Hi,
I imported the NCI Thesaurus into a TDB store. I am using the Jena API to get
references to existing classes. This is my basic setup:
Dataset ds =
TDBFactory.createDataset("C:\\Playground\\Ontology\\TDBStore_Instances");
OntModel modelOnt = ModelFactory.createOntologyModel(OntModelSpec.RDFS_MEM,
ds.getDefaultModel());
For some classes the getOntClass() method works fine, e.g.:
modelOnt.getOntClass(NS_NCI_HASH + "Neoplasm");
modelOnt.getOntClass(NS_NCI_HASH + "Volume");
But for other classes, getOntClass() returns null, e.g.:
modelOnt.getOntClass(NS_NCI_HASH + "Carcinoma");
modelOnt.getOntClass(NS_NCI_HASH + "Malignant_Prostate_Neoplasm");
I tried to get an OntClass reference for these in different ways, too, e.g.:
I used modelOnt.listStatements(...) and stmt.getSubject().as(OntClass.class).
But this throws the exception:
Cannot convert node
http://ncicb.nci.nih.gov/xml/owl/EVS/Thesaurus.owl#Malignant_Prostate_Neoplasm
to OntClass: it does not have rdf:type owl:Class or equivalent
The problem is, that
http://ncicb.nci.nih.gov/xml/owl/EVS/Thesaurus.owl#Malignant_Prostate_Neoplasm
is an owl:Class. I verified this by just printing
stmt.getSubject().listProperties() to the console:
[http://ncicb.nci.nih.gov/xml/owl/EVS/Thesaurus.owl#Malignant_Prostate_Neoplasm,
http://www.w3.org/1999/02/22-rdf-syntax-ns#type,
http://www.w3.org/2002/07/owl#Class]
I also used a Sparql query on the same data set:
String query = PREFIXES
+ " SELECT * "
+ " WHERE { "
+ " nci:Malignant_Prostate_Neoplasm ?p ?o . "
+ " }";
Which prints this:
p | o
rdf:type | owl:Class
nci:Preferred_Name | "Malignant Prostate Neoplasm"^^xsd:string
...
So based on what I can see (and know), Carcinoma and
Malignant_Prostate_Neoplasm are both owl:Class, but getOntClass() does not seem
to agree.
Does anybody know why?
Thanks for your help!
Wolfgang
