# -*- coding: utf-8 -*-
class IMath:
"""Интерфейс для прокси и реального субъекта"""
def add(self, x, y):
raise NotImplementedError()
def sub(self, x, y):
raise NotImplementedError()
def mul(self, x, y):
raise NotImplementedError()
def div(self, x, y):
raise NotImplementedError()
class Math(IMath):
"""Реальный субъект"""
def add(self, x, y):
return x + y
def sub(self, x, y):
return x - y
def mul(self, x, y):
return x * y
def div(self, x, y):
return x / y
class Proxy(IMath):
"""Прокси"""
def __init__(self):
self.math = Math()
def add(self, x, y):
return x + y
def sub(self, x, y):
return x - y
def mul(self, x, y):
return self.math.mul(x, y)
def div(self, x, y):
return float('inf') if y == 0 else self.math.div(x, y)
p = Proxy()
x, y = 4, 2
print '4 + 2 = ' + str(p.add(x, y))
print '4 - 2 = ' + str(p.sub(x, y))
print '4 * 2 = ' + str(p.mul(x, y))
print '4 / 2 = ' + str(p.div(x, y))
