[Zope-dev] Pointer or reference object

[Johan Carlsson]

> 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
> > 6151 West Century Boulevard
> > Suite 900
> > Los Angeles, CA 90045
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> > F. 310.665.3544
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> 
> 
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