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  • Is it a good idea to create an STL iterator which is noncopyable?

    - by BillyONeal
    Most of the time, STL iterators are CopyConstructable, because several STL algorithms require this to improve performance, such as std::sort. However, I've been working on a pet project to wrap the FindXFile API (previously asked about), but the problem is it's impossible to implement a copyable iterator around this API. A find handle cannot be duplicated by any means -- DuplicateHandle specifically forbids passing handles to it. And if you just maintain a reference count to the find handle, then a single increment by any copy results in an increment of all copies -- clearly that is not what a copy constructed iterator is supposed to do. Since I can't satisfy the traditional copy constructible requirement for iterators here, is it even worth trying to create an "STL style" iterator? On one hand, creating some other enumeration method is going to not fall into normal STL conventions, but on the other, following STL conventions are going to confuse users of this iterator if they try to CopyConstruct it later. Which is the lesser of two evils?

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  • Watching a variable for changes without polling.

    - by milkfilk
    I'm using a framework called Processing which is basically a Java applet. It has the ability to do key events because Applet can. You can also roll your own callbacks of sorts into the parent. I'm not doing that right now and maybe that's the solution. For now, I'm looking for a more POJO solution. So I wrote some examples to illustrate my question. Please ignore using key events on the command line (console). Certainly this would be a very clean solution but it's not possible on the command line and my actual app isn't a command line app. In fact, a key event would be a good solution for me but I'm trying to understand events and polling beyond just keyboard specific problems. Both these examples flip a boolean. When the boolean flips, I want to fire something once. I could wrap the boolean in an Object so if the Object changes, I could fire an event too. I just don't want to poll with an if() statement unnecessarily. import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; /* * Example of checking a variable for changes. * Uses dumb if() and polls continuously. */ public class NotAvoidingPolling { public static void main(String[] args) { boolean typedA = false; String input = ""; System.out.println("Type 'a' please."); while (true) { InputStreamReader isr = new InputStreamReader(System.in); BufferedReader br = new BufferedReader(isr); try { input = br.readLine(); } catch (IOException ioException) { System.out.println("IO Error."); System.exit(1); } // contrived state change logic if (input.equals("a")) { typedA = true; } else { typedA = false; } // problem: this is polling. if (typedA) System.out.println("Typed 'a'."); } } } Running this outputs: Type 'a' please. a Typed 'a'. On some forums people suggested using an Observer. And although this decouples the event handler from class being observed, I still have an if() on a forever loop. import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.util.Observable; import java.util.Observer; /* * Example of checking a variable for changes. * This uses an observer to decouple the handler feedback * out of the main() but still is polling. */ public class ObserverStillPolling { boolean typedA = false; public static void main(String[] args) { // this ObserverStillPolling o = new ObserverStillPolling(); final MyEvent myEvent = new MyEvent(o); final MyHandler myHandler = new MyHandler(); myEvent.addObserver(myHandler); // subscribe // watch for event forever Thread thread = new Thread(myEvent); thread.start(); System.out.println("Type 'a' please."); String input = ""; while (true) { InputStreamReader isr = new InputStreamReader(System.in); BufferedReader br = new BufferedReader(isr); try { input = br.readLine(); } catch (IOException ioException) { System.out.println("IO Error."); System.exit(1); } // contrived state change logic // but it's decoupled now because there's no handler here. if (input.equals("a")) { o.typedA = true; } } } } class MyEvent extends Observable implements Runnable { // boolean typedA; ObserverStillPolling o; public MyEvent(ObserverStillPolling o) { this.o = o; } public void run() { // watch the main forever while (true) { // event fire if (this.o.typedA) { setChanged(); // in reality, you'd pass something more useful notifyObservers("You just typed 'a'."); // reset this.o.typedA = false; } } } } class MyHandler implements Observer { public void update(Observable obj, Object arg) { // handle event if (arg instanceof String) { System.out.println("We received:" + (String) arg); } } } Running this outputs: Type 'a' please. a We received:You just typed 'a'. I'd be ok if the if() was a NOOP on the CPU. But it's really comparing every pass. I see real CPU load. This is as bad as polling. I can maybe throttle it back with a sleep or compare the elapsed time since last update but this is not event driven. It's just less polling. So how can I do this smarter? How can I watch a POJO for changes without polling? In C# there seems to be something interesting called properties. I'm not a C# guy so maybe this isn't as magical as I think. private void SendPropertyChanging(string property) { if (this.PropertyChanging != null) { this.PropertyChanging(this, new PropertyChangingEventArgs(property)); } }

