实例解析Python设计模式编程之桥接模式的运用

实例解析Python设计模式编程之桥接模式的运用

这篇文章主要介绍了Python设计模式编程之桥接模式的运用,桥接模式主张把抽象部分与它的实现部分分离,需要的朋友可以参考下

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：

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：

# -*- 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__importdivision

from__future__importprint_function

from__future__importunicode_literals

fromfuture_builtinsimport*

classTravelForm(object):

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

  """

  def__init__(self, form="stay at
home"):

    self.form=form

    pass

  defGetForm(self):

    returnself.form

    pass

  pass

classGroup(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

classIndependent(TravelForm):

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

  implementation.

  """

  def__init__(self, form="by
myself"):

    super(Independent,self).__init__(form)

    pass

classDestination(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

  defGetInfo(self):

    #
imp->Operation();

    returnprint(self.info
" " self.form.GetForm())

    pass

  defSetForm(self, form):

    self.form=form

    pass

classDaLian(Destination):

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

  """

  def__init__(self, info="Go to
DaLian "):

    super(DaLian,self).__init__(info)

    pass

classShangHai(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()

运行结果