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  • How do I keep track of the session for each servlet request, until I use it? Singletons wont work?

    - by corgrath
    For each servlet request I get, I pass, perhaps, 10 methods before I am at where I need to check something in the session and I need the HttpSession. The only way I can get the HttpSession is from the HttpServletRequest, correct? How do I keep track of the session for each servlet request? Unfortuantly I cannot simple make a singleton (ex, SessionInformation.instance().getAttribute("name")) because that session would then be used over all requests. Is there a way to store the session globally for each request without having to pass it (or it's information) down all the methods just in case I need it?

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  • User Defined Exceptions with JMX

    - by Daniel
    I have exposed methods for remote management in my application server using JMX by creating an MXBean interface, and a class to implement it. Included in this interface are operations for setting attributes on my server, and for getting the current value of attributes. For example, take the following methods: public interface WordManagerMXBean { public void addWord(String word); public WordsObject getWords(); public void removeWord(String word); } The WordsObject is a custom, serializable class used to retrieve data about the state of the server. Then I also have a WordManager class that implements the above interface. I then create a JMX agent to manage my resource: MBeanServer mbs = ManagementFactory.getPlatformMBeanServer(); ObjectName wordManagerName = new ObjectName("com.example:type=WordManager"); mbs.registerMBean(wordManager, wordManagerName); I have created a client that invokes these methods, and this works as expected. However, I would like to extend this current configuration by adding user defined exceptions that can be sent back to my client. So I would like to change my interface to something like this: public interface WordManagerMXBean { public void addWord(String word) throws WordAlreadyExistsException; public WordsObject getWords(); public void removeWord(String word); } My WordAlreadyExistsException looks like this: public class WordAlreadyExistsException extends Exception implements Serializable { private static final long serialVersionUID = -9095552123119275304L; public WordAlreadyExistsException() { super(); } } When I call the addWord() method in my client, I would like to get back a WordAlreadyExistsException if the word already exists. However, when I do this, I get an error like this: java.rmi.UnmarshalException: Error unmarshaling return; nested exception is: java.lang.ClassNotFoundException: com.example.WordAlreadyExistsException The WordAlreadyExistsException, the WordsObject and the WordManagerMXBean interface are all in a single jar file that is available to both the client and the server. If I call the getWords() method, the client has no difficulty handling the WordsObject. However, if a user defined exception, like the one above, is thrown, then the client gives the error shown above. Is it possible to configure JMX to handle this exception correctly in the client? Following some searching, I noticed that there is an MBeanException class that is used to wrap exceptions. I'm not sure if this wrapping is performed by the agent automatically, or if I'm supposed to do the wrapping myself. I tried both, but in either case I get the same error on the client. I have also tried this with both checked and unchecked exceptions, again the same error occurs. One solution to this is to simply pass back the error string inside a generic error, as all of the standard java exceptions work. But I'd prefer to get back the actual exception for processing by the client. Is it possible to handle user defined exceptions in JMX? If so, any ideas how?

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  • RAII: Initializing data member in const method

    - by Thomas Matthews
    In RAII, resources are not initialized until they are accessed. However, many access methods are declared constant. I need to call a mutable (non-const) function to initialize a data member. Example: Loading from a data base struct MyClass { int get_value(void) const; private: void load_from_database(void); // Loads the data member from database. int m_value; }; int MyClass :: get_value(void) const { static bool value_initialized(false); if (!value_initialized) { // The compiler complains about this call because // the method is non-const and called from a const // method. load_from_database(); } return m_value; } My primitive solution is to declare the data member as mutable. I would rather not do this, because it suggests that other methods can change the member. How would I cast the load_from_database() statement to get rid of the compiler errors?

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  • How to change object positions in an android layout?

