CODEWITHSUNDEEP
javardfsesameblank-nodesopenrdf
jd466
jd466

Reputation: 579

Handling Blank nodes in Sesame

In Model.filter(), I would like to store the objects. But if the object is a blank node, I would like to retrieve the corresponding triple and store the real object.

The problem in Model.filter() is that If the blank node(object) is _:a , the returning "Value" will be something like :xxxxxxxxxxa. this is fine but when I have (:xxxxxxxxxxa,p,o) in the model, trying to use model.filter(_:xxxxxxxxxxa,null,null) fails. 

   java.util.NoSuchElementException
        at org.openrdf.model.impl.AbstractModel$ValueSet$ValueSetIterator.
next(AbstractModel.java:493)
        at org.openrdf.model.impl.AbstractModel$ValueSet$ValueSetIterator.next(AbstractModel.java:470)

This is the source code which explain the problem in more detain:

    private Model triples;

    private Value filterBySubjectAndPredicate(Resource subject, IRI Predicate, IRI nextPredicate) {

    Value tempValue = triples.filter(subject, vf.createURI(Predicate.getFullIRI()), null).
objects().iterator().next();
            BNode bnode = null;
            if(tempValue instanceof BNode) {
            bnode = vf.createBNode(tempValue.toString());
            return triples.filter(bnode, vf.createURI(nextPredicategetFullIRI()), null).
objects().iterator().next();
            } else
            return triples.filter(subject, vf.createURI(Predicate.getFullIRI()), null).
objects().iterator().next();
        }

Thank you in advance.

Upvotes: 1

Views: 186

Answers (0)

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