How do I make a Class extend Observable when it has extended another class too?

Question

I am learning Java and I want to make my class into an observable class.

However I already have it extending another class.

What should I do?

Answer 1

Use a bridge.

Create a class that extends Observable that the first class just calls the methods of the second class.

Bridge method detail:

 public class XXX {
    public class XXXObservableBridge : Observable {
       public void RaiseEvent();
       // Listeners etc
    }

    private XXXObservableBridge ObservableBridge;

    XXX() {
       ObservableBridge = new ObservableBridge;
    }

    public Observable AsObservable() { return ObservableBidge; }

    public void RaiseEvent() { ObservableBridge.RaiseEvent(); }
 }