Question

I am having an eclipse View. Inside the view I added a Table. Now I am calling a thread from run method of the view using asyncExec.

My View class is like –

public class SampleViewAction implements IWorkbenchWindowActionDelegate{

      Thread t;   

      int Count;


      @Override

      public void run(IAction arg0) {

 }
}

Now I added a thread like this –

  PlatformUI.getWorkbench().getDisplay().asyncExec(new Runnable() {                   

                        @Override

                        public void run() {

                              new UDPReadThread();



                        }

                  });

Where UDPReadThread is a class extends a thread where in UDPReadThread ‘s constructor I started the thread.
But I am getting invalid Thread exception.

How to resolve the issue.

Answer 1

Similar to AWT and the EventDispatchThread, SWT must process everything in the UI thread.

Your SampleViewAction is run on the UI thread already, in response to a menu or tool item selection.

It looks like your problem comes from then using an asyncExec(*) which will post the runnable to be run on the UI thread (which delays it), and starting a new thread from that asyncExec Runnable. You may as well simply start your thread, and get rid of that asyncExec.

Your UDPReadThread is not the UI thread. If you need to update UI widgets from UDPReadThread, that’s the code that needs the asyncExec:

display.asyncExec(
  new Runnable() {
    public void run(){
      label.setText(text);
    }
});

Just as an aside, you should not subclass Thread unless you really are extending threads capabilities. The normal pattern when you just want to start another thread:

UDPReadRunnable udpRunnable = ....;
Thread thread = new Thread(udpRunnable);
thread.start();

You can get more information on the display thread from http://www.eclipse.org/swt/faq.php#uithread