Search Results

Search found 8166 results on 327 pages for 'thread syncronization'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 79/327 | < Previous Page | 75 76 77 78 79 80 81 82 83 84 85 86  | Next Page >

  • Multithreading Errors in C#

    - by Adam
    Hi. I am trying to update a text box. I thought my threading code would fix the problem, but it does not. Can anyone help with this? new Thread((ThreadStart)delegate { txtCapacitance.Text = Math.Round(capacitance, 3).ToString(); }).Start(); Gives the following error: Cross-thread operation not valid: Control 'txtCapacitance' accessed from a thread other than the thread it was created on. Note that all this is being started by a dataReceived function which is called whenever USB data is received.

    Read the article

  • General SQL Server query performance

    - by Kiril
    Hey guys, This might be stupid, but databases are not my thing :) Imagine the following scenario. A user can create a post and other users can reply to his post, thus forming a thread. Everything goes in a single table called Posts. All the posts that form a thread are connected with each other through a generated key called ThreadID. This means that when user #1 creates a new post, a ThreadID is generated, and every reply that follows has a ThreadID pointing to the initial post (created by user #1). What I am trying to do is limit the number of replies to let's say 20 per thread. I'm wondering which of the approaches bellow is faster: 1 I add a new integer column (e.x. Counter) to Posts. After a user replies to the initial post, I update the initial post's Counter field. If it reaches 20 I lock the thread. 2 After a user replies to the initial post, I select all the posts that have the same ThreadID. If this collection has more than 20 items, I lock the thread. For further information: I am using SQL Server database and Linq-to-SQL entity model. I'd be glad if you tell me your opinions on the two approaches or share another, faster approach. Best Regards, Kiril

    Read the article

  • Message queue proxy in Python + Twisted

    - by gasper_k
    Hi, I want to implement a lightweight Message Queue proxy. It's job is to receive messages from a web application (PHP) and send them to the Message Queue server asynchronously. The reason for this proxy is that the MQ isn't always avaliable and is sometimes lagging, or even down, but I want to make sure the messages are delivered, and the web application returns immediately. So, PHP would send the message to the MQ proxy running on the same host. That proxy would save the messages to SQLite for persistence, in case of crashes. At the same time it would send the messages from SQLite to the MQ in batches when the connection is available, and delete them from SQLite. Now, the way I understand, there are these components in this service: message listener (listens to the messages from PHP and writes them to a Incoming Queue) DB flusher (reads messages from the Incoming Queue and saves them to a database; due to SQLite single-threadedness) MQ connection handler (keeps the connection to the MQ server online by reconnecting) message sender (collects messages from SQlite db and sends them to the MQ server, then removes them from db) I was thinking of using Twisted for #1 (TCPServer), but I'm having problem with integrating it with other points, which aren't event-driven. Intuition tells me that each of these points should be running in a separate thread, because all are IO-bound and independent of each other, but I could easily put them in a single thread. Even though, I couldn't find any good and clear (to me) examples on how to implement this worker thread aside of Twisted's main loop. The example I've started with is the chatserver.py, which uses service.Application and internet.TCPServer objects. If I start my own thread prior to creating TCPServer service, it runs a few times, but the it stops and never runs again. I'm not sure, why this is happening, but it's probably because I don't use threads with Twisted correctly. Any suggestions on how to implement a separate worker thread and keep Twisted? Do you have any alternative architectures in mind?

    Read the article

  • Can Ruby Fibers be Concurrent?

    - by Jesse J
    I'm trying to get some speed up in my program and I've been told that Ruby Fibers are faster than threads and can take advantage of multiple cores. I've looked around, but I just can't find how to actually run different fibers concurrently. With threads you can dO this: threads = [] threads << Thread.new {Do something} threads << Thread.new {Do something} threads.each {|thread| thread.join} I can't see how to do something like this with fibers. All I can find is yield and resume which seems like just a bunch of starting and stopping between the fibers. Is there a way to do true concurrency with fibers?

