public abstract class Mediator {//中介者记录各具体同事类的引用, 用于交互// 也可以是集合类记录,如 List, Mapprotected ConcreteColleague1 colleague1;protected ConcreteColleague2 colleague2;// ------------------------- 因为中介者可以有部分同事类, 所以使用setter, getter 注入同事类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;}// ------------------------------------------ 具体同事类依赖中介者的方法//这种方法其实可以精简成通用的发放 sendMessage(String toColleague, message)public abstract void sendMessageToColleague1(String message);//
    public abstract void sendMessageToColleague2(String message);}

public class ConcreteMediator extends  Mediator{  // 具体中介者一般只有一个, 即通用中介者
@Overridepublic void sendMessageToColleague1(String message) {super.colleague1.receiveMessage(message);}@Overridepublic void sendMessageToColleague2(String message) {super.colleague2.receiveMessage(message);}
}

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);}// ---------- self-methodpublic void selfMethod(){System.out.println("colleague1: 自发行为...");}public void receiveMessage(String message){System.out.println("colleague1收到消息: "+message);}// ---------- dependency-methodpublic void sendMessageToColleague2(String message){ // 同事类之间不能直接交互, 同事类不能完成的工作委托给中介者完成super.mediator.sendMessageToColleague2(message);}}

public class ConcreteColleague2 extends Colleague{public ConcreteColleague2(Mediator mediator) {super(mediator);}// ---------- self-methodpublic void selfMethod(){System.out.println("colleague2: 自发行为...");}public void receiveMessage(String message){System.out.println("colleague2收到消息: "+message);}// ---------- dependency-methodpublic void sendMessageToColleague1(String message){ // 同事类之间不能直接交互, 同事类不能完成的工作委托给中介者完成super.mediator.sendMessageToColleague1(message);}}

public class ConcreteColleague3 extends Colleague {public ConcreteColleague3(Mediator mediator) {super(mediator);}public void selfMethod(){System.out.println("colleague3: 自发行为...");}public void sendMessageToColleague1(String message){super.mediator.sendMessageToColleague1(message);}public void sendMessageToColleague2(String message){super.mediator.sendMessageToColleague2(message);}
}

public class Client {public static void main(String[] args) {Mediator mediator=new ConcreteMediator();ConcreteColleague1 colleague1=new ConcreteColleague1(mediator);ConcreteColleague2 colleague2=new ConcreteColleague2(mediator);mediator.setColleague1(colleague1);mediator.setColleague2(colleague2);colleague1.selfMethod();colleague1.sendMessageToColleague2("来自colleague1的贺电...");colleague2.selfMethod();colleague2.sendMessageToColleague1("来自colleague2的贺电...");// 之后新增一个colleague3, 与其他同事类交互很清晰ConcreteColleague3 colleague3=new ConcreteColleague3(mediator);colleague3.selfMethod();colleague3.sendMessageToColleague1("来自colleague3的贺电...");colleague3.sendMessageToColleague2("来自colleague3的贺电...");}}

colleague1: 自发行为...
colleague2收到消息: 来自colleague1的贺电...
colleague2: 自发行为...
colleague1收到消息: 来自colleague2的贺电...
colleague3: 自发行为...
colleague1收到消息: 来自colleague3的贺电...
colleague2收到消息: 来自colleague3的贺电...