de.lemo.dms.test.HibernateDBHandler.java Source code

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Here is the source code for de.lemo.dms.test.HibernateDBHandler.java

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/**
 * File ./src/main/java/de/lemo/dms/test/HibernateDBHandler.java
 * Lemo-Data-Management-Server for learning analytics.
 * Copyright (C) 2013
 * Leonard Kappe, Andreas Pursian, Sebastian Schwarzrock, Boris Wenzlaff
 * 
 * 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, either version 3 of the License, or
 * any later version.
 * 
 * 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, see <http://www.gnu.org/licenses/>.
**/

/**
 * File ./main/java/de/lemo/dms/test/HibernateDBHandler.java
 * Date 2013-01-24
 * Project Lemo Learning Analytics
 */

package de.lemo.dms.test;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import org.apache.log4j.Logger;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import de.lemo.dms.db.EQueryType;
import de.lemo.dms.db.IDBHandler;
import de.lemo.dms.db.hibernate.MiningHibernateUtil;

/**
 * Implementation of the IDBHandler interface for Hibernate.
 * 
 * @author s.schwarzrock
 */
public class HibernateDBHandler implements IDBHandler {

    private final Logger logger = Logger.getLogger(this.getClass());
    private final SessionFactory miningSessionFactory = MiningHibernateUtil.getSessionFactory();

    @Override
    public Session getMiningSession() {
        return this.miningSessionFactory.openSession();
    }

    @Override
    /**
     * Saves a list of generic objects to the database.
     * 
     */
    public void saveCollectionToDB(final Session session, final List<Collection<?>> data) {

        final List<Object> objects = new ArrayList<Object>();
        session.clear();
        try {

            for (final Iterator<Collection<?>> iter = data.iterator(); iter.hasNext();) {
                final Collection<?> l = iter.next();
                for (final Iterator<?> iter2 = l.iterator(); iter2.hasNext();) {
                    final Object o = iter2.next();

                    objects.add(o);
                }
            }
            final Transaction tx = session.beginTransaction();
            int classOb = 0;
            String className = "";
            for (int i = 0; i < objects.size(); i++) {

                if (!className.equals("") && !className.equals(objects.get(i).getClass().getName())) {
                    logger.info("Wrote " + classOb + " objects of class " + className);
                    classOb = 0;
                }
                className = objects.get(i).getClass().getName();

                classOb++;
                session.save(objects.get(i));

                if ((i % 50) == 0) {
                    // flush a batch of inserts and release memory:
                    session.flush();
                    session.clear();
                }
            }
            logger.info("Wrote " + classOb + " objects of class " + className + " to database.");
            tx.commit();
            session.clear();

        } catch (final HibernateException e) {
            logger.error(e.getMessage());
        }

    }

    @Override
    /**
     * Save a single object to the database.
     */
    public void saveToDB(final Session session, final Object data) {
        final Transaction tx = session.beginTransaction();
        session.saveOrUpdate(data);
        tx.commit();
        session.clear();

    }

    @Override
    /**
     * Closes the database connection.
     */
    public void closeSession(final Session session) {
        try {
            session.close();
        } catch (final HibernateException he) {
            this.logger.info(he.getMessage());
        }
    }

    @Override
    /**
     * Performs a Hibernate query.
     */
    public List<?> performQuery(final Session session, final EQueryType queryType, final String query) {
        List<?> l = null;
        try {
            if (queryType == EQueryType.SQL) {
                l = session.createSQLQuery(query).list();
            } else if (queryType == EQueryType.HQL) {
                l = session.createQuery(query).list();
            }
        } catch (final HibernateException he) {
            logger.error(he.getMessage());
        }
        return l;
    }
}