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  • How do you protect a common resource using mutexes?

    - by Steve
    I have a common resource, which I want 1 and only 1 instance of my application (or it's COM API) to have access to at any time. I have tried to protect this resource using mutexes, but when multiple threads of a host dotnet application try to access the COM object, the mutex doesn't seem to be released. This is the code I have used to protect my resource. repeat Mutex := CreateMutex(nil, True, PChar('Connections')); until (Mutex <> 0) and (GetLastError <> ERROR_ALREADY_EXISTS); try //use resource here! finally CloseHandle(Mutex); end; If I run the threads simultaneously, the first thread get's through (obviously, being the first one to create the mutex), but subsequent threads are caught in the repeat loop. If I run each thread at 5 second intervals, then all is ok. I suspect I'm not using mutexes correctly here, but I have found very little documentation about how to do this. Any ideas?

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  • What is likely cause of Android runtime exception "No suitable Log implementation" related to loggin

    - by M.Bearden
    I am creating an Android app that includes a third party jar. That third party jar utilizes internal logging that is failing to initialize when I run the app, with this error: "org.apache.commons.logging.LogConfigurationException: No suitable Log implementation". The 3rd party jar appears to be using org.apache.commons.logging and to depend on log4j, specifically log4j-1.2.14.jar. I have packaged the log4j jar into the Android app. The third party jar was packaged with a log4j.xml configuration file, which I have tried packaging into the app as an XML resource (and also as a raw resource). The "No suitable Log implementation" error message is not very descriptive, and I have no immediate familiarity with Java logging. So I am looking for likely causes of the problem (what class or configuration resources might I be missing?) or for some debugging technique that will result in a different error message that is more explicit about the problem. I do not have access to source code for the 3rd party jar. Here is the exception stack trace. When I run the app, I get the following exception as soon as one of the third party jar classes attempts to initialize its internal logging. DEBUG/AndroidRuntime(15694): Shutting down VM WARN/dalvikvm(15694): threadid=3: thread exiting with uncaught exception (group=0x4001b180) ERROR/AndroidRuntime(15694): Uncaught handler: thread main exiting due to uncaught exception ERROR/AndroidRuntime(15694): java.lang.ExceptionInInitializerError ERROR/AndroidRuntime(15694): Caused by: org.apache.commons.logging.LogConfigurationException: No suitable Log implementation ERROR/AndroidRuntime(15694): at org.apache.commons.logging.impl.LogFactoryImpl.discoverLogImplementation(LogFactoryImpl.java:842) ERROR/AndroidRuntime(15694): at org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:601) ERROR/AndroidRuntime(15694): at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:333) ERROR/AndroidRuntime(15694): at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:307) ERROR/AndroidRuntime(15694): at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:645) ERROR/AndroidRuntime(15694): at org.apache.commons.configuration.ConfigurationFactory.<clinit>(ConfigurationFactory.java:77)

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  • Long running operations (threads) in a web (asp.net) environment

    - by rrejc
    I have an asp.net (mvc) web site. As the part of the functions I will have to support some long running operations, for example: Initiated from user: User can upload (xml) file to the server. On the server I need to extract file, do some manipulation (insert into the db) etc... This can take from one minute to ten minutes (or even more - depends on file size). Of course I don't want to block the request when the import is running , but I want to redirect user to some progress page where he will have a chance to watch the status, errors or even cancel the import. This operation will not be frequently used, but it may happen that two users at the same time will try to import the data. It would be nice to run the imports in parallel. At the beginning I was thinking to create a new thread in the iis (controller action) and run the import in a new thread. But I am not sure if this is a good idea (to create working threads on a web server). Should I use windows services or any other approach? Initiated from system: - I will have to periodically update lucene index with the new data. - I will have to send mass emails (in the future). Should I implement this as a job in the site and run the job via Quartz.net or should I also create a windows service or something? What are the best practices when it comes to running site "jobs"? Thanks!

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  • Keep Hibernate Initializer from Crashing Program

    - by manyxcxi
    I have a Java program using a basic Hibernate session factory. I had an issue with a hibernate hbm.xml mapping file and it crashed my program even though I had the getSessionFactory() call in a try catch try { session = SessionFactoryUtil.getSessionFactory().openStatelessSession(); session.beginTransaction(); rh = getRunHistoryEntry(session); if(rh == null) { throw new Exception("No run history information found in the database for run id " + runId_ + "!"); } } catch(Exception ex) { logger.error("Error initializing hibernate"); } It still manages to break out of this try/catch and crash the main thread. How do I keep it from doing this? The main issue is I have a bunch of cleanup commands that NEED to be run before the main thread shuts down and need to be able to guarantee that even after a failure it still cleans up and goes down somewhat gracefully. The session factory looks like this: public class SessionFactoryUtil { private static final SessionFactory sessionFactory; static { try { // Create the SessionFactory from hibernate.cfg.xml sessionFactory = new Configuration().configure().buildSessionFactory(); } catch (Throwable ex) { // Make sure you log the exception, as it might be swallowed System.err.println("Initial SessionFactory creation failed." + ex); throw new ExceptionInInitializerError(ex); } } public static SessionFactory getSessionFactory() { try { return sessionFactory; } catch(Exception ex) { return null; } } }

