NOTE: the information on this page pertains to AllegroGraph version 3.x. There is no corresponding 4.x page at this time.

AGSparqlGraphs.java

package com.franz.agbase.examples;

import com.franz.agbase.*;

public class AGSparqlGraphs {

    /**
     * Demonstrates how to perform named graph queries in SPARQL.
     * 
     * @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 fresh triple-store.
        AllegroGraph ts = ags.renew("sparqlnamedgraphs", AGPaths.TRIPLE_STORES);
        
        // Load N-Triples data into a named graph
        URINode g = ts.createURI("http://example.org/kennedy/");
        long n = ts.loadNTriples(AGPaths.dataSources("kennedy.ntriples"), g);
        System.out.println("Loaded " + n + " triples.");
        
        // Get some triples from a given graph g and show them.
        TriplesIterator it = ts.getStatements(null, null, ts.createLiteral("Arnold"), g);
        AGUtils.showTriples(it);
        
        // Query for the first 20 place names ordered by name 
        String query =
        "PREFIX ex: <http://example.org/kennedy/> " +
        "SELECT ?name " +
        "FROM NAMED <http://example.org/kennedy/> " +
        "WHERE { GRAPH ex: { " +
          "?place ex:name ?name " +
        "}} " +
        "ORDER BY ?name " +
        "LIMIT 20";

        // Query the store and show the results
        SPARQLQuery sq = new SPARQLQuery();
        sq.setTripleStore(ts);
        sq.setQuery(query);
        AGSparqlSelect.doSparqlSelect(sq);

        // Close the store and disconnect from the server.
        ts.closeTripleStore();
        ags.disable();
    }

}

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