Java抽象工厂模式

1. 基本定义

   抽象工厂模式是所有形态的工厂模式中最为抽
   象和最其一般性的。抽象工厂模式可以向客户端
   提供一个接口，使得客户端在不必指定产品的具
   体类型的情况下，能够创建多个产品族的产品对
   象。

2. 编写具体代码以及测试类

   package abstractFactory;
   
   public abstract class Apple implements Fruit {
   
       public abstract void get();
   
   }
   
   package abstractFactory;
   
   public abstract class Banana implements Fruit {
   
       public abstract void get();
   
   }
   
   package abstractFactory;
   
   public interface Fruit {
   
       public void get();
   
   }
   
   package abstractFactory;
   
   public interface FruitFactory {
   
       //实例化Apple
   
       public Fruit getApple();
   
       //实例化Banana
   
       public Fruit getBanana();
   
   }
   
   package abstractFactory;
   
   public class InnerApple extends Apple {
   
       @Override
   
       public void get() {
   
           System.out.println("长在室内的苹果");
   
       }
   
   }
   
   package abstractFactory;
   
   public class InnerBanana extends Banana {
   
       @Override
   
       public void get() {
   
           System.out.println("长在室内的香蕉");
   
       }
   
   }
   
   package abstractFactory;
   
   public class InnerFruitFactory implements FruitFactory {
   
       @Override
   
       public Fruit getApple() {
   
           return new InnerApple();
   
       }
   
       @Override
   
       public Fruit getBanana() {
   
           return new InnerBanana();
   
       }
   
   }
   
   package abstractFactory;
   
   public class NorthApple extends Apple {
   
       @Override
   
       public void get() {
   
           System.out.println("长在北方的苹果");
   
       }
   
   }
   
   package abstractFactory;
   
   public class NorthBanana extends Banana {
   
       @Override
   
       public void get() {
   
           System.out.println("长在北方的香蕉");
   
       }
   
   }
   
   package abstractFactory;
   
   public class NorthFruitFactory implements FruitFactory {
   
       @Override
   
       public Fruit getApple() {
   
           return new NorthApple();
   
       }
   
       @Override
   
       public Fruit getBanana() {
   
           return new NorthBanana();
   
       }
   
   }
   
   package abstractFactory;
   
   public class SouthApple extends Apple {
   
       @Override
   
       public void get() {
   
           System.out.println("长在南方的苹果");
   
       }
   
   }
   
   package abstractFactory;
   
   public class SouthBanana extends Banana {
   
       @Override
   
       public void get() {
   
           System.out.println("长在南方的香蕉");
   
       }
   
   }
   
   package abstractFactory;
   
   public class SouthFruitFactory implements FruitFactory {
   
       @Override
   
       public Fruit getApple() {
   
           return new SouthApple();
   
       }
   
       @Override
   
       public Fruit getBanana() {
   
           return new SouthBanana();
   
       }
   
   }
   
   //测试类
   
   package abstractFactory;
   
   public class MainClass {
   
       public static void main(String[] args) {
   
           FruitFactory ff = new NorthFruitFactory();
   
           Fruit apple = ff.getApple();
   
           apple.get();
   
           Fruit banana = ff.getBanana();
   
           banana.get();
   
           System.out.println("~~~~~~~~~~~~~~~~~~~~");
   
           FruitFactory bb = new SouthFruitFactory();
   
           Fruit apple2 = bb.getApple();
   
           apple2.get();
   
           Fruit banana2 = bb.getBanana();
   
           banana2.get();
   
           System.out.println("~~~~~~~~~~~~~~~~~~~~");
   
           //比如要增加室内innerApple,InnerBanana
   
           FruitFactory cc = new InnerFruitFactory();
   
           Fruit apple3 = cc.getApple();
   
           apple3.get();
   
           Fruit banana3 = cc.getBanana();
   
           banana3.get();
   
       }
   
   }

3. 模式中包含的角色及其职责

   1.抽象工厂（Creator）角色
   抽象工厂模式的核心，包含对多个产品结构的声明，任何工厂类都必须实现这个接口。(FruitFactory)

   2.具体工厂（ Concrete Creator）角色
   具体工厂类是抽象工厂的一个实现，负责实例化某个产品族中的产品对象。(InnerFruitFactory,NorthFruitFactory,SouthFruitFactory)

   3.抽象（Product）角色
   抽象模式所创建的所有对象的父类，它负责描述所有实例所共有的公共接口。(Fruit)

   4.具体产品（Concrete Product）角色
   抽象模式所创建的具体实例对象(NorthApple,NorthBanana,SouthApple,SouthBanana,InnerBanana,InnerFruitFactory)
   总结：抽象工厂中方法对应产品结构，具体工厂对应产品族。

4. 具体和前面两节模式相比较图形，我整理出来如下图所示：