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  • Shutting down a windows service that has threads

    - by Dave
    I have a windows service written in .NET 3.5 (c#) with a System.Threading.Timer that spawns several Threads in each callback. These are just normal threads (no Thread Pool) and I've set the IsBackground = true on each thread since I'm only going to be running managed code. When a user stops the service, what happens to all the threads? Do they die gracefully? I don't have any code that manages the threads via calling join or abort. Is it correct to assume the IsBackground = true is enough to assume the threads will be disposed and stopped when a user stops the service? What exactly happens when someone stops a windows service via the Service Manager GUI? Does it kill the process after it fires the OnStop event? This would actually be acceptable for me because I've built a separate mechanism that allows a user know for sure there are no threads before they stop the service. This is done via 2 WCF methods exposed from a ServiceHost that runs inside the Windows Service. There's one method to stop spawning new threads and another method to query how many running threads there are left. I'm just curious what happens if they skip those steps and just stop the service... It seems the IsBackground helps achieve this:

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  • Threads in Java

    - by owca
    I've created simple program to test Threads in Java. I'd like it to print me numbers infinitely, like 123123123123123. Dunno why, but currently it stops after one cycle finishing 213 only. Anyone knows why ? public class Main { int number; public Main(int number){ } public static void main(String[] args) { new Infinite(2).start(); new Infinite(1).start(); new Infinite(3).start(); } } class Infinite extends Thread { static int which=1; static int order=1; int id; int number; Object console = new Object(); public Infinite(int number){ id = which; which++; this.number = number; } @Override public void run(){ while(1==1){ synchronized(console){ if(order == id){ System.out.print(number); order++; if(order >= which){ order = 1; } try{ console.notifyAll(); console.wait(); } catch(Exception e) {} } else { try{ console.notifyAll(); console.wait(); } catch(Exception e) {} } } try{Thread.sleep(0);} catch(Exception e) {} } } }

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  • InvalidOperationException when executing SqlCommand with transaction

    - by Serhat Özgel
    I have this code, running parallel in two separate threads. It works fine for a few times, but at some random point it throws InvalidOperationException: The transaction is either not associated with the current connection or has been completed. At the point of exception, I am looking inside the transaction with visual studio and verify its connection is set normally. Also command.Transaction._internalTransaction. _transactionState is set to Active and IsZombied property is set to false. This is a test application and I am using Thread.Sleep for creating longer transactions and causing overlaps. Why may the exception being thrown and what can I do about it? IDbCommand command = new SqlCommand("Select * From INFO"); IDbConnection connection = new SqlConnection(connectionString); command.Connection = connection; IDbTransaction transaction = null; try { connection.Open(); transaction = connection.BeginTransaction(); command.Transaction = transaction; command.ExecuteNonQuery(); // Sometimes throws exception Thread.Sleep(forawhile); // For overlapping transactions running in parallel transaction.Commit(); } catch (ApplicationException exception) { if (transaction != null) { transaction.Rollback(); } } finally { connection.Close(); }

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  • Access denied for pdf to read using itextsharp at server level..

    - by apekshabs
    Am facing error after uploadind to server... as access denied .... can anyone help me.... Document myDocument = new Document(PageSize.A5, 26, 72, 180, 180); string strUniqueFn = "onlineinvoice.pdf"; string imgpath = "logo.gif"; string strUser = Thread.CurrentPrincipal.Identity.Name.Substring(Thread.CurrentPrincipal.Identity.Name.IndexOf("\\") + 1).ToUpper(); string strFolder = Server.MapPath("."); System.IO.DirectoryInfo di = new System.IO.DirectoryInfo(strFolder); System.IO.FileInfo[] fi = di.GetFiles(strUser + "*.*"); for (i = 0; i <= fi.Length - 1; i++) { System.IO.File.Delete(strFolder + "\\" + strUniqueFn); } string strPath = strFolder + "\\" + strUniqueFn; PdfWriter pdfw = PdfWriter.GetInstance(myDocument, new FileStream(strPath, FileMode.Create)); string iPath = strFolder + "\\" + imgpath; pdfw.CloseStream = false; myDocument.Open(); ...................... myDocument.Close(); Am facing error at PdfWriter pdfw = PdfWriter.GetInstance(myDocument, new FileStream(strPath, FileMode.Create)); can anyone help me... Thank you

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  • Replace low level web-service reference call transport with custom one

    - by hoodoos
    I'm not sure if title sounds right actually, so I will give more explanation here. I will begin from very beginning :) I'm using c# and .net for my development. I have an application that makes requests to some soap web-service and for each user request it produces 3 to 10 requests for web-service, they should all run async to finish in one time, so I use Async method of the web-service generated reference and then wait for result on callback. But it seems like it starts a thread (or takes it from pool) for every async call I make, so if I have 10 clients I got to spawn 30 to 100 threads and it sounds terrible even for my 16 cores server :) So i wanted to replace low level transport implementation with my own which uses non-blocking sockets and can handle at least 50 sockets run parallel in one thread with not much overhead. But I actually dunno where to put my override best. I analyzed System.Web.Services.Protocols.SoapHttpClientProtocol class and see that it has some GetWebRequest method which I actually could use. If only I could somehow interupt the object it creates and get a http request with all headers and body from there and then send it with my own sockets.. Any ideas what approach to use? Or maybe there's something built in the framework I can use?

