Python设计模式之策略模式实例详解

 #!/usr/bin/env python # -*- coding:utf-8 -*- __author__ = 'Andy' ''' 大话设计模式 设计模式――策略模式 策略模式(strategy):它定义了算法家族,分别封装起来,让他们之间可以相互替换,此模式让算法的变化,不会影响到使用算法的客户 ''' #现金收费抽象类 class CashSuper(object): def accept_cash(self,money): pass #正常收费子类 class CashNormal(CashSuper): def accept_cash(self,money): return money #打折收费子类 class CashRebate(CashSuper): def __init__(self,discount=1): self.discount = discount def accept_cash(self,money): return money * self.discount #返利收费子类 class CashReturn(CashSuper): def __init__(self,money_condition=0,money_return=0): self.money_condition = money_condition self.money_return = money_return def accept_cash(self,money): if money>=self.money_condition: return money - (money / self.money_condition) * self.money_return return money #具体策略类 class Context(object): def __init__(self,csuper): self.csuper = csuper def GetResult(self,money): return self.csuper.accept_cash(money) if __name__ == '__main__': money = input("原价: ") strategy = {} strategy[1] = Context(CashNormal()) strategy[2] = Context(CashRebate(0.8)) strategy[3] = Context(CashReturn(100,10)) mode = input("选择折扣方式: 1) 原价 2) 8折 3) 满100减10: ") if mode in strategy: csuper = strategy[mode] else: print "不存在的折扣方式" csuper = strategy[1] print "需要支付: ",csuper.GetResult(money)