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 divisionfrom __future__ import print_functionfrom __future__ import unicode_literalsfrom 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 passclass 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 passclass independent(travelform): this class implements the implementor interface and defines its concrete implementation. def __init__(self, form=by myself): super(independent,self).__init__(form) passclass 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 passclass dalian(destination): this class extends the interface defined by abstraction. def __init__(self, info=go to dalian ): super(dalian,self).__init__(info) passclass 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