From: "Alec Mitchell" <apm13@columbia.edu>

Hello zope gurus,

I'm wondering if it is possible to override a method on a single instance of an object in the ZODB. My suspicion is no, but it doesn't hurt to ask. Specifically, I've tried:

def userFolderDelUsers(self, names): pass

from types import MethodType setattr(acl_users, 'userFolderDelUsers', MethodType(userFolderDelUsers, acl_users, acl_users.__class__))

Which works fine until the transaction gets committed, at which point it fails with "TypeError: can't pickle function objects". Which seems pretty much like a lost cause. Can you only do this at the class level? Is there an unrelated way to accomplish the same goal (overriding a method, without monkeypatching or subclassing)?

How about simple acquisition? eg Folder A | | --Method AAA | --Folder B | |-- Method AAA Method AAA in Folder B will be found by acquisition before Method AAA in Folder A (assuming you set up the path that way). Jonathan

Alec Mitchell wrote at 2004-5-27 13:11 -0700:

I'm wondering if it is possible to override a method on a single instance of an object in the ZODB. My suspicion is no, but it doesn't hurt to ask.

You can but it is a bit tricky because Python performs method wrapping only for class attributes. Thus, you need to do your own wrapping. Something like this: from Acquisition import Explicit class _MethodWrapper(Explicit): def __init__(self, f): self.__f = f def __call__(self, *args, **kw): return self.__f(self.aq_parent, *args, **kw) instance.f = _MethodWrapper(your_funcion) Note, that your "your_function" must be pickleable and unpickleable. This means, it must be defined in the module (global) namespace. -- Dieter