Observer pattern with threads?

Hi,

How does the observer pattern work with two threads? For example, I have my main thread, then a background thread which needs to notify the main thread of some event. Something like:


public class MyApp implements INotify
{
     BackgroundThread m_thread;

     public MyApp()
     {
         m_thread = new BackgroundThread(this);
         m_thread.start();
     }
 
     public void notifyMe(String str)
     {
           System.out.println("Background thread says: " + str);
     }
}

public class BackgroundThread implements Runnable
{
     INotify m_observer;

    public BackgroundThread(INotify observer)
    {
        m_observer = observer;
    }

    public void run()
    {
         while (true) {
             m_observer.notifyMe("hello!");
             Thread.Sleep(60 * 1000);
        }
    }
}

I must be using the wrong search terms because I can't find anything that shows how to do this, just large messaging APIs between remote servers and clients. But I just want to implement this within an application, so some classes can subscribe to a thread for message notifications. I've been searching for java + asynchronous notification etc.

Also, this needs to be j2me compliant which for me means java 1.3,


Thanks