我們先來(lái)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：
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(huì)有多種變化，那么就可以把多角度分離出來(lái)，讓它們獨(dú)立變化，減少它們之間的耦合。
下面我們?cè)賮?lái)看一個(gè)實(shí)例：
基本原理請(qǐng)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(lái)可以進(jìn)行選擇。
類圖：
# -*- 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