    - by Pedro Santos
    Hi, I'm currently working on a very simple aplication, and I intended to make it change the visual aspect depending on the screen size. The application just has 6 buttons like this: http://www.freeimagehosting.net/uploads/e1efb4c4d0.jpg I'm using the AbsoluteLayout, and changing the x and y of the buttons with the methods offsetLeftAndRight and offsetTopAndBottom. I'm not changing the layout of the buttons in the xml file, so the all start in the same place. However, if I use this methods inside the onClickMethod they sometimes appear where I want them, sometimes don't (can't figure out why), but if i use them in the onCreate method, nothing happens. Can someone point me in the right direction? Thanks

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  • Is it good practice to put private API in the .m files and public API in .h files in Cocoa?

    - by Paperflyer
    Many of my classes in my current project have several properties and methods that are only ever called from within the class itself. Also, they might mess with the working of the class depending on the current state of the class. Currently, all these interfaces are defined in the main interface declaration in the .h files. Is it considered good practice to put the “private” methods and properties at the top of the .m files? This won't ever affect anything since I am very likely the only person ever to look at this source code, but of course it would be interesting to know for future projects.

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  • Method for exporting drawn flash/flex UIComponent to vector based print file

    - by eshowcase
    Hi, I am creating a flex application where I am using the built in graphics package of flex 3 to draw shapes and things to a UIComponent. I want to be able to export this vector image UIComponent to a vector based file, pdf, eps etc. Are there any tools, libraries, or methods for doing so? I looked at AlivePDF - which works very slick, but its output is effectively a snapshot of the UIComponent drawn out as a bitmap to the PDF. I want true vector output, as this image is for print, needs to be able to scale and be color correct. I read somewhere that it may be possible with Adobe Live Cycle, but in looking at the documentation I'm not sure how to use it. Another possibility is to submit the final image parameters to a server-side PHP script that would re-generate the image in SVG format. But as I understand SVG is not ideal for print, and this is lots of extra work. Any thoughts, ideas, methods? Thanks!

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  • Fixing javascript Array functions in Internet Explorer (indexOf, forEach, etc)

    - by Chas Emerick
    As detailed elsewhere, and otherwise apparently well-known, Internet Explorer (definitely 7, and in some instances, 8) do not implement key functions, in particular on Array (such as forEach, indexOf, etc). There are a number of workarounds here and there, but I'd like to fold a proper, canonical set of implementations into our site rather than copy and paste or hack away at our own implementations. I've found js-methods, which looks promising, but thought I'd post here to see whether another library comes more highly-recommended. A couple of misc. criteria: the lib should just be a no-op for those functions that a browser already has implementations for (js-methods appears to do quite well here) non-GPL, please, though LGPL is acceptable

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  • How does Hibernate detect dirty state of an entity object?

    - by ???'Lenik
    Is it using some kind of byte codes modification to the original classes? Or, maybe Hibernate get the dirty state by compare the given object with previously persisted version? I'm having a problem with hashCode() and equals() methods for complicated objects. I feel it would be very slow to compute hash code if the object has collection members, and cyclic references are also a problem. If Hibernate won't use hashCode()/equals() to check the dirty state, I guess I should not use equals()/hashCode() for the entity object (not value object), but I'm also afraid if the same operator (==) is not enough. So, the questions are: How does Hibernate know if a property of an object is changed? Do you suggest to override the hashCode()/equals() methods for complicated objects? What if they contains cyclic references? And, also, Would hashCode()/equals() with only the id field be enough?

