creating an instance of an HttpHandler that is fired in response to a routed request. Depending on what you are doing this process can be simple or fairly involved as your code is responsible based on the route data provided which handler to instantiate, and more importantly how to pass the route data on to the Handler. Luckily creating a RouteHandler is easy by implementing the IRouteHandler interface which has only a single GetHttpHandler(RequestContext context) method. In this method you can pick up the requestContext.RouteData, instantiate the HttpHandler of choice, and assign the RouteData to it. Then pass back the handler and you’re done.Here’s a simple example of GetHttpHandler() method that dynamically creates a handler based on a passed in Handler type./// <summary> /// Retrieves an Http Handler based on the type specified in the constructor /// </summary> /// <param name="requestContext"></param> /// <returns></returns> IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; // If we're dealing with a Callback Handler // pass the RouteData for this route to the Handler if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; } Note that this code checks for a specific type of handler and if it matches assigns the RouteData to this handler. This is optional but quite a common scenario if you want to work with RouteData. If the handler you need to instantiate isn’t under your control but you still need to pass RouteData to Handler code, an alternative is to pass the RouteData via the HttpContext.Items collection:IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; requestContext.HttpContext.Items["RouteData"] = requestContext.RouteData; return handler; } The code in the handler implementation can then pick up the RouteData from the context collection as needed:RouteData routeData = HttpContext.Current.Items["RouteData"] as RouteData This isn’t as clean as having an explicit RouteData property, but it does have the advantage that the route data is visible anywhere in the Handler’s code chain. It’s definitely preferable to create a custom property on your handler, but the Context work-around works in a pinch when you don’t’ own the handler code and have dynamic code executing as part of the handler execution. An Example of a Custom RouteHandler: Attribute Based Route Implementation In this post I’m going to discuss a custom routine implementation I built for my CallbackHandler class in the West Wind Web & Ajax Toolkit. CallbackHandler can be very easily used for creating AJAX, REST and POX requests following RPC style method mapping. You can pass parameters via URL query string, POST data or raw data structures, and you can retrieve results as JSON, XML or raw string/binary data. It’s a quick and easy way to build service interfaces with no fuss. As a quick review here’s how CallbackHandler works: You create an Http Handler that derives from CallbackHandler You implement methods that have a [CallbackMethod] Attribute and that’s it. Here’s an example of an CallbackHandler implementation in an ashx.cs based handler:// RestService.ashx.cs public class RestService : CallbackHandler { [CallbackMethod] public StockQuote GetStockQuote(string symbol) { StockServer server = new StockServer(); return server.GetStockQuote(symbol); } [CallbackMethod] public StockQuote[] GetStockQuotes(string symbolList) { StockServer server = new StockServer(); string[] symbols = symbolList.Split(new char[2] { ',',';' },StringSplitOptions.RemoveEmptyEntries); return server.GetStockQuotes(symbols); } } CallbackHandler makes it super easy to create a method on the server, pass data to it via POST, QueryString or raw JSON/XML data, and then retrieve the results easily back in various formats. This works wonderful and I’ve used these tools in many projects for myself and with clients. But one thing missing has been the ability to create clean URLs. Typical URLs looked like this: http://www.west-wind.com/WestwindWebToolkit/samples/Rest/StockService.ashx?Method=GetStockQuote&symbol=msfthttp://www.west-wind.com/WestwindWebToolkit/samples/Rest/StockService.ashx?Method=GetStockQuotes&symbolList=msft,intc,gld,slw,mwe&format=xml which works and is clear enough, but also clearly very ugly. It would be much nicer if URLs could look like this: http://www.west-wind.com//WestwindWebtoolkit/Samples/StockQuote/msfthttp://www.west-wind.com/WestwindWebtoolkit/Samples/StockQuotes/msft,intc,gld,slw?format=xml (the Virtual Root in this sample is WestWindWebToolkit/Samples and StockQuote/{symbol} is the route)(If you use FireFox try using the JSONView plug-in make it easier to view JSON