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: PlusSignOperator.java 2887 2007-06-06 17:07:52Z taqua $
028     * ------------
029     * (C) Copyright 2006-2007, by Pentaho Corporation.
030     */
031    package org.jfree.formula.operators;
032    
033    import org.jfree.formula.EvaluationException;
034    import org.jfree.formula.FormulaContext;
035    import org.jfree.formula.LibFormulaErrorValue;
036    import org.jfree.formula.lvalues.TypeValuePair;
037    
038    /**
039     * This is a no-op-operator which is equal to "zero plus x".
040     *
041     * @author Thomas Morgner
042     */
043    public class PlusSignOperator implements PrefixOperator
044    {
045      public PlusSignOperator()
046      {
047      }
048    
049      public TypeValuePair evaluate(final FormulaContext context,
050                                    final TypeValuePair value1) throws EvaluationException
051      {
052        if (value1 == null)
053        {
054          // This is fatal, but should never happen.
055          throw new EvaluationException(LibFormulaErrorValue.ERROR_UNEXPECTED_VALUE);
056        }
057        return value1;
058      }
059    
060      public String toString()
061      {
062        return "+";
063      }
064    
065    }