/*
* This program is free software; you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
* Foundation.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* or from the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* 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 Lesser General Public License for more details.
*
* Copyright (c) 2001 - 2013 Object Refinery Ltd, Pentaho Corporation and Contributors.. All rights reserved.
*/
package org.pentaho.reporting.engine.classic.core.filter;
import org.pentaho.reporting.engine.classic.core.ReportElement;
import org.pentaho.reporting.engine.classic.core.function.ExpressionRuntime;
/**
* A data source that always returns null.
*
* @author Thomas Morgner
*/
public final class EmptyDataSource implements DataSource {
/**
* Default-Constructor.
*/
public EmptyDataSource() {
}
/**
* Returns the value for the data source (always null in this case).
*
* @param runtime
* the expression runtime that is used to evaluate formulas and expressions when computing the value of this
* filter.
* @param element
* @return always null.
*/
public Object getValue( final ExpressionRuntime runtime, final ReportElement element ) {
return null;
}
/**
* Clones the data source.
*
* @return a clone.
* @noinspection CloneDoesntCallSuperClone
*/
public EmptyDataSource clone() {
return this;
}
}