Invoking method on different thread

Question

Hi
I'm developing an addin a application. The addin runs on the main thread. However I need to perform some blocking system calls, which can't be called from the main thread, since it also blocks the application. Therefore, I have a worker thread which performs the blocking call. When the blocking call returns, I need to invoke a method on the main thread. The method must be executed by the main thread, because the method uses some of the applications api functions. If these api functions are called from any other thread than the main thread, the application will crash.
My problem is that I dont know how to invoke a method on a different thread. I guess I need to do the same thing as the SWING package, where gui components should be modified from the event dispatcher thread.
Simplyfied, my code looks something like this:
public class Main
    public static void main(String[] args)
       Main m = new Main();
       m.Test();
    public void Test()
        //runs on main thread here
        //start a new thread which blocks while waiting for user input (simulate my service)
        ThreadClass tc = new ThreadClass();
        new Thread(tc).start();
        while (true)
           //perform normal work on gui thread
           Thread.yield();         
   public void MethodNeedsToRunOnMainThread(int c)
       //Do something on main thread here
public class ThreadClass implements Runnable
    public void run()
        ThreadFunction();
    public void ThreadFunction()
        int c = System.in.read(); //blocking call
        //Invoke method on main thread here!   
        MethodNeedsToRunOnMainThread(int c);
    }Hope some of you might point me in the rigth direction!
\Bjarne

Answer 1

pdm wrote:
Using a BlockingQueue, the main thread will block while waiting for something to be put in the queue by the worker thread. This will block the program in which my add-in runs, since the main thread is responsible for gui updates etc. Therefore, this is not an option.
Maybe it is simply not possible to what I need.
\Bjarnedepending on what kind of responsiveness you need, you could make your add-in periodically check for these events. call poll() instead of take(), and then continue on with your add-in if poll() returns nothing. the frequency with which your code polls the queue will determine the lag between queueing from the other thread and executing on the main thread.