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);
    }
  }
}