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  • .NET Speech recognition plugin Runtime Error: Unhandled Exception. What could possibly cause it?

    - by manuel
    I'm writing a plugin (dll file) for speech recognition, and I'm creating a WinForm as its interface/dialog. When I run the plugin and click the 'Speak' to start the initialization, I get an unhandled exception. Here is a piece of the code: public ref class Dialog : public System::Windows::Forms::Form { public: SpeechRecognitionEngine^ sre; private: System::Void btnSpeak_Click(System::Object^ sender, System::EventArgs^ e) { Initialize(); } protected: void Initialize() { if (System::Threading::Thread::CurrentThread->GetApartmentState() != System::Threading::ApartmentState::STA) { throw gcnew InvalidOperationException("UI thread required"); } //create the recognition engine sre = gcnew SpeechRecognitionEngine(); //set our recognition engine to use the default audio device sre->SetInputToDefaultAudioDevice(); //create a new GrammarBuilder to specify which commands we want to use GrammarBuilder^ grammarBuilder = gcnew GrammarBuilder(); //append all the choices we want for commands. //we want to be able to move, stop, quit the game, and check for the cake. grammarBuilder->Append(gcnew Choices("play", "stop")); //create the Grammar from th GrammarBuilder Grammar^ customGrammar = gcnew Grammar(grammarBuilder); //unload any grammars from the recognition engine sre->UnloadAllGrammars(); //load our new Grammar sre->LoadGrammar(customGrammar); //add an event handler so we get events whenever the engine recognizes spoken commands sre->SpeechRecognized += gcnew EventHandler<SpeechRecognizedEventArgs^> (this, &Dialog::sre_SpeechRecognized); //set the recognition engine to keep running after recognizing a command. //if we had used RecognizeMode.Single, the engine would quite listening after //the first recognized command. sre->RecognizeAsync(RecognizeMode::Multiple); //this->init(); } void sre_SpeechRecognized(Object^ sender, SpeechRecognizedEventArgs^ e) { //simple check to see what the result of the recognition was if (e->Result->Text == "play") { MessageBox(plugin.hwndParent, L"play", 0, 0); } if (e->Result->Text == "stop") { MessageBox(plugin.hwndParent, L"stop", 0, 0); } } };

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  • I need to remove Java Script tags using regular expressions and JRegex

    - by piotr
    I need to remove all the Java Script tags and the content in between and style tags from the HTML code of web pages.So far I've come up with this expression : "(<[ \r\n\t]script([ \r\n\t]|){1,}([ \r\n\t]|.)?)|(<[ \r\n\t]noscript([ \r\n\t]|){1,}([ \r\n\t]|.)?)|(<[ \r\n\t]style([ \r\n\t]|){1,}([ \r\n\t]|.)?)" I use JRegex library to work with regular expressions. When I test it in any regex tester it works just fine, but once I run my program - it all crashes down with this error report: Exception in thread "Thread-0" java.lang.StackOverflowError at java.util.regex.Pattern$BranchConn.match(Unknown Source) at java.util.regex.Pattern$BmpCharProperty.match(Unknown Source) at java.util.regex.Pattern$Branch.match(Unknown Source) at java.util.regex.Pattern$GroupHead.match(Unknown Source) at java.util.regex.Pattern$LazyLoop.match(Unknown Source) at java.util.regex.Pattern$GroupTail.match(Unknown Source) at java.util.regex.Pattern$BranchConn.match(Unknown Source) at java.util.regex.Pattern$CharProperty.match(Unknown Source) at java.util.regex.Pattern$Branch.match(Unknown Source) at java.util.regex.Pattern$GroupHead.match(Unknown Source) at java.util.regex.Pattern$LazyLoop.match(Unknown Source) .................................. And it keeps on going forever. If anyone can give me an advice on this one - I'll be very grateful.

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  • Monotouch threads, GC, WCF

    - by cvista
    Hi This is a question about best practices i guess but it applies directly to my current MT project. I'm using WCF services to communicate with the server. To do this i do the following: services.MethodToCall(params); and the asynch: services.OnMethodToCallCompleted += delegate{ //do stuff and ting }; This can lead to issues if you're not careful in that variables defined within the scope of the asynch callback can sometimes be cleaned up by the gc and this can cause crashes. So - I am making it a practice to declare these outside of the scope of the callback unless I am 100% sure they are not needed. Now - when doing stuff and ting implies changing the ui - i wrap it all in an InvokeOnMainThread call. I guess wrapping everything in this would slow the main thread down and rubbish the point of having multi threads. Even though I'm being careful about all this i am still getting crashes and I have no idea why! I am certain it has something to do with threads, scope and all that. Now - the only thing I can think of outside of updating the UI that may need to happen inside of InvokeOnMainThread is that I have a singleton 'Database' class. This is based on the version 5 code from this thread http://www.yoda.arachsys.com/csharp/singleton.html So now if the service method returns data that needs to be added/updated to the Database class -I also wrap this inside an InvokeOnMainThread call. Still getting random crashes. So... My question is this: I am new to thick client dev - I'm coming from a web dev perspective where we don't need to worry about threads so much :) Aside from what I have mentioned -are there any other things I should be aware of? Is the above stuff correct? Or am i miss-understanding something? Cheers w://

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  • BeginInvoke on ObservableCollection not immediate.

