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)