How
继承又聚合 |
通俗的说:
就是 抽象装饰继承or实现抽象组件,重写其方法,
(必须添加一个形参为抽象组件的构造方法)
然后具体装饰同样有形参为抽象组件的构造方法,
但是调用的是super(抽象组件)这个构造方法
并且在每一个方法中都是调用super+该装饰的逻辑
// 抽象组件
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| <p>interface Coffee {</p>
<p>double cost();</p>
<p>String info();</p>
<p>}</p>
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// 具体组件
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| <p>class SimpleCoffee implements Coffee {</p>
<p>public double cost() { return 5; }</p>
<p>public String info() { return "普通咖啡"; }</p>
<p>}</p>
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// 装饰抽象类
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| <p>abstract class CoffeeDecorator implements Coffee {</p>
<p><span style='background:yellow;mso-highlight:yellow'>protected Coffee coffee;</span></p>
<p><span style='background:yellow;mso-highlight:yellow'> public CoffeeDecorator(Coffee coffee) { this.coffee = coffee; }</span></p>
<p>public double cost() { return coffee.cost(); }</p>
<p>public String info() { return coffee.info(); }</p>
<p>}</p>
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// 具体装饰
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| <p>class MilkDecorator extends CoffeeDecorator {</p>
<p>public MilkDecorator(Coffee coffee) { <span style='background:yellow;mso-highlight:yellow'>super(coffee);</span> }</p>
<p>public double cost() {<span style='background:yellow;mso-highlight:yellow'> return super.cost() + 2;</span> }</p>
<p>public String info() { <span style='background:yellow;mso-highlight:yellow'>return super.info() + " + 牛奶";</span> }</p>
<p>}</p>
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| <p>class SugarDecorator extends CoffeeDecorator {</p>
<p>public SugarDecorator(Coffee coffee) { super(coffee); }</p>
<p>public double cost() { return super.cost() + 1; }</p>
<p>public String info() { return super.info() + " + 糖"; }</p>
<p>}</p>
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// 测试
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| <p>public class Demo {</p>
<p>public static void main(String[] args) {</p>
<p>Coffee coffee = new SimpleCoffee();</p>
<p>coffee = new MilkDecorator(coffee);</p>
<p>coffee = new SugarDecorator(coffee);</p>
<p>System.out.println(coffee.info() + " = " + coffee.cost());</p>
<p>}</p>
<p>}</p></td>
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