    - by Padu Merloti
    In my code I subscribe to an event that happens on a different thread. Every time this event happens, I receive an string that is posted to the observable collection: Dispatcher currentDispatcher = Dispatcher.CurrentDispatcher; var SerialLog = new ObservableCollection<string>(); private void hitStation_RawCommandSent(object sender, StringEventArgs e) { string command = e.Value.Replace("\r\n", ""); Action dispatchAction = () => SerialLog.Add(command); currentDispatcher.BeginInvoke(dispatchAction, DispatcherPriority.Render); } The code below is in my view model (could be in the code behind, it doesn't matter in this case). When I call "hitstation.PrepareHit", the event above gets called a couple times, then I wait and call "hitStation.HitBall", and the event above gets called a couple more times. private void HitBall() { try { try { Mouse.OverrideCursor = Cursors.Wait; //prepare hit hitStation.PrepareHit(hitSpeed); Thread.Wait(1000); PlayWarning(); //hit hitStation.HitBall(hitSpeed); } catch (TimeoutException ex) { MessageBox.Show("Timeout hitting ball: " + ex.Message); } } finally { Mouse.OverrideCursor = null; } } The problem I'm having is that the ListBox that is bound to my SerialLog gets updated only when the HitBall method finishes. I was expecting seeing a bunch of updates from the PrepareHit, a pause and then a bunch more updates from the HitBall. I've tried a couple of DispatcherPriority arguments, but they don't seem to have any effect.

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  • Why are Managed Beans not loaded in Tomcat?

    - by c0d3x
    Hi, I created a JSF 2 web application with facelets. The libs for JSF where stored at tomcat/lib, to share it between several applications. I thought maybe it would be better to store the libs inside the WEB-INF/lib folder of the application, to get the application more independent from server configurations. Now when I start tomcat via eclipse, the managed beans are loaded and working. But when I start tomcat directly / standalone the managed beans are not loaded automatically. I used @ManagedBean @SessionScoped / @RequestScoped annotations to declare classes as managed beans. Why is this? What can I do to fix it? I don't use any faces-config.xml file yet. Thanks in advance. edited: Maybe this helps to see whats going on: javax.el.PropertyNotFoundException: /Artikel.xhtml @12,108 value="#{artikelBackingBean.nameFilterPattern}": Target Unreachable, identifier 'artikelBackingBean' resolved to null at com.sun.faces.facelets.el.TagValueExpression.getType(TagValueExpression.java:93) at com.sun.faces.renderkit.html_basic.HtmlBasicInputRenderer.getConvertedValue(HtmlBasicInputRenderer.java:95) at javax.faces.component.UIInput.getConvertedValue(UIInput.java:1008) at javax.faces.component.UIInput.validate(UIInput.java:934) at javax.faces.component.UIInput.executeValidate(UIInput.java:1189) at javax.faces.component.UIInput.processValidators(UIInput.java:691) at javax.faces.component.UIForm.processValidators(UIForm.java:243) at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1080) at javax.faces.component.UIViewRoot.processValidators(UIViewRoot.java:1180) at com.sun.faces.lifecycle.ProcessValidationsPhase.execute(ProcessValidationsPhase.java:76) at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101) at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:312) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:433) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454) at java.lang.Thread.run(Thread.java:619)

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  • NetBeans parameter fill after code completion

    - by byte
    This is a particularly annoying problem I'm having, and I can't be the only one to have issue with it. In NetBeans, when you type part of a method, then hit CTRL-SPACE, it displays the code-completion popup, whereupon you can hit tab to finish out the word. This is great, and pretty much how all IDE's operate. Example: Thread.sl < CTRL-SPACE Thread.sleep Yay! Problem is that in this context, once you type in a paren, it auto-fills the parameters for the method with their default names, and inserts a closing paren (regardless of whether you have disabled the option to automatically close them on the preferences page for code completion). This behavior is NOT present if you had manually typed out the full name. How is this helpful to anyone? You've got to type over it your actual variable that you will be passing, and NetBeans gives you no option to prevent the closing paren on code-completion. Does anyone have a way to solve this issue, without having to dive into the netbeans source and build it just for this minor of an issue?

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  • Trying to use a grails domain class from the shell

    - by ?????
    I'm new to Grails. I'm trying to experiement with my grails domains from the shell, and I can't get it to work. These domains work fine from the scaffold code when I run the app. Given this domain class class IncomingCall { String caller_id Date call_time int call_length static constraints = { } } I try to create an "IncomingCall" and save it from the shell. No matter what I do, I always get "Null"; the object isn't created. And if I try to create the object and then do a save, I get the "No hibernate session bound to thread" error (see below). groovy:000> new IncomingCall(caller_id:'555-1212', call_time: new Date(), call_length:10).save() ERROR org.hibernate.HibernateException: No Hibernate Session bound to thread, and configuration does not allow creation of non-transactional one here at org.springframework.orm.hibernate3.SpringSessionContext.currentSession (SpringSessionContext.java:63) at org.hibernate.impl.SessionFactoryImpl.getCurrentSession (SessionFactoryImpl.java:574) at groovysh_evaluate.run (groovysh_evaluate:3) ... groovy:000> How can I make this work from the shell?