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  • Accessing protected REST endpoint with JQuery

    - by Andy
    I have a site where members login to their account (FormsAuth). I would like to set up a RESTful service that I can access using jQuery. I would like to protect these services using the same FormsAuth. How would a third-party site be able to access these services? They would need to pass in the Principal/Identity to the service, right? I've only seen examples of Basic Authentication (which Twitter uses and jQuery supports). I'm very new to WCT/REST, so not sure how this should be done.

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  • How To create a Simple NDK Program in Android NDK

    - by Rakesh
    Hi I am new to android Programming and NDK.Yet i am not clear with working in NDK.I just downloaded android ndk r4.If i want to develop appln using NDK,and i refered http://marakana.com/forums/android/android_examples/49.html for reference,But still not clear how to create the header file and implementation,I did nt have any previuos exp in c language.And they asked for run javah tool to create the JNI header file. I dont know how to use javah tool,but i found it in java bin directory and i tried using cmd javah -jni com.pathname.classname is this correct syntax? if so i tried doing it in android bin directory.I want to know ,what classname represents,is this name of header file class that i try to create Regards Rakesh Shankar.P

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  • Setting the Identity/Principal from a MessageInspector in WCF

    - by Robert Wagner
    I am developing a WCF service that receives the user's credentials in the SOAP header. These credentials are read on the server side using a MessageInspector. So far so good. I want to set the Thread.CurrentPrincipal to a custom principal (CustomPrincipal), but when I do this from the MessageInspector, it gets overridden by the time the service is invoked. When is the best time to set the principal? Also what is the best way to pass the principal, identity or credentials from the inspector to that location?

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  • C# Get Type of IEnumerable<TModel>

    - by Jimbo
    I have a method to which I pass an IEnumerable<TModel>. Then depending on the type of TModel, the method carries out a set of instructions as below: public void MyMethod<TModel>(IEnumerable<TModel> items) where TModel : class { int operationType; switch (typeof(TModel)) { case typeof(MyModelOne): operationType = 1; break; case typeof(MyModelTwo): operationType = 2; break; case typeof(MyModelThree): operationType = 3; break; default: throw new Exception("The collection model passed to MyMethod is not recognized"); } ... } This doesnt work, I get the error: There is no application variable or memeber 'TModel'

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  • What is resource-ref in web.xml used for?

    - by Denise
    Hi everyone, I'm just wondering when/why you would define a resource-ref element in your web.xml file? I would have thought that it would be defined in your web/app server using JNDI and then look up the JNDI reference in your Java code? The resource-ref definition seems a bit redundant to me and I can't think of when it might be useful. Example: <resource-ref> <description>Primary database</description> <res-ref-name>jdbc/primaryDB</res-ref-name> <res-type>javax.sql.DataSource</res-type> <res-auth>CONTAINER</res-auth> </resource-ref> Thanks!

