实例解析Python设计模式编程之桥接模式的运用

时间:2022-10-11 12:12:40

我们先来看一个例子:

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#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

 

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# -*- 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()

运行结果

实例解析Python设计模式编程之桥接模式的运用