Query about event and event handling

Question

hi,
how exactly events are bieng generated. And how they are transmitted and how they
are caught and handled at low level. I want to trigger my own event whcih can be listen
by my own listener or some existing listener (obviously implemented from some java listener).
so help me out.
TIA
bhups

Answer 1

Well, first you create an interface such as FooListener where you define methods, such as foo().
Now you can make classes that have the method addFooListener(FooListener foo). Then in that class, you can for example decide that doing a certain thing (or based on the time of day or whatever) the class calls all the foo()'s of it's FooListeners and there you go.
Example code:
public interface FooListener {
    public void foo(FooEvent evt);
public class FooEvent {
   private String reason;
   public FooEvent(String reason) {
       this.reason = reason;
   public String getReason() {
      return reason;
public class Bar {
    List listeners = new LinkedList();
    public void addFooListener(FooListener foo) {
        listeners.add(foo);
    protected void fireFooEvent(String reason) {
       Iterator itr = listeners.iterator();
       FooEvent evt = new FooEvent(reason);
       while(itr.hasNext())
          ((FooListener)itr.next()).foo(evt);
    public void doBar() {
        // code omitted
        fireFooEvent("Bar done");
}Howzat?