net.antidot.semantic.rdf.rdb2rdf.dm.core.DirectMapper.java Source code

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Here is the source code for net.antidot.semantic.rdf.rdb2rdf.dm.core.DirectMapper.java

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/* 
 * Copyright 2011-2013 Antidot opensource@antidot.net
 * https://github.com/antidot/db2triples
 * 
 * This file is part of DB2Triples
 *
 * DB2Triples is free software; you can redistribute it and/or 
 * modify it under the terms of the GNU Lesser General Public License as 
 * published by the Free Software Foundation; either version 2 of 
 * the License, or (at your option) any later version.
 * 
 * DB2Triples 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 Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
/***************************************************************************
 *
 * Direct Mapping : Direct Mapper
 *
 * The Direct Mapper is the main composant which starts the mapping.
 * Its goal consists to extracts generic tuples of a given database in cursor
 * mode and to convert every of them. 
 *
 ****************************************************************************/
package net.antidot.semantic.rdf.rdb2rdf.dm.core;

import java.io.UnsupportedEncodingException;
import java.sql.Connection;
import java.util.HashMap;
import java.util.HashSet;

import net.antidot.semantic.rdf.model.impl.sesame.SesameDataSet;
import net.antidot.semantic.rdf.rdb2rdf.dm.core.DirectMappingEngine.Version;
import net.antidot.sql.model.core.DriverType;
import net.antidot.sql.model.db.Key;
import net.antidot.sql.model.db.Tuple;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.openrdf.model.Statement;

public abstract class DirectMapper extends Thread {

    // Log
    private static Log log = LogFactory.getLog(DirectMapper.class);

    // Namespaces
    public static HashMap<String, String> prefix = new HashMap<String, String>();

    // Load prefix
    static {
        prefix.put("rdf", "http://www.w3.org/1999/02/22-rdf-syntax-ns#");
        prefix.put("rdfs", "http://www.w3.org/2000/01/rdf-schema#");
        prefix.put("xsd", "http://www.w3.org/2001/XMLSchema#");
    }

    // Metrics 
    private static int nbTriples;
    private static int lastModulo;

    public static SesameDataSet generateDirectMapping(Connection conn, Version version, DriverType driver,
            String baseURI, String timeZone, String fileToNativeStore) throws UnsupportedEncodingException {
        log.info("Generate Direct Mapping...");
        Long start = System.currentTimeMillis();
        SesameDataSet result = null;
        // Check if use of native store is required
        if (fileToNativeStore != null) {
            result = new SesameDataSet(fileToNativeStore, false);
        } else {
            result = new SesameDataSet();
        }
        DirectMappingEngine dme = null;
        switch (version) {
        case WD_20110324:
            dme = new DirectMappingEngineWD20110324();
            break;
        case WD_20120529:
            dme = new DirectMappingEngineWD20120529();
            break;
        default:
            // Working draft Mars 2011 by default
            dme = new DirectMappingEngineWD20110324();
            break;
        }
        TupleExtractor te = new TupleExtractor(conn, dme, driver, timeZone);
        nbTriples = 0;
        lastModulo = 0;
        while (te.next()) {
            convertNextTuple(result, te, dme, driver, baseURI);
        }
        Float stop = Float.valueOf(System.currentTimeMillis() - start) / 1000;
        log.info("Database extracted in " + stop + " seconds.");
        log.info(nbTriples + " triples has been extracted.");
        return result;
    }

    private static void convertNextTuple(SesameDataSet result, TupleExtractor te, DirectMappingEngine dme,
            DriverType driver, String baseURI) throws UnsupportedEncodingException {
        Tuple tuple = te.getCurrentTuple();
        //Tuple tuple = null;
        log.debug("[DirectMapper:convertNextTuple] Tuple extracted : " + tuple);
        try {
            // Extract referenced rows
            HashMap<Key, Tuple> referencedTuples = te.getReferencedTuples(driver, tuple);
            // Extract primary-is-foreign Key 
            Key primaryIsForeignKey = te.getCurrentPrimaryIsForeignKey(referencedTuples.keySet(), tuple);
            log.debug("[DirectMapper:convertNextTuple] Number of referenced tuples generated : "
                    + referencedTuples.values().size());

            HashSet<Statement> statements = dme.extractTriplesFrom(tuple, referencedTuples, primaryIsForeignKey,
                    baseURI);
            for (Statement triple : statements) {
                log.debug("[DirectMapper:convertNextTuple] Triple generated : " + triple);
                result.add(triple.getSubject(), triple.getPredicate(), triple.getObject());
                nbTriples++;
            }
            if (nbTriples / 50000 > lastModulo) {
                log.info(nbTriples + " triples has already been extracted.");
                lastModulo = nbTriples / 50000;
            }
        } catch (UnsupportedEncodingException e) {
            log.error("[DirectMapper:generateDirectMapping] Encoding not supported.");
            e.printStackTrace();
        }
    }

}