net.sf.jasperreports.engine.data.JRHibernateListDataSource Maven / Gradle / Ivy
/*
* JasperReports - Free Java Reporting Library.
* Copyright (C) 2001 - 2016 TIBCO Software Inc. 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 .
*/
package net.sf.jasperreports.engine.data;
import java.util.Iterator;
import java.util.List;
import net.sf.jasperreports.engine.JRRewindableDataSource;
import net.sf.jasperreports.engine.query.JRHibernateQueryExecuter;
/**
* Hibernate data source that uses org.hibernate.Query.list()
.
*
* The query result can be paginated by not retrieving all the rows at once.
*
* @author Lucian Chirita ([email protected])
* @see net.sf.jasperreports.engine.query.JRHibernateQueryExecuterFactory#PROPERTY_HIBERNATE_QUERY_LIST_PAGE_SIZE
*/
public class JRHibernateListDataSource extends JRHibernateAbstractDataSource implements JRRewindableDataSource
{
private final int pageSize;
private int pageCount;
private boolean nextPage;
private List returnValues;
private Iterator iterator;
public JRHibernateListDataSource(JRHibernateQueryExecuter queryExecuter, boolean useFieldDescription, int pageSize)
{
super(queryExecuter, useFieldDescription, false);
this.pageSize = pageSize;
pageCount = 0;
fetchPage();
}
protected void fetchPage()
{
if (pageSize <= 0)
{
returnValues = queryExecuter.list();
nextPage = false;
}
else
{
returnValues = queryExecuter.list(pageCount * pageSize, pageSize);
nextPage = returnValues.size() == pageSize;
}
++pageCount;
initIterator();
}
@Override
public boolean next()
{
if (iterator == null)
{
return false;
}
boolean hasNext = iterator.hasNext();
if (!hasNext && nextPage)
{
fetchPage();
hasNext = iterator != null && iterator.hasNext();
}
if (hasNext)
{
setCurrentRowValue(iterator.next());
}
return hasNext;
}
@Override
public void moveFirst()
{
if (pageCount == 1)
{
initIterator();
}
else
{
pageCount = 0;
fetchPage();
}
}
private void initIterator()
{
iterator = returnValues == null ? null : returnValues.iterator();
}
}