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: AbstractNumericOperator.java 2887 2007-06-06 17:07:52Z taqua $
028     * ------------
029     * (C) Copyright 2006-2007, by Pentaho Corporation.
030     */
031    
032    package org.jfree.formula.operators;
033    
034    import org.jfree.formula.EvaluationException;
035    import org.jfree.formula.FormulaContext;
036    import org.jfree.formula.LibFormulaErrorValue;
037    import org.jfree.formula.lvalues.TypeValuePair;
038    import org.jfree.formula.typing.TypeRegistry;
039    import org.jfree.formula.typing.TypeRegistryUtility;
040    import org.jfree.formula.typing.coretypes.NumberType;
041    
042    /**
043     * Creation-Date: 10.04.2007, 15:02:39
044     *
045     * @author Thomas Morgner
046     */
047    public abstract class AbstractNumericOperator implements InfixOperator
048    {
049      protected static final Number ZERO = new Integer(0);
050    
051      protected AbstractNumericOperator()
052      {
053      }
054    
055      public final TypeValuePair evaluate(final FormulaContext context,
056                                          final TypeValuePair value1,
057                                          final TypeValuePair value2)
058          throws EvaluationException
059      {
060        final TypeRegistry typeRegistry = context.getTypeRegistry();
061    
062        if (value1 == null || value2 == null)
063        {
064          // If this happens, then one of the implementations has messed up.
065          throw new EvaluationException(LibFormulaErrorValue.ERROR_UNEXPECTED_VALUE);
066        }
067    
068        final Object raw1 = value1.getValue();
069        final Object raw2 = value2.getValue();
070        if (raw1 == null || raw2 == null)
071        {
072          throw new EvaluationException (LibFormulaErrorValue.ERROR_NA_VALUE);
073        }
074    
075        final Number number1 = TypeRegistryUtility.convertToNumber(typeRegistry, value1.getType(), raw1, ZERO);
076        final Number number2 = TypeRegistryUtility.convertToNumber(typeRegistry, value2.getType(), raw2, ZERO);
077        return new TypeValuePair(NumberType.GENERIC_NUMBER, evaluate(number1, number2));
078      }
079    
080      protected abstract Number evaluate (final Number number1, final Number number2) throws EvaluationException;
081    }