Source for org.jfree.formula.function.information.IsErrorFunction

   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: IsErrorFunction.java,v 1.4 2007/04/01 13:51:52 taqua Exp $
  28:  * ------------
  29:  * (C) Copyright 2006-2007, by Pentaho Corporation.
  30:  */
  31: package org.jfree.formula.function.information;
  32: 
  33: import org.jfree.formula.ErrorValue;
  34: import org.jfree.formula.EvaluationException;
  35: import org.jfree.formula.FormulaContext;
  36: import org.jfree.formula.LibFormulaErrorValue;
  37: import org.jfree.formula.function.Function;
  38: import org.jfree.formula.function.ParameterCallback;
  39: import org.jfree.formula.lvalues.TypeValuePair;
  40: import org.jfree.formula.typing.Type;
  41: import org.jfree.formula.typing.coretypes.ErrorType;
  42: import org.jfree.formula.typing.coretypes.LogicalType;
  43: 
  44: /**
  45:  * This function returns true if the parameter is of error.
  46:  *
  47:  * @author Cedric Pronzato
  48:  *
  49:  */
  50: public class IsErrorFunction implements Function
  51: {
  52:   private static final TypeValuePair RETURN_TRUE = new TypeValuePair(LogicalType.TYPE, Boolean.TRUE);
  53:   private static final TypeValuePair RETURN_FALSE = new TypeValuePair(LogicalType.TYPE, Boolean.FALSE);
  54: 
  55:   public IsErrorFunction()
  56:   {
  57:   }
  58: 
  59:   public TypeValuePair evaluate(FormulaContext context, ParameterCallback parameters) throws EvaluationException
  60:   {
  61:     if(parameters.getParameterCount() != 1)
  62:     {
  63:       throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
  64:     }
  65: 
  66:     try
  67:     {
  68:       final Type type = parameters.getType(0);
  69:       Object value = parameters.getValue(0);
  70: 
  71:       if(ErrorType.TYPE.equals(type) && value instanceof ErrorValue)
  72:       {
  73:         return RETURN_TRUE;
  74:       }
  75:     } catch (EvaluationException e)
  76:     {
  77:       return RETURN_TRUE;
  78:     }
  79: 
  80:     return RETURN_FALSE;
  81:   }
  82: 
  83:   public String getCanonicalName()
  84:   {
  85:     return "ISERROR";
  86:   }
  87: 
  88: }