Diff for "ProxyPattern" - Woodpecker Wiki for CPUG

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-- flyaflya [DateTime(2005-08-04T09:20:24Z)] TableOfContents

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。BR attachment: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()

}}} 使用： >>> rgb = RGB( 100, 192, 240 )