实例解析Python设计模式编程之桥接模式的运用_Python

我们先来看一个例子：

				?

									#encoding=utf-8 

									# 

									#by panda 

									#桥接模式 

									def printInfo(info): 

									  print unicode(info, 'utf-8').encode('gbk') 

									#抽象类：手机品牌 

									class HandsetBrand(): 

									  soft = None

									  def SetHandsetSoft(self, soft): 

									    self.soft = soft 

									  def Run(self): 

									    pass

									#具体抽象类：手机品牌1 

									class HandsetBrand1(HandsetBrand): 

									  def Run(self): 

									    printInfo('手机品牌1:') 

									    self.soft.Run() 

									#具体抽象类：手机品牌2 

									class HandsetBrand2(HandsetBrand): 

									  def Run(self): 

									    printInfo('手机品牌2:') 

									    self.soft.Run() 

									#功能类：手机软件 

									class HandsetSoft(): 

									  def Run(self): 

									    pass

									#具体功能类：游戏   

									class HandsetGame(HandsetSoft): 

									  def Run(self): 

									    printInfo('运行手机游戏') 

									#具体功能类：通讯录   

									class HandsetAddressList(HandsetSoft): 

									  def Run(self): 

									    printInfo('运行手机通信录') 

									def clientUI(): 

									  h1 = HandsetBrand1() 

									  h1.SetHandsetSoft(HandsetAddressList()) 

									  h1.Run() 

									  h1.SetHandsetSoft(HandsetGame()) 

									  h1.Run() 

									  h2 = HandsetBrand2() 

									  h2.SetHandsetSoft(HandsetAddressList()) 

									  h2.Run() 

									  h2.SetHandsetSoft(HandsetGame()) 

									  h2.Run()   

									  return

									if __name__ == '__main__': 

									  clientUI();

可以总结出类图是这样的：

实例解析Python设计模式编程之桥接模式的运用

所以，桥接模式的概念在于将系统抽象部分与它的实现部分分离，使它们可以独立地变化。
由于目标系统存在多个角度的分类，每一种分类都会有多种变化，那么就可以把多角度分离出来，让它们独立变化，减少它们之间的耦合。

下面我们再来看一个实例：

基本原理请参考相关书籍，这里直接给实例

假期旅游从目的地角度可以分为上海和大连，从方式角度可以分为跟团和独体

桥接模式把这两种分类连接起来可以进行选择。

类图：

实例解析Python设计模式编程之桥接模式的运用

				?

									# -*- coding: utf-8 -*-

									#######################################################

									# 

									# tour.py

									# Python implementation of the Class DaLian

									# Generated by Enterprise Architect

									# Created on:   11-十二月-2012 16:53:52

									# 

									#######################################################

									from __future__ import division

									from __future__ import print_function

									from __future__ import unicode_literals

									from future_builtins import *

									class TravelForm(object):

									  """This class defines the interface for implementation classes.

									  """

									  def __init__(self, form="stay at home"):

									    self.form=form

									    pass

									  def GetForm(self):

									    return self.form

									    pass

									  pass

									class Group(TravelForm):

									  """This class implements the Implementor interface and defines its concrete

									  implementation.

									  """

									  def __init__(self, form="by group"):

									    super(Group,self).__init__(form)    

									    pass

									  pass

									class Independent(TravelForm):

									  """This class implements the Implementor interface and defines its concrete

									  implementation.

									  """

									  def __init__(self, form="by myself"):

									    super(Independent,self).__init__(form)

									    pass

									class Destination(object):

									  """This class (a) defines the abstraction's interface, and (b) maintains a

									  reference to an object of type Implementor.

									  """

									  m_TravelForm= TravelForm()

									  def __init__(self, info):

									    self.info=info

									    pass

									  def GetInfo(self):

									    # imp->Operation();

									    return print(self.info + " " +self.form.GetForm())

									    pass

									  def SetForm(self, form):

									    self.form=form

									    pass

									class DaLian(Destination):

									  """This class extends the interface defined by Abstraction.

									  """

									  def __init__(self, info="Go to DaLian "):

									    super(DaLian,self).__init__(info)

									    pass

									class ShangHai(Destination):

									  """This class extends the interface defined by Abstraction.

									  """

									  def __init__(self, info="Go to ShangHai"):

									    super(ShangHai,self).__init__(info)

									    pass

									#客户端

									if(__name__=="__main__"):

									  destination=ShangHai()

									  destination.SetForm(Group())

									  destination.GetInfo()

									  destination=DaLian()

									  destination.SetForm(Independent())

									  destination.GetInfo()