设计模式——建造者模式(BuilderPattern)

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

UML图：

Builder：

package com.cnblog.clarck;

/**
 * 抽象建造者，确定产品有两个部分A和B组成,并声明一个得到产品组合后得到结果的方法getResult.
 *
 * @author clarck
 *
 */
public abstract class Builder {
    public abstract void buildPartA();

    public abstract void buildPartB();

    public abstract Product getResult();
}

Director：

package com.cnblog.clarck;

/**
 * 指挥者
 *
 * @author clarck
 *
 */
public class Director {
    public void Construct(Builder builder) {
        builder.buildPartA();
        builder.buildPartB();
    }
}

Product：

package com.cnblog.clarck;

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

/**
 * 产品类，由多个部分组成
 *
 * @author clarck
 *
 */
public class Product {
    private List<String> parts = new ArrayList<String>();

    public void add(String part) {
        parts.add(part);
    }

    public void show() {
        System.out.println("产品 创建-----");
        for (String part : parts) {
            System.out.println(part);
        }
    }
}

ConcrateBuilder1：

package com.cnblog.clarck;

/**
 * 具体建造者
 *
 * @author clarck
 *
 */
public class ConcrateBuilder1 extends Builder {
    private Product product = new Product();

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

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

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

}

ConcrateBuilder2：

package com.cnblog.clarck;

public class ConcrateBuilder2 extends Builder {
    private Product product = new Product();

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

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

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

}

Client：

package com.cnblog.clarck;

/**
 * 测试类
 *
 * @author clarck
 *
 */
public class Client {
    public static void main(String[] args) {
        Director director = new Director();
        Builder builder1 = new ConcrateBuilder1();
        Builder builder2 = new ConcrateBuilder2();

        director.Construct(builder1);
        Product product1 = builder1.getResult();
        product1.show();

        director.Construct(builder2);
        Product product2 = builder2.getResult();
        product2.show();
    }
}