Python: Decorator Pattern

 

DuDecorator.py

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# 装饰模式 Decorator  Pattern import six  # https://pypi.org/project/six/ from abc import ABCMeta     @six.add_metaclass(ABCMeta) class Abstract_Coffee(object):       def get_cost(self):         pass       def get_ingredients(self):         pass       def get_tax(self):         return 0.1 * self.get_cost()     class Concrete_Coffee(Abstract_Coffee):       def get_cost(self):         return 1.00       def get_ingredients(self):         return '咖啡'     @six.add_metaclass(ABCMeta) class Abstract_Coffee_Decorator(Abstract_Coffee):       def __init__(self, decorated_coffee):         self.decorated_coffee = decorated_coffee       def get_cost(self):         return self.decorated_coffee.get_cost()       def get_ingredients(self):         return self.decorated_coffee.get_ingredients()     class Sugar(Abstract_Coffee_Decorator):       def __init__(self, decorated_coffee):         Abstract_Coffee_Decorator.__init__(self, decorated_coffee)       def get_cost(self):         return self.decorated_coffee.get_cost()       def get_ingredients(self):         return self.decorated_coffee.get_ingredients() + ', 糖果'     class Milk(Abstract_Coffee_Decorator):       def __init__(self, decorated_coffee):         Abstract_Coffee_Decorator.__init__(self, decorated_coffee)       def get_cost(self):         return self.decorated_coffee.get_cost() + 0.25       def get_ingredients(self):         return self.decorated_coffee.get_ingredients() + ', 牛奶'     class Vanilla(Abstract_Coffee_Decorator):       def __init__(self, decorated_coffee):         Abstract_Coffee_Decorator.__init__(self, decorated_coffee)       def get_cost(self):         return self.decorated_coffee.get_cost() + 0.75       def get_ingredients(self):         return self.decorated_coffee.get_ingredients() + ', 香草'

　　

main.py

调用：

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# 装饰模式 Decorator  Pattern myCoffee = DuDecorator.Concrete_Coffee() print('Geovin Du买材料: '+myCoffee.get_ingredients()+    '; geovindu付费用: '+str(myCoffee.get_cost())+'; 涂聚文交营业税 = '+str(myCoffee.get_tax()))   myCoffee = DuDecorator.Milk(myCoffee) print('Geovin Du买材料: '+myCoffee.get_ingredients()+    '; geovindu付费用: '+str(myCoffee.get_cost())+'; 涂聚文交营业税 = '+str(myCoffee.get_tax()))   myCoffee = DuDecorator.Vanilla(myCoffee) print('Geovin Du买材料: '+myCoffee.get_ingredients()+    '; geovindu付费用: '+str(myCoffee.get_cost())+'; 涂聚文交营业税 = '+str(myCoffee.get_tax()))   myCoffee = DuDecorator.Sugar(myCoffee) print('Geovin Du买材料: '+myCoffee.get_ingredients()+    '; geovindu付费用: '+str(myCoffee.get_cost())+'; 涂聚文交营业税 = '+str(myCoffee.get_tax()))

　　

输出：

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Geovin Du买材料: 咖啡; geovindu付费用: 1.0; 涂聚文交营业税 = 0.1 Geovin Du买材料: 咖啡, 牛奶; geovindu付费用: 1.25; 涂聚文交营业税 = 0.125 Geovin Du买材料: 咖啡, 牛奶, 香草; geovindu付费用: 2.0; 涂聚文交营业税 = 0.2 Geovin Du买材料: 咖啡, 牛奶, 香草, 糖果; geovindu付费用: 2.0; 涂聚文交营业税 = 0.2