Source for org.jfree.formula.operators.AbstractNumericOperator

   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: AbstractNumericOperator.java 2887 2007-06-06 17:07:52Z taqua $
  28:  * ------------
  29:  * (C) Copyright 2006-2007, by Pentaho Corporation.
  30:  */
  31: 
  32: package org.jfree.formula.operators;
  33: 
  34: import org.jfree.formula.EvaluationException;
  35: import org.jfree.formula.FormulaContext;
  36: import org.jfree.formula.LibFormulaErrorValue;
  37: import org.jfree.formula.lvalues.TypeValuePair;
  38: import org.jfree.formula.typing.TypeRegistry;
  39: import org.jfree.formula.typing.TypeRegistryUtility;
  40: import org.jfree.formula.typing.coretypes.NumberType;
  41: 
  42: /**
  43:  * Creation-Date: 10.04.2007, 15:02:39
  44:  *
  45:  * @author Thomas Morgner
  46:  */
  47: public abstract class AbstractNumericOperator implements InfixOperator
  48: {
  49:   protected static final Number ZERO = new Integer(0);
  50: 
  51:   protected AbstractNumericOperator()
  52:   {
  53:   }
  54: 
  55:   public final TypeValuePair evaluate(final FormulaContext context,
  56:                                       final TypeValuePair value1,
  57:                                       final TypeValuePair value2)
  58:       throws EvaluationException
  59:   {
  60:     final TypeRegistry typeRegistry = context.getTypeRegistry();
  61: 
  62:     if (value1 == null || value2 == null)
  63:     {
  64:       // If this happens, then one of the implementations has messed up.
  65:       throw new EvaluationException(LibFormulaErrorValue.ERROR_UNEXPECTED_VALUE);
  66:     }
  67: 
  68:     final Object raw1 = value1.getValue();
  69:     final Object raw2 = value2.getValue();
  70:     if (raw1 == null || raw2 == null)
  71:     {
  72:       throw new EvaluationException (LibFormulaErrorValue.ERROR_NA_VALUE);
  73:     }
  74: 
  75:     final Number number1 = TypeRegistryUtility.convertToNumber(typeRegistry, value1.getType(), raw1, ZERO);
  76:     final Number number2 = TypeRegistryUtility.convertToNumber(typeRegistry, value2.getType(), raw2, ZERO);
  77:     return new TypeValuePair(NumberType.GENERIC_NUMBER, evaluate(number1, number2));
  78:   }
  79: 
  80:   protected abstract Number evaluate (final Number number1, final Number number2) throws EvaluationException;
  81: }