content) So, taking a clue from the WCF REST tools that use RouteUrls I set out to create a way to specify RouteUrls for each of the endpoints. The change made basically allows changing the above to: [CallbackMethod(RouteUrl="RestService/StockQuote/{symbol}")] public StockQuote GetStockQuote(string symbol) { StockServer server = new StockServer(); return server.GetStockQuote(symbol); } [CallbackMethod(RouteUrl = "RestService/StockQuotes/{symbolList}")] public StockQuote[] GetStockQuotes(string symbolList) { StockServer server = new StockServer(); string[] symbols = symbolList.Split(new char[2] { ',',';' },StringSplitOptions.RemoveEmptyEntries); return server.GetStockQuotes(symbols); } where a RouteUrl is specified as part of the Callback attribute. And with the changes made with RouteUrls I can now get URLs like the second set shown earlier. So how does that work? Let’s find out… How to Create Custom Routes As mentioned earlier Routing is made up of several steps: Creating a custom RouteHandler to create HttpHandler instances Mapping the actual Routes to the RouteHandler Retrieving the RouteData and actually doing something useful with it in the HttpHandler In the CallbackHandler routing example above this works out to something like this: Create a custom RouteHandler that includes a property to track the method to call Set up the routes using Reflection against the class Looking for any RouteUrls in the CallbackMethod attribute Add a RouteData property to the CallbackHandler so we can access the RouteData in the code of the handler Creating a Custom Route Handler To make the above work I created a custom RouteHandler class that includes the actual IRouteHandler implementation as well as a generic and static method to automatically register all routes marked with the [CallbackMethod(RouteUrl="…")] attribute. Here’s the code:/// <summary> /// Route handler that can create instances of CallbackHandler derived /// callback classes. The route handler tracks the method name and /// creates an instance of the service in a predictable manner /// </summary> /// <typeparam name="TCallbackHandler">CallbackHandler type</typeparam> public class CallbackHandlerRouteHandler : IRouteHandler { /// <summary> /// Method name that is to be called on this route. /// Set by the automatically generated RegisterRoutes /// invokation. /// </summary> public string MethodName { get; set; } /// <summary> /// The type of the handler we're going to instantiate. /// Needed so we can semi-generically instantiate the /// handler and call the method on it. /// </summary> public Type CallbackHandlerType { get; set; } /// <summary> /// Constructor to pass in the two required components we /// need to create an instance of our handler. /// </summary> /// <param name="methodName"></param> /// <param name="callbackHandlerType"></param> public CallbackHandlerRouteHandler(string methodName, Type callbackHandlerType) { MethodName = methodName; CallbackHandlerType = callbackHandlerType; } /// <summary> /// Retrieves an Http Handler based on the type specified in the constructor /// </summary> /// <param name="requestContext"></param> /// <returns></returns> IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; // If we're dealing with a Callback Handler // pass the RouteData for this route to the Handler if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; } /// <summary> /// Generic method to register all routes from a CallbackHandler /// that have RouteUrls defined on the [CallbackMethod] attribute /// </summary> /// <typeparam name="TCallbackHandler">CallbackHandler Type</typeparam> /// <param name="routes"></param> public static void RegisterRoutes<TCallbackHandler>(RouteCollection routes) { // find all methods var methods = typeof(TCallbackHandler).GetMethods(BindingFlags.Instance | BindingFlags.Public); foreach (var method in methods) { var attrs = method.GetCustomAttributes(typeof(CallbackMethodAttribute), false); if (attrs.Length < 1) continue; CallbackMethodAttribute attr = attrs[0] as CallbackMethodAttribute; if (string.IsNullOrEmpty(attr.RouteUrl)) continue; // Add the route routes.Add(method.Name, new Route(attr.RouteUrl, new CallbackHandlerRouteHandler(method.Name, typeof(TCallbackHandler)))); } } } The RouteHandler implements IRouteHandler, and its responsibility via the GetHandler method is to create an HttpHandler based on the route data. When ASP.NET calls GetHandler it passes a requestContext parameter which includes a requestContext.RouteData property. This parameter holds the current request’s route data as well as an instance of the current RouteHandler. If you look