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: NotEqualOperator.java 3521 2007-10-16 10:55:14Z tmorgner $
028     * ------------
029     * (C) Copyright 2006-2007, by Pentaho Corporation.
030     */
031    package org.jfree.formula.operators;
032    
033    import org.jfree.formula.lvalues.TypeValuePair;
034    import org.jfree.formula.EvaluationException;
035    import org.jfree.formula.FormulaContext;
036    import org.jfree.formula.typing.TypeRegistry;
037    import org.jfree.formula.typing.ExtendedComparator;
038    import org.jfree.formula.typing.coretypes.LogicalType;
039    
040    /**
041     * Creation-Date: 31.10.2006, 16:34:11
042     *
043     * @author Thomas Morgner
044     */
045    public class NotEqualOperator implements InfixOperator
046    {
047      private static final TypeValuePair RETURN_TRUE = new TypeValuePair(LogicalType.TYPE, Boolean.TRUE);
048      private static final TypeValuePair RETURN_FALSE = new TypeValuePair(LogicalType.TYPE, Boolean.FALSE);
049    
050      public NotEqualOperator()
051      {
052      }
053    
054      public TypeValuePair evaluate(final FormulaContext context,
055                                    final TypeValuePair value1, final TypeValuePair value2)
056          throws EvaluationException
057      {
058        final TypeRegistry typeRegistry = context.getTypeRegistry();
059    
060        final ExtendedComparator comparator =
061            typeRegistry.getComparator(value1.getType(), value2.getType());
062        final boolean result = comparator.isEqual
063            (value1.getType(), value1.getValue(),
064                value2.getType(), value2.getValue());
065    
066        if (result == false)
067        {
068          return RETURN_TRUE;
069        }
070        else
071        {
072          return RETURN_FALSE;
073        }
074      }
075    
076      public int getLevel()
077      {
078        return 400;
079      }
080    
081      public String toString()
082      {
083        return "<>";
084      }
085    
086      /**
087       * Defines the bind-direction of the operator. That direction defines, in
088       * which direction a sequence of equal operators is resolved.
089       *
090       * @return true, if the operation is left-binding, false if right-binding
091       */
092      public boolean isLeftOperation()
093      {
094        return true;
095      }
096    
097      /**
098       * Defines, whether the operation is associative. For associative operations,
099       * the evaluation order does not matter, if the operation appears more than
100       * once in an expression, and therefore we can optimize them a lot better than
101       * non-associative operations (ie. merge constant parts and precompute them
102       * once).
103       *
104       * @return true, if the operation is associative, false otherwise
105       */
106      public boolean isAssociative()
107      {
108        return false;
109      }
110    
111    }