    Read the article

  • Java Process.waitFor() and IO streams

    - by lynks
    I have the following code; String[] cmd = { "bash", "-c", "~/path/to/script.sh" }; Process p = Runtime.getRuntime().exec(cmd); PipeThread a = new PipeThread(p.getInputStream(), System.out); PipeThread b = new PipeThread(p.getErrorStream(), System.err); p.waitFor(); a.die(); b.die(); The PipeThread class is quite simple so I will include it in full; public class PipeThread implements Runnable { private BufferedInputStream in; private BufferedOutputStream out; public Thread thread; private boolean die = false; public PipeThread(InputStream i, OutputStream o) { in = new BufferedInputStream(i); out = new BufferedOutputStream(o); thread = new Thread(this); thread.start(); } public void die() { die = true; } public void run() { try { byte[] b = new byte[1024]; while(!die) { int x = in.read(b, 0, 1024); if(x > 0) out.write(b, 0, x); else die(); out.flush(); } } catch(Exception e) { e.printStackTrace(); } try { in.close(); out.close(); } catch(Exception e) { } } } My problem is this; p.waitFor() blocks endlessly, even after the subprocess has terminated. If I do not create the pair of PipeThread instances, then p.waitFor() works perfectly. What is it about the piping of io streams that is causing p.waitFor() to continue blocking? I'm confused as I thought the IO streams would be passive, unable to keep a process alive, or to make Java think the process is still alive.

    Read the article

  • xcode loading the images in background process, it leads to crash the application when i scroll the

    - by Srinivas G
    Hi, I have developed an application which has retrieved the information from remote location...so i put those in UITableView's Section.In response, i will be getting images also..for this i put the background process(only for images..because the app will take more time to retrieve images than text based information..).It is working fine...But if i scroll the tableview while loading the images..it is going to be crashed.... crash Log: Tried to obtain the web lock from a thread other than the main thread or the web thread. This may be a result of calling to UIKit from a secondary thread. Crashing now... could anyone has the solution for this..please let me know..how to resolve this crash...Even i used NSThread class for this.. but i didn't get the solution... Thanks, Srinivas G

    Read the article

  • use .net webbrowser control by multithread, throw "EXCEPTION code=ACCESS_VIOLATION"

    - by user1507827
    i want to make a console program to monitor a webpage's htmlsourcecode, because some of the page content are created by some javescript, so i have to use webbrowser control. like : View Generated Source (After AJAX/JavaScript) in C# my code is below: public class WebProcessor { public string GeneratedSource; public string URL ; public DateTime beginTime; public DateTime endTime; public object GetGeneratedHTML(object url) { URL = url.ToString(); try { Thread[] t = new Thread[10]; for (int i = 0; i < 10; i++) { t[i] = new Thread(new ThreadStart(WebBrowserThread)); t[i].SetApartmentState(ApartmentState.STA); t[i].Name = "Thread" + i.ToString(); t[i].Start(); //t[i].Join(); } } catch (Exception ex) { Console.WriteLine(ex.ToString()); } return GeneratedSource; } private void WebBrowserThread() { WebBrowser wb = new WebBrowser(); wb.ScriptErrorsSuppressed = true; wb.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler( wb_DocumentCompleted); while(true ) { beginTime = DateTime.Now; wb.Navigate(URL); while (wb.ReadyState != WebBrowserReadyState.Complete) { Thread.Sleep(new Random().Next(10,100)); Application.DoEvents(); } } //wb.Dispose(); } private void wb_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e) { WebBrowser wb = (WebBrowser)sender; if (wb.ReadyState == WebBrowserReadyState.Complete) { GeneratedSource= wb.Document.Body.InnerHtml; endTime = DateTime.Now; Console.WriteLine("WebBrowser " + (endTime-beginTime).Milliseconds + Thread.CurrentThread.Name + wb.Document.Title); } } } when it run, after a while (20-50 times), it throw the exception like this EXCEPTION code=ACCESS_VIOLATION (null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(nul l)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(n ull)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null) (null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(nul l)(null)BACKTRACE: 33 stack frames: #0 0x083dba8db0 at MatchExactGetIDsOfNames in mshtml.dll #1 0x0879f9b837 at StrongNameErrorInfo in mscorwks.dll #2 0x0879f9b8e3 at StrongNameErrorInfo in mscorwks.dll #3 0x0879f9b93a at StrongNameErrorInfo in mscorwks.dll #4 0x0879f9b9e0 at StrongNameErrorInfo in mscorwks.dll #5 0x0879f9b677 at StrongNameErrorInfo in mscorwks.dll #6 0x0879f9b785 at StrongNameErrorInfo in mscorwks.dll #7 0x0879f192a8 at InstallCustomModule in mscorwks.dll #8 0x0879f19444 at InstallCustomModule in mscorwks.dll #9 0x0879f194ab at InstallCustomModule in mscorwks.dll #10 0x0879fa6491 at StrongNameErrorInfo in mscorwks.dll #11 0x0879f44bcf at DllGetClassObjectInternal in mscorwks.dll #12 0x089bbafa at in #13 0x087b18cc10 at in System.Windows.Forms.ni.dll #14 0x087b91f4c1 at in System.Windows.Forms.ni.dll #15 0x08d00669 at in #16 0x08792d6e46 at in mscorlib.ni.dll #17 0x08792e02cf at in mscorlib.ni.dll #18 0x08792d6dc4 at in mscorlib.ni.dll #19 0x0879e71b4c at in mscorwks.dll #20 0x0879e896ce at in mscorwks.dll #21 0x0879e96ea9 at CoUninitializeEE in mscorwks.dll #22 0x0879e96edc at CoUninitializeEE in mscorwks.dll #23 0x0879e96efa at CoUninitializeEE in mscorwks.dll #24 0x0879f88357 at GetPrivateContextsPerfCounters in mscorwks.dll #25 0x0879e9cc8f at CoUninitializeEE in mscorwks.dll #26 0x0879e9cc2b at CoUninitializeEE in mscorwks.dll #27 0x0879e9cb51 at CoUninitializeEE in mscorwks.dll #28 0x0879e9ccdd at CoUninitializeEE in mscorwks.dll #29 0x0879f88128 at GetPrivateContextsPerfCounters in mscorwks.dll #30 0x0879f88202 at GetPrivateContextsPerfCounters in mscorwks.dll #31 0x0879f0e255 at InstallCustomModule in mscorwks.dll #32 0x087c80b729 at GetModuleFileNameA in KERNEL32.dll i have try lots of methods to solve the problem, finally, i found that if i thread sleep more millseconds, it will run for a longer time, but the exception is still throw. hope somebody give me the answer of how to slove ... thanks very much !!!

