设计模式--Builder模式

 本文地址:http://www.cnblogs.com/masque/p/3817310.html

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 1   public class Main5{
 2       
 3       private final int servingSize;
 4       
 5       private final int servings;
 6       
 7       private final int calories;
 8       
 9       private final int fat;
10      
11      private final int sodium;
12      
13      private final int carbohydrate;
14      
15      public static class Builder{
16          
17          private final int servingSize;
18          
19          private final int servings;
20          
21          private int calories = 0;
22          
23          private int fat = 0;
24          
25          private int sodium = 0;
26          
27          private int carbohydrate = 0;
28          
29          public Builder(int servingSize,int servings){
30              this.servingSize = servingSize;
31              this.servings = servings;
32          }
33          
34          public Builder calories(int calories){
35              this.calories = calories;
36              return this;
37          }
38          
39          public Builder fat(int fat){
40              this.fat = fat;
41              return this;
42          }
43          
44          public Builder sodium(int sodium){
45              this.sodium = sodium;
46              return this;
47          }
48          
49          public Builder carbohydrate(int carbohydrate){
50              this.carbohydrate = carbohydrate;
51              return this;
52          }
53          
54          public Main5 build(){
55              return new Main5(this);
56          }
57      }
58      
59      private Main5(Builder builder){
60          servingSize = builder.servingSize;
61          servings = builder.servings;
62          calories = builder.calories;
63          fat = builder.fat;
64          sodium = builder.sodium;
65          carbohydrate = builder.carbohydrate;
66      }
67  }

 

 

当一个类有很多属性

有很多的熟悉可以是默认的值的时候

可以通过写多个不同参数的构造方法去实现

但是很麻烦

这种方式设计上很灵活

基本上可以上任意的组合见Effective java （中文第二版） 第11页

posted on 2014-06-30 21:25  masque  阅读(351)  评论(0)  编辑  收藏  举报

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