[Zope-dev] Pointer or reference object
Johan Carlsson
johanc@torped.se
Sun, 5 Mar 2000 16:42:54 +0100
> One problem with having a reference count base class that's
> responsible for inactivate/delete the reference object is
> that Zope lacks a event model.
> If a folder/container is deleted it doesn't inform its
> siblings before it's deleted. And that may lead to invalid
> reference objects.
> I think ZCatalog have the same problem?
>
> There is a pointer product in the download section,
> have you looked at it?
Opps, it is not in the download sction any more.
Anyway, it's a Symbolic Link Product by Ty Sarna at Endicor Technologies, Inc
that reference a pointer object to a folder object base on a URL.
There is no way to control the acqusition path nor detect object if the object
is moved or deleted. Only links to folder are supported (as far as I can see).
If you what to play with it I could send you a copy of the tar ball.
//Johan
>
> //Johan
>
>
>
>
>
> > I meant to use resolve_url, to find any references to an object
> upon it's
> > deletion. Changes in an object's state really wouldn't matter
> if there is
> > a way to truely 'mirror' an object. The name spaces would have
> to either
> > be selectable, or since it is a mirror, then it aquires the
> name space of
> > the object that it is mirroring (and exact mirror). Like I
> said, I don't
> > have any idea if this 'pointer' is even possible in the ZODB.
> Anyone from
> > DC thinkning about this?
> >
> > All my best,
> >
> > Jason
> >
> >
> >
> > Johan Carlsson writes:
> >
> > >
> > > Yes, I have thought about it.
> > >
> > > One solution I thought of is use an object referens counter
> > > base class for "referencable objects".
> > > The base class should be responsible for manageing references
> > > and take action on the references when the objects state changes.
> > >
> > > One problem is how to handle acqusition.
> > > Should the referenced object be viewed in it's own context or
> > > the reference objects context? Or should the contexts merge?
> > >
> > >
> > > How did you intend to use ZCataloges for the ZMirror?
> > >
> > >
> > > //Johan
> > >
> > >
> > >
> > >
> > > > Zopsters,
> > > >
> > > > This is very out of the blue, but has anyone thought about
> > tackling the
> > > > 'reference' question by using a phantom Zope object? I don't know
> > > > nearly enough Python to answer this question, but maybe
> someone can.
> > > >
> > > > Is it possible to create a 'Reference' object that really
> > stores the url
> > > > of another object and maquerades as the other object's meta_type.
> > > > Anything that is asked of the 'Reference' object, just get's passed
> > > > along to the real object in it's place? Obviously whenever
> you delete
> > > > an object any 'References' with that object's url stored in them get
> > > > deleted too(ZCatalog could hold these). Sort of like a reflective
> > > > mirror. You see the object in the mirror but you aren't actually
> > > > looking at the object, you are looking at the mirror. A ZMirror.
> > > >
> > > > All my best,
> > > >
> > > >
> > > > --
> > > > Jason Spisak
> > > > 444@hiretechs.com
> > > >
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> >
> >
> > Jason Spisak
> > CIO
> > HireTechs.com
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