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: IfFunction.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 IfFunction implements Function
048 {
049 private static final TypeValuePair RETURN_FALSE = new TypeValuePair(LogicalType.TYPE, Boolean.FALSE);
050
051 public IfFunction()
052 {
053 }
054
055 public String getCanonicalName()
056 {
057 return "IF";
058 }
059
060 public TypeValuePair evaluate(final FormulaContext context,
061 final ParameterCallback parameters)
062 throws EvaluationException
063 {
064 final int parameterCount = parameters.getParameterCount();
065 if (parameterCount < 2)
066 {
067 throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
068 }
069
070 final Type conditionType = parameters.getType(0);
071 final Object conditionValue = parameters.getValue(0);
072 final Boolean condition = context.getTypeRegistry().convertToLogical(conditionType, conditionValue);
073 if(condition == null)
074 {
075 throw new EvaluationException(LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
076 }
077 if (Boolean.TRUE.equals(condition))
078 {
079 final Object value = parameters.getValue(1);
080 final Type type = parameters.getType(1);
081 return new TypeValuePair(type, value);
082 }
083 // if condition is false and no third parameter, return false
084 if(parameterCount == 2 || parameters.getValue(2) == null)
085 {
086 return RETURN_FALSE;
087 }
088 // else return third parameter
089 final Object value = parameters.getValue(2);
090 final Type type = parameters.getType(2);
091 return new TypeValuePair(type, value);
092 }
093 }