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實(shí)例解析Python設(shè)計(jì)模式編程之橋接模式的運(yùn)用

更新時(shí)間：2016年03月02日 11:50:37 作者：hitzjm

這篇文章主要介紹了Python設(shè)計(jì)模式編程之橋接模式的運(yùn)用,橋接模式主張把抽象部分與它的實(shí)現(xiàn)部分分離,需要的朋友可以參考下

我們先來看一個(gè)例子：

#encoding=utf-8 
# 
#by panda 
#橋接模式 
 
def printInfo(info): 
  print unicode(info, 'utf-8').encode('gbk') 
 
#抽象類：手機(jī)品牌 
class HandsetBrand(): 
  soft = None 
  def SetHandsetSoft(self, soft): 
    self.soft = soft 
   
  def Run(self): 
    pass 
   
#具體抽象類：手機(jī)品牌1 
class HandsetBrand1(HandsetBrand): 
  def Run(self): 
    printInfo('手機(jī)品牌1:') 
    self.soft.Run() 
 
#具體抽象類：手機(jī)品牌2 
class HandsetBrand2(HandsetBrand): 
  def Run(self): 
    printInfo('手機(jī)品牌2:') 
    self.soft.Run() 
 
   
#功能類：手機(jī)軟件 
class HandsetSoft(): 
  def Run(self): 
    pass 
 
#具體功能類：游戲   
class HandsetGame(HandsetSoft): 
  def Run(self): 
    printInfo('運(yùn)行手機(jī)游戲') 
     
#具體功能類：通訊錄   
class HandsetAddressList(HandsetSoft): 
  def Run(self): 
    printInfo('運(yùn)行手機(jī)通信錄') 
 
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();

可以總結(jié)出類圖是這樣的：

201632114505183.gif (678×256)

所以，橋接模式的概念在于將系統(tǒng)抽象部分與它的實(shí)現(xiàn)部分分離，使它們可以獨(dú)立地變化。
由于目標(biāo)系統(tǒng)存在多個(gè)角度的分類，每一種分類都會有多種變化，那么就可以把多角度分離出來，讓它們獨(dú)立變化，減少它們之間的耦合。

下面我們再來看一個(gè)實(shí)例：

基本原理請參考相關(guān)書籍，這里直接給實(shí)例

假期旅游從目的地角度可以分為上海和大連，從方式角度可以分為跟團(tuán)和獨(dú)體

橋接模式把這兩種分類連接起來可以進(jìn)行選擇。

類圖：

201632114527959.jpg (614×251)

# -*- 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
#客戶端
if(__name__=="__main__"):
  
  destination=ShangHai()
  destination.SetForm(Group())
  destination.GetInfo()
  
  
  destination=DaLian()
  destination.SetForm(Independent())
  destination.GetInfo()

運(yùn)行結(jié)果

201632114549246.jpg (201×60)