[Zope3-dev] Re: Object hub?

[Garrett Smith]

We use the object hub extensively as an inventory of objects. What is 
the recommended 'best practice' here? Continue using the hub, but just 
as a utility? Or create and maintain our own hub service/index?

Will the object hub utility be available by default in the bootstrapped 
Zope 3 site?

  -- Garrett


Jim Fulton wrote:

> 
> The original puroses for the object hub were:
> 
> 1. To allow location-independent object references.  These were
>    references that remained valid even if the referenced object
>    was moved.
> 
>    This need is now supported through direct object references,
>    which were made possible through parentgeddon. You can now
>    have a direct reference to an object without losing location
>    information.
> 
> 2. Track containment or location relationships.
> 
>    This is now handled through ILocation/IContained
>    and ISublocations/IContainer.
> 
> 3. Provide compact identifiers for use in indexing.
> 
>    Having this broken out into a separate component (versus
>    providing the capability as an internal catalog implementation
>    as was done in Zope 2), supports cross-index/cross-catalog
>    merges.
> 
> I think that there is still a role for an object hub, although
> it is now a much smaller role, and far less central.
> 
> I propose to to do away with the object hub as a service, replacing it
> with a utility.
> 
> I further suggest that provide a two-way mapping between object references
> and short ids (integers).
> 
> We will define an interface (like):
> 
>   class IObjectReference(IHashKey, IPicklable):
>      """An object reference
>      """
> 
>      def __call__():
>          """Return the referenced object
>          """
> 
> When we register the object with the utility, we'll adapt it to this 
> interface
> to get a reference.
> 
> Jim
>