/*
 * ============================================================================
 * GNU Lesser General Public License
 * ============================================================================
 *
 * JasperReports - Free Java report-generating library.
 * Copyright (C) 2001-2006 JasperSoft Corporation http://www.jaspersoft.com
 * 
 * This library 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 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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 library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307, USA.
 * 
 * JasperSoft Corporation
 * 303 Second Street, Suite 450 North
 * San Francisco, CA 94107
 * http://www.jaspersoft.com
 */
package net.sf.jasperreports.engine.data;

import org.hibernate.ScrollableResults;

import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.JRRewindableDataSource;
import net.sf.jasperreports.engine.query.JRHibernateQueryExecuter;

/**
 * Hibernate data source that uses <code>org.hibernate.Query.scroll()</code>.
 * 
 * @author Lucian Chirita (lucianc@users.sourceforge.net)
 * @version $Id: JRHibernateScrollDataSource.java,v 1.2 2006/04/19 10:18:26 teodord Exp $
 */
public class JRHibernateScrollDataSource extends JRHibernateAbstractDataSource implements JRRewindableDataSource
{
	private ScrollableResults scrollableResults;

	public JRHibernateScrollDataSource(JRHibernateQueryExecuter queryExecuter, boolean useFieldDescription)
	{
		super(queryExecuter, useFieldDescription, true);

		scrollableResults = queryExecuter.scroll();
	}

	public boolean next() throws JRException
	{
		if (scrollableResults != null && scrollableResults.next())
		{
			setCurrentRowValue(scrollableResults.get());
			return true;
		}
		
		return false;
	}

	public void moveFirst()
	{
		queryExecuter.closeScrollableResults();
		scrollableResults = queryExecuter.scroll();
	}
}