JRHibernateScrollDataSource.java

/*
 * JasperReports - Free Java Reporting Library.
 * Copyright (C) 2001 - 2009 Jaspersoft Corporation. All rights reserved.
 * http://www.jaspersoft.com
 *
 * Unless you have purchased a commercial license agreement from Jaspersoft,
 * the following license terms apply:
 *
 * This program is part of JasperReports.
 *
 * JasperReports 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 3 of the License, or
 * (at your option) any later version.
 *
 * JasperReports 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 JasperReports. If not, see <http://www.gnu.org/licenses/>.
 */
package net.sf.jasperreports.engine.data;

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

import org.hibernate.ScrollableResults;

/**
 * Hibernate data source that uses <code>org.hibernate.Query.scroll()</code>.
 * 
 * @author Lucian Chirita (lucianc@users.sourceforge.net)
 * @version $Id: JRHibernateScrollDataSource.java 3659 2010-03-31 10:20:49Z shertage $
 */
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();
	}
}