注:本文为译文,原文出处java-design-patterns-in-stories
中介者设计模式应用于协作一组同事. 那些同事互相之间不会直接沟通, 而是通过中介者.
下面的例子中, 同事A想聊天, 同事B想打架. 当他们做出一些行为时(例如: doSomething()
), 会调用中介者去做那些事儿.
package designpatterns.mediator;
interface IMediator {
public void fight();
public void talk();
public void registerA(ColleagueA a);
public void registerB(ColleagueB a);
}
//concrete mediator
class ConcreteMediator implements IMediator{
ColleagueA talk;
ColleagueB fight;
public void registerA(ColleagueA a){
talk = a;
}
public void registerB(ColleagueB b){
fight = b;
}
public void fight(){
System.out.println("Mediator is fighting");
//let the fight colleague do some stuff
}
public void talk(){
System.out.println("Mediator is talking");
//let the talk colleague do some stuff
}
}
abstract class Colleague {
IMediator mediator;
public abstract void doSomething();
}
//concrete colleague
class ColleagueA extends Colleague {
public ColleagueA(IMediator mediator) {
this.mediator = mediator;
}
@Override
public void doSomething() {
this.mediator.talk();
this.mediator.registerA(this);
}
}
//concrete colleague
class ColleagueB extends Colleague {
public ColleagueB(IMediator mediator) {
this.mediator = mediator;
this.mediator.registerB(this);
}
@Override
public void doSomething() {
this.mediator.fight();
}
}
public class MediatorTest {
public static void main(String[] args) {
IMediator mediator = new ConcreteMediator();
ColleagueA talkColleague = new ColleagueA(mediator);
ColleagueB fightColleague = new ColleagueB(mediator);
talkColleague.doSomething();
fightColleague.doSomething();
}
}
在其他行为模式中, 观察者模式是与中介者模式最相似的. 你可以阅读观察者模式来比较两者的不同之处.