常用設計模式總結--抽象工廠

Abstract Factory ，抽象工廠

抽象工廠是一種創建型方法，所謂工廠，顧名思義就是一個車間，裏面生產各種各樣的組件，既然是抽象的，對應到代碼裏面，就是定義一些抽象的方法，然後在集體的工廠裏面實現。

用傳統的製造業來舉例比較恰當，比如汽車製造業，現在的汽車製造業都已經集團化了，每家汽車製造商都有好多工廠，每個工廠用來生產某幾個具體型號的轎車。站在集團的角度，每個工廠都生產引擎，輪胎，然後拼裝成整車。

從軟件的角度抽象，引擎、輪胎都有統一的父類 element, 而每個工廠也有着統一的父類 VehicleFactory.

類圖如下

 

 

 

來看具體的源代碼

 

1 Element.java

package zl.study.designpattern.abstfactory; public interface Element { }

2 Engine.java

package zl.study.designpattern.abstfactory; public class Engine implements Element { public static int NORMAL_ENGINE = 180; public static int RACE_ENGINE = 400; /* 引擎的馬力*/ public int power ; public Engine(int power){ this.power = power; } }

2.1 NormalEngine.java

package zl.study.designpattern.abstfactory; public class NormalEngine extends Engine{ public NormalEngine(){ super(NORMAL_ENGINE); } }

2.2 RaceEngine.java

package zl.study.designpattern.abstfactory; public class RaceEngine extends Engine{ public RaceEngine(){ super(RACE_ENGINE); } }

3 Wheel.java

package zl.study.designpattern.abstfactory; public class Wheel { public static int NORMAL_WHEEL = 15; public static int RACE_WHEEL = 20; public int width; public Wheel(int width){ this.width = width; } }

3.1 NormalWheel.java

package zl.study.designpattern.abstfactory; public class NormalWheel extends Wheel{ public NormalWheel(){ super(NORMAL_WHEEL); } } 

3.2 RaceWheel.java

package zl.study.designpattern.abstfactory; public class RaceWheel extends Wheel{ public RaceWheel(){ super(RACE_WHEEL); } }

 

4 Vehicle.java

package zl.study.designpattern.abstfactory; import java.util.LinkedList; import java.util.List; public abstract class Vehicle { public Engine engine; public List<Wheel> wheels; public void setEngine( Engine engine){ this.engine = engine; } public Engine getEngine(){ return this.engine; } public void addWheel(Wheel wheel){ if( null == wheels){ wheels = new LinkedList<Wheel>(); } wheels.add(wheel); } }

4.1 NormalVehicle.java

package zl.study.designpattern.abstfactory; /** * 最終產品：普通交通工具 * @author peter * */ public class NormalVehicle extends Vehicle{ public String toString(){ return new String("this is normal car!"); } }

4.2 RaceVehicle.java

package zl.study.designpattern.abstfactory; /** * 最終產品：高性能交通工具 * @author peter * */ public class RaceVehicle extends Vehicle{ public String toString(){ return new String("this is race car"); } }

5 VehicleFactory.java

package zl.study.designpattern.abstfactory; public interface VehicleFactory { public Vehicle makeVehicle(); public Wheel makeWheel(); public Engine makeEngine(); }

5.1 NormalVehicleFactory.java

package zl.study.designpattern.abstfactory; /** * 生產普通交通工具的工廠 * @author peter * */ public class NormalVehicleFactory implements VehicleFactory{ @Override public Vehicle makeVehicle() { return new NormalVehicle(); } @Override public Engine makeEngine() { return new NormalEngine(); } @Override public Wheel makeWheel() { return new NormalWheel(); } }

5.2 RaceVehicleFactory.java

package zl.study.designpattern.abstfactory; /** * 生產高性能交通工具的工廠 * @author peter * */ public class RaceVehicleFactory implements VehicleFactory{ @Override public Vehicle makeVehicle() { // TODO Auto-generated method stub return new RaceVehicle(); } @Override public Engine makeEngine() { return new RaceEngine(); } @Override public Wheel makeWheel() { return new RaceWheel(); } }

 

6 測試程序

 

package zl.study.designpattern.abstfactory.test; import zl.study.designpattern.abstfactory.Engine; import zl.study.designpattern.abstfactory.NormalVehicleFactory; import zl.study.designpattern.abstfactory.RaceVehicleFactory; import zl.study.designpattern.abstfactory.Vehicle; import zl.study.designpattern.abstfactory.VehicleFactory; import zl.study.designpattern.abstfactory.Wheel; public class AbstFactoryTest { public static void main(String args[]){ VehicleFactory normalFactory = new NormalVehicleFactory(); Vehicle normalCar = normalFactory.makeVehicle(); Wheel wheel1 = normalFactory.makeWheel(); Wheel wheel2 = normalFactory.makeWheel(); Wheel wheel3 = normalFactory.makeWheel(); Wheel wheel4 = normalFactory.makeWheel(); Engine engine = normalFactory.makeEngine(); /** * 向外暴露了生產汽車的細節 */ normalCar.setEngine(engine); normalCar.addWheel(wheel1); normalCar.addWheel(wheel2); normalCar.addWheel(wheel3); normalCar.addWheel(wheel4); System.out.println(normalCar); } }