中介者模式

 直接代码：

public abstract class Mediator {
    public abstract void send(String message,Colleague coll);
}

public class ConcreteMediator extends Mediator {
    private ConcreteColleague1 colleague1;
    private ConcreteColleague2 colleague2;
    @Override
    public void send(String message, Colleague coll) {
        if(coll==colleague1){
            colleague2.notify(message);
        }else{
            colleague1.notify(message);
        }
    }
    public ConcreteColleague1 getColleague1() {
        return colleague1;
    }
    public void setColleague1(ConcreteColleague1 colleague1) {
        this.colleague1 = colleague1;
    }
    public ConcreteColleague2 getColleague2() {
        return colleague2;
    }
    public void setColleague2(ConcreteColleague2 colleague2) {
        this.colleague2 = colleague2;
    }
}

public abstract class Colleague {
    protected Mediator mediator;

    public Colleague(Mediator mediator) {
        this.mediator = mediator;
    }
}

public class ConcreteColleague1 extends Colleague {

    public ConcreteColleague1(Mediator mediator) {
        super(mediator);
    }
    
    public void sent(String message){
        mediator.send(message, this);
    }
    public void notify(String message){
        System.out.println("同事1得到消息"+message);
    }
    
}

public class ConcreteColleague2 extends Colleague {

    public ConcreteColleague2(Mediator mediator) {
        super(mediator);
    }
    public void sent(String message){
        mediator.send(message, this);
    }
    public void notify(String message){
        System.out.println("同事2得到消息"+message);
    }

}

public class MediatorTest {
    public static void main(String[] args) {
        ConcreteMediator me = new ConcreteMediator();
        
        ConcreteColleague1 c1 =new ConcreteColleague1(me);
        ConcreteColleague2 c2 =new ConcreteColleague2(me);
        
        me.setColleague1(c1);
        me.setColleague2(c2);
        
        c1.sent("吃饭了吗？");
        c2.sent("没有呢，你打算请客");
    }
}

同事2得到消息吃饭了吗？
同事1得到消息没有呢，你打算请客