装饰者模式

【装饰者模式】动态地给对象添加一些额外的职责。就功能来说装饰模式相比生成子类更为灵活。

package com.demo.decorator;

//具体装饰
public class SparrowDecorator extends Decorator {

	public final int DISTANCE=50;
	SparrowDecorator(Bird bird){
		super(bird);
	}
	public int fly(){
		int distance=0;
		//委托被装饰者bird调用fly(),然后再调用eleFly()
		distance=bird.fly()+eleFly();
		return distance;
	}
	//eleFly方法能飞行50米
	//装饰者添加的新方法
	private int eleFly(){
		return DISTANCE;
	}
}

package com.demo.decorator;

public class Application {

	public void needBird(Bird bird){
		int flyDistance=bird.fly();
		System.out.println("这只鸟能飞行"+flyDistance+"米");
	}
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Application client=new Application();
		//无装饰
		Bird sparrow=new Sparrow();
		//一层装饰过的麻雀
		Bird sparrowDecorator1=new SparrowDecorator(sparrow);
		//二层装饰过的麻雀
		Bird sparrowDecorator2=new SparrowDecorator(sparrowDecorator1);
		
		client.needBird(sparrow);//100
		client.needBird(sparrowDecorator1);//150
		client.needBird(sparrowDecorator2);//200
	}
}