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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