学习设计模式之适配器模式

首先声明一个鸟类的接口,鸟会飞,还会唱歌

package com.adapter;

public interface Bird {
	public void sing();
	public void fly();
}

创建老鹰类,实现鸟类接口

package com.adapter;

public class Eagle implements Bird {

	public void fly() {
		System.out.println("I am an eagle, I can fly high");
	}
	public void sing() {
		System.out.println("I can sing loud");
	}
}

创建家禽接口,家禽也能飞,叫

package com.adapter;

public interface JiaQin {
	public void fly();
	public void jiao();
	
}

创建家禽实现类鸭子,鸭子飞得不高,只会嘎嘎叫

package com.adapter;

public class Duck implements JiaQin {
	public void fly() {
		System.out.println("I can fly a little");
	}
	public void jiao() {
		System.out.println("I can quack");
	}
}

现在领导要来观察老鹰,但是现在没有老鹰,好吧,那就抓一只鸭子来冒充吧,披上老鹰皮的鸭子

package com.adapter;

public class BirdTest {
	public static void main(String[] args){		
		JiaQin duck = new Duck();
        //假的老鹰,去冒充鸟类,使之也可以被观察		
		Adapter phonyEagle = new Adapter(duck);	
		observerTheBird(phonyEagle);				
	}
	//观察鸟类方法
	public static void observerTheBird(Bird b){
		b.fly();
		b.sing();		
	}
}

让鸭子能披上老鹰皮的,就是那个适配器Adapter,里面真的包了一只鸭子,会装的鸭子

package com.adapter;

public class Adapter implements Bird {
	private JiaQin duck;
	
	Adapter(JiaQin duck){
		this.duck = duck;
	}
	public void fly() {
		duck.fly();
	}
	public void sing() {
		duck.jiao();
	}
}

运行结果如下:

I can fly a little
I can quack

总结:适配器模式的用处在于装,将类从一个接口,转换到另外一个接口,使原来不一样的类,至少可以看起来是一样的