at GetHttpHandler() you can see that the code creates an instance of the handler we are interested in and then sets the RouteData property on the handler. This is how you can pass the current request’s RouteData to the handler. The RouteData object also has a  RouteData.RouteHandler property that is also available to the Handler later, which is useful in order to get additional information about the current route. In our case here the RouteHandler includes a MethodName property that identifies the method to execute in the handler since that value no longer comes from the URL so we need to figure out the method name some other way. The method name is mapped explicitly when the RouteHandler is created and here the static method that auto-registers all CallbackMethods with RouteUrls sets the method name when it creates the routes while reflecting over the methods (more on this in a minute). The important point here is that you can attach additional properties to the RouteHandler and you can then later access the RouteHandler and its properties later in the Handler to pick up these custom values. This is a crucial feature in that the RouteHandler serves in passing additional context to the handler so it knows what actions to perform. The automatic route registration is handled by the static RegisterRoutes<TCallbackHandler> method. This method is generic and totally reusable for any CallbackHandler type handler. To register a CallbackHandler and any RouteUrls it has defined you simple use code like this in Application_Start (or other application startup code):protected void Application_Start(object sender, EventArgs e) { // Register Routes for RestService CallbackHandlerRouteHandler.RegisterRoutes<RestService>(RouteTable.Routes); } If you have multiple CallbackHandler style services you can make multiple calls to RegisterRoutes for each of the service types. RegisterRoutes internally uses reflection to run through all the methods of the Handler, looking for CallbackMethod attributes and whether a RouteUrl is specified. If it is a new instance of a CallbackHandlerRouteHandler is created and the name of the method and the type are set. routes.Add(method.Name,           new Route(attr.RouteUrl, new CallbackHandlerRouteHandler(method.Name, typeof(TCallbackHandler) )) ); While the routing with CallbackHandlerRouteHandler is set up automatically for all methods that use the RouteUrl attribute, you can also use code to hook up those routes manually and skip using the attribute. The code for this is straightforward and just requires that you manually map each individual route to each method you want a routed: protected void Application_Start(objectsender, EventArgs e){    RegisterRoutes(RouteTable.Routes);}void RegisterRoutes(RouteCollection routes) { routes.Add("StockQuote Route",new Route("StockQuote/{symbol}",                     new CallbackHandlerRouteHandler("GetStockQuote",typeof(RestService) ) ) );     routes.Add("StockQuotes Route",new Route("StockQuotes/{symbolList}",                     new CallbackHandlerRouteHandler("GetStockQuotes",typeof(RestService) ) ) );}I think it’s clearly easier to have CallbackHandlerRouteHandler.RegisterRoutes() do this automatically for you based on RouteUrl attributes, but some people have a real aversion to attaching logic via attributes. Just realize that the option to manually create your routes is available as well. Using the RouteData in the Handler A RouteHandler’s responsibility is to create an HttpHandler and as mentioned earlier, natively IHttpHandler doesn’t have any support for RouteData. In order to utilize RouteData in your handler code you have to pass the RouteData to the handler. In my CallbackHandlerRouteHandler when it creates the HttpHandler instance it creates the instance and then assigns the custom RouteData property on the handler:IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; Again this only works if you actually add a RouteData property to your handler explicitly as I did in my CallbackHandler implementation:/// <summary> /// Optionally store RouteData on this handler /// so we can access it internally /// </summary> public RouteData RouteData {get; set; } and the RouteHandler needs to set it when it creates the handler instance. Once you have the route data in your handler you can access Route Keys and Values and also the RouteHandler. Since my RouteHandler has a custom property for the MethodName to retrieve it from within the handler I can do something like this now to retrieve the MethodName (this example is actually not in the handler but target is an instance pass to the