//如果不适应工厂模式,你的代码就必须在某处指定将要创建的service的确切类型,以便调用合适的构造器
//: interfaces/Factories.java

package object;

import static net.mindview.util.Print.*;

interface Service {

  void method1();

  void method2();

}

interface ServiceFactory {

  Service getService();

}

class Implementation1 implements Service {

  Implementation1() {} // Package access

  public void method1() {print("Implementation1 method1");}

  public void method2() {print("Implementation1 method2");}

}    

class Implementation1Factory implements ServiceFactory {

  public Service getService() {

    return new Implementation1();

  }

}

class Implementation2 implements Service {

  Implementation2() {} // Package access

  public void method1() {print("Implementation2 method1");}

  public void method2() {print("Implementation2 method2");}

}

class Implementation2Factory implements ServiceFactory {

  public Service getService() {

    return new Implementation2();

  }

}    

public class Factories {

  public static void serviceConsumer(ServiceFactory fact) {

    Service s = fact.getService();

    s.method1();

    s.method2();

  }

  public static void main(String[] args) {

    serviceConsumer(new Implementation1Factory());

    // Implementations are completely interchangeable:

    serviceConsumer(new Implementation2Factory());

  }

} /* Output:

Implementation1 method1

Implementation1 method2

Implementation2 method1

Implementation2 method2

*///:~

//如果Games 是一段复杂的代码,那么这种方式就允许你在不同类型的游戏中复用这段代码
//: interfaces/Games.java

// A Game framework using Factory Methods.

package object;

import static net.mindview.util.Print.*;

interface Game { boolean move(); }

interface GameFactory { Game getGame(); }

class Checkers implements Game {

  private int moves = 0;

  private static final int MOVES = 3;

  public boolean move() {

    print("Checkers move " + moves);

    return ++moves != MOVES;

  }

}

class CheckersFactory implements GameFactory {

  public Game getGame() { return new Checkers(); }

}    

class Chess implements Game {

  private int moves = 0;

  private static final int MOVES = 4;

  public boolean move() {

    print("Chess move " + moves);

    return ++moves != MOVES;

  }

}

class ChessFactory implements GameFactory {

  public Game getGame() { return new Chess(); }

}    

public class Games {

  public static void playGame(GameFactory factory) {

    Game s = factory.getGame();

    while(s.move())

      ;

  }

  public static void main(String[] args) {

    playGame(new CheckersFactory());

    playGame(new ChessFactory());

  }

} /* Output:

Checkers move 0

Checkers move 1

Checkers move 2

Chess move 0

Chess move 1

Chess move 2

Chess move 3

*///:~