行为型模式--中介者模式（Mediator）

User类统一接口，User1和User2分别是不同的对象，二者之间有关联，如果不采用中介者模式，则需要二者相互持有引用，这样二者的耦合度很高，为了解耦，引入了Mediator类，提供统一接口，MyMediator为其实现类，里面持有User1和User2的实例，用来实现对User1和User2的控制。这样User1和User2两个对象相互独立，他们只需要保持好和Mediator之间的关系就行，剩下的全由MyMediator类来维护！基本实现：

?

[java]?view plaincopy

1. public?interface?Mediator?{??
2. ????public?void?createMediator();??
3. ????public?void?workAll();??
4. }??

[java]?view plaincopy

1. public?class?MyMediator?implements?Mediator?{??
2. ??
3. ????private?User?user1;??
4. ????private?User?user2;??
5. ??????
6. ????public?User?getUser1()?{??
7. ????????return?user1;??
8. ????}??
9. ??
10. ????public?User?getUser2()?{??
11. ????????return?user2;??
12. ????}??
13. ??
14. ????@Override??
15. ????public?void?createMediator()?{??
16. ????????user1?=?new?User1(this);??
17. ????????user2?=?new?User2(this);??
18. ????}??
19. ??
20. ????@Override??
21. ????public?void?workAll()?{??
22. ????????user1.work();??
23. ????????user2.work();??
24. ????}??
25. }??

[java]?view plaincopy

1. public?abstract?class?User?{??
2. ??????
3. ????private?Mediator?mediator;??
4. ??????
5. ????public?Mediator?getMediator(){??
6. ????????return?mediator;??
7. ????}??
8. ??????
9. ????public?User(Mediator?mediator)?{??
10. ????????this.mediator?=?mediator;??
11. ????}??
12. ??
13. ????public?abstract?void?work();??
14. }??

[java]?view plaincopy

1. public?class?User1?extends?User?{??
2. ??
3. ????public?User1(Mediator?mediator){??
4. ????????super(mediator);??
5. ????}??
6. ??????
7. ????@Override??
8. ????public?void?work()?{??
9. ????????System.out.println("user1?exe!");??
10. ????}??
11. }??

[java]?view plaincopy

1. public?class?User2?extends?User?{??
2. ??
3. ????public?User2(Mediator?mediator){??
4. ????????super(mediator);??
5. ????}??
6. ??????
7. ????@Override??
8. ????public?void?work()?{??
9. ????????System.out.println("user2?exe!");??
10. ????}??
11. }??

测试类：

1. public?class?Test?{??
2. ??
3. ????public?static?void?main(String[]?args)?{??
4. ????????Mediator?mediator?=?new?MyMediator();??
5. ????????mediator.createMediator();??
6. ????????mediator.workAll();??
7. ????}??
8. }??

输出：

user1 exe!
user2 exe!