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
@Override
public void setPart1() {
//为product安装部件1
}

@Override
public void setPart2() {
//为product安装部件2
}

@Override
public void setPart3() {
//为product安装部件2
}

//建造一个产品
@Override
public 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);
}
}