Java设计模式探究之观察者模式详解

/**
 * 抽象观察者接口
 */
public interface Observer {
    /**
     * 抽象方法
     */
    public void uPdate();
    public void remove();
}

/**
 * 抽象被观察者
 */
public interface Observed {
    public void addObserver(Observer observer);
    public void deleteObserver(Observer observer);
    public void notifyObservers();
}

/**
 * 观察者实现
 */
public class ObserverImpl implements Observer {
    public ObserverImpl(){
    }
    @Override
    public void uPdate() {
        System.out.println("update....");
    }
}

/**
 * 观察者实现
 */
public class ObserverImpl implements Observer {
    public ObserverImpl(){
    }
    private Observed observed;
    public ObserverImpl(Observed observed){
        this.observed = observed;
        observed.addObserver(this);
    }
    @Override
    public void uPdate() {
        System.out.println("观察者更新数据变化....");
    }
    @Override
    public void remove() {
        if(observed!=null){
            observed.deleteObserver(this);
        }
    }
}

public class TestObserver {
    public static void main(String args []){
        ObservedImpl subject = new ObservedImpl();
        ObserverImpl observer1 =  new ObserverImpl(subject);
        subject.notifyObservers();
    }
}