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  • VOS.VirtJenaSPARQLExample9(Last) -- DAVWikiAdmin? , 2017-06-13 05:43:52 Edit WebDAV System Administrator 2017-06-13 01:43:52

    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);
    
    
    	}
    }