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

   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: IsTextFunction.java 3521 2007-10-16 10:55:14Z tmorgner $
  28:  * ------------
  29:  * (C) Copyright 2006-2007, by Pentaho Corporation.
  30:  */
  31: package org.jfree.formula.function.information;
  32: 
  33: import org.jfree.formula.EvaluationException;
  34: import org.jfree.formula.FormulaContext;
  35: import org.jfree.formula.LibFormulaErrorValue;
  36: import org.jfree.formula.function.Function;
  37: import org.jfree.formula.function.ParameterCallback;
  38: import org.jfree.formula.lvalues.TypeValuePair;
  39: import org.jfree.formula.typing.Type;
  40: import org.jfree.formula.typing.coretypes.LogicalType;
  41: 
  42: /**
  43:  * This function retruns true if the given value is of type Text.
  44:  *
  45:  * @author Cedric Pronzato
  46:  *
  47:  */
  48: public class IsTextFunction implements Function
  49: {
  50:   private static final TypeValuePair RETURN_TRUE = new TypeValuePair(LogicalType.TYPE, Boolean.TRUE);
  51:   private static final TypeValuePair RETURN_FALSE = new TypeValuePair(LogicalType.TYPE, Boolean.FALSE);
  52: 
  53:   public IsTextFunction()
  54:   {
  55:   }
  56: 
  57:   public TypeValuePair evaluate(final FormulaContext context, final ParameterCallback parameters) throws EvaluationException
  58:   {
  59:     final int parameterCount = parameters.getParameterCount();
  60:     if (parameterCount < 1)
  61:     {
  62:       throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
  63:     }
  64: 
  65:     final Type type1 = parameters.getType(0);
  66:     final Object value1 = parameters.getValue(0);
  67:     if(type1.isFlagSet(Type.TEXT_TYPE) || value1 instanceof String)
  68:     {
  69:       return RETURN_TRUE;
  70:     }
  71: 
  72:     return RETURN_FALSE;
  73:   }
  74: 
  75:   public String getCanonicalName()
  76:   {
  77:     return "ISTEXT";
  78:   }
  79: 
  80: }