中介者模式解决智能家电问题

• 方案类图
  

• 代码实现

package com.atguigu.mediator.smarthouse;
//同事抽象类
public abstract class Colleague {
	
	private Mediator mediator;
	
	public String name;
 
	public Colleague(Mediator mediator, String name) {
		this.mediator = mediator;
		this.name = name;
	}
 
	public Mediator GetMediator() {
		return this.mediator;
	}
 
	public abstract void SendMessage(int stateChange);
}
 
package com.atguigu.mediator.smarthouse;
//具体的同事类
public class Alarm extends Colleague {
 
	//构造器
	public Alarm(Mediator mediator, String name) {
		super(mediator, name);
		//在创建Alarm 同事对象时，将自己放入到ConcreteMediator 对象中[集合]
		mediator.Register(name, this);
	}
 
	public void SendAlarm(int stateChange) {
		SendMessage(stateChange);
	}
 
	@Override
	public void SendMessage(int stateChange) {
		//调用的中介者对象的getMessage
		this.GetMediator().GetMessage(stateChange, this.name);
	}
 
}
 
package com.atguigu.mediator.smarthouse;
public abstract class Mediator {
	//将给中介者对象，加入到集合中
	public abstract void Register(String colleagueName, Colleague colleague);
 
	//接收消息, 具体的同事对象发出
	public abstract void GetMessage(int stateChange, String colleagueName);
 
	public abstract void SendMessage();
}
 
package com.atguigu.mediator.smarthouse;
import java.util.HashMap;
//具体的中介者类
public class ConcreteMediator extends Mediator {
	//集合，放入所有的同事对象
	private HashMap<String, Colleague> colleagueMap;
	
	private HashMap<String, String> interMap;
 
	public ConcreteMediator() {
		colleagueMap = new HashMap<String, Colleague>();
		interMap = new HashMap<String, String>();
	}
 
	@Override
	public void Register(String colleagueName, Colleague colleague) {
		colleagueMap.put(colleagueName, colleague);
		
		if (colleague instanceof Alarm) {
			interMap.put("Alarm", colleagueName);
		} else if (colleague instanceof CoffeeMachine) {
			interMap.put("CoffeeMachine", colleagueName);
		} else if (colleague instanceof TV) {
			interMap.put("TV", colleagueName);
		} else if (colleague instanceof Curtains) {
			interMap.put("Curtains", colleagueName);
		}
 
	}
 
	//具体中介者的核心方法
	//1. 根据得到消息，完成对应任务
	//2. 中介者在这个方法，协调各个具体的同事对象，完成任务
	@Override
	public void GetMessage(int stateChange, String colleagueName) {
		// TODO Auto-generated method stub
 
		//处理闹钟发出的消息
		if (colleagueMap.get(colleagueName) instanceof Alarm) {
			if (stateChange == 0) {
				((CoffeeMachine) (colleagueMap.get(interMap
						.get("CoffeeMachine")))).StartCoffee();
				((TV) (colleagueMap.get(interMap.get("TV")))).StartTv();
			} else if (stateChange == 1) {
				((TV) (colleagueMap.get(interMap.get("TV")))).StopTv();
			}
 
		} else if (colleagueMap.get(colleagueName) instanceof CoffeeMachine) {
			((Curtains) (colleagueMap.get(interMap.get("Curtains"))))
					.UpCurtains();
 
		} else if (colleagueMap.get(colleagueName) instanceof TV) {//如果TV发现消息
 
		} else if (colleagueMap.get(colleagueName) instanceof Curtains) {
			//如果是以窗帘发出的消息，这里处理...
		}
 
	}
 
	@Override
	public void SendMessage() {
	}
 
}
 
package com.atguigu.mediator.smarthouse;
public class ClientTest {
 
	public static void main(String[] args) {
		//创建一个中介者对象
		Mediator mediator = new ConcreteMediator();
		//创建Alarm 并且加入到  ConcreteMediator 对象的HashMap
		Alarm alarm = new Alarm(mediator, "alarm");
		//创建了CoffeeMachine 对象，并  且加入到  ConcreteMediator 对象的HashMap
		CoffeeMachine coffeeMachine = new CoffeeMachine(mediator,
				"coffeeMachine");
		//创建 Curtains , 并  且加入到  ConcreteMediator 对象的HashMap
		Curtains curtains = new Curtains(mediator, "curtains");
		TV tV = new TV(mediator, "TV");
		//让闹钟发出消息
		alarm.SendAlarm(0);
		coffeeMachine.FinishCoffee();
		alarm.SendAlarm(1);
	}
 
}

• 中介者模式的注意事项和细节

1) 多个类相互耦合，会形成网状结构, 使用中介者模式将网状结构分离为星型结构，进行解耦
2) 减少类间依赖，降低了耦合，符合迪米特原则
3) 中介者承担了较多的责任，一旦中介者出现了问题，整个系统就会受到影响
4) 如果设计不当，中介者对象本身变得过于复杂，这点在实际使用时，要特别注意