package Bean; import java.util.ArrayList; import java.util.Iterator; import Interface.QuackObservable; import Interface.Observer; /** * Created by Administrator on 2017/7/14. */ public class Observable implements QuackObservable { ArrayList observers = new ArrayList<>(); QuackObservable duck; public Observable(QuackObservable duck) { this.duck = duck; } @Override public void registerObserver(Interface.Observer observer) { observers.add(observer); } @Override public void notifyObservers() { Iterator iterator = observers.iterator(); while (iterator.hasNext()) { Observer observer = (Observer) iterator.next(); observer.update(duck); } } }