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  • Java UnknownHostException When and Why?

    - by interstar
    I'm trying to post to a website from a Processing Sketch. (Processing is basically Java running in a fancy environment). I'm using this library : http://libraries.seltar.org/postToWeb/ but I don't know if that makes a difference. You can see from the stack trace below that this is just a wrapper for the Java standard library. Anyway, the important point is that the host "mysite.com" is up and running. I am seeing it from the browser. But when I try to post to it from Java I just get the UnknownHostException appearing. Given that the site is up. What else might this mean? The program is currently running inside the Processing environment. Presumably as an Applet. java.net.UnknownHostException: mysite.com at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:195) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366) at java.net.Socket.connect(Socket.java:529) at java.net.Socket.connect(Socket.java:478) at sun.net.NetworkClient.doConnect(NetworkClient.java:163) at sun.net.www.http.HttpClient.openServer(HttpClient.java:394) at sun.net.www.http.HttpClient.openServer(HttpClient.java:529) at sun.net.www.http.HttpClient.<init>(HttpClient.java:233) at sun.net.www.http.HttpClient.New(HttpClient.java:306) at sun.net.www.http.HttpClient.New(HttpClient.java:323) at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:970) at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:911) at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:836) at sun.net.www.protocol.http.HttpURLConnection.getOutputStream(HttpURLConnection.java:1014) at org.seltar.Bytes2Web.PostToWeb._post(PostToWeb.java:90) at org.seltar.Bytes2Web.ByteToWeb.post(ByteToWeb.java:66) at experimentPostToWeb.keyPressed(experimentPostToWeb.java:35) at processing.core.PApplet.handleKeyEvent(Unknown Source) at processing.core.PApplet.dequeueKeyEvents(Unknown Source) at processing.core.PApplet.handleDraw(Unknown Source) at processing.core.PApplet.run(Unknown Source) at java.lang.Thread.run(Thread.java:662)

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  • Special technology needed for browser based chat?

    - by orokusaki
    On this post, I read about the usage of XMPP. Is this sort of thing necessary, and more importantly, my main question expanded: Can a chat server and client be built efficiently using only standard HTTP and browser technologies (such as PHP and JS, or RoR and JS, etc)? Or, is it best to stick with old protocols like XMPP find a way to integrate them with my application? I looked into CampFire via LiveHTTPHeaders and Firebug for about 5 minutes, and it appears to use Ajax to send a request which is never answered until another chat happens. Is this just CampFire opening a new thread on the server to listen for an update and then returning a response to the request when the thread hears an update? I noticed that they're requesting on a specific port (8043 if memory serves me) which makes me think that they're doing something more complex than just what I mentioned. Also, the URL requested started with /tcp/ which I found interesting. Note: I don't expect to ever have more than 150 users live-chatting in all the rooms combined at the same time. I understand that if I was building a hosted pay for chat service like CampFire with thousands of concurrent users, it would behoove me to invest time in researching special technologies vs trying to reinvent the wheel in a simple way in my app. Also, if you're going to do it with server polling, how often would you personally poll to maximize response without slamming the server?

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  • Python 4 step setup with progressBars

    - by Samuel Taylor
    I'm having a problem with the code below. When I run it the progress bar will pulse for around 10 secs as meant to and then move on to downloading and will show the progress but when finished it will not move on to the next step it just locks up. import sys import time import pygtk import gtk import gobject import threading import urllib import urlparse class WorkerThread(threading.Thread): def __init__ (self, function, parent, arg = None): threading.Thread.__init__(self) self.function = function self.parent = parent self.arg = arg self.parent.still_working = True def run(self): # when does "run" get executed? self.parent.still_working = True if self.arg == None: self.function() else: self.function(self.arg) self.parent.still_working = False def stop(self): self = None class MainWindow: def __init__(self): gtk.gdk.threads_init() self.wTree = gtk.Builder() self.wTree.add_from_file("gui.glade") self.mainWindows() def mainWindows(self): self.mainWindow = self.wTree.get_object("frmMain") dic = { "on_btnNext_clicked" : self.mainWindowNext, } self.wTree.connect_signals(dic) self.mainWindow.show() self.installerStep = 0 # 0 = none, 1 = preinstall, 2 = download, 3 = install info, 4 = install #gtk.main() self.mainWindowNext() def pulse(self): self.wTree.get_object("progress").pulse() if self.still_working == False: self.mainWindowNext() return self.still_working def preinstallStep(self): self.wTree.get_object("progress").set_fraction(0) self.wTree.get_object("btnNext").set_sensitive(0) self.wTree.get_object("notebook1").set_current_page(0) self.installerStep = 1 WT = WorkerThread(self.heavyWork, self) #Would do a heavy function here like setup some thing WT.start() gobject.timeout_add(75, self.pulse) def downloadStep(self): self.wTree.get_object("progress").set_fraction(0) self.wTree.get_object("btnNext").set_sensitive(0) self.wTree.get_object("notebook1").set_current_page(0) self.installerStep = 2 urllib.urlretrieve('http://mozilla.mirrors.evolva.ro//firefox/releases/3.6.3/win32/en-US/Firefox%20Setup%203.6.3.exe', '/tmp/firefox.exe', self.updateHook) self.mainWindowNext() def updateHook(self, blocks, blockSize, totalSize): percentage = float ( blocks * blockSize ) / totalSize if percentage > 1: percentage = 1 self.wTree.get_object("progress").set_fraction(percentage) while gtk.events_pending(): gtk.main_iteration() def installInfoStep(self): self.wTree.get_object("btnNext").set_sensitive(1) self.wTree.get_object("notebook1").set_current_page(1) self.installerStep = 3 def installStep(self): self.wTree.get_object("progress").set_fraction(0) self.wTree.get_object("btnNext").set_sensitive(0) self.wTree.get_object("notebook1").set_current_page(0) self.installerStep = 4 WT = WorkerThread(self.heavyWork, self) #Would do a heavy function here like setup some thing WT.start() gobject.timeout_add(75, self.pulse) def mainWindowNext(self, widget = None): if self.installerStep == 0: self.preinstallStep() elif self.installerStep == 1: self.downloadStep() elif self.installerStep == 2: self.installInfoStep() elif self.installerStep == 3: self.installStep() elif self.installerStep == 4: sys.exit(0) def heavyWork(self): time.sleep(10) if __name__ == '__main__': MainWindow() gtk.main()

