這種工廠模式用得少，

可能在遊戲類的編程中用得比較多吧。

這個思路清晰一定要OK的。

class Frog:
    def __init__(self, name):
        self.name = name

    def __str__(self):
        return self.name

    def interact_with(self, obstacle):
        print(‘{} the Frog encouners {} and {}!‘.format(self,
                                                        obstacle,
                                                        obstacle.action()))

 
class Bug:
    def __str__(self):
        return ‘a bug‘

    def action(self):
        return ‘eats it‘

class FrogWorld:
    def __init__(self, name):
        print(self)
        self.player_name =name

    def __str__(self):
        return ‘\n\n\t-------- Frog World ------‘

    def
 
 make_character(self):
        return Frog(self.player_name)

    def make_obstacle(self):
        return Bug()

class Wizard:
    def __init__(self, name):
        self.name = name

    def __str__(self):
        return self.name

    def interact_with(self, obstacle):
        print(‘
 
{} the Wizard battles against {} and {}!‘.format(self,
                                                                obstacle,
                                                                obstacle.action()))

class Ork:
    def __str__(self):
        return ‘an evil ork‘

    def action(self):
        return ‘kills it‘

class WizardWorld:
    def __init__(self, name):
        print(self)
        self.player_name = name

    def __str__(self):
        return ‘\n\n\t-------- Wizard World ------‘

    def make_character(self):
        return Wizard(self.player_name)

    def make_obstacle(self):
        return Ork()

class GameEnvironment:
    def __init__(self, factory):
        self.hero = factory.make_character()
        self.obstacle = factory.make_obstacle()

    def play(self):
        self.hero.interact_with(self.obstacle)


def validate_age(name):
    try:
        age = input(‘Welcome {}. How old are you? ‘.format(name))
        age = int(age)
    except ValueError as err:
        print(‘Age {} is invalid, please try again...‘.format(age))
        return (False, age)
    return (True, age)

def main():
    name = input("Hello. What‘s your name? ")
    valid_input = False
    while not valid_input:
        valid_input, age = validate_age(name)
    game = FrogWorld if age < 18 else WizardWorld
    environment = GameEnvironment(game(name))
    environment.play()

if __name__ == ‘__main__‘:
    main()

    

《精通Python設計模式》學習之抽象工廠