设计模式-装饰者模式[Decorator]

装饰者模式

本文地址:http://www.cnblogs.com/masque/p/3833141.html                       

部分资料来自网络,代码都是已运行实践,转载请在明显位置注明出处.

下面是一个咖啡添加不同的调料得到价钱和名称的算法

先定义了一个接口

 1 package org.masque.designpatterns.decorator;
 2 /**
 3  * 
 4  * Description:
 5  * InterForAll.java Create on 2014年7月9日 上午10:59:50 
 6  * @author masque.java@outlook.com
 7  * @version 1.0
 8  * Copyright (c) 2014 Company,Inc. All Rights Reserved.
 9  */
10 public interface InterForAll {
11 
12     double display();
13     
14     String print();
15 }

实现价钱和描述.
抽象方法的父类有价钱和描述的属性,计算价钱和合并名称的方法.

 1 package org.masque.designpatterns.decorator;
 2 /**
 3  * 
 4  * Description:
 5  * AbstractParent.java Create on 2014年7月9日 上午11:00:04 
 6  * @author masque.java@outlook.com
 7  * @version 1.0
 8  * Copyright (c) 2014 Company,Inc. All Rights Reserved.
 9  */
10 public abstract class AbstractParent implements InterForAll {
11 
12     protected String describe;
13     
14     protected double price;
15     
16     @Override
17     public abstract double display();
18     
19     @Override
20     public abstract String print();
21 
22     public String getDescribe() {
23         return describe;
24     }
25 
26     public void setDescribe(String describe) {
27         this.describe = describe;
28     }
29 
30     public double getPrice() {
31         return price;
32     }
33 
34     public void setPrice(double price) {
35         this.price = price;
36     }
37 
38     @Override
39     public String toString() {
40         return "AbstractParent [describe=" + describe + ", price=" + price
41                 + "]";
42     }
43 }

 一个咖啡类

 1 package org.masque.designpatterns.decorator;
 2 /**
 3  * 
 4  * Description:
 5  * Coffee.java Create on 2014年7月9日 上午11:00:11 
 6  * @author masque.java@outlook.com
 7  * @version 1.0
 8  * Copyright (c) 2014 Company,Inc. All Rights Reserved.
 9  */
10 public final class Coffee extends AbstractParent {
11 
12     public Coffee(){
13         this.describe = "Coffee";
14         this.price = .95;
15     }
16 
17     @Override
18     public double display() {
19         return this.price;
20     }
21 
22     @Override
23     public String print() {
24         return this.describe;
25     }
26 }

 一个牛奶类

 1 package org.masque.designpatterns.decorator;
 2 /**
 3  * 
 4  * Description:
 5  * Milk.java Create on 2014年7月9日 上午11:00:32 
 6  * @author masque.java@outlook.com
 7  * @version 1.0
 8  * Copyright (c) 2014 Company,Inc. All Rights Reserved.
 9  */
10 public final class Milk extends AbstractParent {
11 
12     private AbstractParent abstractParent;
13     
14     public Milk(AbstractParent abstractParent){
15         this.describe = "Milk";
16         this.price = .2;
17         this.abstractParent = abstractParent;
18     }
19     
20     @Override
21     public double display() {
22         return abstractParent.display() + price;
23     }
24     
25     @Override
26     public String print() {
27         return abstractParent.print() + "," + describe;
28     }
29 }

 一个莫妮卡类

 1 package org.masque.designpatterns.decorator;
 2 /**
 3  * 
 4  * Description:
 5  * Mocha.java Create on 2014年7月9日 上午11:00:39 
 6  * @author masque.java@outlook.com
 7  * @version 1.0
 8  * Copyright (c) 2014 Company,Inc. All Rights Reserved.
 9  */
10 public final class Mocha extends AbstractParent {
11 
12     private AbstractParent abstractParent;
13     
14     public Mocha(AbstractParent abstractParent){
15         this.describe = "Mocha";
16         this.price = .3;
17         this.abstractParent = abstractParent;
18     }
19     
20     @Override
21     public double display() {
22         return abstractParent.display() + price;
23     }
24     
25     @Override
26     public String print() {
27         return abstractParent.print() + "," + describe;
28     }
29 }

 我们来实现咖啡加牛奶加莫妮卡的实现

 1 package org.masque.designpatterns.decorator;
 2 /**
 3  * 
 4  * Description:
 5  * Main.java Create on 2014年7月9日 上午11:00:22 
 6  * @author masque.java@outlook.com
 7  * @version 1.0
 8  * Copyright (c) 2014 Company,Inc. All Rights Reserved.
 9  */
10 public class Main {
11 
12     public static void main(String[] args) {
13         AbstractParent coffee1 = new Coffee();
14         System.out.println(coffee1.toString());
15         
16         AbstractParent coffee2 = new Coffee();
17         coffee2 = new Milk(coffee2);
18         System.out.println("------+Milk----------");
19         System.out.println(coffee2.toString());
20         System.out.println(coffee2.display());
21         System.out.println(coffee2.print());
22         
23         System.out.println("------+Mocha----------");
24         coffee2 = new Mocha(coffee2);
25         System.out.println(coffee2.toString());
26         System.out.println(coffee2.display());
27         System.out.println(coffee2.print());
28     }
29 }

 运行结果