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: NullFunctionDescription.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.userdefined;
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.AnyType;
038
039 /**
040 * Creation-Date: 04.11.2006, 18:28:55
041 *
042 * @author Thomas Morgner
043 */
044 public class NullFunctionDescription extends AbstractFunctionDescription
045 {
046 public NullFunctionDescription()
047 {
048 super("org.jfree.formula.function.userdefined.Null-Function");
049 }
050
051 public int getParameterCount()
052 {
053 return 0;
054 }
055
056 public boolean isInfiniteParameterCount()
057 {
058 return false;
059 }
060
061 public Type getParameterType(final int position)
062 {
063 return AnyType.TYPE;
064 }
065
066 public Type getValueType()
067 {
068 return AnyType.TYPE;
069 }
070
071 /**
072 * Defines, whether the parameter at the given position is mandatory. A
073 * mandatory parameter must be filled in, while optional parameters need not
074 * to be filled in.
075 *
076 * @return
077 */
078 public boolean isParameterMandatory(final int position)
079 {
080 return false;
081 }
082
083 /**
084 * Returns the default value for an optional parameter. If the value returned
085 * here is null, then this either means, that the parameter is mandatory or
086 * that the default value is computed by the expression itself.
087 *
088 * @param position
089 * @return
090 */
091 public Object getDefaultValue(final int position)
092 {
093 return null;
094 }
095
096 public FunctionCategory getCategory()
097 {
098 return UserDefinedFunctionCategory.CATEGORY;
099 }
100
101 }