    Read the article

  • ~1 second TcpListener Pending()/AcceptTcpClient() lag

    - by cpf
    Probably just watch this video: http://screencast.com/t/OWE1OWVkO As you see, the delay between a connection being initiated (via telnet or firefox) and my program first getting word of it. Here's the code that waits for the connection public IDLServer(System.Net.IPAddress addr,int port) { Listener = new TcpListener(addr, port); Listener.Server.NoDelay = true;//I added this just for testing, it has no impact Listener.Start(); ConnectionThread = new Thread(ConnectionListener); ConnectionThread.Start(); } private void ConnectionListener() { while (Running) { while (Listener.Pending() == false) { System.Threading.Thread.Sleep(1); }//this is the part with the lag Console.WriteLine("Client available");//from this point on everything runs perfectly fast TcpClient cl = Listener.AcceptTcpClient(); Thread proct = new Thread(new ParameterizedThreadStart(InstanceHandler)); proct.Start(cl); } } (I was having some trouble getting the code into a code block) I've tried a couple different things, could it be I'm using TcpClient/Listener instead of a raw Socket object? It's not a mandatory TCP overhead I know, and I've tried running everything in the same thread, etc.

    Read the article

  • .NET: Control Invoke() in Reflector

    - by sheepsimulator
    So, I was getting back into some .NET programming, and through a new feature in VS.NET 2010, it detected a case where I was trying to modify a control from a thread that didn't create that control, and pointed me to an article on MSDN about how you do this correctly... ' HOW TO WRITE TO A FORM CONTROL FROM A THREAD THAT DIDN'T CREATE THE CONTROL ' =========================================================================== ' Say you need to write to a UI text box that logs stuff... Delegate Sub WriteLogDelegate(ByVal [text] As String) Private Sub WriteLog(ByVal [text] As String) If Me.rtfLog.InvokeRequired Then ' We are not in the same thread! ' Create new WriteLogDelegate and invoke it on the same thread Dim d As New WriteLogDelegate(AddressOf WriteLog) Me.rtfLog.Invoke(d, New Object() {[text]}) Else ' We are totally in the same thread... ' Call AppendText like normal! Me.rtfLog.AppendText([text]) End If End Sub AND I WAS SO EXCITED BECAUSE I HAVE BEEN PUZZLED BY HOW TO DO THIS FOR LIKE 5 YEARS BECAUSE PREVIOUS VERSIONS OF VS.NET DIDN'T FLAG THIS SINCE I WAS AN UNDERGRAD ON A PROJECT AND... Umm... Sorry bout that. Composure regained. Anyway, now that I know this bit of .NET-fu, I'd like to learn more about what's going on and how it works. Where can I find the code for Invoke() in .NET Reflector?

