[Zope] Seeking tips for persistence in external methods

[Oliver Bleutgen]

Hi, 

I'm having a tree structure which is defined in a flat
file via simple x.y.z tokens. I wrote an external method 
which gets passed such a token, parses this file and returns 
a dummy method in order to be able to represent this hierachy 
in zope via the tree tag.

Now, this works, but naturally takes very long because 
it parses the file with every invocation from the tree tag.

Now I can pre-build the whole tree out of objects, but the 
question is how to store that tree. I don't want to use zopes
ZODB, because the tree changes potentially every hour.

As I found out, pickling from an external method seems to
be not an option.

anybody any ideas?

TIA,
oliver