用一个中介对象来封装一系列的对象交互。中介者使各对象不需要显示地相互引用，从而使其耦合松散，而且可以独立地改变它们之间地交互。
类图
实现
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| public abstract class Mediator {
public abstract void send(String message, Colleague colleague);
}
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| public class ConcreteMediator extends Mediator {
private ConcreteColleague1 c1;
private ConcreteColleague2 c2;
public ConcreteColleague1 getC1() {
return c1;
}
public void setC1(ConcreteColleague1 c1) {
this.c1 = c1;
}
public ConcreteColleague2 getC2() {
return c2;
}
public void setC2(ConcreteColleague2 c2) {
this.c2 = c2;
}
@Override
public void send(String message, Colleague colleague) {
if (colleague == c1) {
c2.receive(message);
} else {
c1.receive(message);
}
}
}
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| public abstract class Colleague {
protected Mediator mediator;
public Colleague(Mediator mediator) {
this.mediator = mediator;
}
}
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| public class ConcreteColleague1 extends Colleague {
public ConcreteColleague1(Mediator mediator) {
super(mediator);
}
public void send(String message) {
mediator.send(message, this);
}
public void receive(String message) {
System.out.println("-> Colleague 1: " + message);
}
}
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| public class ConcreteColleague2 extends Colleague {
public ConcreteColleague2(Mediator mediator) {
super(mediator);
}
public void send(String message) {
mediator.send(message, this);
}
public void receive(String message) {
System.out.println("-> Colleague 2: " + message);
}
}
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| public class Client {
public static void main(String[] args) {
ConcreteMediator mediator = new ConcreteMediator();
ConcreteColleague1 c1 = new ConcreteColleague1(mediator);
ConcreteColleague2 c2 = new ConcreteColleague2(mediator);
mediator.setC1(c1);
mediator.setC2(c2);
c1.send("I'm ConcreteColleague1.");
}
}
|