Virtuoso Jena Provider - SPARQL Example 9
import com.hp.hpl.jena.query.*; import com.hp.hpl.jena.rdf.model.RDFNode; import com.hp.hpl.jena.graph.Triple; import com.hp.hpl.jena.graph.Node; import com.hp.hpl.jena.graph.Graph; import com.hp.hpl.jena.rdf.model.*; import java.util.Iterator; import virtuoso.jena.driver.*; public class VirtuosoSPARQLExample9 { /** * Executes a SPARQL query against a virtuoso url and prints results. */ public static void main(String[] args) { String url; if(args.length == 0) url = "jdbc:virtuoso://localhost:1111"; else url = args[0]; /* STEP 1 */ VirtGraph set = new VirtGraph (url, "dba", "dba"); /* STEP 2 */ String str = "CLEAR GRAPH <http://test1>"; VirtuosoUpdateRequest vur = VirtuosoUpdateFactory.create(str, set); vur.exec(); str = "INSERT INTO GRAPH <http://test1> { <http://aa> <http://bb> 'cc' . <http://aa1> <http://bb> 123. }"; vur = VirtuosoUpdateFactory.create(str, set); vur.exec(); /* Select all data in virtuoso */ Query sparql = QueryFactory.create("SELECT * FROM <http://test1> WHERE { ?s ?p ?o }"); VirtuosoQueryExecution vqe = VirtuosoQueryExecutionFactory.create (sparql, set); ResultSet results = vqe.execSelect(); System.out.println("\nSELECT results:"); while (results.hasNext()) { QuerySolution rs = results.nextSolution(); RDFNode s = rs.get("s"); RDFNode p = rs.get("p"); RDFNode o = rs.get("o"); System.out.println(" { " + s + " " + p + " " + o + " . }"); } sparql = QueryFactory.create("DESCRIBE <http://aa> FROM <http://test1>"); vqe = VirtuosoQueryExecutionFactory.create (sparql, set); Model model = vqe.execDescribe(); Graph g = model.getGraph(); System.out.println("\nDESCRIBE results:"); for (Iterator i = g.find(Node.ANY, Node.ANY, Node.ANY); i.hasNext();) { Triple t = (Triple)i.next(); System.out.println(" { " + t.getSubject() + " " + t.getPredicate() + " " + t.getObject() + " . }"); } sparql = QueryFactory.create("CONSTRUCT { ?x <http://test> ?y } FROM <http://test1> WHERE { ?x <http://bb> ?y }"); vqe = VirtuosoQueryExecutionFactory.create (sparql, set); model = vqe.execConstruct(); g = model.getGraph(); System.out.println("\nCONSTRUCT results:"); for (Iterator i = g.find(Node.ANY, Node.ANY, Node.ANY); i.hasNext();) { Triple t = (Triple)i.next(); System.out.println(" { " + t.getSubject() + " " + t.getPredicate() + " " + t.getObject() + " . }"); } sparql = QueryFactory.create("ASK FROM <http://test1> WHERE { <http://aa> <http://bb> ?y }"); vqe = VirtuosoQueryExecutionFactory.create (sparql, set); boolean res = vqe.execAsk(); System.out.println("\nASK results: "+res); } }