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: MinusSignOperator.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 java.math.BigDecimal;
034    
035    import org.jfree.formula.EvaluationException;
036    import org.jfree.formula.FormulaContext;
037    import org.jfree.formula.LibFormulaErrorValue;
038    import org.jfree.formula.lvalues.TypeValuePair;
039    import org.jfree.formula.typing.Type;
040    import org.jfree.formula.typing.TypeRegistry;
041    
042    /**
043     * Creation-Date: 02.11.2006, 10:27:03
044     *
045     * @author Thomas Morgner
046     */
047    public class MinusSignOperator implements PrefixOperator
048    {
049      private static final BigDecimal ZERO = new BigDecimal(0);
050    
051    
052      public MinusSignOperator()
053      {
054      }
055    
056      public TypeValuePair evaluate(final FormulaContext context,
057                                    final TypeValuePair value1)
058          throws EvaluationException
059      {
060        final Type type = value1.getType();
061        final Object val = value1.getValue();
062        if (val == null)
063        {
064          throw new EvaluationException(LibFormulaErrorValue.ERROR_NA_VALUE);
065        }
066        
067        if (type.isFlagSet(Type.NUMERIC_TYPE))
068        {
069          final TypeRegistry typeRegistry = context.getTypeRegistry();
070          // return the same as zero minus value.
071          final Number number = typeRegistry.convertToNumber(type, val);
072          final BigDecimal value = getAsBigDecimal(number);
073          return new TypeValuePair(type, ZERO.subtract(value));
074        }
075    
076        if(val instanceof Number)
077        {
078          final BigDecimal value = getAsBigDecimal((Number)val);
079          return new TypeValuePair(type, ZERO.subtract(value));
080        }
081    
082        throw new EvaluationException
083            (LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
084      }
085    
086      private BigDecimal getAsBigDecimal(final Number number)
087      {
088        if (number instanceof BigDecimal)
089        {
090          return (BigDecimal) number;
091        }
092        return new BigDecimal(number.toString());
093      }
094    
095      public String toString()
096      {
097        return "-";
098      }
099    }