strategy_pattern.py

#!/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)