装饰器模式

装饰器模式：给一个对象添加一些额外的操作，虽然此功能可以用继承实现，但装饰模式比生成子类更灵活。核心思想是动态组合，和aop很相似，关键步骤在于对装饰器类的继承。

package com.jerry.design.decorator;



	// 测试类
public class Test {

	public static void main(String[] args) {
		    Component component = new ConcreteComponent();    
	        component.operation();    
	        System.out.println("-------------");    
	        component = new Decorator1(new ConcreteComponent());    
	        component.operation();    
    }
}

interface Component {    
    
    void operation();    
}  

class ConcreteComponent implements Component {    
    
    public void operation() {    
        System.out.println("I'm in ConcreteComponent's operation");    
    }    
    
} 


class Decorator implements Component {    
    
    private Component component;    
    
    public Decorator(Component component) {    
        this.component = component;    
    }    
    
    public void operation() {    
        component.operation();    
    }    
    
}   

class Decorator1 extends Decorator {    
    
    public Decorator1(Component component) {    
        super(component);    
    }    
    
    public void operation() {    
        doSomething();    
        super.operation();    
    }    
    
    private void doSomething() {    
        System.out.println("doSomething: I'm in Decorator1's operation");    
    }    
    
}