Source for org.jfree.formula.function.datetime.YearFunction

   1: /**
   2:  * =========================================
   3:  * LibFormula : a free Java formula library
   4:  * =========================================
   5:  *
   6:  * Project Info:  http://reporting.pentaho.org/libformula/
   7:  *
   8:  * (C) Copyright 2006-2007, by Pentaho Corporation and Contributors.
   9:  *
  10:  * This library is free software; you can redistribute it and/or modify it under the terms
  11:  * of the GNU Lesser General Public License as published by the Free Software Foundation;
  12:  * either version 2.1 of the License, or (at your option) any later version.
  13:  *
  14:  * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
  15:  * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  16:  * See the GNU Lesser General Public License for more details.
  17:  *
  18:  * You should have received a copy of the GNU Lesser General Public License along with this
  19:  * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  20:  * Boston, MA 02111-1307, USA.
  21:  *
  22:  * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
  23:  * in the United States and other countries.]
  24:  *
  25:  *
  26:  * ------------
  27:  * $Id: YearFunction.java 2822 2007-05-20 21:47:52Z mimil $
  28:  * ------------
  29:  * (C) Copyright 2006-2007, by Pentaho Corporation.
  30:  */
  31: package org.jfree.formula.function.datetime;
  32: 
  33: import java.util.Calendar;
  34: import java.util.Date;
  35: 
  36: import org.jfree.formula.EvaluationException;
  37: import org.jfree.formula.FormulaContext;
  38: import org.jfree.formula.LibFormulaErrorValue;
  39: import org.jfree.formula.function.Function;
  40: import org.jfree.formula.function.ParameterCallback;
  41: import org.jfree.formula.lvalues.TypeValuePair;
  42: import org.jfree.formula.typing.TypeRegistry;
  43: import org.jfree.formula.typing.coretypes.NumberType;
  44: import org.jfree.formula.util.DateUtil;
  45: 
  46: /**
  47:  * This function extracts the year from a date.
  48:  * 
  49:  * @author Cedric Pronzato
  50:  */
  51: public class YearFunction implements Function
  52: {
  53:   public YearFunction()
  54:   {
  55:   }
  56: 
  57:   public String getCanonicalName()
  58:   {
  59:     return "YEAR";
  60:   }
  61: 
  62:   public TypeValuePair evaluate(final FormulaContext context,
  63:       final ParameterCallback parameters) throws EvaluationException
  64:   {
  65:     if (parameters.getParameterCount() != 1)
  66:     {
  67:       throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
  68:     }
  69: 
  70:     final TypeRegistry typeRegistry = context.getTypeRegistry();
  71: 
  72:     final Date d = typeRegistry.convertToDate(parameters.getType(0), parameters
  73:         .getValue(0));
  74: 
  75:     if (d == null)
  76:     {
  77:       throw new EvaluationException(
  78:           LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
  79:     }
  80: 
  81:     final Calendar gc = DateUtil.createCalendar(d, context
  82:         .getLocalizationContext());
  83: 
  84:     final int year = gc
  85:             .get(Calendar.YEAR);
  86:     return new TypeValuePair(NumberType.GENERIC_NUMBER, new Integer(year));
  87:   }
  88: }