001    /**
002     * =========================================
003     * LibFormula : a free Java formula library
004     * =========================================
005     *
006     * Project Info:  http://reporting.pentaho.org/libformula/
007     *
008     * (C) Copyright 2006-2007, by Pentaho Corporation and Contributors.
009     *
010     * This library is free software; you can redistribute it and/or modify it under the terms
011     * of the GNU Lesser General Public License as published by the Free Software Foundation;
012     * either version 2.1 of the License, or (at your option) any later version.
013     *
014     * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
015     * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
016     * See the GNU Lesser General Public License for more details.
017     *
018     * You should have received a copy of the GNU Lesser General Public License along with this
019     * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
020     * Boston, MA 02111-1307, USA.
021     *
022     * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
023     * in the United States and other countries.]
024     *
025     *
026     * ------------
027     * $Id: NullFunction.java 3521 2007-10-16 10:55:14Z tmorgner $
028     * ------------
029     * (C) Copyright 2006-2007, by Pentaho Corporation.
030     */
031    
032    package org.jfree.formula.function.userdefined;
033    
034    import org.jfree.formula.FormulaContext;
035    import org.jfree.formula.function.ParameterCallback;
036    import org.jfree.formula.lvalues.TypeValuePair;
037    import org.jfree.formula.typing.coretypes.AnyType;
038    
039    /**
040     * Creation-Date: Dec 18, 2006, 12:54:55 PM
041     *
042     * @author Thomas Morgner
043     */
044    public class NullFunction
045    {
046      private static final TypeValuePair NULL = new TypeValuePair(AnyType.TYPE, null);
047    
048      public NullFunction()
049      {
050      }
051    
052      public String getCanonicalName()
053      {
054        return "NULL";
055      }
056    
057      public TypeValuePair evaluate(final FormulaContext context,
058                                    final ParameterCallback parameters)
059      {
060        return NULL;
061      }
062    
063    }