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: ModFunction.java 3521 2007-10-16 10:55:14Z tmorgner $
028     * ------------
029     * (C) Copyright 2006-2007, by Pentaho Corporation.
030     */
031    package org.jfree.formula.function.math;
032    
033    import org.jfree.formula.EvaluationException;
034    import org.jfree.formula.FormulaContext;
035    import org.jfree.formula.LibFormulaErrorValue;
036    import org.jfree.formula.function.Function;
037    import org.jfree.formula.function.ParameterCallback;
038    import org.jfree.formula.lvalues.TypeValuePair;
039    import org.jfree.formula.typing.Type;
040    import org.jfree.formula.typing.coretypes.NumberType;
041    import org.jfree.formula.util.NumberUtil;
042    
043    import java.math.BigDecimal;
044    
045    /**
046     * This function returns the remainder when one number is divided by another number.
047     *
048     * @author Cedric Pronzato
049     */
050    public class ModFunction implements Function
051    {
052      public ModFunction()
053      {
054      }
055    
056      public TypeValuePair evaluate(final FormulaContext context, final ParameterCallback parameters) throws EvaluationException
057      {
058        final int parameterCount = parameters.getParameterCount();
059        if (parameterCount != 2)
060        {
061          throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
062        }
063        final Type type1 = parameters.getType(0);
064        final Object value1 = parameters.getValue(0);
065        final BigDecimal divided = NumberUtil.getAsBigDecimal(context.getTypeRegistry().convertToNumber(type1, value1));
066        final Type type2 = parameters.getType(1);
067        final Object value2 = parameters.getValue(1);
068        final BigDecimal divisor = NumberUtil.getAsBigDecimal(context.getTypeRegistry().convertToNumber(type2, value2));
069        if(divisor.signum() == 0)
070        {
071          throw new EvaluationException(LibFormulaErrorValue.ERROR_ARITHMETIC_VALUE);
072        }
073    
074        final BigDecimal divide = new BigDecimal(divided.divide(divisor, 0, BigDecimal.ROUND_FLOOR).intValue());
075        BigDecimal reminder = divided.subtract(divisor.multiply(divide));
076        if(divide.signum() == 0)
077        {
078          if((divided.signum() == -1 && divisor.signum() != -1) || (divisor.signum() == -1 && divided.signum() != -1))
079          {
080            reminder = divided.add(divisor);
081          }
082        }
083    
084        return new TypeValuePair(NumberType.GENERIC_NUMBER, reminder);
085      }
086    
087      public String getCanonicalName()
088      {
089        return "MOD";
090      }
091    
092    }