[topicmapmail] reification and other funny things

[Lars Heuer]

Hi Joril,

[...]
> ....the data model 2.0 says that a topic has null or one information item in
> its reified property.

> In the TMAPI the topic.getReified() method returns a set of topic map 
> constructs that this topic reifies.
> Which is correct?

The TMDM is correct. :)

The 'old' reification method was: Assgign a subject identifier to a
topic that is equals to an item identifier (source locator) of an
other Topic Maps construct (that is not a topic) ==> The topic reifies
the construct.

Example:
        Topic has subject identifier "X"
        Name has item identifier "X"

        ==> Topic reifies name


A possible implementation for TMAPI Topic.getReified() is:

  public Set<TopicMapObject> getReified() {
         Set<TopicMapObject> reified = new HashSet<TopicMapObject>();
         for (Locator sid : _subjectIdentifiers) {
             TopicMapObject tmo = getObjectsWithItemIdentifier(sid);
             if (tmo != null) {
                reified.add(tmo);
             }
         }
         return reified;

  }

Since the topic has more than one subject identifier it is possible
that the topic reifies more than one Topic Maps construct.

But this violates the TMDM.
  
> If a topic reifies an occurrence, I would think that this occurrence can be
> assigned to several topics.And hence the reified topic would contain a set
> with alle these occurrence items in the different topics? A document on
> well-known composers could be attached to both Puccini(topic) and 
> Verdi(topic)? Or should an occurrence be more specificly related to a topic?
> During deserialization, wouldn't the list of reified properties be created
> for each topic?

This paragraphs I do not understand. :(

Best regards,
Lars
-- 
http://www.semagia.com
http://www.topicgarden.com/mailinglist/ German Topic Maps mailinglist