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)