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  • Referring to the type of an inner class in Scala

    - by saucisson
    The following code tries to mimic Polymorphic Embedding of DSLs: rather than giving the behavior in Inner, it is encoded in the useInner method of its enclosing class. I added the enclosing method so that user has only to keep a reference to Inner instances, but can always get their enclosing instance. By doing this, all Inner instances from a specific Outer instance are bound to only one behavior (but it is wanted here). abstract class Outer { sealed class Inner { def enclosing = Outer.this } def useInner(x:Inner) : Boolean } def toBoolean(x:Outer#Inner) : Boolean = x.enclosing.useInner(x) It does not compile and scala 2.8 complains about: type mismatch; found: sandbox.Outer#Inner required: _81.Inner where val _81:sandbox.Outer From Programming Scala: Nested classes and A Tour of Scala: Inner Classes, it seems to me that the problem is that useInnerexpects as argument an Inner instance from a specific Outer instance. What is the true explanation and how to solve this problem ?

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  • how to implement IOC without a global static service (non-service locator solution)?

    - by Michel
    Hi, we want to use Unity for IOC. All i've seen is the implementation that there is one global static service which holds a reference to the Unity container, which registers all interface/class combinations and every class asks that object: give me an implementation for Ithis or IThat. Frequently i see a response that this pattern is not good because it leads to a dependency from ALL classes to this service. But what i don't see often, is: what is the alternative way? Michel EDIT: found out that the global static service is called the service locator, added that to the title.

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  • ajax response byte size

    - by Alex Pacurar
    Im using jQuery's getJSONP and I want to log the duration of the call and the size of the response to be able to have some statistics about the usage of my application. This is a cross domain ajax call, so I need to use JSONP, but as the JSONP call is not done with an XMLHttpRequest object, the complete callback from jquery's ajax doesnt pass the response content. So my question is how to get the response size (content lenght) from a JSONP call. $.ajaxSetup( { complete:function(x,e) { log(x.responseText.length, x.responseText); } } here x is a XMLHttpRequest object for a JSON call , but for JSONP call is undefined.

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  • Rails, using jQuery without jrails

    - by ibuck
    Hello all, I have been trying to convert my rails 2.2.2 app over to jQuery, and would like so without using jrails. The only reference material I can find on the subject is Railscasts Episode 136. Ryan goes over how to use jQuery to post a form and handle the response in a .js.erb file. My questions is has anyone tried to use jQuery with .js.erb files with anchors as the trigger? As a replacement for "link_to_remote". I have gotten jQuery to do a .get to submit this link on click to the controller, but I cannot seem to get it to go into the .js.erb file. Thanks

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  • PHP/Javascript - get php variable within javascript

    - by McNabbToSkins
    I have run into an interesting problem. I am currently developing php page and need to access a php variable within the javascript onload. $(document).ready(function() { var temp = <?php $page_id ?> } is this valid? I know that this might seem weird and not be allowed but I am developing a page that has two popup windows. The windows are created using the same view template and there is no way to distinguish between each other. If I stored a hidden value on the page with information unique to the page like so <input type="hidden" value="<?php $page_id ?> id="page_id" /> if there are two views open at the same time there is no way for me to get a unique page id like so var temp = $("#page_id").val(); Because there are two views witht he same input id that is not unique. Long story short is it valid to reference a php variable in the javascript.

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  • Ruby File IO question; Maintain file read position between script executions

    - by macek
    I have two files a.txt and b.txt (henceforth a and b). My script iterates through a, does some operation, and potentially inserts a line to b. In the event the script stops, I need it to pick up where it left off. In the example below: foo was copied to b bar was copied to b zim was not copied to b (did not pass some criteria) gaz was copied to b Script stops (for whatever reason) When script starts again, how to open a and start on line "dib"? a.txt foo bar zim gaz // <= last successful copy dib // <= I want to start here on next script execution gir b.txt foo bar gaz // <= note omission of "zim" above gaz

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  • How do I get Tycho?

    - by Jens Schauder
    Tycho is supposed to be a plug-in for maven for building eclipse plug-ins. I have found various blogs and other articles about it, but the contained links to Tycho are all dead or not accessible for the general public, for example: http://www.sonatype.com/people/2009/04/tycho-040-roadmap/ The only thing I found is a project proposal on the eclipse site, but it doesn't reference any downloads: http://www.eclipse.org/proposals/tycho/ I found a svn repository, but it seems to be extremely dated: http://svn.codehaus.org/m2eclipse/tycho/trunk/ So my question is: where do I get tycho from? Or is it dead and I should stop bothering? I doubt it's dead, since I found out there is a talk about it on JAX2010 ...

