Source for org.jfree.formula.function.math.SumFunction

   1: /**
   2:  * =========================================
   3:  * LibFormula : a free Java formula library
   4:  * =========================================
   5:  *
   6:  * Project Info:  http://reporting.pentaho.org/libformula/
   7:  *
   8:  * (C) Copyright 2006-2007, by Pentaho Corporation and Contributors.
   9:  *
  10:  * This library is free software; you can redistribute it and/or modify it under the terms
  11:  * of the GNU Lesser General Public License as published by the Free Software Foundation;
  12:  * either version 2.1 of the License, or (at your option) any later version.
  13:  *
  14:  * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
  15:  * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  16:  * See the GNU Lesser General Public License for more details.
  17:  *
  18:  * You should have received a copy of the GNU Lesser General Public License along with this
  19:  * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  20:  * Boston, MA 02111-1307, USA.
  21:  *
  22:  * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
  23:  * in the United States and other countries.]
  24:  *
  25:  *
  26:  * ------------
  27:  * $Id: SumFunction.java 3186 2007-08-15 16:54:01Z mimil $
  28:  * ------------
  29:  * (C) Copyright 2006-2007, by Pentaho Corporation.
  30:  */
  31: package org.jfree.formula.function.math;
  32: 
  33: import org.jfree.formula.EvaluationException;
  34: import org.jfree.formula.FormulaContext;
  35: import org.jfree.formula.LibFormulaErrorValue;
  36: import org.jfree.formula.function.Function;
  37: import org.jfree.formula.function.ParameterCallback;
  38: import org.jfree.formula.lvalues.TypeValuePair;
  39: import org.jfree.formula.typing.Type;
  40: import org.jfree.formula.typing.coretypes.NumberType;
  41: import org.jfree.formula.typing.sequence.NumberSequence;
  42: import org.jfree.formula.util.NumberUtil;
  43: 
  44: import java.math.BigDecimal;
  45: 
  46: /**
  47:  * Creation-Date: 31.10.2006, 17:39:19
  48:  *
  49:  * @author Thomas Morgner
  50:  */
  51: public class SumFunction implements Function
  52: {
  53:   public static final BigDecimal ZERO = new BigDecimal(0);
  54: 
  55:   public SumFunction()
  56:   {
  57:   }
  58: 
  59:   public String getCanonicalName()
  60:   {
  61:     return "SUM";
  62:   }
  63: 
  64:   public TypeValuePair evaluate(final FormulaContext context,
  65:                                 final ParameterCallback parameters)
  66:       throws EvaluationException
  67:   {
  68:     BigDecimal computedResult = ZERO;
  69:     final int parameterCount = parameters.getParameterCount();
  70: 
  71:     if (parameterCount == 0)
  72:     {
  73:       throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
  74:     }
  75: 
  76:     for (int paramIdx = 0; paramIdx < parameterCount; paramIdx++)
  77:     {
  78:       final Type type = parameters.getType(paramIdx);
  79:       final Object value = parameters.getValue(paramIdx);
  80:       final NumberSequence sequence = context.getTypeRegistry().convertToNumberSequence(type, value);
  81: 
  82:       while (sequence.hasNext())
  83:       {
  84:         computedResult = compute(sequence.nextNumber(), computedResult);
  85:       }
  86:     }
  87: 
  88:     return new TypeValuePair(NumberType.GENERIC_NUMBER, computedResult);
  89:   }
  90: 
  91:   private BigDecimal compute(final Number value,
  92:                              final BigDecimal computedResult) throws EvaluationException
  93:   {
  94:     if (value == null)
  95:     {
  96:       // no-op ..
  97:       return computedResult;
  98:     }
  99: 
 100:     return computedResult.add(NumberUtil.getAsBigDecimal(value));
 101:   }
 102: }