Source for org.jfree.formula.function.text.RightFunction

   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: RightFunction.java 2752 2007-04-10 14:10:41Z taqua $
  28:  * ------------
  29:  * (C) Copyright 2006-2007, by Pentaho Corporation.
  30:  */
  31: package org.jfree.formula.function.text;
  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.TypeRegistry;
  41: import org.jfree.formula.typing.coretypes.TextType;
  42: 
  43: /**
  44:  * This function returns a selected number of text characters from the right.<br/>
  45:  * This function depends on <code>MidFunction</code>.
  46:  *
  47:  * @see MidFunction
  48:  *
  49:  * @author Cedric Pronzato
  50:  *
  51:  */
  52: public class RightFunction implements Function
  53: {
  54:   public RightFunction()
  55:   {
  56:   }
  57: 
  58:   public TypeValuePair evaluate(final FormulaContext context,
  59:                                 final ParameterCallback parameters) throws EvaluationException
  60:   {
  61:     final int parameterCount = parameters.getParameterCount();
  62:     if (parameterCount < 1 || parameterCount > 2)
  63:     {
  64:       throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
  65:     }
  66:     final TypeRegistry typeRegistry = context.getTypeRegistry();
  67: 
  68:     final Type textType = parameters.getType(0);
  69:     final Object textValue = parameters.getValue(0);
  70: 
  71:     final String text = typeRegistry.convertToText(textType, textValue);
  72:     final int length;
  73:     if(parameterCount == 2)
  74:     {
  75:       final Number lengthVal = typeRegistry.convertToNumber(parameters.getType(1), parameters.getValue(1));
  76:       if (lengthVal.doubleValue() < 0)
  77:       {
  78:         throw new EvaluationException(LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
  79:       }
  80:       length = lengthVal.intValue();
  81:     }
  82:     else
  83:     {
  84:       length = 1;
  85:     }
  86: 
  87:     if(text == null || length < 0)
  88:     {
  89:       throw new EvaluationException(LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
  90:     }
  91: 
  92:     int s = text.length()-length +1;
  93:     if(s < 1)
  94:     {
  95:       s = 1;
  96:     }
  97:     final MidFunction function = new MidFunction();
  98:     return new TypeValuePair(TextType.TYPE, function.process(text, new Integer(s), new Integer(length)));
  99:   }
 100: 
 101:   public String getCanonicalName()
 102:   {
 103:     return "RIGHT";
 104:   }
 105: