中介者模式

描述

用来降低类类之间的耦合的，因为如果类类之间有依赖关系的话，不利于功能的拓展和维护，因为只要修改一个对象，其它关联的对象都得进行修改。如果使用中介者模式，只需关心和Mediator类的关系，具体类类之间的关系及调度交给Mediator就行，这有点像spring容器的作用

UML

示例

interface Mediator{
    public void createMediator();
    public void workAll();
}
abstract class User { 
    private Mediator mediator; 
    public Mediator getMediator(){ 
        return mediator; 
    } 
    public User(Mediator mediator) { 
        this.mediator = mediator; 
    } 
    public abstract void work(); 
} 
class User1 extends User { 
    public User1(Mediator mediator){ 
        super(mediator); 
    } 
    @Override 
    public void work() { 
        Test.printMsg("user1 exe!"); 
    } 
} 
class User2 extends User { 
    public User2(Mediator mediator){ 
        super(mediator); 
    } 
    @Override 
    public void work() { 
        Test.printMsg("user2 exe!"); 
    } 
} 
class MyMediator implements Mediator {
    private User user1; 
    private User user2;  
    public User getUser1() { 
        return user1; 
    } 
    public User getUser2() { 
        return user2; 
    } 
    @Override 
    public void createMediator() { 
        user1 = new User1(this); 
        user2 = new User2(this); 
    } 
    @Override 
    public void workAll() { 
        user1.work(); 
        user2.work(); 
    } 
}
//测试
public class Test {
    public static void printMsg(String msg){
        System.out.println(msg);
    }
    public static void main(String[] args){
        Mediator mediator = new MyMediator(); 
        mediator.createMediator(); 
        mediator.workAll();
    }
}