Python: Decorator Pattern

DuDecorator.py

# 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：

# 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：

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