ExampleTDB_02.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.jena.examples;

import java.io.InputStream;

import org.apache.jena.query.Dataset;
import org.apache.jena.query.Query;
import org.apache.jena.query.QueryExecution;
import org.apache.jena.query.QueryExecutionFactory;
import org.apache.jena.query.QueryFactory;
import org.apache.jena.query.QuerySolution;
import org.apache.jena.query.ReadWrite;
import org.apache.jena.query.ResultSet;
import org.apache.jena.rdf.model.Literal;
import org.apache.jena.tdb.TDBFactory;
import org.apache.jena.tdb.TDBLoader;
import org.apache.jena.tdb.base.file.Location;
import org.apache.jena.tdb.sys.TDBInternal;
import org.apache.jena.util.FileManager;

public class ExampleTDB_02 {

    public static void main(String[] args) {
        FileManager fm = FileManager.get();
        fm.addLocatorClassLoader(ExampleTDB_02.class.getClassLoader());
        InputStream in = fm.open("data/data.nt");

        Location location = Location.create ("target/TDB");

        // Load some initial data
        TDBLoader.load(TDBInternal.getBaseDatasetGraphTDB(TDBFactory.createDatasetGraph(location)), in, false);
        
        String queryString = 
            "PREFIX foaf: <http://xmlns.com/foaf/0.1/> " +
            "SELECT ?name WHERE { " +
            "    ?person foaf:mbox <mailto:alice@example.org> . " +
            "    ?person foaf:name ?name . " +
            "}";
        
        Dataset dataset = TDBFactory.createDataset(location);
        dataset.begin(ReadWrite.READ);
        try {
            Query query = QueryFactory.create(queryString);
            QueryExecution qexec = QueryExecutionFactory.create(query, dataset);
            try {
                ResultSet results = qexec.execSelect();
                while ( results.hasNext() ) {
                    QuerySolution soln = results.nextSolution();
                    Literal name = soln.getLiteral("name");
                    System.out.println(name);
                }
            } finally {
                qexec.close();
            }
        } finally {
            dataset.end();
        }
    }

}