Re: [Tm4j-developers] Drill-down topic maps

[Gerd M. <ge...@sm...>]

On Wed, 27 Jun 2001 09:01:37 +0100
"Kal Ahmed" <ka...@te...> wrote:

> >
> > >   But, what about an occurrence that happens to be stored in your local
> > > persistent store?  How do you reference it?  Particularly, how do you
> > > reference it such that others could, at a minimum, write and
> > ask you for a
> > > copy--given that you might have published the topic map on the
> > web or sent
> > > it off for merging elsewhere.
> > >
> > > All TopicMapObjects stored in a given persistent topic map have
> > an object ID
> > > assigned to them. So the URI for any TopicMapObject in the
> > persistent store
> > > would be the baseURL of the TopicMap with the object ID appended as a
> > > fragment identifier. TopicMapObjects also have their sourceURL
> > stored with
> > > them (this is really to maintain the provenance of a topic map
> > object and is
> > > not intended to be a means of locating it). An application wishing to
> > > resolve a URI to a topic map object would have to first split
> > the URI into
> > > the document part and the fragment identifier part, then look in the
> > > TopicMapManager for the topic map with that ID.
> >
> > The ID should not be the object ID in the persistent store, since
> > those IDs are normally hidden to the application layer, in our case the
> > topicmap implementation. Also the validity of a topicmap object
> > reference would depend on the database that contains it. So, if a
> > topicmap provider changes the database, all references to it become
> > invalid. We should better use the ID provided by TopicMapObject.getID()
> > or the resourceID (or is this what you mean with persistent object ID ?).
> > We could also use some kind of XPointer notation to point into another
> > TopicMap.
> >
> 
> My feeling is that the ID returned by TopicMapObject.getID() would be the
> best choice. TopicMapObject.getResourceID() is meant to return the "source"
> ID of the topic map object. If a TopicMap is created by merging two or more
> different sources, you will have resourceIDs which specify different URLs
> all mixed up within the same TopicMap - this is useful if your goal is to
> determine which objects came from where, but useless if you want some
> consistent form of addressing - hence the get/setID() function on
> TopicMapObject.

+1

--
________________________________________________________________
Gerd Mueller                                    ge...@sm...     
SMB GmbH                                  http://www.smb-tec.com