On 18/09/16 16:41, javed khan wrote:
This code does not work.


You haven't shown us the data and haven't said in what way it doesn't work.

I want to save student marks/GPA in the file and
based on GPA assign students to GoodStudent or WorstStudents sub classes of
Student via Jena rules.

[snip]

 String rule="[rule1:(?x   http://www.w3.org/1999/02/22-rdf-syntax-ns#type
http://www.semanticweb.org#Student) " +
         "( http://www.semanticweb.org#Student
http://www.semanticweb.org#GPA  ?marks +   )"

That *still" has the spurious + in from your last question.

Furthermore it is highly unlikely you mean the subject of that pattern to be the Student class, it should be ?x.

A simplified version of your code, which doesn't require any input data is:

    public void temp() throws Exception {
OntModel model = ModelFactory.createOntologyModel( OntModelSpec.OWL_MEM );
        String ns = "http://www.semanticweb.org#";;

        OntClass Student = model.createClass(ns + "Student");
        OntClass GoodStudent = model.createClass(ns + "GoodStudent");
        Individual indiv = Student.createIndividual(ns + "s1");
        Property prop = model.getProperty(ns, "GPA");
        indiv.addLiteral(prop, 3);

String rule = "[rule1:(?x http://www.w3.org/1999/02/22-rdf-syntax-ns#type http://www.semanticweb.org#Student) "
                + "( ?x http://www.semanticweb.org#GPA  ?marks )"
                + "greaterThan(?marks, 2) "
+ " -> (?x http://www.w3.org/1999/02/22-rdf-syntax-ns#type http://www.semanticweb.org#GoodStudent )]";

Reasoner reasoner2 = new GenericRuleReasoner(Rule.parseRules(rule));
        InfModel inf = ModelFactory.createInfModel(reasoner2, model);

for (Iterator i = inf.listResourcesWithProperty(RDF.type, GoodStudent); i.hasNext();) {
            System.out.println("Good student: " + i.next());
        }
    }

Which produces the output:

Good student: http://www.semanticweb.org#s1

Dave

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