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  • Does Android AsyncTaskQueue or similar exist?

    - by Ben L.
    I read somewhere (and have observed) that starting threads is slow. I always assumed that AsyncTask created and reused a single thread because it required being started inside the UI thread. The following (anonymized) code is called from a ListAdapter's getView method to load images asynchronously. It works well until the user moves the list quickly, and then it becomes "janky". final File imageFile = new File(getCacheDir().getPath() + "/img/" + p.image); image.setVisibility(View.GONE); view.findViewById(R.id.imageLoading).setVisibility(View.VISIBLE); (new AsyncTask<Void, Void, Bitmap>() { @Override protected Bitmap doInBackground(Void... params) { try { Bitmap image; if (!imageFile.exists() || imageFile.length() == 0) { image = BitmapFactory.decodeStream(new URL( "http://example.com/images/" + p.image).openStream()); image.compress(Bitmap.CompressFormat.JPEG, 85, new FileOutputStream(imageFile)); image.recycle(); } image = BitmapFactory.decodeFile(imageFile.getPath(), bitmapOptions); return image; } catch (MalformedURLException ex) { // TODO Auto-generated catch block ex.printStackTrace(); return null; } catch (IOException ex) { // TODO Auto-generated catch block ex.printStackTrace(); return null; } } @Override protected void onPostExecute(Bitmap image) { if (view.getTag() != p) // The view was recycled. return; view.findViewById(R.id.imageLoading).setVisibility( View.GONE); view.findViewById(R.id.image) .setVisibility(View.VISIBLE); ((ImageView) view.findViewById(R.id.image)) .setImageBitmap(image); } }).execute(); I'm thinking that a queue-based method would work better, but I'm wondering if there is one or if I should attempt to create my own implementation.

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  • Problem when trying to connect to a desktop server from android on wifi

