[Zope3-Users] Re: object id / name / name within parent?
fg at nuxeo.com
Mon Jan 10 08:22:23 EST 2005
Philipp von Weitershausen <philipp at weitershausen.de> wrote:
> Florent Guillaume wrote:
> > Petri Savolainen <petri.savolainen at iki.fi> wrote:
> >>Wow I've got a real newbie question here: How does the identification
> >>and naming of objects work in Zope3?
> >>I understand that objects have names, stored in the __name__ attribute
> >>of an object, and that this 'name' is what containers know contained
> >>objects by. To what extent is this analogous to a Zope2 id? Or do Z3
> >>objects have an id, in addition to name?
> > The name is indeed comparable to Zope 2's id. Except that in Zope 2,
> > both an object and its container know the id (which makes for redundant
> > information that can get out of sync etc), whereas in Zope 3 the name is
> > only stored with the object itself.
> Wrong. The container keeps the name, too. Containers are usually simple
> mapping objects (like a dict). The fact that the name is also stored on
> the object is an extra feature that you really shouldn't know about
Ok sorry for the confusion. I was actually mixing up container/object
here, mistake further compounded by other stuff. I remember that
initially in Z3 only the container stored the name. Then optimizations
kicked in, and the model for object reference changed a bit I guess.
> because you should use
> >>> zapi.getName(obj)
> anyways. That will adapt 'obj' to IPhysicallyLocatable and extract its
> name from wherever the implementation wants to get it from. For most
> persistent objects (or contained proxied ones), this is __name__. It
> doesn't have to be, though.
> For retrieving and manipulating contained information (name and
> parents), one should preferrably use the provided machinery, meaning the
> zapi methods (getName, getParent, getParents, etc.) and the
> contained/setitem functions from zope.app.container.contained.
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Florent Guillaume, Nuxeo (Paris, France) CTO, Director of R&D
+33 1 40 33 71 59 http://nuxeo.com fg at nuxeo.com
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