Java抽象工廠模式

Java抽象工廠模式

1. 基本定義
   

   抽象工廠模式是所有形態的工廠模式中最為抽
   象和最其一般性的。抽象工廠模式可以向客戶端
   提供一個接口，使得客戶端在不必指定產品的具
   體類型的情況下，能夠創建多個產品族的產品對
   象。

2. 編寫具體代碼以及測試類
   

   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 {
       //實例化Apple
       public Fruit getApple();
   
       //實例化Banana
       public Fruit getBanana();
   }
   
   package abstractFactory;
   
   public class InnerApple extends Apple {
       @Override
       public void get() {
           System.out.println("長在室內的蘋果");
       }
   }
   
   package abstractFactory;
   
   public class InnerBanana extends Banana {
       @Override
       public void get() {
           System.out.println("長在室內的香蕉");
       }
   }
   
   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("長在北方的蘋果");
       }
   }
   
   package abstractFactory;
   
   public class NorthBanana extends Banana {
       @Override
       public void get() {
           System.out.println("長在北方的香蕉");
       }
   }
   
   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("長在南方的蘋果");
       }
   }
   
   package abstractFactory;
   
   public class SouthBanana extends Banana {
       @Override
       public void get() {
           System.out.println("長在南方的香蕉");
       }
   }
   
   package abstractFactory;
   
   public class SouthFruitFactory implements FruitFactory {
       @Override
       public Fruit getApple() {
           return new SouthApple();
       }
   
       @Override
       public Fruit getBanana() {
           return new SouthBanana();
       }
   }
   
   //測試類
   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("~~~~~~~~~~~~~~~~~~~~");
           //比如要增加室內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職責

   1.抽象工廠（Creator）角色
   抽象工廠模式的核心，包含對多個產品結構的聲明，任何工廠類都必須實現這個接口。(FruitFactory)

   2.具體工廠（ Concrete Creator）角色
   具體工廠類是抽象工廠的一個實現，負責實例化某個產品族中的產品對象。(InnerFruitFactory,NorthFruitFactory,SouthFruitFactory)

   3.抽象（Product）角色
   抽象模式所創建的所有對象的父類，它負責描述所有實例所共有的公共接口。(Fruit)

   4.具體產品（Concrete Product）角色
   抽象模式所創建的具體實例對象(NorthApple,NorthBanana,SouthApple,SouthBanana,InnerBanana,InnerFruitFactory)
   總結：抽象工廠中方法對應產品結構，具體工廠對應產品族。

4. 具體和前面兩節模式相比較圖形，我整理出來如下圖所示：