Source for org.jfree.formula.operators.SubtractOperator

   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: SubtractOperator.java 2752 2007-04-10 14:10:41Z taqua $
  28:  * ------------
  29:  * (C) Copyright 2006-2007, by Pentaho Corporation.
  30:  */
  31: package org.jfree.formula.operators;
  32: 
  33: import java.math.BigDecimal;
  34: 
  35: import org.jfree.formula.EvaluationException;
  36: 
  37: /**
  38:  * Creation-Date: 31.10.2006, 16:34:11
  39:  *
  40:  * @author Thomas Morgner
  41:  */
  42: public class SubtractOperator extends AbstractNumericOperator
  43: {
  44:   public SubtractOperator()
  45:   {
  46:   }
  47: 
  48:   protected Number evaluate(final Number number1, final Number number2) throws EvaluationException
  49:   {
  50:     if ((number1 instanceof Integer || number1 instanceof Short) &&
  51:         (number2 instanceof Integer || number2 instanceof Short))
  52:     {
  53:       return new BigDecimal (number1.longValue() - number2.longValue());
  54:     }
  55: 
  56:     final BigDecimal bd1 = new BigDecimal(number1.toString());
  57:     final BigDecimal bd2 = new BigDecimal(number2.toString());
  58:     return bd1.subtract(bd2);
  59:   }
  60: 
  61:   public int getLevel()
  62:   {
  63:     return 200;
  64:   }
  65: 
  66:   public String toString()
  67:   {
  68:     return "-";
  69:   }
  70: 
  71:   public boolean isLeftOperation()
  72:   {
  73:     return true;
  74:   }
  75: 
  76:   /**
  77:    * Defines, whether the operation is associative. For associative operations,
  78:    * the evaluation order does not matter, if the operation appears more than
  79:    * once in an expression, and therefore we can optimize them a lot better than
  80:    * non-associative operations (ie. merge constant parts and precompute them
  81:    * once).
  82:    *
  83:    * @return true, if the operation is associative, false otherwise
  84:    */
  85:   public boolean isAssociative()
  86:   {
  87:     return false;
  88:   }
  89: 
  90: }