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: EqualOperator.java 2887 2007-06-06 17:07:52Z taqua $
028     * ------------
029     * (C) Copyright 2006-2007, by Pentaho Corporation.
030     */
031    package org.jfree.formula.operators;
032    
033    import org.jfree.formula.EvaluationException;
034    import org.jfree.formula.FormulaContext;
035    import org.jfree.formula.LibFormulaErrorValue;
036    import org.jfree.formula.typing.ExtendedComparator;
037    import org.jfree.formula.typing.TypeRegistry;
038    import org.jfree.formula.typing.Type;
039    import org.jfree.formula.typing.coretypes.LogicalType;
040    import org.jfree.formula.lvalues.TypeValuePair;
041    
042    /**
043     * Creation-Date: 31.10.2006, 16:34:11
044     *
045     * @author Thomas Morgner
046     */
047    public class EqualOperator implements InfixOperator
048    {
049      private static final TypeValuePair RETURN_TRUE = new TypeValuePair(LogicalType.TYPE, Boolean.TRUE);
050      private static final TypeValuePair RETURN_FALSE = new TypeValuePair(LogicalType.TYPE, Boolean.FALSE);
051    
052      public EqualOperator()
053      {
054      }
055    
056      public TypeValuePair evaluate(final FormulaContext context,
057                                    final TypeValuePair value1,
058                                    final TypeValuePair value2)
059          throws EvaluationException
060      {
061        final TypeRegistry typeRegistry = context.getTypeRegistry();
062        final Object value1Raw = value1.getValue();
063        final Object value2Raw = value2.getValue();
064        if (value1Raw == null || value2Raw == null)
065        {
066          throw new EvaluationException(LibFormulaErrorValue.ERROR_NA_VALUE);
067        }
068    
069        final Type type1 = value1.getType();
070        final Type type2 = value2.getType();
071        final ExtendedComparator comparator = typeRegistry.getComparator(type1, type2);
072        final boolean result = comparator.isEqual (type1, value1Raw, type2, value2Raw);
073        if (result)
074        {
075          return RETURN_TRUE;
076        }
077        else
078        {
079          return RETURN_FALSE;
080        }
081      }
082    
083      public int getLevel()
084      {
085        return 400;
086      }
087    
088    
089      public String toString()
090      {
091        return "=";
092      }
093    
094      public boolean isLeftOperation()
095      {
096        return true;
097      }
098    
099      /**
100       * Defines, whether the operation is associative. For associative operations,
101       * the evaluation order does not matter, if the operation appears more than
102       * once in an expression, and therefore we can optimize them a lot better than
103       * non-associative operations (ie. merge constant parts and precompute them
104       * once).
105       *
106       * @return true, if the operation is associative, false otherwise
107       */
108      public boolean isAssociative()
109      {
110        return false;
111      }
112    
113    }