监听器模式

public class Event {

    // 存放事件源的引用
    Object object;

    public Event(Object object) {
        super();
        this.object = object;
    }

    public Object getObject() {
        return object;
    }
    
}

public interface DogListener {
    
    public void playListener(Event event);
    
    public void studyListener(Event event);

}

package listenerpatten;

public class MyDogListener implements DogListener {

    @Override
    public void playListener(Event event) {
        System.out.println("监听器：监听到" +  event.getObject().getClass().getName() + "在玩");
    }

    @Override
    public void studyListener(Event event) {
        System.out.println("监听器：监听到" +  event.getObject().getClass().getName() + "在学习");
    }

}

public class Dog {
    
    private MyDogListener myDogListener;
    public void setDogListener(MyDogListener myDogListener) {
        this.myDogListener = myDogListener;
    }

    public void play(){
        System.out.println("Dog: i am playing");
        Event event = new Event(this);
        myDogListener.playListener(event);
    }

    public void study(){
        System.out.println("Dog: i am studying");
        Event event = new Event(this);
        myDogListener.studyListener(event);
    }
}

public class test {
    
    public static void main(String[] args) {
        
        Dog dog = new Dog();
        MyDogListener myDogListener = new MyDogListener();
        dog.setDogListener(myDogListener);
        
        dog.play();
        dog.study();
        
    }
}

Dog: i am playing
监听器：监听到listenerpatten.Dog在玩
Dog: i am studying
监听器：监听到listenerpatten.Dog在学习