public class GooseAdapter implements Quackable {
    Goose goose;
    Observable observable;

    public GooseAdapter(Goose goose) {
        this.goose = goose;
        observable = new Observable(this);
    }

    public void quack() {
        goose.honk();
        notifyObservers();
    }

    public void registerObserver(Observer observer) {
        observable.registerObserver(observer);
    }

    public void notifyObservers() {
        observable.notifyObservers();
    }

    @Override
    public String toString() {
        return "Goose pretending to be a Duck!";
    }
}

• Explanation:

1. public class GooseAdapter implements Quackable {
   • This declares a public class named GooseAdapter.
   • It implements the Quackable interface, indicating that instances of this class can quack.
2. Goose goose;
   • This declares a member variable named goose of type Goose.
   • It represents the goose that is being adapted to quack.
3. Observable observable;
   • This declares a member variable named observable of type Observable.
   • It is used to manage observers interested in the quacking events of this goose adapter.
4. public GooseAdapter(Goose goose) { this.goose = goose; observable = new Observable(this); }
   • This is the constructor of the GooseAdapter class.
   • It takes a Goose parameter (goose) and initializes the goose member variable with the provided goose.
   • It also initializes the observable variable with a new instance of Observable, passing itself (this) as the QuackObservable object.
5. public void quack() { goose.honk(); notifyObservers(); }
   • This method is part of the Quackable interface implementation.
   • It delegates the quacking behavior to the honk method of the Goose object and notifies observers.
6. public void registerObserver(Observer observer) { observable.registerObserver(observer); }
   • This method is part of the Quackable interface implementation.
   • It delegates the responsibility of registering observers to the Observable object.
7. public void notifyObservers() { observable.notifyObservers(); }
   • This method is part of the Quackable interface implementation.
   • It delegates the responsibility of notifying observers to the Observable object.
8. @Override public String toString() { return "Goose pretending to be a Duck!"; }
   • This overrides the toString method to provide a custom string representation of the object.
9. }
   • Closes the GooseAdapter class.

• Overall Explanation:
  • The GooseAdapter class adapts a Goose object to behave like a Quackable object.
  • It implements the Quackable interface, providing the necessary methods for quacking, registering observers, and notifying observers.
  • The Goose's honk method is used to simulate quacking.
  • The observable member variable is used to manage observers interested in the quacking events of the goose adapter.
  • The toString method provides a descriptive string representation of the object.
  • This adapter pattern allows a Goose to be used in scenarios expecting a Quackable object, demonstrating how different types of quackable entities can be treated uniformly in the code.