[JENA-1135] Cannot query named graph in in-memory dataset

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Won't Fix
• Affects Version/s: Jena 3.0.1
• Component/s: ARQ, Jena
• Assignee: Rob Vesse
• Reporter: Todd Schiller
• Created: 09/Feb/16 19:03
• Updated: 14/May/16 09:54
• Resolved: 10/Feb/16 09:36

Description

I'm trying to query an in-memory named graph with SPARQL. Any ideas why the following would be returning no results?

I'm guessing that the "<urn:graph>" is not being resolved as I would expect?

GraphTest.java

import org.apache.jena.query.*;
import org.apache.jena.rdf.model.*;
import org.apache.jena.vocabulary.RDFS;

public class GraphTest {
    public static void main(String [] args) {
        Dataset data = DatasetFactory.create();

        Model model = ModelFactory.createDefaultModel();
        model.getResource("urn:foo").addLiteral(RDFS.label, "foobar");
        data.addNamedModel("urn:graph", model);

        String sparql = "SELECT ?s ?p ?o FROM <urn:graph> WHERE { ?s ?p ?o }";
        ResultSet results = QueryExecutionFactory.create(sparql, data).execSelect();
        int cnt = 0;
        while (results.hasNext()) {
            cnt++;
            results.next();
        }
         
        // should both print 1
        System.out.println("# results: " + cnt); // prints 0
        System.out.println("Model size: " + data.getNamedModel("urn:graph").size()); // prints 1
    }
}