code: package it.unibz.inf.ontop.owlapi.example;
  
  /*
   * #%L
   * ontop-quest-owlapi
   * %%
   * Copyright (C) 2009 - 2014 Free University of Bozen-Bolzano
   * %%
   * Licensed 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.
   * #L%
   */
  
  import java.io.*;
  
  import it.unibz.inf.ontop.injection.OntopSQLOWLAPIConfiguration;
  import it.unibz.inf.ontop.owlapi.resultset.MaterializedGraphOWLResultSet;
  import it.unibz.inf.ontop.owlapi.OntopOWLAPIMaterializer;
  import org.semanticweb.owlapi.model.OWLAxiom;
  
  /**
   * A very simple example that shows how to generate triples in an N-Triple file,
   * using the data of a database and a set of mappings from the OBDA file.
   * 
   * NOTE: This process does not involve reasoning since no ontology is given. The
   * result are the DIRECT triples generated by the mappings.
   */
  public class ABoxMaterializerExample {
  
  	/*
  	 * Use the sample database using H2 from
  	 * https://babbage.inf.unibz.it/trac/obdapublic/wiki/InstallingTutorialDatabases
  	 */
  	private static final String OBDA_FILE = "src/test/resources/example/exampleBooks.obda";
  	private static final String PROPERTY_FILE = "src/test/resources/example/exampleBooks.properties";
  	private static final String OUTPUT_FILE = "src/test/resources/example/exampleBooks.txt";
  
  	
  	public void generateTriples() throws Exception {
  
  		OntopSQLOWLAPIConfiguration configuration = OntopSQLOWLAPIConfiguration.defaultBuilder()
  				.nativeOntopMappingFile(OBDA_FILE)
  				.propertyFile(PROPERTY_FILE)
  				.enableTestMode()
  				.build();
  
  		/*
  		 * Start materializing data from database to triples.
  		 */
  		OntopOWLAPIMaterializer materializer = OntopOWLAPIMaterializer.defaultMaterializer(configuration);
  
  		try (MaterializedGraphOWLResultSet graphResultSet = materializer.materialize()) {
  
  			/*
  			 * Print the triples into an external file.
  			 */
  			File fout = new File(OUTPUT_FILE);
  			if (fout.exists()) {
  				fout.delete(); // clean any existing output file.
  			}
  
  			try (PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(fout, true)))) {
  				while (graphResultSet.hasNext()) {
  					OWLAxiom individual = graphResultSet.next();
  					out.println(individual.toString());
  				}
  				out.flush();
  			}
  
  			long numberOfTriples = graphResultSet.getTripleCountSoFar();
  			System.out.println("Generated triples: " + numberOfTriples);
  		}
  	}
  
  	public static void main(String[] args) {
  		try {
  			ABoxMaterializerExample example = new ABoxMaterializerExample();
  			example.generateTriples();
  		} catch (Exception e) {
  			e.printStackTrace();
  		}
  	}
  }
  