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: HasChangedFunctionDescription.java 3521 2007-10-16 10:55:14Z tmorgner $
028 * ------------
029 * (C) Copyright 2006-2007, by Pentaho Corporation.
030 */
031
032 package org.jfree.formula.function.information;
033
034 import org.jfree.formula.function.AbstractFunctionDescription;
035 import org.jfree.formula.function.FunctionCategory;
036 import org.jfree.formula.typing.Type;
037 import org.jfree.formula.typing.coretypes.LogicalType;
038 import org.jfree.formula.typing.coretypes.TextType;
039
040 /**
041 * Creation-Date: 31.10.2006, 17:41:12
042 *
043 * @author Thomas Morgner
044 */
045 public class HasChangedFunctionDescription extends AbstractFunctionDescription
046 {
047 public HasChangedFunctionDescription()
048 {
049 super("org.jfree.formula.function.information.HasChanged-Function");
050 }
051
052 public Type getValueType()
053 {
054 return LogicalType.TYPE;
055 }
056
057 public int getParameterCount()
058 {
059 return 1;
060 }
061
062 public boolean isInfiniteParameterCount()
063 {
064 return true;
065 }
066
067 public Type getParameterType(final int position)
068 {
069 return TextType.TYPE;
070 }
071
072 /**
073 * Defines, whether the parameter at the given position is mandatory. A
074 * mandatory parameter must be filled in, while optional parameters need not
075 * to be filled in.
076 *
077 * @return false
078 */
079 public boolean isParameterMandatory(final int position)
080 {
081 return false;
082 }
083
084 /**
085 * Returns the default value for an optional parameter. If the value returned
086 * here is null, then this either means, that the parameter is mandatory or
087 * that the default value is computed by the expression itself.
088 *
089 * @param position
090 * @return null.
091 */
092 public Object getDefaultValue(final int position)
093 {
094 return null;
095 }
096
097 public boolean isVolatile()
098 {
099 return true;
100 }
101
102 public FunctionCategory getCategory()
103 {
104 return InformationFunctionCategory.CATEGORY;
105 }
106 }