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: XorFunction.java 3521 2007-10-16 10:55:14Z tmorgner $
028 * ------------
029 * (C) Copyright 2006-2007, by Pentaho Corporation.
030 */
031 package org.jfree.formula.function.logical;
032
033 import org.jfree.formula.EvaluationException;
034 import org.jfree.formula.FormulaContext;
035 import org.jfree.formula.LibFormulaErrorValue;
036 import org.jfree.formula.function.Function;
037 import org.jfree.formula.function.ParameterCallback;
038 import org.jfree.formula.lvalues.TypeValuePair;
039 import org.jfree.formula.typing.Type;
040 import org.jfree.formula.typing.coretypes.LogicalType;
041
042 /**
043 * Creation-Date: 04.11.2006, 18:28:15
044 *
045 * @author Thomas Morgner
046 */
047 public class XorFunction implements Function
048 {
049 private static final TypeValuePair RETURN_FALSE = new TypeValuePair(LogicalType.TYPE, Boolean.FALSE);
050 private static final TypeValuePair RETURN_TRUE = new TypeValuePair(LogicalType.TYPE, Boolean.TRUE);
051
052
053 public XorFunction()
054 {
055 }
056
057 public String getCanonicalName()
058 {
059 return "XOR";
060 }
061
062
063 public TypeValuePair evaluate(final FormulaContext context,
064 final ParameterCallback parameters)
065 throws EvaluationException
066 {
067 if(parameters.getParameterCount() < 1)
068 {
069 throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
070 }
071 int count = 0;
072 final int parameterCount = parameters.getParameterCount();
073 for (int i = 0; i < parameterCount; i++)
074 {
075 final Type conditionType = parameters.getType(i);
076 final Object conditionValue = parameters.getValue(i);
077 final Boolean condition = context.getTypeRegistry().convertToLogical(conditionType, conditionValue);
078 if(condition == null)
079 {
080 throw new EvaluationException(LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
081 }
082 if (Boolean.TRUE.equals(condition))
083 {
084 count += 1;
085 }
086 }
087 if (count == 1)
088 {
089 return RETURN_TRUE;
090 }
091 else
092 {
093 return RETURN_FALSE;
094 }
095
096 }
097 }