Question

I have created an RDF/OWL file using Protege 4.1 alpha.
I also created a defined class in Protege called CheapPhone. This class has a restriction which is shown below :

(hasPrice some integer[< 350])

Whenever, a price of a phone is below 350, it is inferred as CheapPhone.
There is no problem for inferring this in Protege 4.1 alpha. However, I cannot infer this using Jena.

I also created a defined class called SmartPhone. This class also has a restriction which is shown below :

(has3G value true) and (hasInternet value true)

Whenever, a phone has 3G and Internet, it is inferred as SmartPhone.
In this situation, there is no problem inferring this in both Protege and Jena.

I have started to think that there is a problem in default inference engine of Jena.
The code that I use in Java is below :

Reasoner reasoner = ReasonerRegistry.getOWLReasoner();

reasoner = reasoner.bindSchema(ontModel);
    OntModelSpec ontModelSpec = OntModelSpec.OWL_MEM_MINI_RULE_INF;
    ontModelSpec.setReasoner(reasoner);
    // Create ontology model with reasoner support
            // ontModel was created and read before, so I don't share the code in order
            // not to create garbage here
    OntModel model = ModelFactory.createOntologyModel(ontModelSpec, ontModel);

    OntClass sPhone = model.getOntClass(ns + "SmartPhone");
    ExtendedIterator s = sPhone.listInstances();
    while(s.hasNext()) {
        OntResource mp = (OntResource)s.next();
        System.out.println(mp.getURI());
    }

This code works perfectly and returns me the instances, but when I change the code below and make it appropriate for CheapPhone, it doesn’t return anything.

OntClass sPhone = model.getOntClass(ns + "CheapPhone");

Am I doing something wrong ?

Answer 1

Data ranges (the [< 350] bit) is a feature of OWL 2. Jena doesn’t support OWL 2. See W3C’s OWL 2 Implementations page for a list of tools with OWL 2 support—you’ll have to use one of those. (Some experimental ongoing work for Jena is listed there, but this definitely hasn’t made it into a Jena release yet.)