工厂模式的意图:
定义一个用户创建对象的接口,让子类决定实例化哪一个类。Factory Method使一个类的实例化延迟到其子类。
结构图:
场景:
这里制造两个手机product:Nokia、Motorola,为了制造这两个Product需要使用两个Creator(Factory)来制造它们。这两个Creator都有各自的Concreator(类似生产线)。这两个手机都实现必须实现两个最基本的功能:call(打电话)、photo(拍照)。
product:
/// <summary> /// Product /// </summary> public abstract class Mobilephone { public abstract void Call(); public abstract void Photo(); }
/// <summary> /// Creator /// </summary> public interface IMobilephoneFactory { Mobilephone CreateMobilephone(); }
/// <summary> /// ConcreateCreator:NokiaFactory /// </summary> public class NokiaFactory:IMobilephoneFactory { public Mobilephone CreateMobilephone() { return new Nokia(); } }
/// <summary> /// ConcreateCreator:MotorolaFactory /// </summary> public class MotorolaFactory:IMobilephoneFactory { public Mobilephone CreateMobilephone() { return new Motorola(); } }
/// <summary> /// Product:Nokia /// </summary> public class Nokia : Mobilephone { public override void Call() { Console.WriteLine("The Nokia's call function"); } public override void Photo() { Console.WriteLine("The Nokia's Photo function"); } }
/// <summary> /// Product:Motorola /// </summary> public class Motorola:Mobilephone { public override void Call() { Console.WriteLine("The motorola's call function"); } public override void Photo() { Console.WriteLine("The motorola's Photo function"); } }
static void Main(string[] args) { IMobilephoneFactory factory = new MotorolaFactory(); //create Motorola Mobilephone mobilePhone = factory.CreateMobilephone(); mobilePhone.Call(); mobilePhone.Photo(); factory = new NokiaFactory(); mobilePhone = factory.CreateMobilephone(); mobilePhone.Call(); mobilePhone.Photo(); Console.Read(); }
然后,我们使用了产品的功能:
可以看到,我们实现了我们的意图:定义一个用户创建对象的接口(IMobilephoneFactory ),让子类决定实例化哪一个类。Factory Method使一个类的实例化延迟到其子类。
好了,以上就是Factory Method partten的一个简要实现(这个不是重点)。我们看到了要实现这样一个模式,需要大概做哪些事情。
那么,有没有稍微优雅点的实现方式呢。其实,在Java中,使用匿名类,可以有更简便的做法:
product:
/* * product:Mobilephone */ public abstract class Mobilephone { public abstract void call(); public abstract void photo(); }
/* * Creator */ public interface IMobilephoneFactory { Mobilephone CreateMobilephone(); }
public class Nokia extends Mobilephone { @Override public void call() { System.out.println("The Nokia's call function"); } @Override public void photo() { System.out.println("The Nokia's Photo function"); } private Nokia(){} public static IMobilephoneFactory factory= new IMobilephoneFactory() { @Override public Mobilephone CreateMobilephone() { return new Nokia(); } }; }
public class Motorola extends Mobilephone { @Override public void call() { System.out.println("The Motorola's call function"); } @Override public void photo() { System.out.println("The Motorola's Photo function"); } private Motorola(){} public static IMobilephoneFactory factory = new IMobilephoneFactory() { @Override public Mobilephone CreateMobilephone() { return new Motorola(); } }; }
下面看一下,我们怎么对外提供服务呢?
public static void mobileMaker(IMobilephoneFactory factory) { Mobilephone mobilephone=factory.CreateMobilephone(); mobilephone.call(); mobilephone.photo(); }
public static void mobileServiceWith(IMobilephoneFactory factory) { Mobilephone mobilephone=factory.CreateMobilephone(); mobilephone.call(); mobilephone.photo(); }
/** * @param args */ public static void main(String[] args) { System.out.println("nokia factory to make nokia and service:"); //make nokia mobileServiceWith(Nokia.factory); System.out.println(); System.out.println("motorola factory to make motorola and service:"); //make motorola mobileMaker(Motorola.factory); }
调用结果: