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    }