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: SumFunction.java 3186 2007-08-15 16:54:01Z mimil $
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.typing.sequence.NumberSequence;
042    import org.jfree.formula.util.NumberUtil;
043    
044    import java.math.BigDecimal;
045    
046    /**
047     * Creation-Date: 31.10.2006, 17:39:19
048     *
049     * @author Thomas Morgner
050     */
051    public class SumFunction implements Function
052    {
053      public static final BigDecimal ZERO = new BigDecimal(0);
054    
055      public SumFunction()
056      {
057      }
058    
059      public String getCanonicalName()
060      {
061        return "SUM";
062      }
063    
064      public TypeValuePair evaluate(final FormulaContext context,
065                                    final ParameterCallback parameters)
066          throws EvaluationException
067      {
068        BigDecimal computedResult = ZERO;
069        final int parameterCount = parameters.getParameterCount();
070    
071        if (parameterCount == 0)
072        {
073          throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
074        }
075    
076        for (int paramIdx = 0; paramIdx < parameterCount; paramIdx++)
077        {
078          final Type type = parameters.getType(paramIdx);
079          final Object value = parameters.getValue(paramIdx);
080          final NumberSequence sequence = context.getTypeRegistry().convertToNumberSequence(type, value);
081    
082          while (sequence.hasNext())
083          {
084            computedResult = compute(sequence.nextNumber(), computedResult);
085          }
086        }
087    
088        return new TypeValuePair(NumberType.GENERIC_NUMBER, computedResult);
089      }
090    
091      private BigDecimal compute(final Number value,
092                                 final BigDecimal computedResult) throws EvaluationException
093      {
094        if (value == null)
095        {
096          // no-op ..
097          return computedResult;
098        }
099    
100        return computedResult.add(NumberUtil.getAsBigDecimal(value));
101      }
102    }