java设计模式观察者模式

package com.zjh.designmodel.ObseverModel;

import java.sql.Array;
import java.util.ArrayList;
import java.util.List;

/*
`````````````````观察者模式`````````````````
 */
public class ObserverModel {
    public static void main(String[] args) {
        ObserverImpl o1 = new ObserverImpl("O1");
        ObserverImpl o2 = new ObserverImpl("O2");
        ObserverImpl o3 = new ObserverImpl("O3");
        SubjectImpl subject = new SubjectImpl();
        subject.addObserver(o1);
        subject.addObserver(o2);
        subject.addObserver(o3);
        subject.executeUpdate("执行");
        subject.removeObserver(o2);
        subject.executeUpdate("执行");
    }

}
/* 定义被观察者
 */
interface Observer{
    void update(String message);
}
class ObserverImpl implements Observer{
    private String ObserverName;

    public ObserverImpl(String observerName)
    {
        this.ObserverName=observerName;
    }

    private void MyNotifyMethod(){
        System.out.println("被观察者:"+this.ObserverName+"=>执行");
    }
    @Override
    public void update(String message) {
        if (message.equals("执行"))
        {
            this.MyNotifyMethod();
        }
    }
}
interface Subject {//订阅中心接口
    void addObserver(Observer observer);
    void removeObserver(Observer observer);
    void executeUpdate(String message);
}
class SubjectImpl implements Subject{
    private List<Observer> observers=new ArrayList<Observer>();
    @Override
    public void addObserver(Observer observer) {
        this.observers.add(observer);
    }

    @Override
    public void removeObserver(Observer observer) {
        this.observers.remove(observer);
    }

    @Override
    public void executeUpdate(String message) {
            observers.forEach(e->{
                e.update(message);
            });
    }
}