-- flyaflya [2005-08-04 09:20:24]

1. Proxy(代理)

1.1. 意图

为其他对象提供一种代理以控制对这个对象的访问。
ProxyPattern.gif

1.2. 代码

   1 class Proxy:
   2     def __init__( self, subject ):
   3         self.__subject = subject
   4     def __getattr__( self, name ):
   5         return getattr( self.__subject, name )   

1.3. 例子

   1 class RGB:
   2     def __init__( self, red, green, blue ):
   3         self.__red = red
   4         self.__green = green
   5         self.__blue = blue
   6     def Red( self ):
   7         return self.__red
   8     def Green( self ):
   9         return self.__green
  10     def Blue( self ):
  11         return self.__blue 

使用Proxy改变Blue函数:

   1 class NoBlueProxy( Proxy ):
   2     def Blue( self ):
   3         return 0

使用:

>>> rgb = RGB( 100, 192, 240 )
>>> rgb.Red()
100

>>> proxy = Proxy( rgb )
>>> proxy.Green()
192

>>> noblue = NoBlueProxy( rgb )
>>> noblue.Green()
192

>>> noblue.Blue()
0  

1.4. 特殊说明

1.5. 反馈

ProxyPattern (last edited 2009-12-25 07:15:56 by localhost)