Design Pattern_Java：Builder Pattern

Design Pattern：Builder Pattern

建造者模式 Builder Pattern

Separate the construction of a complex object from its representation so that the same construction process can create different representations.

将一个复杂对象的构建与它的表示分离，是的同样的构建过程可以创建不同的表示。

抽象建造者角色（Builder）：该角色用于规范产品的各个组成部分，并进行抽象，一般独立于应用程序的逻辑。

public abstract class Builder {//设置产品的不同部分，以获得不同的产品public abstract void setPart1();public abstract void setPart2();public abstract void setPart3();//建造产品public abstract Product builderProduct();}

具体建造者角色（Concrete Builder）:该角色实现抽象建造者中定义的所有方法，并且返回一个组建好的产品实例。

public class ConcreteBuilder extends Builder{private Product product=new Product();//设置产品零件@Overridepublic void setPart1() {    //为product安装部件1}@Overridepublic void setPart2() {    //为product安装部件2}@Overridepublic void setPart3() {    //为product安装部件2}//建造一个产品@Overridepublic Product builderProduct() {    return product;}}

产品角色（Product）：该角色是建造中的复杂对象，一个系统中会有多于一个的产品类，这些产品类并一定有共同的接口，完全可以是不想关联的。

public class Product{    //产品类的业务处理方法}

导演者角色（Director）：该角色负责安排已有模块的顺序，然后告诉Builder开始建造。

public class Director{    private Builder builder=new ConcreteBuilder();    //构造产品，负责调用各个零件建造方法    public Product build(){        builder.setPart1();        builder.setPart2();        builder.setPart3();        return builder.builderProduct();    }}

建造者模式的实例

Computer.java

package com.DesignPattern.Creational.Builder;public abstract class Computer {    private String type;    private String cpu;    private String ram;    private String hardDisk;    private String monitor;    private String os;    public String getType() {        return type;    }    public void setType(String type) {        this.type = type;    }    public String getCpu() {        return cpu;    }    public void setCpu(String cpu) {        this.cpu = cpu;    }    public String getRam() {        return ram;    }    public void setRam(String ram) {        this.ram = ram;    }    public String getHardDisk() {        return hardDisk;    }    public void setHardDisk(String hardDisk) {        this.hardDisk = hardDisk;    }    public String getMonitor() {        return monitor;    }    public void setMonitor(String monitor) {        this.monitor = monitor;    }    public String getOs() {        return os;    }    public void setOs(String os) {        this.os = os;    }}

T410.java

package com.DesignPattern.Creational.Builder;public class T410 extends Computer {    private String graphicCard;    public T410() {        this.setType("ThinkPad T410i");    }    public String getGraphicCard() {        return graphicCard;    }    public void setGraphicCard(String graphicCard) {        this.graphicCard = graphicCard;    }    @Override    public String toString() {        return "T410 [graphicCard=" + graphicCard + ", getType()=" + getType()                + ", getCpu()=" + getCpu() + ", getRam()=" + getRam()                + ", getHardDisk()=" + getHardDisk() + ", getMonitor()="                + getMonitor() + ", getOs()=" + getOs() + "]";    }}

X201.java

package com.DesignPattern.Creational.Builder;public class X201 extends Computer {    public X201() {        this.setType("ThinkPad X201i");    }    @Override    public String toString() {        return "X201 [getType()=" + getType() + ", getCpu()=" + getCpu()                + ", getRam()=" + getRam() + ", getHardDisk()=" + getHardDisk()                + ", getMonitor()=" + getMonitor() + ", getOs()=" + getOs()                + "]";    }}

ComputerBuilder.java

package com.DesignPattern.Creational.Builder;public interface ComputerBuilder {    void buildCpu();    void buildRam();    void buildHardDisk();    void buildGraphicCard();    void buildMonitor();    void buildOS();    Computer getResult();}

T410Builder.java

package com.DesignPattern.Creational.Builder;public class T410Builder implements ComputerBuilder {    private T410 computer = new T410();    @Override    public void buildCpu() {        computer.setCpu("i5-450");    }    @Override    public void buildRam() {        computer.setRam("4GB 1333MHz");    }    @Override    public void buildHardDisk() {        computer.setHardDisk("500G 7200转");    }    @Override    public void buildGraphicCard() {        computer.setGraphicCard("Nvidia NVS 3100M");    }    @Override    public void buildMonitor() {        computer.setMonitor("14英寸 1280*800");    }    @Override    public void buildOS() {        computer.setOs("Windows 7旗舰版");    }    @Override    public Computer getResult() {        return computer;    }}

X201Builder.java

package com.DesignPattern.Creational.Builder;public class X201Builder implements ComputerBuilder {    private X201 computer = new X201();    @Override    public void buildCpu() {        computer.setCpu("i3-350");    }    @Override    public void buildRam() {        computer.setRam("2GB 1333MHz");    }    @Override    public void buildHardDisk() {        computer.setHardDisk("250G 5400转");    }    @Override    public void buildGraphicCard() {        // 无显卡    }    @Override    public void buildMonitor() {        computer.setMonitor("12英寸 1280*800");    }    @Override    public void buildOS() {        computer.setOs("Windows 7 Home版");    }    @Override    public Computer getResult() {        return computer;    }}

ComputerDirector.java

package com.DesignPattern.Creational.Builder;public class ComputerDirector {    ComputerBuilder builder;    public T410 constructT410(){        builder=new T410Builder();        builder.buildCpu();        builder.buildRam();        builder.buildHardDisk();        builder.buildGraphicCard();        builder.buildMonitor();        builder.buildOS();        return (T410)builder.getResult();    }    public X201 constructX210(){        builder=new X201Builder();        builder.buildCpu();        builder.buildRam();        builder.buildHardDisk();        builder.buildMonitor();        builder.buildOS();        return (X201)builder.getResult();    }}

ComputerTest.java

package com.DesignPattern.Creational.Builder;public class ComputerTest {    public static void main(String[] args){        ComputerDirector director=new ComputerDirector();        Computer t410=director.constructT410();        System.out.println(t410);        System.out.println("-------------------------------");        Computer x201=director.constructX210();        System.out.println(x201);    }}