processor): // check for Route Data method name if (target is CallbackHandler) { var routeData = ((CallbackHandler)target).RouteData; if (routeData != null) methodToCall = ((CallbackHandlerRouteHandler)routeData.RouteHandler).MethodName; } When I need to access the dynamic values in the route ( symbol in StockQuote/{symbol}) I can retrieve it easily with the Values collection (RouteData.Values["symbol"]). In my CallbackHandler processing logic I’m basically looking for matching parameter names to Route parameters: // look for parameters in the routeif(routeData != null){    string parmString = routeData.Values[parameter.Name] as string;    adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType);} And with that we’ve come full circle. We’ve created a custom RouteHandler() that passes the RouteData to the handler it creates. We’ve registered our routes to use the RouteHandler, and we’ve utilized the route data in our handler. For completeness sake here’s the routine that executes a method call based on the parameters passed in and one of the options is to retrieve the inbound parameters off RouteData (as well as from POST data or QueryString parameters):internal object ExecuteMethod(string method, object target, string[] parameters, CallbackMethodParameterType paramType, ref CallbackMethodAttribute callbackMethodAttribute) { HttpRequest Request = HttpContext.Current.Request; object Result = null; // Stores parsed parameters (from string JSON or QUeryString Values) object[] adjustedParms = null; Type PageType = target.GetType(); MethodInfo MI = PageType.GetMethod(method, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic); if (MI == null) throw new InvalidOperationException("Invalid Server Method."); object[] methods = MI.GetCustomAttributes(typeof(CallbackMethodAttribute), false); if (methods.Length < 1) throw new InvalidOperationException("Server method is not accessible due to missing CallbackMethod attribute"); if (callbackMethodAttribute != null) callbackMethodAttribute = methods[0] as CallbackMethodAttribute; ParameterInfo[] parms = MI.GetParameters(); JSONSerializer serializer = new JSONSerializer(); RouteData routeData = null; if (target is CallbackHandler) routeData = ((CallbackHandler)target).RouteData; int parmCounter = 0; adjustedParms = new object[parms.Length]; foreach (ParameterInfo parameter in parms) { // Retrieve parameters out of QueryString or POST buffer if (parameters == null) { // look for parameters in the route if (routeData != null) { string parmString = routeData.Values[parameter.Name] as string; adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType); } // GET parameter are parsed as plain string values - no JSON encoding else if (HttpContext.Current.Request.HttpMethod == "GET") { // Look up the parameter by name string parmString = Request.QueryString[parameter.Name]; adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType); } // POST parameters are treated as methodParameters that are JSON encoded else if (paramType == CallbackMethodParameterType.Json) //string newVariable = methodParameters.GetValue(parmCounter) as string; adjustedParms[parmCounter] = serializer.Deserialize(Request.Params["parm" + (parmCounter + 1).ToString()], parameter.ParameterType); else adjustedParms[parmCounter] = SerializationUtils.DeSerializeObject( Request.Params["parm" + (parmCounter + 1).ToString()], parameter.ParameterType); } else if (paramType == CallbackMethodParameterType.Json) adjustedParms[parmCounter] = serializer.Deserialize(parameters[parmCounter], parameter.ParameterType); else adjustedParms[parmCounter] = SerializationUtils.DeSerializeObject(parameters[parmCounter], parameter.ParameterType); parmCounter++; } Result = MI.Invoke(target, adjustedParms); return Result; } The code basically uses Reflection to loop through all the parameters available on the method and tries to assign the parameters from RouteData, QueryString or POST variables. The parameters are converted into their appropriate types and then used to eventually make a Reflection based method call. What’s sweet is that the RouteData retrieval is just another option for dealing with the inbound data in this scenario and it adds exactly two lines of code plus the code to retrieve the MethodName I showed previously – a seriously low impact addition that adds a lot of extra value to this endpoint callback processing implementation. Debugging your Routes If you create a lot of routes it’s easy to run into Route conflicts where multiple routes have the same path and overlap with each other. This can be difficult to debug especially if you are using automatically generated