//: C10:AbstractFactory.cpp
// From "Thinking in C++, Volume 2", by Bruce Eckel & Chuck Allison.
// (c) 1995-2004 MindView, Inc. All Rights Reserved.
// See source code use permissions stated in the file 'License.txt',
// distributed with the code package available at www.MindView.net.
// A gaming environment.
#include <iostream>
using namespace std;

class Obstacle {
public:
  virtual void action() = 0;
};

class Player {
public:
  virtual void interactWith(Obstacle*) = 0;
};

class Kitty: public Player {
  virtual void interactWith(Obstacle* ob) {
    cout << "Kitty has encountered a ";
    ob->action();
  }
};

class KungFuGuy: public Player {
  virtual void interactWith(Obstacle* ob) {
    cout << "KungFuGuy now battles against a ";
    ob->action();
  }
};

class Puzzle: public Obstacle {
public:
  void action() { cout << "Puzzle" << endl; }
};

class NastyWeapon: public Obstacle {
public:
  void action() { cout << "NastyWeapon" << endl; }
};

// The abstract factory:
class GameElementFactory {
public:
  virtual Player* makePlayer() = 0;
  virtual Obstacle* makeObstacle() = 0;
};

// Concrete factories:
class KittiesAndPuzzles : public GameElementFactory {
public:
  virtual Player* makePlayer() { return new Kitty; }
  virtual Obstacle* makeObstacle() { return new Puzzle; }
};

class KillAndDismember : public GameElementFactory {
public:
  virtual Player* makePlayer() { return new KungFuGuy; }
  virtual Obstacle* makeObstacle() {
    return new NastyWeapon;
  }
};

class GameEnvironment {
  GameElementFactory* gef;
  Player* p;
  Obstacle* ob;
public:
  GameEnvironment(GameElementFactory* factory)
  : gef(factory), p(factory->makePlayer()),
    ob(factory->makeObstacle()) {}
  void play() { p->interactWith(ob); }
  ~GameEnvironment() {
    delete p;
    delete ob;
    delete gef;
  }
};

int main() {
  GameEnvironment
    g1(new KittiesAndPuzzles),
    g2(new KillAndDismember);
  g1.play();
  g2.play();
}
/* Output:
Kitty has encountered a Puzzle
KungFuGuy now battles against a NastyWeapon */ ///:~