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AGSparqlConstruct.java

package com.franz.agbase.examples;



import com.franz.agbase.*;



public class AGSparqlConstruct {



    /**

     * Demonstrates some basics of using the CONSTRUCT query form 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 for this example.

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

                

        // Register any namespaces

        ts.registerNamespace("org", "http://example.com/ns#");

        

        // Define blank nodes

        BlankNode a = (BlankNode)ts.createBNode("_:a");

        BlankNode b = (BlankNode)ts.createBNode("_:b");

        

        // Add some data to the store

        ts.addStatement(a,"!org:employeeName",ts.createLiteral("Alice"));

        ts.addStatement(a,"!org:employeeId",ts.createLiteral(12345));

        ts.addStatement(b,"!org:employeeName",ts.createLiteral("Bob"));

        ts.addStatement(b,"!org:employeeId",ts.createLiteral(67890));



        // A query using CONSTRUCT builds an RDF Graph based on

        // triples matching the query's graph pattern

        String query =

        "PREFIX foaf:   <http://xmlns.com/foaf/0.1/> " +

        "PREFIX org:    <http://example.com/ns#> " +

        "CONSTRUCT { ?x foaf:name ?name } " +

        "WHERE  { ?x org:employeeName ?name }";

        

        // Query the store and show the results

        SPARQLQuery sq = new SPARQLQuery();

        TriplesIterator cc = sq.construct(ts,query);

        AGUtils.showTriples(cc);

        

        // Close the triple store and disconnect from the server.

        ts.closeTripleStore();

        ags.disable();

    }



}
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