设计模式--建造者模式

　　建造者模式（builder），将一个复杂对象的构建与他的表示分离，使得同样的构建过程可以创建不同的表示。

 1 package com.sun.builder;
 2 
 3 import java.util.ArrayList;
 4 import java.util.List;
 5 
 6 /**
 7  * 产品类 由多个部件组成
 8  * 
 9  * @author sunafei
10  * 
11  */
12 public class Product {
13     List<String> parts = new ArrayList<String>();
14 
15     public void add(String part) {//添加产品部件
16         this.parts.add(part);
17     }
18 
19     public void show() {//列举所有产品部件
20         System.out.println("产品创建");
21         for (String part : parts) {
22             System.out.println(part);
23         }
24     }
25 }

 1 package com.sun.builder;
 2 
 3 /**
 4  * 抽象建造者类，确定产品有两个部件组成，并声明一个得到产品建造后结果的方法getResult
 5  * @author SunAFei
 6  *
 7  */
 8 public abstract class Builder {
 9     public abstract void builderPartA();
10 
11     public abstract void builderPartB();
12     
13     public abstract Product getResult();
14 }

 1 package com.sun.builder;
 2 
 3 /**
 4  * 具体建造者类
 5  * @author SunAFei
 6  *
 7  */
 8 public class ConcreteBuilder1 extends Builder {
 9 
10     Product product = new Product();
11 
12     @Override
13     public void builderPartA() {
14         product.add("A");
15     }
16 
17     @Override
18     public void builderPartB() {
19         product.add("B");
20     }
21 
22     @Override
23     public Product getResult() {
24         return product;
25     }
26 
27 }

 1 package com.sun.builder;
 2 
 3 public class ConcreteBuilder2 extends Builder {
 4 
 5     Product product = new Product();
 6 
 7     @Override
 8     public void builderPartA() {
 9         product.add("X");
10     }
11 
12     @Override
13     public void builderPartB() {
14         product.add("Y");
15     }
16 
17     @Override
18     public Product getResult() {
19         return product;
20     }
21 
22 }

package com.sun.builder;

/**
 * 指挥者类
 * @author SunAFei
 *
 */
public class Director {
    
    public void construct(Builder builder) {//指挥建造过程
        builder.builderPartA();
        builder.builderPartB();
    }
}

 1 package com.sun.builder;
 2 
 3 public class BuilderDemo {
 4 
 5     public static void main(String[] args) {
 6         Director director = new Director();
 7         Builder b1 = new ConcreteBuilder1();
 8         Builder b2 = new ConcreteBuilder2();
 9         
10         director.construct(b1);
11         Product p1 = b1.getResult();//客户不需要知道具体的建造过程
12         p1.show();
13         
14         director.construct(b2);
15         Product p2 = b2.getResult();
16         p2.show();
17     }
18 
19 }