Re: [tinyTiM-discuss] Mergin of Topics

[Lars H. <he...@se...>]

Hi Christian,

> i tried to merge two topic maps and received an IdentityConstraintException
> because the same identifier was added to two different topics which in my
> opinion is correct behaviour according to the TMDM.
> So I wrote the following test program where I added the same subject 
> identifier to two different topics which should be merged by the engine. The
> result was the same exception. Am I missing something?

Thanks for your e-mail. tinyTiM does not merge topics automatically.
That means, the IdentityConstraintException is correct. You can always
catch is and merge topics manually:

Topic topic1 =
testMap.createTopicBySubjectIdentifier(testMap.createLocator(test_locator));
topic1.createName("Test1");
                        
Topic topic2 = testMap.createTopic();
topic2.createName("Test2");
try {
   topic2.addSubjectIdentifier(testMap.createLocator(test_locator));
catch (IdentityConstraintException ex) {
   Topic existing = (Topic) ex.getExisting();
   topic2.mergeIn(existing);
}


An alternative, and much better approach would be:

  Topic topic1 = testMap.createTopicBySubjectIdentifier(
                     testMap.createLocator(test_locator));
  topic1.createName("Test1");

  Topic topic2 = testMap.createTopicBySubjectIdentifier(test_locator);
  topic2.createName("Test2");


Here, topic2 would be equals to topic1 since the engine ensures that
it either returns an existing topic with the provided subject
identifier or creates a topic with that subject identifier in the
"TopicMap.createTopicBySubjectIdentifier" method. TMAPI 2.0 supports
also "createTopicByItemIdentifier" and "createTopicBySubjectLocator"
with the same semantics.
  
Best regards,
Lars
-- 
Semagia 
<http://www.semagia.com>