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  • how to set a tableview delegate

    - by dubbeat
    Hi, I'm trying to use a tableview without using a nib and without using a UITableViewController. I have added a UITableView instance to a UIViewController Like So mytable = [[UITableView alloc] initWithFrame:CGRectMake(22, 207, 270, 233)]; [mytable setDelegate:self]; [self.view mytable]; Also I have added the following table view methods to my UIViewController (cut for brevities sake) - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { I am getting a warning saying that my UIViewController does not implement UITableView delegate protocol. Whats the correct way to tell the table view where its delegate methods are? (This is my first attempt at trying to use a UITableView without selecting the UITableTableview controller from the new file options)

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  • Letting Wcf data service implement another contract

    - by Wasim
    Hi all , I have a wcf data service with the standart configuration . I want to add another functionality to it , so I built a contract interface and let my wcf data service implements it . Now I see in the service the InitializeService method , and the contract interface methods . When I come to connect the service , I get an error , that there is no end point declared to the contract I added . How can do that ? examples ? links ? I choosed to add the contract interface to the wcf data service and not adding another service , because the client application uses the wcf data service generated objects , and I want to use the same obkject to make operations not related to data , for more coplex processing . If I do the methods in another service , then I have types incompatibility . Thanks in advance ...

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  • How to automatically start a C# WebService?

    - by hancock
    Hi, I have written a C# WebService. The problem is that after I publish it to IIS it won't automatically start unless any of its methods is called. This is very frustrating because this WebService has to continuously do some background work immediately after it starts (its constructor executes). If IIS is restarted, the WebService will just sit idly until one of its methods is called. Is there a way to overcome this and force the WebService to execute its constructor immediately after it is published or IIS restarted?

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  • Get touches from UIScrollView

    - by Peter Lapisu
    Basically i want to subclass UIScrollView and hande the touches, however, the touch methods dont get called (i searched the web for a solution and i found out people pointing to override the hit test, what i did, but with no result :( ) .h @interface XScroller : UIScrollView @end .m - (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event { UIView *result = nil; for (UIView *child in self.subviews) { if ([child pointInside:point withEvent:event]) { if ((result = [child hitTest:point withEvent:event]) != nil) { break; } } } return result; } - (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { NSLog(@"BEGAN"); [super touchesBegan:touches withEvent:event]; } - (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { NSLog(@"MOVED"); [super touchesMoved:touches withEvent:event]; } - (void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { NSLog(@"ENDED"); [super touchesEnded:touches withEvent:event]; } - (void) touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event { NSLog(@"CANCELED"); [super touchesCancelled:touches withEvent:event]; } none of the - (void) touches* methods get called, the scrolling works ok

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  • Java Program Design Layout Recommendations?

    - by Leebuntu
    I've learned enough to begin writing programs from scratch, but I'm running into the problem of not knowing how to design the layout and implementation of a program. To be more precise, I'm having difficulty finding a good way to come up with an action plan before I dive in to the programming part. I really want to know what classes, methods, and objects I would need beforehand instead of just adding them along the way. My intuition is leading me to using some kind of charting software that gives a hierarchal view of all the classes and methods. I've been using OmniGraffle Pro and while it does seem to work somewhat, I'm still having trouble planning out the program in its entirety. How should I approach this problem? What softwares out there are available to help with this problem? Any good reads out there on this issue? Thanks so much! Edit: Oh yeah, I'm using Eclipse and I code mainly in Java right now.

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  • Configuration and Model-View

    - by HH
    I am using the Model-View pattern on a small application I'm writing. Here's the scenario: The model maintains a list of directories from where it can extract the data that it needs. The View has a Configuration or a Setting dialog where the user can modify this list of directories (the dialog has a JList displaying the list in addition to add and remove buttons). I need some advice from the community: The View needs to communicate these changes to the model. I thought first of adding to the model these methods: addDirectory() and removeDirectory(). But I am trying to limit the number of methods (or channels) that the View can use to communicate with and manipulate the model. Is there any good practice for this? Thank you.

