Source for org.jfree.formula.operators.NotEqualOperator

   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: NotEqualOperator.java,v 1.6 2007/04/01 13:51:54 taqua Exp $
  28:  * ------------
  29:  * (C) Copyright 2006-2007, by Pentaho Corporation.
  30:  */
  31: package org.jfree.formula.operators;
  32: 
  33: import org.jfree.formula.lvalues.TypeValuePair;
  34: import org.jfree.formula.EvaluationException;
  35: import org.jfree.formula.FormulaContext;
  36: import org.jfree.formula.typing.TypeRegistry;
  37: import org.jfree.formula.typing.ExtendedComparator;
  38: import org.jfree.formula.typing.coretypes.LogicalType;
  39: 
  40: /**
  41:  * Creation-Date: 31.10.2006, 16:34:11
  42:  *
  43:  * @author Thomas Morgner
  44:  */
  45: public class NotEqualOperator implements InfixOperator
  46: {
  47:   private static final TypeValuePair RETURN_TRUE = new TypeValuePair(LogicalType.TYPE, Boolean.TRUE);
  48:   private static final TypeValuePair RETURN_FALSE = new TypeValuePair(LogicalType.TYPE, Boolean.FALSE);
  49: 
  50:   public NotEqualOperator()
  51:   {
  52:   }
  53: 
  54:   public TypeValuePair evaluate(final FormulaContext context,
  55:                                 TypeValuePair value1, TypeValuePair value2)
  56:       throws EvaluationException
  57:   {
  58:     final TypeRegistry typeRegistry = context.getTypeRegistry();
  59: 
  60:     final ExtendedComparator comparator =
  61:         typeRegistry.getComparator(value1.getType(), value2.getType());
  62:     final boolean result = comparator.isEqual
  63:         (value1.getType(), value1.getValue(),
  64:             value2.getType(), value2.getValue());
  65: 
  66:     if (result == false)
  67:     {
  68:       return RETURN_TRUE;
  69:     }
  70:     else
  71:     {
  72:       return RETURN_FALSE;
  73:     }
  74:   }
  75: 
  76:   public int getLevel()
  77:   {
  78:     return 400;
  79:   }
  80: 
  81:   public String toString()
  82:   {
  83:     return "<>";
  84:   }
  85: 
  86:   /**
  87:    * Defines the bind-direction of the operator. That direction defines, in
  88:    * which direction a sequence of equal operators is resolved.
  89:    *
  90:    * @return true, if the operation is left-binding, false if right-binding
  91:    */
  92:   public boolean isLeftOperation()
  93:   {
  94:     return true;
  95:   }
  96: 
  97:   /**
  98:    * Defines, whether the operation is associative. For associative operations,
  99:    * 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: }