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

[Kal A. <ka...@te...>]

>
> >   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.

Cheers,

Kal