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  • Using Apache Velocity with StringBuilders/CharSequences

    - by mindas
    We are using Apache Velocity for dynamic templates. At the moment Velocity has following methods for evaluation/replacing: public static boolean evaluate(Context context, Writer writer, String logTag, Reader reader) public static boolean evaluate(Context context, Writer out, String logTag, String instring) We use these methods by providing StringWriter to write evaluation results. Our incoming data is coming in StringBuilder format so we use StringBuilder.toString and feed it as instring. The problem is that our templates are fairly large (can be megabytes, tens of Ms on rare cases), replacements occur very frequently and each replacement operation triples the amount of required memory (incoming data + StringBuilder.toString() which creates a new copy + outgoing data). I was wondering if there is a way to improve this. E.g. if I could find a way to provide a Reader and Writer on top of same StringBuilder instance that only uses extra memory for in/out differences, would that be a good approach? Has anybody done anything similar and could share any source for such a class? Or maybe there any better solutions to given problem?

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  • What is Ruby's double-colon (::) all about?

    - by Meltemi
    I'd probably be able to answer this for myself if "::" wasn't so hard to Google. Didn't see anything on SO so thought I'd try my luck. What is this double-colon :: all about? I see it everywhere in Rails: class User < ActiveRecord::Base or… ActionController::Routing::Routes.draw do |map| I found a definition from this guy: The :: is a unary operator that allows: constants, instance methods and class methods defined within a class or module, to be accessed from anywhere outside the class or module. but that just leads to more questions. What good is scope (private, protected) if you can just use :: to expose anything?

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  • Avoiding duplication in JavaDoc comments

    - by TERACytE
    I am writing a class where the same xml is used between some methods. e.g. /** * Sample Response: * <xmp> * <myXML> * <stuff> data </stuff> * </myXML> * </xmp> */ CommonXML Method1(); /** * Sample Submission: * <xmp> * <myXML> * <stuff> data </stuff> * </myXML> * </xmp> */ void Method2(CommonXML xml); I would like to write my documentation so that if the xml changes I have one resource to modify, rather than updating all of the JavaDoc for the affected methods. Does anyone know how to accomplish this?

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  • Using a general class for execution with try/catch/finally?

    - by antirysm
    I find myself having a lot of this in different methods in my code: try { runABunchOfMethods(); } catch (Exception ex) { logger.Log(ex); } What about creating this: public static class Executor { private static ILogger logger; public delegate void ExecuteThis(); static Executor() { // logger = ...GetLoggerFromIoC(); } public static void Execute(ExecuteThis executeThis) { try { executeThis(); } catch (Exception ex) { logger.Log(ex); } } } And just using it like this: private void RunSomething() { Method1(someClassVar); Method2(someOtherClassVar); } ... Executor.Execute(RunSomething); Are there any downsides to this approach? (You could add Executor-methods and delegates when you want a finally and use generics for the type of Exeception you want to catch...)

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  • url rewriting - build paths

    - by Cristian Boariu
    Hi guys, I have started to work on a site without url rewriting. Now, the request is to use friendly urls so i started to use Intelligencia.UrlRewriter. Let's take an example: I have a method: public static string getCategoriesIndexLink(string category) { string baseUrl = getBaseUrl() + (String)HttpContext.GetGlobalResourceObject("Paths", "categorii.index"); return baseUrl.AddQueryParam(CQueryStringParameters.CATEGORY, category); } which build this kind of urls "~/Site/Categorii.aspx?category=$1" Now i've added the following rule in web.config: <rewrite url="~/Site/Categorii/(.+)" to="~/Site/Categorii.aspx?category=$1" /> The question is HOW i can make the above method to build that kind of nice url? So no longer return "~/Site/Categorii.aspx?category=m1" but "~/Site/Categorii/m1" without beeing needed to modify its structure? I mean, i have about 30 methods like the one from the above; it would be extremely helpfull if i can be guided to use a regex at the output of the methods iso modifying the url construction... Thanks in advance...

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  • How can a Delphi TPersistent object calculate its own deserialization time?