    Read the article

  • Atomic swap in GNU C++

    - by Steve
    I want to verify that my understanding is correct. This kind of thing is tricky so I'm almost sure I am missing something. I have a program consisting of a real-time thread and a non-real-time thread. I want the non-RT thread to be able to swap a pointer to memory that is used by the RT thread. From the docs, my understanding is that this can be accomplished in g++ with: // global Data *rt_data; Data *swap_data(Data *new_data) { #ifdef __GNUC__ // Atomic pointer swap. Data *old_d = __sync_lock_test_and_set(&rt_data, new_data); #else // Non-atomic, cross your fingers. Data *old_d = rt_data; rt_data = new_data; #endif return old_d; } This is the only place in the program (other than initial setup) where rt_data is modified. When rt_data is used in the real-time context, it is copied to a local pointer. For old_d, later on when it is sure that the old memory is not used, it will be freed in the non-RT thread. Is this correct? Do I need volatile anywhere? Are there other synchronization primitives I should be calling? By the way I am doing this in C++, although I'm interested in whether the answer differs for C. Thanks ahead of time.

    Read the article

  • Multi-Threading Question Concerning WPF

    - by Andrew
    Hello, I'm a newbie to threading, and I don't really know how to code a particular task. I would like to handle a mouse click event on a window that will kick off a while loop in a seperate thread. This thread, which is distinct from the UI thread, should call a function in the while loop which updates a label on the window being serviced by the UI thread. The while loop should stop running when the left mouse button is no longer being pressed. All the loop does is increment a counter, and then repeatedly call the function which displays the updated value in the window. The code for the window and all of the threading is given below (I keep getting some error about STA threading, but don't know where to put the attribute). Also, I'm hoping to use this solution, if it ever works, in another project that makes asynchronous calls elsewhere to a service via wcf, so I was hoping not to make any application-wide special configurations, since I'm really new to multi-threading and am quite worried about breaking other code in a larger program... Here's what I have: <Window x:Class="WpfApplication2.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:WpfApplication2" Name="MyMainWindow" Title="MainWindow" Width="200" Height="150" PreviewMouseLeftButtonDown="MyMainWindow_PreviewMouseLeftButtonDown"> <Label Height="28" Name="CounterLbl" /> </Window> And here's the code-behind: using System.Windows; using System.Windows.Input; using System.Threading; namespace WpfApplication2 { /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class MainWindow : Window { private int counter = 0; public MainWindow() { InitializeComponent(); } private delegate void EmptyDelegate(); private void MyMainWindow_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e) { Thread counterThread = new Thread(new ThreadStart(MyThread)); counterThread.Start(); } private void MyThread() { while (Mouse.LeftButton == MouseButtonState.Pressed) { counter++; Dispatcher.Invoke(new EmptyDelegate(UpdateLabelContents), null); } } private void UpdateLabelContents() { CounterLbl.Content = counter.ToString(); } } } Anyways, multi-threading is really new to me, and I don't have any experience implementing it, so any thoughts or suggestions are welcome! Thanks, Andrew

    Read the article

  • rails Rake and mysql ssh port forwarding.

    - by rube_noob
    Hello, I need to create a rake task to do some active record operations via a ssh tunnel. The rake task is run on a remote windows machine so I would like to keep things in ruby. This is my latest attempt. desc "Syncronizes the tablets DB with the Server" task(:sync => :environment) do require 'rubygems' require 'net/ssh' begin Thread.abort_on_exception = true tunnel_thread = Thread.new do Thread.current[:ready] = false hostname = 'host' username = 'tunneluser' Net::SSH.start(hostname, username) do|ssh| ssh.forward.local(3333, "mysqlhost.com", 3306) Thread.current[:ready] = true puts "ready thread" ssh.loop(0) { true } end end until tunnel_thread[:ready] == true do end puts "tunnel ready" Importer.sync rescue StandardError => e puts "The Database Sync Failed." end end The task seems to hang at "tunnel ready" and never attempts the sync. I have had success when running first a rake task to create the tunnel and then running the rake sync in a different terminal. I want to combine these however so that if there is an error with the tunnel it will not attempt the sync. This is my first time using ruby Threads and Net::SSH forwarding so I am not sure what is the issue here. Any Ideas!? Thanks

    Read the article

  • Creating a blocking Queue<T> in .NET?