    - by thiagolee
    Hello, I am trying to send a file from the phone running Android 1.5 to a server on a desktop. I wrote some code, which works on emulator, but on the phone it doesn't. I'm connecting to the network through WiFi. It works, I can access the internet through my phone and I've configured my router. The application stops when I'm trying to connect. I have the permissions. Someone have any ideas, below is my code. Running on Android package br.ufs.reconhecimento; import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.net.Socket; import android.app.Activity; import android.app.AlertDialog; import android.content.DialogInterface; import android.content.Intent; import android.os.Bundle; import android.util.Log; import android.view.View; import android.view.View.OnClickListener; import android.widget.EditText; import android.widget.ImageButton; /** * Sample code that invokes the speech recognition intent API. */ public class Reconhecimento extends Activity implements OnClickListener { static final int VOICE_RECOGNITION_REQUEST_CODE = 1234; static final String LOG_VOZ = "UFS-Reconhecimento"; final int INICIAR_GRAVACAO = 01; int porta = 5158; // Porta definida no servidor int tempoEspera = 1000; String ipConexao = "172.20.0.189"; EditText ipEdit; /** * Called with the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Inflate our UI from its XML layout description. setContentView(R.layout.main); // Get display items for later interaction ImageButton speakButton = (ImageButton) findViewById(R.id.btn_speak); speakButton.setPadding(10, 10, 10, 10); speakButton.setOnClickListener(this); //Alerta para o endereço IP AlertDialog.Builder alerta = new AlertDialog.Builder(this); alerta.setTitle("IP");//+mainWifi.getWifiState()); ipEdit = new EditText(this); ipEdit.setText(ipConexao); alerta.setView(ipEdit); alerta.setMessage("Por favor, Confirme o endereço IP."); alerta.setPositiveButton("OK", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int which) { ipConexao = ipEdit.getText().toString(); Log.d(LOG_VOZ, "Nova Atribuição do Endreço IP: " + ipConexao); } }); alerta.create(); alerta.show(); } /** * Handle the click on the start recognition button. */ public void onClick(View v) { if (v.getId() == R.id.btn_speak) { //startVoiceRecognitionActivity(); Log.d(LOG_VOZ, "Iniciando a próxima tela"); Intent recordIntent = new Intent(this, GravacaoAtivity.class); Log.d(LOG_VOZ, "Iniciando a tela (instancia criada)"); startActivityForResult(recordIntent, INICIAR_GRAVACAO); Log.d(LOG_VOZ, "Gravação iniciada ..."); } } /** * Handle the results from the recognition activity. */ @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { Log.d(LOG_VOZ, "Iniciando onActivityResult()"); if (requestCode == INICIAR_GRAVACAO && resultCode == RESULT_OK) { String path = data.getStringExtra(GravacaoAtivity.RETORNO); conexaoSocket(path); } else Log.e(LOG_VOZ, "Resultado Inexperado ..."); } private void conexaoSocket(String path) { Socket socket = SocketOpener.openSocket(ipConexao, porta, tempoEspera); if(socket == null) return; try { DataOutputStream conexao = new DataOutputStream(socket.getOutputStream()); Log.d(LOG_VOZ, "Acessando arquivo ..."); File file = new File(path); DataInputStream arquivo = new DataInputStream(new FileInputStream(file)); Log.d(LOG_VOZ, "Iniciando Transmissão ..."); conexao.writeLong(file.length()); for(int i = 0; i < file.length(); i++) conexao.writeByte(arquivo.readByte()); Log.d(LOG_VOZ, "Transmissão realizada com sucesso..."); Log.d(LOG_VOZ, "Fechando a conexão..."); conexao.close(); socket.close(); Log.d(LOG_VOZ, "============ Processo finalizado com Sucesso =============="); } catch (IOException e) { Log.e(LOG_VOZ, "Erro ao fazer a conexão via Socket. " + e.getMessage()); // TODO Auto-generated catch block } } } class SocketOpener implements Runnable { private String host; private int porta; private Socket socket; public SocketOpener(String host, int porta) { this.host = host; this.porta = porta; socket = null; } public static Socket openSocket(String host, int porta, int timeOut) { SocketOpener opener = new SocketOpener(host, porta); Thread t = new Thread(opener); t.start(); try { t.join(timeOut); } catch(InterruptedException e) { Log.e(Reconhecimento.LOG_VOZ, "Erro ao fazer o join da thread do socket. " + e.getMessage()); //TODO: Mensagem informativa return null; } return opener.getSocket(); } public void run() { try { socket = new Socket(host, porta); }catch(IOException e) { Log.e(Reconhecimento.LOG_VOZ, "Erro na criação do socket. " + e.getMessage()); //TODO: Mensagem informativa } } public Socket getSocket() { return socket; } } Running on the desktop Java: import java.io.BufferedReader; import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStreamReader; import java.net.ServerSocket; import java.net.Socket; public class ServidorArquivo { private static int porta = 5158; static String ARQUIVO = "voz.amr"; /** * Caminho que será gravado o arquivo de audio */ static String PATH = "/home/iade/Trabalho/lib/"; public static void main(String[] args) { int i = 1; try { System.out.println("Iniciando o Servidor Socket - Android."); ServerSocket s = new ServerSocket(porta); System.out.println("Servidor Iniciado com Sucesso..."); System.out.println("Aguardando conexões na porta: " + porta); while(true) { Socket recebendo = s.accept(); System.out.println("Aceitando conexão de nº " + i); new ThreadedHandler(recebendo).start(); i++; } } catch (Exception e) { System.out.println("Erro: " + e.getMessage()); e.printStackTrace(); } } } class ThreadedHandler extends Thread { private Socket socket; public ThreadedHandler(Socket so) { socket = so; } public void run() { DataInputStream entrada = null; DataOutputStream arquivo = null; try { entrada = new DataInputStream(socket.getInputStream()); System.out.println("========== Iniciando a leitura dos dados via Sockets =========="); long tamanho = entrada.readLong(); System.out.println("Tamanho do vetor " + tamanho); File file = new File(ServidorArquivo.PATH + ServidorArquivo.ARQUIVO); if(!file.exists()) file.createNewFile(); arquivo = new DataOutputStream(new FileOutputStream(file)); for(int j = 0; j < tamanho; j++) { arquivo.write(entrada.readByte()); } System.out.println("========== Dados recebidos com sucesso =========="); } catch (Exception e) { System.out.println("Erro ao tratar do socket: " + e.getMessage()); e.printStackTrace(); } finally { System.out.println("**** Fechando as conexões ****"); try { entrada.close(); socket.close(); arquivo.close(); } catch (IOException e) { System.out.println("Erro ao fechar conex&#65533;es " + e.getMessage()); e.printStackTrace(); } } System.out.println("============= Fim da Gravação ==========="); // tratar o arquivo String cmd1 = "ffmpeg -i voz.amr -ab 12288 -ar 16000 voz.wav"; String cmd2 = "soundstretch voz.wav voz2.wav -tempo=100"; String dir = "/home/iade/Trabalho/lib"; File workDir = new File(dir); File f1 = new File(dir+"/voz.wav"); File f2 = new File(dir+"/voz2.wav"); f1.delete(); f2.delete(); try { executeCommand(cmd1, workDir); System.out.println("realizou cmd1"); executeCommand(cmd2, workDir); System.out.println("realizou cmd2"); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } private void executeCommand(String cmd1, File workDir) throws IOException, InterruptedException { String s; Process p = Runtime.getRuntime().exec(cmd1,null,workDir); int i = p.waitFor(); if (i == 0) { BufferedReader stdInput = new BufferedReader(new InputStreamReader(p.getInputStream())); // read the output from the command while ((s = stdInput.readLine()) != null) { System.out.println(s); } } else { BufferedReader stdErr = new BufferedReader(new InputStreamReader(p.getErrorStream())); // read the output from the command while ((s = stdErr.readLine()) != null) { System.out.println(s); } } } } Thanks in advance.

