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AGJenaQueryExecution.java

package com.franz.agjena.examples;







import com.franz.agbase.AllegroGraphException;

import com.franz.agbase.AllegroGraph;

import com.franz.agbase.AllegroGraphConnection;

import com.franz.agbase.examples.AGPaths;

import com.franz.agjena.AllegroGraphGraphMaker;

import com.franz.agjena.AllegroGraphModel;

import com.franz.agjena.query.AllegroGraphQueryExecutionFactory;

import com.hp.hpl.jena.graph.Graph;

import com.hp.hpl.jena.query.QueryExecution;

import com.hp.hpl.jena.query.QuerySolution;

import com.hp.hpl.jena.query.ResultSet;

import com.hp.hpl.jena.rdf.model.Model;

import com.hp.hpl.jena.rdf.model.RDFNode;

import com.hp.hpl.jena.rdf.model.Resource;

import com.hp.hpl.jena.vocabulary.DC;



public class AGJenaQueryExecution {



    /**

     * Demonstrates QueryExecution

     *

     * @param args unused

     * @throws AllegroGraphException

     */

    public static void main(String[] args) throws AllegroGraphException {

        // Connect to server, which must already be running.

        AllegroGraphConnection ags = new AllegroGraphConnection();

        try {

            ags.enable();

        } catch (Exception e) {

            throw new AllegroGraphException("Server connection problem", e);

        }



        // Create a fresh triple store

        AllegroGraph ts = ags.renew("jenatest2", AGPaths.TRIPLE_STORES);



        // Create a Graph maker for the store, and work in the default graph

        AllegroGraphGraphMaker maker = new AllegroGraphGraphMaker(ts);

        Graph graph = maker.getGraph();

        Model model = new AllegroGraphModel(graph);



        // Add some data to the default graph

        Resource r1 = model.createResource("http://example.org/book#1") ;

        Resource r2 = model.createResource("http://example.org/book#2") ;

        r1.addProperty(DC.title, "SPARQL - the book")

          .addProperty(DC.description, "A book about SPARQL");

        r2.addProperty(DC.title, "Advanced techniques for SPARQL");

        

        // A SPARQL query

        String queryString = 

            "PREFIX dc: <" + DC.NS + ">\n" +

            "SELECT ?title WHERE {?x dc:title ?title}" ;

        

        // Run the query

        QueryExecution qexec = AllegroGraphQueryExecutionFactory.create(queryString, model) ;

        System.out.println("Titles: ") ;

        try {

            ResultSet rs = qexec.execSelect() ;

            while(rs.hasNext()) {

                QuerySolution rb = rs.nextSolution() ;

                RDFNode x = rb.get("title") ;

                System.out.println("   "+x) ;

            }

        } finally  {

            qexec.close() ;

        }

        

        // Close the triple store and disconnect from the server

        ts.closeTripleStore();

        ags.disable();

    }



}
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