    - by spoon16
    I have a scenario where I have multiple threads adding to a queue and multiple threads reading from the same queue. If the queue reaches a specific size all threads that are filling the queue will be blocked on add until an item is removed from the queue. The solution below is what I am using right now and my question is: How can this be improved? Is there an object that already enables this behavior in the BCL that I should be using? internal class BlockingCollection<T> : CollectionBase, IEnumerable { //todo: might be worth changing this into a proper QUEUE private AutoResetEvent _FullEvent = new AutoResetEvent(false); internal T this[int i] { get { return (T) List[i]; } } private int _MaxSize; internal int MaxSize { get { return _MaxSize; } set { _MaxSize = value; checkSize(); } } internal BlockingCollection(int maxSize) { MaxSize = maxSize; } internal void Add(T item) { Trace.WriteLine(string.Format("BlockingCollection add waiting: {0}", Thread.CurrentThread.ManagedThreadId)); _FullEvent.WaitOne(); List.Add(item); Trace.WriteLine(string.Format("BlockingCollection item added: {0}", Thread.CurrentThread.ManagedThreadId)); checkSize(); } internal void Remove(T item) { lock (List) { List.Remove(item); } Trace.WriteLine(string.Format("BlockingCollection item removed: {0}", Thread.CurrentThread.ManagedThreadId)); } protected override void OnRemoveComplete(int index, object value) { checkSize(); base.OnRemoveComplete(index, value); } internal new IEnumerator GetEnumerator() { return List.GetEnumerator(); } private void checkSize() { if (Count < MaxSize) { Trace.WriteLine(string.Format("BlockingCollection FullEvent set: {0}", Thread.CurrentThread.ManagedThreadId)); _FullEvent.Set(); } else { Trace.WriteLine(string.Format("BlockingCollection FullEvent reset: {0}", Thread.CurrentThread.ManagedThreadId)); _FullEvent.Reset(); } } }

    Read the article

  • uh-oh windows mobile threading issues!

    - by violet313
    specifically WM6x, winCE5x Now my current understanding from trawling the msdn etal is that the IMAPIAdviseSink::OnNotify callback can be made from any old thread; from (ce)mapi or perhaps even from a third-party service provider. Under WM6x, i cannot seem to coax an in-thread response by invoking HrThisThreadAdviseSink, since while this function is declared in mapiutil.h, a definition appears not to exist (in cemapi.lib or wherever??) ~But i notice that all the OnNotify callbacks i get, derive from windows messages that i am receiving on my thread (=looks to me like an in-thread implementation in any case under cemapi)... So, can anyone confirm that this is infact always the case -or am i just getting lucky right now? ah, i should add that my advise source is IMAPISession::Advise (ActiveSync) erm i should also say that i might have cross-posted this on the msdn forum -but they're mostly numptys over there,,

    Read the article

  • My multithread program works slowly or appear deadlock on dual core machine, please help

    - by Shangping Guo
    I have a program with several threads, one thread will change a global when it exits itself and the other thread will repeatedly poll the global. No any protection on the globals. The program works fine on uni-processor. On dual core machine, it works for a while and then halt either on Sleep(0) or SuspendThread(). Would anyone be able to help me out on this? The code would be like this: Thread 1: do something... while(1) { ..... flag_thread1_running=false; SuspendThread(GetCurrentThread()); continue; } Thread 2 .... while(flag_thread1_running==false) Sleep(0); ....

    Read the article

  • What is a good method to use with multithreading to simulate this?

    - by user1504257
    I am writing a program in c++ in visual studio to be able to handle a line at a park. I have all of my customers in a line at the park and I want to be able to service them using multithreading with openmp. When I put the pragma and such in, I have multiple threads servicing the same customer at the same time for each and every customer I create, not what I want. I want for example, if I had two threads and four customers, that thread one to do customer one while thread 2 does customer 2. Then I would like thread 1 to do customer 3 and thread 2 customer 4 at the same time. I don't know if its possible or if there is a better way, but I need to use openmp. Thanks for your input.

