设计模式学习之中介者模式

1.名词解释：

中介者模式：用一个中介对象来封装一序列的对象交互。中介者使各对象不需要显式地引用，从而使其耦合松散，而且可以独立第改变它们之间的交互。

 

2.代码示例：同事A、同事B通过中介者互相通信。

主控程序类，通过中介者，ColleagueA与ColleagueB进行通信

package DesignPattern.MeditorPattern;

public class Client {

	public static void main(String[] args) {
		ConcreateMeditor m = new ConcreateMeditor();
		Colleague A = new ColleagueA(m);
		Colleague B = new ColleagueB(m);
		m.SetColleagueA((ColleagueA) A);
		m.SetColleagueB((ColleagueB) B);
		((ColleagueA) A).send("B, May I love you?");
		((ColleagueB) B).send("A, I'm sorry, I already have a boy friend.");
	}
}

运行结果：Colleague B get a message: B, May I love you?
Colleague A get a message: A, I'm sorry, I already have a boy friend.

 

中介者抽象类：
package DesignPattern.MeditorPattern;

abstract class Meditor {

	public abstract void send(String message, Colleague colleague);
}

 

具体中介者类：
package DesignPattern.MeditorPattern;

public class ConcreateMeditor extends Meditor{

	private ColleagueA colleagueA;
	private ColleagueB colleagueB;
	
	public void SetColleagueA(Colleague colleague) {
		if(colleague instanceof ColleagueA) {
			this.colleagueA = (ColleagueA) colleague;
		}
	}
	
	public void SetColleagueB(Colleague colleague) {
		if(colleague instanceof ColleagueB) {
			this.colleagueB = (ColleagueB) colleague;
		}
	}
	
	@Override
	public void send(String message, Colleague colleague) {
		// TODO Auto-generated method stub
		if(colleague == colleagueA) {
			colleagueB.notify(message);
		} else {
			colleagueA.notify(message);
		}
	}
}

 

同事抽象类：
package DesignPattern.MeditorPattern;

public abstract class Colleague {

	protected Meditor meditor;
	
	public Colleague(Meditor meditor) {
		this.meditor = meditor;
	}
}

 

同事A类：
package DesignPattern.MeditorPattern;

public class ColleagueA extends Colleague {

	public ColleagueA(Meditor meditor) {
		super(meditor);
		// TODO Auto-generated constructor stub
	}
	
	public void send(String message) {
		meditor.send(message, this);
	}
	
	public void notify(String message) {
		System.out.println("Colleague A get a message: " + message);
	}

}

 

同事B类：
package DesignPattern.MeditorPattern;

public class ColleagueB extends Colleague {

	public ColleagueB(Meditor meditor) {
		super(meditor);
		// TODO Auto-generated constructor stub
	}
	
	public void send(String message) {
		meditor.send(message, this);
	}
	
	public void notify(String message) {
		System.out.println("Colleague B get a message: " + message);
	}

}