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__ 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
