1.中介者模式定义
用一个中介对象来封装一系列的对象交互。中介者使得各对象不需要显式的相互调用,从而使其耦合松散,而且可以独立的改变他们之间的交互
2.中介者模式UML图
Mediater:中介者接口。在里面定义各个同事之间相互调用的方法,可以是公共的相互之间的通信,也可以是小范围之间的相互调用
ConcreteMediator:中介者接口的具体实现,它需要了解并维护各个同事对象,并负责具体的各个同事之间的相互调用
Colleague:同事的抽象类 或者是接口。
ConcreteColleague:具体的同事类,是现在自己的业务,在需要与其他同事之间通信的时候就持有中介者对象,中介者负责与其他同事进行交互
3.代码实现
public abstract class Colleague{ private Mediator mediator; public Colleague(Mediator mediator){ this.mediator=mediator; } public Mediator getMediator(){ return this.metiator; } } public class ConcreteColleagueA extends Colleague{ public ConcreteColleagueA(Mediator mediator){ super(mediator); } public void someOperation(){ this.getMediator().changed(this); } } public class ConcreteColleagueB extends Colleague{ public ConcreteColleagueB(Mediator mediator){ super(mediator); } public void someOperation(){ this.getMediator().changed(this); } } public interface Mediator{ public void changed(Colleague colleague); } public class ConcreteMediator implements Mediator{ private ConcreteColleagueA colleagueA; private ConcreteColleagueB colleagueB; public void setConcreteColleagueA(ConcreteColleagueA colleagueA){ this.colleagueA=colleagueA; } public void setConcreteColleagueB(ConcreteColleagueA colleagueB){ this.colleagueB=colleagueB; } public void changed(Colleague colleague){ //某个同事发生变化,通常需要与其他同事交互 //具体协调相应同事对象来实现协作行为 } }
4.中介者模式的本质:封装交互