二、Python 设计模式之抽象工厂

设计模式之抽象工厂

例子的内容：

两个游戏： 1.青蛙世界 2.巫妖世界

每个游戏由三个类组成 主人公 敌人 游戏世界创建

用户启动的时候，输入主人公英雄名字 和 年龄

程序会根据年龄来判断，启动具体的哪一个游戏

class Frog:

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

    def __str__(self):
        return self.name

    def interact_with(self, obstacle):
        print('{} the Frog encounters {} 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()