routes like the routes created by CallbackHandlerRouteHandler.RegisterRoutes. Luckily there’s a tool that can help you out with this nicely. Phill Haack created a RouteDebugging tool you can download and add to your project. The easiest way to do this is to grab and add this to your project is to use NuGet (Add Library Package from your Project’s Reference Nodes):   which adds a RouteDebug assembly to your project. Once installed you can easily debug your routes with this simple line of code which needs to be installed at application startup:protected void Application_Start(object sender, EventArgs e) { CallbackHandlerRouteHandler.RegisterRoutes<StockService>(RouteTable.Routes); // Debug your routes RouteDebug.RouteDebugger.RewriteRoutesForTesting(RouteTable.Routes); } Any routed URL then displays something like this: The screen shows you your current route data and all the routes that are mapped along with a flag that displays which route was actually matched. This is useful – if you have any overlap of routes you will be able to see which routes are triggered – the first one in the sequence wins. This tool has saved my ass on a few occasions – and with NuGet now it’s easy to add it to your project in a few seconds and then remove it when you’re done. Routing Around Custom routing seems slightly complicated on first blush due to its disconnected components of RouteHandler, route registration and mapping of custom handlers. But once you understand the relationship between a RouteHandler, the RouteData and how to pass it to a handler, utilizing of Routing becomes a lot easier as you can easily pass context from the registration to the RouteHandler and through to the HttpHandler. The most important thing to understand when building custom routing solutions is to figure out how to map URLs in such a way that the handler can figure out all the pieces it needs to process the request. This can be via URL routing parameters and as I did in my example by passing additional context information as part of the RouteHandler instance that provides the proper execution context. In my case this ‘context’ was the method name, but it could be an actual static value like an enum identifying an operation or category in an application. Basically user supplied data comes in through the url and static application internal data can be passed via RouteHandler property values. Routing can make your application URLs easier to read by non-techie types regardless of whether you’re building Service type or REST applications, or full on Web interfaces. Routing in ASP.NET 4.0 makes it possible to create just about any extensionless URLs you can dream up and custom RouteHanmdler References Sample ProjectIncludes the sample CallbackHandler service discussed here along with compiled versionsof the Westwind.Web and Westwind.Utilities assemblies.  (requires .NET 4.0/VS 2010) West Wind Web Toolkit includes full implementation of CallbackHandler and the Routing Handler West Wind Web Toolkit Source CodeContains the full source code to the Westwind.Web and Westwind.Utilities assemblies usedin these samples. Includes the source described in the post.(Latest build in the Subversion Repository) CallbackHandler Source(Relevant code to this article tree in Westwind.Web assembly) JSONView FireFoxPluginA simple FireFox Plugin to easily view JSON data natively in FireFox.For IE you can use a registry hack to display JSON as raw text.© Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  AJAX  HTTP  

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  • Chinese IME input method in AZERTY on windows (Google IME)

    - by TimothyP
    I'm using a Belgian Azerty keyboard. The chinese input method on Mac OS works just fine, but on Windows, if I use the Google IME for example, a = z q = w etc... so it uses a qwerty layout even though my keyboard is azerty. Can I make Google IME use an azerty layout, or is there other software that uses the azerty layout instead of qwerty

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  • Excel VBA (2007) Subtotal method of Range class failed

    - by robihot
    Hi, I'm getting a Subtotal method of Range class failed Error when i try to run a macro. Code works GREAT (no errors) when i run it using Excel 2003. Here's a snippet... 'SubTotal Sheet Range("A1").Select Selection.Subtotal GroupBy:=1, Function:=xlSum, TotalList:=Array(3, 4, 5, 6, 7, _ 8, 9), Replace:=True, PageBreaks:=False, SummaryBelowData:=True Any help would be appreciated !!!

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  • HttpModule Init method is called several times - why?

