/**
* ========================================
* JFreeReport : a free Java report library
* ========================================
*
* Project Info: http://reporting.pentaho.org/
*
* (C) Copyright 2000-2007, by Object Refinery Limited, Pentaho Corporation and Contributors.
*
* 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.
*
* [Java is a trademark or registered trademark of Sun Microsystems, Inc.
* in the United States and other countries.]
*
* ------------
* $Id: IsEmptyDataExpression.java 6659 2008-12-02 15:35:06Z tmorgner $
* ------------
* (C) Copyright 2000-2005, by Object Refinery Limited.
* (C) Copyright 2005-2007, by Pentaho Corporation.
*/
package org.jfree.report.expressions.sys;
import org.jfree.report.DataSourceException;
import org.jfree.report.ReportData;
import org.jfree.report.expressions.AbstractExpression;
import org.jfree.report.expressions.ExpressionRuntime;
/**
* Creation-Date: 31.01.2006, 18:55:09
*
* @author Thomas Morgner
*/
public class IsEmptyDataExpression extends AbstractExpression
{
public IsEmptyDataExpression()
{
}
/**
* Return the current expression value. <P> The value depends (obviously) on
* the expression implementation.
*
* @return the value of the function.
*/
public Object computeValue() throws DataSourceException
{
final ExpressionRuntime runtime = getRuntime();
if (runtime == null)
{
return null;
}
final ReportData data = runtime.getData();
if (data == null)
{
return null;
}
synchronized(data)
{
if (data.getCursorPosition() > 0)
{
return Boolean.FALSE;
}
if (data.isAdvanceable() == false)
{
return Boolean.TRUE;
}
return Boolean.FALSE;
}
}
}