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  • C# DynamicMethod prelink

    - by soywiz
    I'm the author of a psp emulator made in C#. I'm generating lots of "DynamicMethod" using ILGenerator. I'm converting assembly code into an AST, and then generating IL code and building that DynamicMethod. I'm doing this in another thread, so I can generate new methods while the program is executing others so it can run smoothly. My problem is that the native code generation is lazy, so the machine code is generated when the function is called, not when the IL is generated. So it generates in the program executing thread, native code generation is prettly slow as it is the asm-ast-il step. I have tried the Marshal.Prelink method that it is suposed to generate the machine code before executing the function. It does work on Mono, but it doesn't work on MS .NET. Marshal.Prelink(MethodInfo); Is there a way of prelinking a DynamicMethod on MS .NET? I thought adding a boolean parameter to the function that if set, exits the function immediately so no code is actually executed. I could "prelink" that way, but I think that's a nasty solution I want to avoid. Any idea?

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  • Java - If statement with String comparison fails

    - by Andrea
    I really don't know why the if statement below is not executing: if (s == "/quit") { System.out.println("quitted"); } Below is the whole class. It is probably a really stupid logic problem but I have been pulling my hair out over here not being able to figure this out. Thanks for looking :) class TextParser extends Thread { public void run() { while (true) { for(int i = 0; i < connectionList.size(); i++) { try { System.out.println("reading " + i); Connection c = connectionList.elementAt(i); Thread.sleep(200); System.out.println("reading " + i); String s = ""; if (c.in.ready() == true) { s = c.in.readLine(); //System.out.println(i + "> "+ s); if (s == "/quit") { System.out.println("quitted"); } if(! s.equals("")) { for(int j = 0; j < connectionList.size(); j++) { Connection c2 = connectionList.elementAt(j); c2.out.println(s); } } } } catch(Exception e){ System.out.println("reading error"); } } } } }

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  • C# - Take Screenshot based on a Timer

    - by APShredder
    Hello everybody. I'm trying to create a WinForms app that takes a screenshot on a set interval. I think my code is correct, but when I try to run it, I get the error message "System.Runtime.InteropServices.ExternalException was unhandled, A generic error occurred in GDI+." System.Windows.Forms.Timer t = new System.Windows.Forms.Timer(); Thread th; private static Bitmap bmpScreenshot; private static Graphics gfxScreenshot; void TakeScreenShot() { bmpScreenshot = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height, PixelFormat.Format32bppArgb); gfxScreenshot = Graphics.FromImage(bmpScreenshot); gfxScreenshot.CopyFromScreen(Screen.PrimaryScreen.Bounds.X, Screen.PrimaryScreen.Bounds.Y, 0, 0, Screen.PrimaryScreen.Bounds.Size, CopyPixelOperation.SourceCopy); bmpScreenshot.Save(Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory) + @"\ScreenCaptures", ImageFormat.Png); th.Abort(); } void StartThread(object sender, EventArgs e) { th = new Thread(new ThreadStart(TakeScreenShot)); th.Start(); } private void Form1_Load(object sender, EventArgs e) { Directory.CreateDirectory(Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory) + @"\ScreenCaptures"); t.Interval = 500; t.Tick += new EventHandler(StartThread); t.Start(); } The line that's giving my trouble is: bmpScreenshot.Save(Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory) + @"\ScreenCaptures", ImageFormat.Png); Any ideas about what is going wrong? Thanks in advance.

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  • How to tell when a Socket has been disconnected

    - by BowserKingKoopa
    On the client side I need to know when/if my socket connection has been broken. However the Socket.Connected property always returns true, even after the server side has been disconnected and I've tried sending data through it. Can anyone help me figure out what's going on here. I need to know when a socket has been disconnected. Socket serverSocket = null; TcpListener listener = new TcpListener(1530); listener.Start(); listener.BeginAcceptSocket(new AsyncCallback(delegate(IAsyncResult result) { Debug.WriteLine("ACCEPTING SOCKET CONNECTION"); TcpListener currentListener = (TcpListener)result.AsyncState; serverSocket = currentListener.EndAcceptSocket(result); }), listener); Socket clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); Debug.WriteLine("client socket connected: " + clientSocket.Connected);//should be FALSE, and it is clientSocket.Connect("localhost", 1530); Debug.WriteLine("client socket connected: " + clientSocket.Connected);//should be TRUE, and it is Thread.Sleep(1000); serverSocket.Close();//closing the server socket here Thread.Sleep(1000); clientSocket.Send(new byte[0]);//sending data should cause the socket to update its Connected property. Debug.WriteLine("client socket connected: " + clientSocket.Connected);//should be FALSE, but its always TRUE

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