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 }