代表在python [英] Delegates in python

问题描述

我已经实现了这个简短的例子来尝试演示一个简单的委托模式。我的问题是。这样看起来像我已经明白了授权吗？

I've implemented this short example to try to demonstrate a simple delegation pattern. My question is. Does this look like I've understood delegation right?

class Handler:
    def __init__(self, parent = None):
        self.parent = parent
    def Handle(self, event):
        handler = 'Handle_' +event
        if hasattr(self, handler):
            func = getattr(self, handler)
            func()
        elif self.parent:
            self.parent.Handle(event)

class Geo():
    def __init__(self, h):
        self.handler = h

    def Handle(self, event):
        func = getattr(self.handler, 'Handle')
        func(event)

class Steve():
    def __init__(self, h):
        self.handler = h

    def Handle(self, event):
        func = getattr(self.handler, 'Handle')
        func(event)

class Andy():
    def Handle(self, event):
        print 'Andy is handling %s' %(event)

if __name__ == '__main__':        
    a = Andy()
    s = Steve(a)
    g = Geo(s)
    g.Handle('lab on fire')

推荐答案

这是基本概念，是的 - 传递一些传入的请求给另一个对象来照顾of。

That's the basic concept, yes - passing on some incoming request to another object to take care of.

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