装饰者模式
定义
项目：星巴兹饮料
类图
部分实现代码
python
from abc import ABC, abstractmethod
class Beverage(ABC):
"""饮料"""
description = "Unknown Beverage"
def get_description(self):
return self.description
@abstractmethod
def cost(self) -> float: # python中无需区分double和float
pass
class CondimentDecorator(Beverage):
"""调料"""
@abstractmethod
def get_description(self):
pass
python
class Espresso(Beverage):
"""浓缩咖啡"""
def get_description(self) -> str:
return "浓缩咖啡"
def cost(self) -> float:
return 1.99
class HouseBlend(Beverage):
"""家常咖啡"""
def get_description(self) -> str:
return "家常咖啡"
def cost(self) -> float:
return 0.89
python
class Mocha(CondimentDecorator):
"""摩卡"""
def __init__(self, beverage:Beverage):
self.beverage = beverage
def get_description(self) -> str:
return self.beverage.get_description() + ', 摩卡'
def cost(self) -> float:
return self.beverage.cost() + 0.2完整代码
python
from abc import ABC, abstractmethod
class Beverage(ABC):
"""饮料"""
description = "Unknown Beverage"
def get_description(self) -> str:
return self.description
@abstractmethod
def cost(self) -> float: # python中无需区分double和float
pass
class CondimentDecorator(Beverage):
"""调料"""
@abstractmethod
def get_description(self) -> str:
pass
class Espresso(Beverage):
"""浓缩咖啡"""
def get_description(self) -> str:
return "浓缩咖啡"
def cost(self) -> float:
return 1.99
class HouseBlend(Beverage):
"""综合咖啡"""
def get_description(self) -> str:
return "综合咖啡"
def cost(self) -> float:
return 0.89
class DarkRoast(Beverage):
"""深焙咖啡"""
def get_description(self) -> str:
return "深焙咖啡"
def cost(self) -> float:
return 0.99
class Decaf(Beverage):
"""低咖啡因"""
def get_description(self) -> str:
return "低咖啡因"
def cost(self) -> float:
return 1.05
class Mocha(CondimentDecorator):
"""摩卡"""
def __init__(self, beverage: Beverage):
self.beverage = beverage
def get_description(self) -> str:
return self.beverage.get_description() + '+摩卡'
def cost(self) -> float:
return self.beverage.cost() + 0.2
class Soy(CondimentDecorator):
"""豆浆"""
def __init__(self, beverage: Beverage):
self.beverage = beverage
def get_description(self) -> str:
return self.beverage.get_description() + '+豆浆'
def cost(self) -> float:
return self.beverage.cost() + 0.15
class Whip(CondimentDecorator):
"""奶泡"""
def __init__(self, beverage: Beverage):
self.beverage = beverage
def get_description(self) -> str:
return self.beverage.get_description() + '+奶泡'
def cost(self) -> float:
return self.beverage.cost() + 0.1
class Milk(CondimentDecorator):
"""牛奶"""
def __init__(self, beverage: Beverage):
self.beverage = beverage
def get_description(self) -> str:
return self.beverage.get_description() + '+牛奶'
def cost(self) -> float:
return self.beverage.cost() + 0.1
if __name__ == '__main__':
beverage = Espresso()
print(f"{beverage.get_description()}：${beverage.cost()}")
beverage2 = DarkRoast()
beverage2 = Mocha(beverage2)
beverage2 = Mocha(beverage2)
beverage2 = Whip(beverage2)
print(f"{beverage2.get_description()}：${beverage2.cost()}")
beverage3 = HouseBlend()
beverage3 = Soy(beverage3)
beverage3 = Mocha(beverage3)
beverage3 = Whip(beverage3)
print(f"{beverage3.get_description()}：${beverage3.cost()}")
"""运行结果：
浓缩咖啡：$1.99
深焙咖啡+摩卡+摩卡+奶泡：$1.49
综合咖啡+豆浆+摩卡+奶泡：$1.34
"""总结
