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: AbstractCompareOperator.java 3522 2007-10-16 10:56:57Z tmorgner $
028     * ------------
029     * (C) Copyright 2006-2007, by Pentaho Corporation.
030     */
031    
032    package org.jfree.formula.operators;
033    
034    import org.jfree.formula.lvalues.TypeValuePair;
035    import org.jfree.formula.FormulaContext;
036    import org.jfree.formula.EvaluationException;
037    import org.jfree.formula.LibFormulaErrorValue;
038    import org.jfree.formula.typing.TypeRegistry;
039    import org.jfree.formula.typing.Type;
040    import org.jfree.formula.typing.ExtendedComparator;
041    import org.jfree.formula.typing.coretypes.LogicalType;
042    
043    /**
044     * Creation-Date: 06.06.2007, 18:52:25
045     *
046     * @author Thomas Morgner
047     */
048    public abstract class AbstractCompareOperator implements InfixOperator
049    {
050      private static final TypeValuePair RETURN_TRUE = new TypeValuePair(LogicalType.TYPE, Boolean.TRUE);
051      private static final TypeValuePair RETURN_FALSE = new TypeValuePair(LogicalType.TYPE, Boolean.FALSE);
052    
053      public AbstractCompareOperator()
054      {
055      }
056    
057      public final TypeValuePair evaluate(final FormulaContext context,
058                                          final TypeValuePair value1,
059                                          final TypeValuePair value2)
060          throws EvaluationException
061      {
062        final TypeRegistry typeRegistry = context.getTypeRegistry();
063        final Type type1 = value1.getType();
064        final Type type2 = value2.getType();
065        final Object value1Raw = value1.getValue();
066        final Object value2Raw = value2.getValue();
067        if (value1Raw == null || value2Raw == null)
068        {
069          throw new EvaluationException(LibFormulaErrorValue.ERROR_NA_VALUE);
070        }
071    
072        final ExtendedComparator comparator = typeRegistry.getComparator(type1, type2);
073        final Integer result = comparator.compare (type1, value1Raw, type2, value2Raw);
074        if (result == null)
075        {
076          throw new EvaluationException
077              (LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
078        }
079    
080        if (evaluate(result.intValue()))
081        {
082          return RETURN_TRUE;
083        }
084        return RETURN_FALSE;
085      }
086    
087      protected abstract boolean evaluate(int compareResult);
088    }