[ZODB-Dev] Implementing Storage Decorators

[Dieter Maurer]

Jim Fulton wrote at 2007-5-4 14:40 -0400:
>
>On May 4, 2007, at 2:33 PM, Dieter Maurer wrote:
>
>> Jim Fulton wrote at 2007-5-2 11:52 -0400:
>>> ...
>>> I think I still rather like explicit, but I'm on the fence about
>>> which approach is best.  What do other people think?
>>
>>> From your description, I would use a subclassing (and forget about
>> proxy and copying).
>
>That would be a nightmare, on multiple levels:
>
>- All of the separate implementations would become tightly coupled,  
>which is what happens with inheritance.
>
>- Either someone would have to create classes for the various  
>permutations of features, or consumers would have to mix and match  
>multiple classes to get what they want and sort out the variate  
>internal implementation incompatibilities.

Your decorators would become mixin classes
and the final classes would list the features they like -- simpler
than ZCML binding together...

Of course, some features may not play well with one another.
But, that will make problems also with proxies or copying...


-- 
Dieter