    - by mjustin
    For performance tests I need a way to measure the time needed for a form to load its definition from the DFM. All existing forms inherit a custom form class. To capture the current time, this base class needs overriden methods as "extension points": start of the deserialization process after the deserialization (can be implemented by overriding the Loaded procedure) the moment just before the execution of the OnFormCreate event So the log for TMyForm.Create(nil) could look like: - 00.000 instance created - 00.010 before deserialization - 01.823 after deserialization - 02.340 before OnFormCreate Which TObject (or TComponent) methods are best suited? Maybe there are other extension points in the form creation process, please feel free to make suggestions.

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  • Modifying annotation attribute value at runtime in java

    - by Lici
    Hi folks: some methods in our model pojos have been annotated like this: @Column(name="cli_clipping_id", updatable=false, columnDefinition = "varchar(" + ModelUtils.ID_LENGTH + ") COLLATE utf8_bin") columnDefinition attribute is database vendor dependant, so when trying to drop schema in HSQLDB using Hibernate it fails: [ERROR] 16 jun 12:58:42.480 PM main [org.hibernate.tool.hbm2ddl.SchemaExport] Unexpected token: COLLATE in statement [create table cms.edi_editorial_obj (edi_uuid varchar(23) COLLATE ] To fix this, i'm thinking on this solution (but don't want to spend time if it isn't possible) , at runtime, for each method column annotated: Get @Column annotation Create a copy of the column annotation, setting columnDefinition null using javaassist. set column method annotation to the copy column annotation object overriding the old one (i don't know it this is possible) Is it possible to "hack" these methods this way? Any help would be much appreciated ...

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  • C++ - Breaking code implementation into different parts

    - by Kotti
    Hi! The question plot (a bit abstract, but answering this question will help me in my real app): So, I have some abstract superclass for objects that can be rendered on the screen. Let's call it IRenderable. struct IRenderable { // (...) virtual void Render(RenderingInterface& ri) = 0; virtual ~IRenderable() { } }; And suppose I also have some other objects that derive from IRenderable, e.g. Cat and Dog. So far so good. I add some Cat and Dog specific methods, like SeekForWhiskas(...) and Bark(...). After that I add specific Render(...) method for them, so my code looks this way: class Cat : public IRenderable { public: void SeekForWhiskas(...) { // Implementation could be here or moved // to a source file (depends on me wanting // to inline it or not) } virtual void Render(...) { // Here comes the rendering routine, that // is specific for cats SomehowDrawAppropriateCat(...); } }; class Dog : public IRenderable { public: void Bark(...) { // Same as for 'SeekForWhiskas(...)' } virtual void Render(...) { // Here comes the rendering routine, that // is specific for dogs DrawMadDog(...); } }; And then somewhere else I can do drawing the way that an appropriate rendering routine is called: IRenderable* dog = new Dog(); dog->Render(...); My question is about logical wrapping of such kind of code. I want to break apart the code, that corresponds to rendering of the current object and it's own methods (Render and Bark in this example), so that my class implementation doesn't turn into a mess (imagine that I have 10 methods like Bark and of course my Render method doesn't fit in their company and would be hard to find). Two ways of making what I want to (as far as I know) are: Making appropriate routines that look like RenderCat(Cat& cat, RenderInterface* ri), joining them to render namespace and then the functions inside a class would look like virtual void Render(...) { RenderCat(*this, ...); }, but this is plain stupid, because I'll lose access to Cat's private members and friending these functions looks like a total design disaster. Using visitor pattern, but this would also mean I have to rebuild my app's design and looks like an inadequate way to make my code complicated from the very beginning. Any brilliant ideas? :)

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  • How can I measure TForm deserialization time in Delphi?

    - by mjustin
    For performance tests I need a way to measure the time needed for a form to load its definition from the DFM. All existing forms inherit a custom form class. To capture the current time, this base class needs overriden methods as "extension points": before the beginning of the deserialization process after the completion of deserialization (can be implemented by overriding the Loaded procedure) the moment just before the execution of the OnFormCreate event Which TObject (or TComponent) methods are best suited? Maybe there are other extension points in the form creation process, please feel free to make suggestions.

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