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/**

Copyright (C) SYSTAP, LLC 2006-2015.  All rights reserved.

Contact:
     SYSTAP, LLC
     2501 Calvert ST NW #106
     Washington, DC 20008
     [email protected]

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

/**
 * See Sesame API embedded mode
 */

package sample.sesame.embedded;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.util.Properties;

import org.apache.log4j.Logger;
import org.openrdf.OpenRDFException;
import org.openrdf.query.BindingSet;
import org.openrdf.query.QueryLanguage;
import org.openrdf.query.TupleQuery;
import org.openrdf.query.TupleQueryResult;
import org.openrdf.repository.Repository;
import org.openrdf.repository.RepositoryConnection;
import org.openrdf.rio.RDFFormat;

import com.bigdata.rdf.sail.BigdataSail;
import com.bigdata.rdf.sail.BigdataSailRepository;


public class SampleBlazegraphSesameEmbedded {
	
	protected static final Logger log = Logger.getLogger(SampleBlazegraphSesameEmbedded.class);

	public static void main(String[] args) throws IOException, OpenRDFException {

		// load journal properties from resources
		final Properties props = loadProperties("/blazegraph.properties");

		// instantiate a sail
		final BigdataSail sail = new BigdataSail(props);
		final Repository repo = new BigdataSailRepository(sail);

		try{
			repo.initialize();
			
			/*
			 * Load data from resources 
			 * src/main/resources/data.n3
			 */
	
			loadDataFromResources(repo, "/data.n3", "");
			
			final String query = "select * { ?p ?o}";
			final TupleQueryResult result = executeSelectQuery(repo, query, QueryLanguage.SPARQL);
			
			try {
				while(result.hasNext()){
					
					final BindingSet bs = result.next();
					log.info(bs);
					
				}
			} finally {
				result.close();
			}
		} finally {
			repo.shutDown();
		}
	}

	/*
	 * Load a Properties object from a file.
	 */
	public static Properties loadProperties(final String resource) throws IOException {
		final Properties p = new Properties();
		final InputStream is = SampleBlazegraphSesameEmbedded.class
				.getResourceAsStream(resource);
		final Reader reader  = new InputStreamReader(new BufferedInputStream(is));
		try{
			p.load(reader);
		}finally{
			reader.close();
			is.close();
		}
		return p;
	}

	/*
	 * Load data from resources into a repository.
	 */
	public static void loadDataFromResources(final Repository repo, final String resource, final String baseURL)
			throws OpenRDFException, IOException {

		final RepositoryConnection cxn = repo.getConnection();
		
		try {
			cxn.begin();
			try {
				final InputStream is = SampleBlazegraphSesameEmbedded.class.getResourceAsStream(resource);
				if (is == null) {
					throw new IOException("Could not locate resource: " + resource);
				}
				final Reader reader = new InputStreamReader(new BufferedInputStream(is));
				try {
					cxn.add(reader, baseURL, RDFFormat.N3);
				} finally {
					reader.close();
				}
				cxn.commit();
			} catch (OpenRDFException ex) {
				cxn.rollback();
				throw ex;
			}
		} finally {
			// close the repository connection
			cxn.close();
		}
	}

	/*
	 * Execute sparql select query.
	 */
	public static TupleQueryResult executeSelectQuery(final Repository repo, final String query,
			final QueryLanguage ql) throws OpenRDFException  {

		RepositoryConnection cxn;
		if (repo instanceof BigdataSailRepository) {
			cxn = ((BigdataSailRepository) repo).getReadOnlyConnection();
		} else {
			cxn = repo.getConnection();
		}

		try {

			final TupleQuery tupleQuery = cxn.prepareTupleQuery(ql, query);
			tupleQuery.setIncludeInferred(true /* includeInferred */);
			return tupleQuery.evaluate();
			
		} finally {
			// close the repository connection
			cxn.close();
		}
	}
}