【工厂模式】抽象工厂

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问题

一个对象的创建，依赖于多个不同的工厂方法，如何使这个对象的创建更容易呢？

工厂方法

将多个工厂方法组合在一起，作为一个抽象工厂

Demo

背景&&需求

根据用户年龄，决定玩儿童游戏（青蛙吃虫子），还是成人游戏（巫师对抗怪物）

代码

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

    def interact_with(self, obstacle):
        act = obstacle.action()
        msg = f'{self} the Frog encounters {obstacle} and {act}!'
        print(msg)
    
class Bug:
    def __str__(self):
        return 'a bug'
    
    def action(self):
        return 'eats it'

# 抽象工厂（创建青蛙、虫子）
class FrogWorld:
    def __init__(self, name):
        print(self)
        self.player_name = name
    
    def __str__(self):
        return '------ Frog World ------'

    # 工厂方法
    def make_character(self):
        return Frog(self.player_name)

    # 工厂方法
    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):
        act = obstacle.action()
        msg = f'{self} the Wizard battles against {obstacle} and {act}!'
        print(msg)

class Ork:
    def __str__(self):
        return 'an evil ork'
    
    def action(self):
        return 'kills it'


# 抽象工厂（创建巫师、怪物）
class WizardWorld:
    def __init__(self, name):
        print(self)
        self.player_name = name
    
    def __str__(self):
        return '------ Wizard World ------'

    # 工厂方法
    def make_character(self):
        return Wizard(self.player_name)

    # 工厂方法
    def make_obstacle(self):
        return Ork()


class Game:
    def __init__(self, factory):
        self.hero = factory.make_character()
        self.obstacle = factory.make_obstacle()
    
    def play(self):
        self.hero.interact_with(self.obstacle)

if __name__=="__main__":
    name = 'user'
    age = int(input('please input age: '))
    game = age < 18 and FrogWorld or WizardWorld
    Game(game(name)).play()

输出

please input age: 18
—— Wizard World ——
user the Wizard battles against an evil ork and kills it!

please input age: 10
—— Frog World ——
user the Frog encounters a bug and eats it!