Fire Event Through Interface

Question

I have been using this interface
public class InputHandler implements VoteListener
public void onVote(Response[] responses)
}I get the call back with out registering the class. How can I implement my own interface without the user registering their class? I do not know how to fire the events through an interface without registering the class.
Edited by: MrGreen2 on Feb 5, 2008 4:01 PM

Answer 1

What do you mean "registering a class?"
If you don't care about which thread the events are fired on, the observable item should maintain a list of Listeners then call the relevant method when needed:
   public static void addVoterListener(VoterListener l) {
        m_voterListenerList.add(l);
   public static void removeFeatureListener(VoterListener l) {
       m_voterListenerList.remove(l);
   someMethod() {
         for (VoterListener l : m_voterListenerList) {
              l.onVote(responses);
}If you want the events to fire on the EDT, you'll have to wrap up the Responses into a Runnable and use SwingUtilities.invokeLater to enqueue the trigger there. If the trigger may alter the listener list, you'll also want to make something like the AWTEventMulticaster for your listeners.
If you consider the "addVoterListener" method as "registering" then you'll have to find some other way to devise the list of listeners. But somehow, the obervable needs to know which observers are interested in the events.