[Pellet-users] null pointer exception at getIndividuals()

[Alexander Becker]

Dear all!

I want to fetch all individuals of an ontology, that have a certain property.
Unfortunately, I get one of these ugly null pointer exceptions, and as usual, I don't have any idea where the error comes from (no, the line number is no sufficent information :>).

This is the error:
[quote]
Testcase: get_ind_by_props_depr(Test.ReasonerTest):	Caused an ERROR
null
java.lang.NullPointerException
        at org.mindswap.pellet.owlapi.PelletVisitor.addSimpleProperty(PelletVisitor.java:220)
        at org.mindswap.pellet.owlapi.PelletVisitor.visit(PelletVisitor.java:683)
        at uk.ac.manchester.cs.owl.OWLObjectSelfRestrictionImpl.accept(OWLObjectSelfRestrictionImpl.java:53)
        at org.mindswap.pellet.owlapi.PelletLoader.term(PelletLoader.java:173)
        at org.mindswap.pellet.owlapi.Reasoner.getIndividuals(Reasoner.java:550)
        at Test.ReasonerTest.get_ind_by_props_depr(ReasonerTest.java:270)
[/quote]

And here is the code:
[code]
    @Test
    /**
     * Get all individuals by property. Uses a depreciated api.
     */
    public void get_ind_by_props_depr() {
        
        // input:
        String property = "hasCase";
        String propertyValue = "Genitive";
        
        
        // The way we do it atm.
        Set result = new HashSet();

        Set<OWLIndividual> all_ind = new HashSet();
        all_ind = reasoner.getIndividuals();
        
        for( OWLIndividual owl_individual : all_ind ) {
            Map opv = reasoner.getObjectPropertyRelationships(owl_individual);
            
            Set<OWLProperty> object_property_values_keyset = opv.keySet();
            
            if (opv.size() > 0) {
                for( OWLProperty oprop : object_property_values_keyset ) {
                    
                    if (oprop.toString().endsWith(property)) {
						if (reasoner.getPropertyValue(owl_individual, (OWLObjectProperty) oprop).toString().endsWith(propertyValue.toLowerCase())) {
							result.add(owl_individual.getURI().getFragment());
						}
					}
                    
                }
            }
        }
        
		System.out.println("get_ind_by_props_depr: " + result.toString());
     
        
        // Thats how it should (propably) work, but it doesn't.
        OWLDataFactory factory = OWLManager.createOWLOntologyManager().getOWLDataFactory();
		OWLObjectProperty objectprop = factory.getOWLObjectProperty(URI.create(url + "#hasCase"));
        OWLObjectSelfRestriction clsC = factory.getOWLObjectSelfRestriction(objectprop);

        Set result2 = reasoner.getIndividuals(clsC, false); // line 270 here
        System.out.println("get_ind_by_props_depr: " + result2.toString());

        
        assertTrue(result.equals(result2));
        
    }
[/code]

Maybe someone sees the error and / or may help me with that task.

Best regards, Alex
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