从特工的角度来看设计模式之中介者模式

  转载请声明：http://www.cnblogs.com/courtier/p/4292201.html

• 中介者模式简介：

       多个类之间的通讯方式封装成一个对象，只能，从这个对象转发给多个类。

      

• 从代码的角度来理解（特工与特工之间只能通过情况报站（MEDIATOR）来交换信息）

package mediator;
//特工类
public abstract class ColleaugeAgent {
    //特工必须是相互是不能认识的，不能交流的，不能说话，只有，通过情报站，所以，每个特工都有情报站
    private MediatorIn mediatorIn;

    public ColleaugeAgent(MediatorIn mediatorIn)
    {
        this.mediatorIn = mediatorIn;
    }

    protected MediatorIn getAgentOfLocation()
    {
        return mediatorIn;
    }
}

• 特工A：

package mediator;
//特工A
public class ColleaugeAgentA extends ColleaugeAgent{

    public ColleaugeAgentA(MediatorIn mediatorIn) {
        super(mediatorIn);
        // TODO Auto-generated constructor stub
    }

    //我想去通知特工B
    public void notifyB(ColleaugeAgentB agentB)
    {
        //得到情报站,然后,给情报
        getAgentOfLocation().notifyOtheragent(agentB);
    }

    public void getMsg()
    {
        System.out.println("A:我被知道有任务了，但是，我不知道是谁通知我的");
    }

}

• 特工B：

package mediator;
//特工A
public class ColleaugeAgentB extends ColleaugeAgent{

    public ColleaugeAgentB(MediatorIn mediatorIn) {
        super(mediatorIn);
        // TODO Auto-generated constructor stub
    }

    //我想去通知特工A
    public void notifyA(ColleaugeAgentA agentA)
    {
        //得到情报站,然后,给情报
        getAgentOfLocation().notifyOtheragent(agentA);
    }

    public void getMsg()
    {
        System.out.println("B:我被知道有任务了，但是，我不知道是谁通知我的");
    }
}

• 情报站：

package mediator;

public interface MediatorIn {
    //通知到特工类
    void notifyOtheragent(ColleaugeAgent colleaugeAgent);
}

package mediator;
//情报站必须持有特工名单，不然，怎么通知呢？
public class ConcreteMediator implements MediatorIn{
    private ColleaugeAgentA colleaugeAgentA;
    private ColleaugeAgentB colleaugeAgentB;

    public void setColleaugeAgentA(ColleaugeAgentA colleaugeAgentA) {
        this.colleaugeAgentA = colleaugeAgentA;
    }

    public void setColleaugeAgentB(ColleaugeAgentB colleaugeAgentB) {
        this.colleaugeAgentB = colleaugeAgentB;
    }

    //通知其他特工
    @Override
    public void notifyOtheragent(ColleaugeAgent colleaugeAgent) {
        // TODO Auto-generated method stub
        if ( colleaugeAgent instanceof ColleaugeAgentA)
        {
            colleaugeAgentB.getMsg();
        }
        else
        {
            colleaugeAgentA.getMsg();
        }
    }

}

• 运行结果：

(源代码：https://github.com/aliencool/Design-Pattrn/tree/master/mediator)

• 结束语：

       中介者模式是GOF经典模式之一，主要用于反射的INVOKE