常用设计模式总结--生成器模式

Builder ，生成器模式。
Builder 模式将一个对象的创建与表示分离，从而使得相同的创建过程可以创建出不同的表示对象。
仍以汽车工厂举例，一个汽车集团下面有许多工厂，每个工厂生产出不同的车型。站在集团的层面，其实集团只需要知道工厂造轮子，造引擎，而并不关心轮子的具体尺寸，引擎的具体马力，它只需要知道工厂最终返回的给它的是一辆完整的汽车，就一切 ok
类图



在这个类图中，省略了 Wheel,Engine,Vehicle 。 DasAuto 为新引入的一个类，包含着一个对具体 builder 父类的引用。而 VehicleBuilder 中加入一个 getVehicle （）的方法，用来返回创建的 Vehicle

代码
对于汽车的零件，参考抽象工厂的日志

1 DasAuto

package zl.study.designpattern.builder;
/**
* DasAuto能够提供汽车和摩托车，具体的车型则要看是
* 哪个工厂提供。
*
* @author peter
*
*/
public class DasAuto {

public Vehicle createNormalCar(VehicleBuilder builder){
builder.buildVehicle();
builder.buildEngine();
builder.buildWheel();
return builder.getVehicle();
}

public Vehicle createRaceCar(VehicleBuilder builder ){
builder.buildVehicle();
builder.buildEngine();

builder.buildWheel();
builder.buildWheel();

return builder.getVehicle();
}
}

2 VehicleBuilder

package zl.study.designpattern.builder;

public interface VehicleBuilder {

public void buildVehicle();
public void buildEngine();
public void buildWheel();

public Vehicle getVehicle();
}

3 NormalVehicleBuilder

package zl.study.designpattern.builder;

public class NormalVehicleBuilder implements VehicleBuilder{

private Vehicle vehicle;

@Override
public void buildEngine() {
Engine engine = new NormalEngine();
vehicle.setEngine(engine);
}
@Override
public void buildVehicle() {
if( null == vehicle)
vehicle = new NormalVehicle();

}
@Override
public void buildWheel() {
Wheel wheel1 = new NormalWheel();
Wheel wheel2 = new NormalWheel();
Wheel wheel3 = new NormalWheel();
Wheel wheel4 = new NormalWheel();
vehicle.addWheel(wheel1);
vehicle.addWheel(wheel2);
vehicle.addWheel(wheel3);
vehicle.addWheel(wheel4);
}
@Override
public Vehicle getVehicle() {

return this.vehicle;
}
}

4 RaceVehicleBuilder

package zl.study.designpattern.builder;

public class RaceVehicleBuilder implements VehicleBuilder{

private Vehicle vehicle;

@Override
public void buildEngine() {
Engine engine = new RaceEngine();
vehicle.setEngine(engine);

}
@Override
public void buildVehicle() {
if( null == vehicle){
vehicle = new RaceVehicle();
}

}
@Override
public void buildWheel() {
Wheel wheel1 = new RaceWheel();
Wheel wheel2 = new RaceWheel();
Wheel wheel3 = new RaceWheel();
Wheel wheel4 = new RaceWheel();
vehicle.addWheel(wheel1);
vehicle.addWheel(wheel2);
vehicle.addWheel(wheel3);
vehicle.addWheel(wheel4);

}
@Override
public Vehicle getVehicle() {
// TODO Auto-generated method stub
return null;
}
}

5 测试程序

package zl.study.designpattern.builder.test;

import zl.study.designpattern.builder.DasAuto;
import zl.study.designpattern.builder.NormalVehicleBuilder;
import zl.study.designpattern.builder.Vehicle;
import zl.study.designpattern.builder.VehicleBuilder;
public class BuilderTest {
public static void main(String args[]){
VehicleBuilder builder = new NormalVehicleBuilder();

DasAuto dasAuto = new DasAuto();

Vehicle normalVehicle = dasAuto.createNormalCar(builder);

System.out.println(normalVehicle);

}
}