    Read the article

  • Is ReaderWriterLockSlim.EnterUpgradeableReadLock() essentially the same as Monitor.Enter()?

    - by Neil Barnwell
    So I have a situation where I may have many, many reads and only the occasional write to a resource shared between multiple threads. A long time ago I read about ReaderWriterLock, and have read about ReaderWriterGate which attempts to mitigate the issue where many writes coming in trump reads and hurt performance. However, now I've become aware of ReaderWriterLockSlim... From the docs, I believe that there can only be one thread in "upgradeable mode" at any one time. In a situation where the only access I'm using is EnterUpgradeableReadLock() (which is appropriate for my scenario) then is there much difference to just sticking with lock(){}? Here's the excerpt: A thread that tries to enter upgradeable mode blocks if there is already a thread in upgradeable mode, if there are threads waiting to enter write mode, or if there is a single thread in write mode. Or, does the recursion policy make any difference to this?

    Read the article

  • serial port does not exist in current context: c#

    - by I__
    here's the code: using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Threading; namespace WindowsFormsApplication1 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } public class ThreadWork { private static SerialPort serialPort1; public static void DoWork() { serialPort1.Open(); serialPort1.Write("AT+CMGF=1\r\n"); //Thread.Sleep(500); serialPort1.Write("AT+CNMI=2,2\r\n"); //Thread.Sleep(500); serialPort1.Write("AT+CSCA=\"+4790002100\"\r\n"); //Thread.Sleep(500); serialPort1.DataReceived += serialPort1_DataReceived_1; } } private void Form1_Load(object sender, EventArgs e) { ThreadStart myThreadDelegate = new ThreadStart(ThreadWork.DoWork); Thread myThread = new Thread(myThreadDelegate); myThread.Start(); } private void serialPort1_DataReceived_1(object sender, System.IO.Ports.SerialDataReceivedEventArgs e) { string response = serialPort1.ReadLine(); this.BeginInvoke(new MethodInvoker(() => textBox1.AppendText(response + "\r\n"))); } } } and i get an error on this line: string response = serialPort1.ReadLine(); it says:: Error 1 The name 'serialPort1' does not exist in the current context C:\Users\alexluvsdanielle\AppData\Local\Temporary Projects\WindowsFormsApplication1\Form1.cs 44 31 WindowsFormsApplication1 what am i doing wrong?

    Read the article

  • redefineClasses in JVMTI

    I have two questions Does redefineClasses work with JIT enabled JVM? If so, in multithreaded applications, if one thread uses redefineClasses to redefine a class, does another thread see that redefined class? (especially, if the other thread is running jit compiled code?)

    Read the article

  • How to detect that the internet connection has got disconnected through a java desktop application?

    - by Yatendra Goel
    I am developing a Java Desktop Application that access internet. It is a multi-threaded application, each thread do the same work (means each thread is an instance of same Thread class). Now, as all the threads need internet connection to be active, there should be some mechanism that detects whether an internet connection is active or not. Q1. How to detect whether the internet connection is active or not? Q2. Where to implement this internet-status-check-mechanism code? Should I start a separate thread for checking internet status regularly and notifies all the threads when the status changes from one state to another? Or should I let each thread check for the internet-status itself? Q3. This issue should be a very common issue as every application accessing an internet should deal with this problem. So how other developers usually deal with this problem? Q4. If you could give me a reference to a good demo application that addresses this issue then it would greatly help me.

