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: DateValueFunction.java 3522 2007-10-16 10:56:57Z tmorgner $
028     * ------------
029     * (C) Copyright 2006-2007, by Pentaho Corporation.
030     */
031    package org.jfree.formula.function.datetime;
032    
033    import java.util.Date;
034    
035    import org.jfree.formula.EvaluationException;
036    import org.jfree.formula.FormulaContext;
037    import org.jfree.formula.LibFormulaErrorValue;
038    import org.jfree.formula.function.Function;
039    import org.jfree.formula.function.ParameterCallback;
040    import org.jfree.formula.lvalues.TypeValuePair;
041    import org.jfree.formula.typing.Type;
042    import org.jfree.formula.typing.TypeRegistry;
043    import org.jfree.formula.typing.coretypes.DateTimeType;
044    
045    /**
046     * This function returns
047     * 
048     * 
049     * @author Cedric Pronzato
050     */
051    public class DateValueFunction implements Function
052    {
053    
054      public DateValueFunction()
055      {
056      }
057    
058      public String getCanonicalName()
059      {
060        return "DATEVALUE";
061      }
062    
063      public TypeValuePair evaluate(final FormulaContext context,
064          final ParameterCallback parameters) throws EvaluationException
065      {
066        if (parameters.getParameterCount() != 1)
067        {
068          throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
069        }
070    
071        final TypeRegistry typeRegistry = context.getTypeRegistry();
072        final Type type = parameters.getType(0);
073        final Object value = parameters.getValue(0);
074    
075        final Date date1 = typeRegistry.convertToDate(type, value);
076        return new TypeValuePair(DateTimeType.DATE_TYPE, date1);
077    
078      }
079    }