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");
  }
}