    Read the article

  • Producer and Consumer Threads Hang

    - by user972425
    So this is my first foray into threads and thus far it is driving me insane. My problem seems to be some kind of synchronization error that causes my consumer thread to hang. I've looked at other code and just about everything I could find and I can't find what my error is. There also seems to be a discrepancy between the code being executed in Eclipse and via javac in the command line. Intention - Using a bounded buffer (with 1000 slots) create and consume 1,000,000 doubles. Use only notify and wait. Problem - In Eclipse the consumer thread will occasionally hang around 940,000 iterations, but other times completes. In the command line the consumer thread always hangs. Output - Eclipse - Successful Producer has produced 100000 doubles. Consumer has consumed 100000 doubles. Producer has produced 200000 doubles. Consumer has consumed 200000 doubles. Producer has produced 300000 doubles. Consumer has consumed 300000 doubles. Producer has produced 400000 doubles. Consumer has consumed 400000 doubles. Producer has produced 500000 doubles. Consumer has consumed 500000 doubles. Producer has produced 600000 doubles. Consumer has consumed 600000 doubles. Producer has produced 700000 doubles. Consumer has consumed 700000 doubles. Producer has produced 800000 doubles. Consumer has consumed 800000 doubles. Producer has produced 900000 doubles. Consumer has consumed 900000 doubles. Producer has produced 1000000 doubles. Producer has produced all items. Consumer has consumed 1000000 doubles. Consumer has consumed all items. Exitting Output - Command Line/Eclipse - Unsuccessful Producer has produced 100000 doubles. Consumer has consumed 100000 doubles. Producer has produced 200000 doubles. Consumer has consumed 200000 doubles. Producer has produced 300000 doubles. Consumer has consumed 300000 doubles. Producer has produced 400000 doubles. Consumer has consumed 400000 doubles. Producer has produced 500000 doubles. Consumer has consumed 500000 doubles. Producer has produced 600000 doubles. Consumer has consumed 600000 doubles. Producer has produced 700000 doubles. Consumer has consumed 700000 doubles. Producer has produced 800000 doubles. Consumer has consumed 800000 doubles. Producer has produced 900000 doubles. Consumer has consumed 900000 doubles. Producer has produced 1000000 doubles. Producer has produced all items. At this point it just sits and hangs. Any help you can provide about where I might have misstepped is greatly appreciated. Code - Producer thread import java.text.DecimalFormat;+ " doubles. Cumulative value of generated items= " + temp) import java.util.*; import java.io.*; public class producer implements Runnable{ private buffer produceBuff; public producer (buffer buff){ produceBuff = buff; } public void run(){ Random random = new Random(); double temp = 0, randomElem; DecimalFormat df = new DecimalFormat("#.###"); for(int i = 1; i<=1000000; i++) { randomElem = (Double.parseDouble( df.format(random.nextDouble() * 100.0))); try { produceBuff.add(randomElem); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } temp+= randomElem; if(i%100000 == 0) {produceBuff.print("Producer has produced "+ i ); } } produceBuff.print("Producer has produced all items."); } } Consumer thread import java.util.*; import java.io.*; public class consumer implements Runnable{ private buffer consumBuff; public consumer (buffer buff){ consumBuff = buff; } public void run(){ double temp = 0; for(int i = 1; i<=1000000; i++) { try { temp += consumBuff.get(); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } if(i%100000 == 0) {consumBuff.print("Consumer has consumed "+ i ); //if(i>999000) //{System.out.println("Consuming item " + i);} } consumBuff.print("Consumer has consumed all items."); } } Buffer/Main import java.util.*; import java.io.*; public class buffer { private double buff[]; private int addPlace; private int getPlace; public buffer(){ buff = new double[1000]; addPlace = 0; getPlace = 0; } public synchronized void add(double add) throws InterruptedException{ if((addPlace+1 == getPlace) ) { try { wait(); } catch (InterruptedException e) {throw e;} } buff[addPlace] = add; addPlace = (addPlace+1)%1000; notify(); } public synchronized double get()throws InterruptedException{ if(getPlace == addPlace) { try { wait(); } catch (InterruptedException e) {throw e;} } double temp = buff[getPlace]; getPlace = (getPlace+1)%1000; notify(); return temp; } public synchronized void print(String view) { System.out.println(view); } public static void main(String args[]){ buffer buf = new buffer(); Thread produce = new Thread(new producer(buf)); Thread consume = new Thread(new consumer(buf)); produce.start(); consume.start(); try { produce.join(); consume.join(); } catch (InterruptedException e) {return;} System.out.println("Exitting"); } }

    Read the article

  • .NET Windows Service, threads and garbage collection (possible memory leaks)

    - by Evgeny
    I am developing a .NET Windows service that is creating a couple of threads and then uses these threads to send print jobs to printers (there is a thread for each printer). I have some issues which sometimes can be fixed by restarting the service. Some issues also arise when the service has been running for a while. This makes me suspect a possible memory leak. So, a couple of questions: Would a garbage collector collect an object if it was created inside a thread, or will the object exist until the thread is stopped/terminated? What tools can I use to monitor the amount of memory used by a Windows service and by a thread that I am starting programmatically?

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 75 76 77 78 79 80 81 82 83 84 85 86  | Next Page >