設計模式---中介者模式

代碼展示

以前的 

package com.ibeifeng.ex1;

public class Man extends Person {

	public Man(String name, int condition) {
		super(name, condition);
	}

	public void getPartner(Person person) {
		if(person instanceof Man) {
			System.out.println("汗，我不是同志！");
		} else {
			if(this.getCondition() == person.getCondition()) {
				System.out.println(this.getName() + "和" + person.getName() + "絕配");
			} else {
				System.out.println(this.getName() + "和" + person.getName() + "不相配");
			}
		}
	}

}
           

package com.ibeifeng.ex1;

public abstract class Person {
	private String name;
	private int condition;
	
	public Person(String name, int condition) {
		this.name = name;
		this.condition = condition;
	}
	
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getCondition() {
		return condition;
	}
	
	public void setCondition(int condition) {
		this.condition = condition;
	}
	
	public abstract void getPartner(Person person);
	
}
           

package com.ibeifeng.ex1;

public class Woman extends Person {

	public Woman(String name, int condition) {
		super(name, condition);
	}

	public void getPartner(Person person) {
		if(person instanceof Woman) {
			System.out.println("汗，我不是同志！");
		} else {
			if(this.getCondition() == person.getCondition()) {
				System.out.println(this.getName() + "和" + person.getName() + "絕配");
			} else {
				System.out.println(this.getName() + "和" + person.getName() + "不相配");
			}
		}
	}
	
}
           

package com.ibeifeng.ex1;

public class MainClass {
	public static void main(String[] args) {
		Person zhangsan = new Man("張三",5);
		Person lisi = new Man("李四",6);
		
		Person xiaofang = new Woman("小芳", 6);
		
		zhangsan.getPartner(xiaofang);
		lisi.getPartner(xiaofang);
		zhangsan.getPartner(lisi);
		
	}
}	
           

現在的

package com.ibeifeng.ex2;

public abstract class Person {
	private String name;
	private int condition;
	private Mediator mediator;

	
	public Person(String name, int condition, Mediator mediator) {
		super();
		this.name = name;
		this.condition = condition;
		this.mediator = mediator;
	}
	
	public Mediator getMediator() {
		return mediator;
	}

	public void setMediator(Mediator mediator) {
		this.mediator = mediator;
	}

	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getCondition() {
		return condition;
	}
	
	public void setCondition(int condition) {
		this.condition = condition;
	}
	
	public abstract void getPartner(Person person);
	
}
           

package com.ibeifeng.ex2;

public class Man extends Person {

	public Man(String name, int condition,Mediator mediator) {
		super(name, condition, mediator);
	}

	public void getPartner(Person person) {
		this.getMediator().setMan(this);
		this.getMediator().getPartner(person);
	}
}
           

package com.ibeifeng.ex2;

public class Woman extends Person {

	public Woman(String name, int condition,Mediator mediator) {
		super(name, condition, mediator);
	}

	public void getPartner(Person person) {
		this.getMediator().setWoman(this);
		this.getMediator().getPartner(person);
	}
	
}
           

package com.ibeifeng.ex2;

public class Mediator {
	private Man man;
	private Woman woman;
	
	public void setMan(Man man) {
		this.man = man;
	}
	public void setWoman(Woman woman) {
		this.woman = woman;
	}
	
	public void getPartner(Person person) {
		//将搭檔設定上
		if(person instanceof Man) {
			this.setMan((Man)person);
		} else {
			this.setWoman((Woman)person);
		}
		//判斷條件
		if(man == null || woman == null) {
			System.out.println("汗，我不是同志!");
		} else {
			
			if(man.getCondition() == woman.getCondition()) {
				System.out.println(man.getName() + "和" + woman.getName() + "絕配");
			} else {
				System.out.println(man.getName() + "和" + woman.getName() + "不相配");
			}
		}
	}
	
}
           

package com.ibeifeng.ex2;

public class MainClass {
	public static void main(String[] args) {
		Mediator mediator = new Mediator();
		Person zhangsan = new Man("張三",7,mediator);
		Person lisi = new Man("李四",7,mediator);
		Person xiaofang = new Woman("小芳",7,mediator);
		
		zhangsan.getPartner(lisi);
		
		xiaofang.getPartner(lisi);
	}
}
           

外觀模式、代理模式和中介者模式的差別

外觀模式（Facade Pattern）

定義一個外觀類，外觀類隐藏系統的複雜性，為用戶端提供簡化的方法和對現有系統類方法的委托調用。

例如：二手房交易的中介，屬于外觀模式。買房者通過中介可以簡單地買到二手房，中介自己把聯系房東看房砍價、過戶、交稅這些複雜的事情都搞定了。

代理模式（Proxy Pattern）

用一個代理類代表另一個類的功能，但是不改變被代理類的功能。目的是控制對被代理類的通路。

中介者模式（Mediator Pattern）

用一個中介對象來封裝一系列的對象互動，中介者使各對象不需要顯式地互相引用，進而使其耦合松散，而且可以獨立地改變它們之間的互動。将各對象之間的網狀結構分離為星型結構。

例如：MVC 架構，其中C（控制器）就是 M（模型）和 V（視圖）的中介者。微信群是各群員之間的中介者。