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    }