常用設計模式總結--生成器模式

Builder ，生成器模式。

Builder 模式將一個對象的創建與表示分離，從而使得相同的創建過程可以創建出不同的表示對象。

仍以汽車工廠舉例，一個汽車集團下面有許多工廠，每個工廠生產出不同的車型。站在集團的層面，其實集團只需要知道工廠造輪子，造引擎，而並不關心輪子的具體尺寸，引擎的具體馬力，它只需要知道工廠最終返回的給它的是一輛完整的汽車，就一切 ok

類圖

 

在這個類圖中，省略了 Wheel,Engine,Vehicle 。 DasAuto 爲新引入的一個類，包含着一個對具體 builder 父類的引用。而 VehicleBuilder 中加入一個 getVehicle （）的方法，用來返回創建的 Vehicle

 

代碼

對於汽車的零件，參考抽象工廠的日誌

 

1 DasAuto

package zl.study.designpattern.builder; /** * DasAuto能夠提供汽車和摩托車，具體的車型則要看是 * 哪個工廠提供。 * * @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 測試程序

 

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);
  
  
 }
}