    - by MartinF
    I was creating a http module and while debugging I noticed something which at first (at least) seemed like weird behaviour. When i set a breakpoint in the init method of the httpmodule i can see that the http module init method is being called several times even though i have only started up the website for debugging and made one single request (sometimes it is hit only 1 time, other times as many as 10 times). I know that I should expect several instances of the HttpApplication to be running and for each the http modules will be created, but when i request a single page it should be handled by a single http application object and therefore only fire the events associated once, but still it fires the events several times for each request which makes no sense - other than it must have been added several times within that httpApplication - which means it is the same httpmodule init method which is being called every time and not a new http application being created each time it hits my break point (see my code example at the bottom etc.). What could be going wrong here ? is it because i am debugging and set a breakpoint in the http module? It have noticed that it seems that if i startup the website for debugging and quickly step over the breakpoint in the httpmodule it will only hit the init method once and the same goes for the eventhandler. If I instead let it hang at the breakpoint for a few seconds the init method is being called several times (seems like it depends on how long time i wait before stepping over the breakpoint). Maybe this could be some build in feature to make sure that the httpmodule is initialised and the http application can serve requests , but it also seems like something that could have catastrophic consequences. This could seem logical, as it might be trying to finish the request and since i have set the break point it thinks something have gone wrong and try to call the init method again ? soo it can handle the request ? But is this what is happening and is everything fine (i am just guessing), or is it a real problem ? What i am specially concerned about is that if something makes it hang on the "production/live" server for a few seconds a lot of event handlers are added through the init and therefore each request to the page suddenly fires the eventhandler several times. This behaviour could quickly bring any site down. I have looked at the "original" .net code used for the httpmodules for formsauthentication and the rolemanagermodule etc but my code isnt any different that those modules uses. My code looks like this. public void Init(HttpApplication app) { if (CommunityAuthenticationIntegration.IsEnabled) { FormsAuthenticationModule formsAuthModule = (FormsAuthenticationModule) app.Modules["FormsAuthentication"]; formsAuthModule.Authenticate += new FormsAuthenticationEventHandler(this.OnAuthenticate); } } here is an example how it is done in the RoleManagerModule from the .NET framework public void Init(HttpApplication app) { if (Roles.Enabled) { app.PostAuthenticateRequest += new EventHandler(this.OnEnter); app.EndRequest += new EventHandler(this.OnLeave); } } Do anyone know what is going on? (i just hope someone out there can tell me why this is happening and assure me that everything is perfectly fine) :) UPDATE: I have tried to narrow down the problem and so far i have found that the Init method being called is always on a new object of my http module (contary to what i thought before). I seems that for the first request (when starting up the site) all of the HttpApplication objects being created and its modules are all trying to serve the first request and therefore all hit the eventhandler that is being added. I cant really figure out why this is happening. If i request another page all the HttpApplication's created (and their moduless) will again try to serve the request causing it to hit the eventhandler multiple times. But it also seems that if i then jump back to the first page (or another one) only one HttpApplication will start to take care of the request and everything is as expected - as long as i dont let it hang at a break point. If i let it hang at a breakpoint it begins to create new HttpApplication's objects and starts adding HttpApplications (more than 1) to serve/handle the request (which is already in process of being served by the HttpApplication which is currently stopped at the breakpoint). I guess or hope that it might be some intelligent "behind the scenes" way of helping to distribute and handle load and / or errors. But I have no clue. I hope some out there can assure me that it is perfectly fine and how it is supposed to be?

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  • rJava - how to call an abstract class method?

    - by Sarah
    I am trying to create an R function that taps into my JAVA code. I have an abstract class, let's say StudentGroup, that has abstract methods, and one method "getAppropriateStudentGroup" which returns (based on config) a class which extends StudentGroup. This allows calling classes to behave the same regardless of which StudentGroups is actually appropriate. 1) How can I use rJava to call getAppropriateStudentGroup? and 2) How can I call the methods on the returned class? Thank you!

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