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  • Why does this program crash: passing of std::string between DLLs

    - by msiemeri
    Hello together. I have some trouble figuring out why the following crashes (MSVC9): //// the following compiles to A.dll with release runtime linked dynamically //A.h class A { __declspec(dllexport) std::string getString(); }; //A.cpp #include "A.h" std::string A::getString() { return "I am a string."; } //// the following compiles to main.exe with debug runtime linked dynamically #include "A.h" int main() { A a; std::string s = A.getString(); return 0; } // crash on exit Obviously (?) this is due to the different memory models for the executable and DLL. Could it be that the string A::getString() returns is being allocated in A.dll and freed in main.exe? If so, why - and what would be a safe way to pass strings between DLLs (or executables, for that matter)? Without using wrappers like shared_ptr with a custom deleter.

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  • WCF Runtime Error while using Constructor

    - by Pranesh Nair
    Hi all, I am new to WCF i am using constructor in my WCF service.svc.cs file....It throws this error when i use the constructor The service type provided could not be loaded as a service because it does not have a default (parameter-less) constructor. To fix the problem, add a default constructor to the type, or pass an instance of the type to the host. When i remove the constructor its working fine....But its compulsory that i have to use constructor... This is my code namespace UserAuthentication { [ServiceBehavior(InstanceContextMode=System.ServiceModel.InstanceContextMode.Single)] public class UserAuthentication : UserRepository,IUserAuthentication { private ISqlMapper _mapper; private IRoleRepository _roleRepository; public UserAuthentication(ISqlMapper mapper): base(mapper) { _mapper = mapper; _roleRepository = new RoleRepository(_mapper); } public string EduvisionLogin(EduvisionUser aUser, int SchoolID) { UserRepository sampleCode= new UserRepository(_mapper); sampleCode.Login(aUser); return "Login Success"; } } } can anyone provide ideas or suggestions or sample code hw to resolve this issue...

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  • iphone - passing an object on an UIToolbarButton action

    - by Mike
    Is that possible to make a UIToolbarButton pass an object to its target by using some exoteric method (as it seems not to be possible using regular button use)? I mean something like UIBarButtonItem *Button = [[UIBarButtonItem alloc] initWithImage:buttonImage style:UIBarButtonItemStylePlain target:self action:@selector(doSomething:) **withObject:usingThis**]; I know I can trigger a method that will launch the full method with the object, but for the sake of elegance I was trying to minimize the code... I suspect it is not possible, but as you guys out there are insanely good you may come with an transcendental answer... who knows...

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  • How do I create an ImageView in java code, within an existing Layout?

    - by Dan T
    I'm looking for an easy way for the user to see how many drinks they've had for a BAC calculator. PICTURE OF THE APP, for reference On button press, I would like an image to be added to the screen, directly under the spinner and with left alignment. When I press the button again, I want another image to be added to the screen. So if I pressed the add beer button, a drawable of a beer would appear below the spinner. If I pressed the add beer button again, I want there to be TWO drawables of beers under the spinner, preferably with them being added from the right. (Also, having them reach their width limit, wrapping around, and starting again on the left, but below a full line, would be AWESOME) I can't figure out how to do this. I assume adding a ImageView in code to a relative layout (because it needs to be positioned to the right) would be the best route, but if it's possible in xml I'd be more than happy to use that. Any help?

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  • How does load balancing work with multiple server with multiple DBs

    - by Matt
    I guess what im looking for is a description on how this all works together. I'm used to setting up one server with maybe another server to handel the DB. My question is how does the load balancer work where do all the script(php,python) files go? If i make a change to one i have to rsync them to all the server that the balancer refers to? Also does each server need client side DB's installed so they can reference the DB's that are on other servers? If there is a site that explains all this i would be happy to read it.

