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。

package com.sun.builder;

import java.util.ArrayList;
import java.util.List;

/**
 * 产品类 由多个部件组成
 * 
 * @author sunafei
 * 
 */
public class Product {
    List<String> parts = new ArrayList<String>();

    public void add(String part) {//添加产品部件
        this.parts.add(part);
    }

    public void show() {//列举所有产品部件
        System.out.println("产品创建");
        for (String part : parts) {
            System.out.println(part);
        }
    }
}

package com.sun.builder;

/**
 * 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
 * @author SunAFei
 *
 */
public abstract class Builder {
    public abstract void builderPartA();

    public abstract void builderPartB();
    
    public abstract Product getResult();
}

package com.sun.builder;

/**
 * 具体建造者类
 * @author SunAFei
 *
 */
public class ConcreteBuilder1 extends Builder {

    Product product = new Product();

    @Override
    public void builderPartA() {
        product.add("A");
    }

    @Override
    public void builderPartB() {
        product.add("B");
    }

    @Override
    public Product getResult() {
        return product;
    }

}

package com.sun.builder;

public class ConcreteBuilder2 extends Builder {

    Product product = new Product();

    @Override
    public void builderPartA() {
        product.add("X");
    }

    @Override
    public void builderPartB() {
        product.add("Y");
    }

    @Override
    public Product getResult() {
        return product;
    }

}

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();
    }
}

package com.sun.builder;

public class BuilderDemo {

    public static void main(String[] args) {
        Director director = new Director();
        Builder b1 = new ConcreteBuilder1();
        Builder b2 = new ConcreteBuilder2();
        
        director.construct(b1);
        Product p1 = b1.getResult();//客户不需要知道具体的建造过程
        p1.show();
        
        director.construct(b2);
        Product p2 = b2.getResult();
        p2.show();
    }

}