abstract class Mediator {
  abstract public void send(String name , Colleague colleague);
}

public class ConcreteMediator extends Mediator {
  ConcreteColleague1 colleague1;
  ConcreteColleague2 colleague2;

  public void setConcreteColleague1(ConcreteColleague1 colleague1) {
    this.colleague1 = colleague1;
  }
  public void setConcreteColleague2(ConcreteColleague2 colleague2) {
    this.colleague2 = colleague2;
  }
  public void send(String message,Colleague colleague) {
    if (colleague==colleague1) {
      colleague2.notify(message);
    } else if (colleague==colleague2) {
      colleague1.notify(message);
    }
  }
}

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 send(String message) {
    mediator.send(message, this);
  }

  public void notify(String message) {
    System.out.println("ConcreteColleague1は" + message + "を受け取りました");
  }
}

public class ConcreteColleague2 extends Colleague{
  public ConcreteColleague2(Mediator mediator) {
    super(mediator);
  }

  public void send(String message) {
    mediator.send(message, this);
  }

  public void notify(String message) {
    System.out.println("ConcreteColleague2は" + message + "を受け取りました");
  }
}

public class Client {
  public static void main(String[] args) {
    ConcreteMediator mediator = new ConcreteMediator();
    ConcreteColleague1 colleague1 = new ConcreteColleague1(mediator);
    ConcreteColleague2 colleague2 = new ConcreteColleague2(mediator);

    mediator.setConcreteColleague1(colleague1);
    mediator.setConcreteColleague2(colleague2);

    colleague1.send("Hello World");
    colleague2.send("こんにちわ　世界");
  }
}

C:\JavaHello\Mediator>java Client
ConcreteColleague2はHello Worldを受け取りました
ConcreteColleague1はこんにちわ　世界を受け取りました

C:\JavaHello\Mediator>