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  • Marshal a list of objects from VB6 to C#

    - by Andrew
    I have a development which requires the passing of objects between a VB6 application and a C# class library. The objects are defined in the C# class library and are used as parameters for methods exposed by other classes in the same library. The objects all contain simple string/numeric properties and so marshaling has been relatively painless. We now have a requirement to pass an object which contains a list of other objects. If I was coding this in VB6 I might have a class containing a collection as a member variable. In C# I might have a class with a List member variable. Is it possible to construct a C# class in such a way that the VB6 application could populate this inner list and marshal it successfully? I don't have a lot of experience here but I would guess Id have to use an array of Object types.

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  • How to structure javascript callback so that function scope is maintained properly

    - by Chetan
    I'm using XMLHttpRequest, and I want to access a local variable in the success callback function. Here is the code: function getFileContents(filePath, callbackFn) { var xhr = new XMLHttpRequest(); xhr.onreadystatechange = function() { if (xhr.readyState == 4) { callbackFn(xhr.responseText); } } xhr.open("GET", chrome.extension.getURL(filePath), true); xhr.send(); } And I want to call it like this: var test = "lol"; getFileContents("hello.js", function(data) { alert(test); }); Here, test would be out of the scope of the callback function, since only the enclosing function's variables are accessible inside the callback function. What is the best way to pass test to the callback function so the alert(test); will display test correctly?

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  • Assigning to struct in different class

    - by 4thSpace
    I have a struct in ClassA and want to assign it to the same struct in ClassB (the two structs are the same with different names). ClassA and ClassB are view controllers. Basically, I need to pass this struct to another class. However, structs don't seem to be exposed as members, which means I can't access them. Here is ClassA's struct declared in its header file: typedef struct { NSString *startDate; NSString *endDate; NSString *classId; } selectedItemsClassAStruct; selectedItemsClassAStruct selectedItemsClassA; and the same for ClassB (just with ClassA text replaced) It doesn't appear in code hints for ClassB. I see this error if I try to access it: request for member 'selectedItemsClassBStruct' in something not a structure or union How should it be done?

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  • VB.net 'cross-referencing' tables.

    - by Lee
    Hello, I have a DataGridView that is being filled with data from a table. Inside this table is a column called 'group' that has the ID of an individual group in another table. What I would like to do, is when the DataGridView is filled, instead of showing the ID contained in 'group', I'd like it to display the name of the group. Is there some type of VB.net 'magic' that can do this, or do I need to cross-reference the data myself? Here is a breakdown of what the 2 tables look like: table1 id group (this holds the value of column id in table 2) weight last_update table2 id description (this is what I would like to be displayed in the DGV.) take care, lee BTW - I am using Visual Studios Express.

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  • Consuming Web Services in Netbeans

    - by Seven
    Hi. I've setup a project in Netbeans 6.5 with some web services that I've created myself and some web services that I've imported from WSDL files. I've setup a couple of desktop application through Netbeans in order to consume these web services. I'm not too sure where to go from here. I have the GUI setup but not sure how to reference the web services so they can be consumed. I was wondering would anybody be able to guide me through this process or point me in the direction of a relevant tutorial. I'd also like to learn how to consume a web service through a JSP (also created in Netbeans) if possible. Thanks.

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  • Parameter to swf loader with loader class

    - by alejandrobog
    Hi im loading a child swf into my parent swf and I want to pass some parameters to the child swf. Any idea on how to do this. Here is my code: var req:URLRequest = new URLRequest( "test.swf" ); var loader:Loader = new Loader(); loader.contentLoaderInfo.addEventListener( Event.COMPLETE, loadComplete ); loader.load(req); function loadComplete(e:Event){ var childSwf:DisplayObject = e.target.content as DisplayObject; //Im guessing here I need to set the parameter VideoContainer.addChild(childSwf); }

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