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

   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: AbsFunction.java,v 1.3 2007/04/10 14:10:41 taqua Exp $
  28:  * ------------
  29:  * (C) Copyright 2006-2007, by Pentaho Corporation.
  30:  */
  31: package org.jfree.formula.function.math;
  32: 
  33: import java.math.BigDecimal;
  34: 
  35: import org.jfree.formula.EvaluationException;
  36: import org.jfree.formula.FormulaContext;
  37: import org.jfree.formula.LibFormulaErrorValue;
  38: import org.jfree.formula.function.Function;
  39: import org.jfree.formula.function.ParameterCallback;
  40: import org.jfree.formula.lvalues.TypeValuePair;
  41: import org.jfree.formula.typing.Type;
  42: import org.jfree.formula.typing.coretypes.NumberType;
  43: 
  44: /**
  45:  * This function returns the absolute (nonnegative) of the value.
  46:  *
  47:  * @author Cedric Pronzato
  48:  *
  49:  */
  50: public class AbsFunction implements Function
  51: {
  52:   public AbsFunction()
  53:   {
  54:   }
  55: 
  56:   public TypeValuePair evaluate(FormulaContext context, ParameterCallback parameters) throws EvaluationException
  57:   {
  58:     final int parameterCount = parameters.getParameterCount();
  59:     if (parameterCount < 1)
  60:     {
  61:       throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
  62:     }
  63:     final Type type1 = parameters.getType(0);
  64:     final Object value1 = parameters.getValue(0);
  65:     final Number result = context.getTypeRegistry().convertToNumber(type1, value1);
  66: 
  67:     final BigDecimal num = new BigDecimal(result.toString());
  68:     return new TypeValuePair(NumberType.GENERIC_NUMBER, num.abs());
  69:   }
  70: 
  71:   public String getCanonicalName()
  72:   {
  73:     return "ABS";
  74:   }
  75: 
  76: }