Jason Swails於 2013年1月31日星期四UTC+8上午8時34分03秒寫道：
> Hello,
>
>
> I was having some trouble understanding decorators and inheritance and all
> that. This is what I was trying to do:
>
>
>
> # untested
> class A(object):
> def _protector_decorator(fcn):
>
> def newfcn(self, *args, **kwargs):
> return fcn(self, *args, **kwargs)
> return newfcn
>
>
>
> @_protector_decorator
> def my_method(self, *args, **kwargs):
> """ do something here """
>
>
>
> class B(A):
> def _protector_decorator(fcn):
> def newfcn(self, *args, **kwargs):
>
> raise MyException('I do not want B to be able to access the
> protected functions')
> return newfcn
>
>
>
> The goal of all that was to be able to change the behavior of my_method
> inside class B simply by redefining the decorator. Basically, what I want is
> B.my_method() to be decorated by B._protector_decorator, but in the code I'm
> running it's decorated by A._protector_decorator.
>
>
>
> I presume this is because once the decorator is applied to my_method in class
> A, A.my_method is immediately bound to the new, 'decorated' function, which
> is subsequently inherited (and not decorated, obviously), by B.
>
>
>
> Am I correct here? My workaround was to simply copy the method from class A
> to class B, after which B._protector_decorator decorated the methods in B.
> While this doesn't make the use of decorators completely pointless (the
> decorators actually do something in each class, it's just different), it does
> add a bunch of code duplication which I was at one point hopeful to avoid.
>
>
>
> I'm still stumbling around with decorators a little, but this exercise has
> made them a lot clearer to me.
>
>
> Thanks!
> Jason
It sounds that you need a decorator mapper to
perform the functionality of your designs.
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