VirtJenaSPARQLExample12

<docbook><section><title>VirtJenaSPARQLExample12</title><title> Virtuoso Jena Provider - SPARQL Example 12</title> Virtuoso Jena Provider - SPARQL Example 12
<programlisting>import org.apache.jena.query.*;
import org.apache.jena.graph.Triple;
import org.apache.jena.graph.Node;
import org.apache.jena.graph.Graph;
import org.apache.jena.rdf.model.*;
import org.apache.jena.rdf.model.RDFNode;
import org.apache.jena.vocabulary.DC;
import java.util.Iterator;

import virtuoso.jena.driver.*;

public class VirtuosoSPARQLExample12 {

    /**
     * Executes a SPARQL query against a virtuoso url and prints results.
     */
    public static void main(String[] args) 
    {
    String url;
    if(args.length == 0)
        url = &quot;jdbc:virtuoso://localhost:1111&quot;;
    else
        url = args[0];

        Model m = VirtModel.openDatabaseModel(&quot;my:test&quot;, url, &quot;dba&quot;, &quot;dba&quot;);
        m.removeAll();

        Resource r1 = m.createResource(&quot;http://example.org/book#1&quot;) ;
        Resource r2 = m.createResource(&quot;http://example.org/book#2&quot;) ;
        
        r1.addProperty(DC.title, &quot;SPARQL - the book&quot;)
          .addProperty(DC.description, &quot;A book about SPARQL&quot;) ;
        
        r2.addProperty(DC.title, &quot;Advanced techniques for SPARQL&quot;) ;

        String prolog = &quot;PREFIX dc: &lt;&quot;+DC.getURI()+&quot;&gt; \n&quot; ;
        
        // Query string.
        String queryString = prolog + &quot;SELECT ?title WHERE {?x dc:title ?title}&quot; ; 
        System.out.println(&quot;Execute query=\n&quot;+queryString) ;
        System.out.println() ;

    Query query = QueryFactory.create(queryString) ;

System.out.println(&quot;\n==CASE 1 ==Parse ARQ  Execute ARQ  GraphStore Virtuoso&quot;);
//NOTE: query is parsed &amp; executed by ARQ, so it works slow
// and you can&#39;t use Virtuoso SPARQL features
        QueryExecution qexec = QueryExecutionFactory.create(query, m) ;
        // Or QueryExecutionFactory.create(queryString, model) ;
        System.out.println(&quot;Titles: &quot;) ;
        try {
            ResultSet rs = qexec.execSelect() ;
            for ( ; rs.hasNext() ; ) {
                QuerySolution rb = rs.nextSolution() ;
                RDFNode x = rb.get(&quot;title&quot;) ;
                if ( x.isLiteral() ) {
                    Literal titleStr = (Literal)x  ;
                    System.out.println(&quot;    &quot;+titleStr) ;
                } else
                    System.out.println(&quot;Strange - not a literal: &quot;+x) ;
            }
        } finally {
            qexec.close() ;
        }


    }
}
</programlisting></section></docbook>