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 4100 2007-11-26 21:04:25Z dkincade $
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    import org.jfree.formula.typing.coretypes.NumberType;
042    
043    /**
044     * Creation-Date: 02.11.2006, 10:27:03
045     *
046     * @author Thomas Morgner
047     */
048    public class MinusSignOperator implements PrefixOperator
049    {
050      private static final BigDecimal ZERO = new BigDecimal(0);
051    
052    
053      public MinusSignOperator()
054      {
055      }
056    
057      public TypeValuePair evaluate(final FormulaContext context,
058                                    final TypeValuePair value1)
059          throws EvaluationException
060      {
061        final Type type = value1.getType();
062        final Object val = value1.getValue();
063        if (val == null)
064        {
065          throw new EvaluationException(LibFormulaErrorValue.ERROR_NA_VALUE);
066        }
067        
068        if (type.isFlagSet(Type.NUMERIC_TYPE))
069        {
070          final TypeRegistry typeRegistry = context.getTypeRegistry();
071          // return the same as zero minus value.
072          final Number number = typeRegistry.convertToNumber(type, val);
073          final BigDecimal value = getAsBigDecimal(number);
074          return new TypeValuePair(NumberType.GENERIC_NUMBER, ZERO.subtract(value));
075        }
076    
077        if(val instanceof Number)
078        {
079          final BigDecimal value = getAsBigDecimal((Number)val);
080          return new TypeValuePair(type, ZERO.subtract(value));
081        }
082    
083        throw new EvaluationException
084            (LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
085      }
086    
087      private BigDecimal getAsBigDecimal(final Number number)
088      {
089        if (number instanceof BigDecimal)
090        {
091          return (BigDecimal) number;
092        }
093        return new BigDecimal(number.toString());
094      }
095    
096      public String toString()
097      {
098        return "-";
099      }
100    }