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: RightFunction.java 2752 2007-04-10 14:10:41Z taqua $
028     * ------------
029     * (C) Copyright 2006-2007, by Pentaho Corporation.
030     */
031    package org.jfree.formula.function.text;
032    
033    import org.jfree.formula.EvaluationException;
034    import org.jfree.formula.FormulaContext;
035    import org.jfree.formula.LibFormulaErrorValue;
036    import org.jfree.formula.function.Function;
037    import org.jfree.formula.function.ParameterCallback;
038    import org.jfree.formula.lvalues.TypeValuePair;
039    import org.jfree.formula.typing.Type;
040    import org.jfree.formula.typing.TypeRegistry;
041    import org.jfree.formula.typing.coretypes.TextType;
042    
043    /**
044     * This function returns a selected number of text characters from the right.<br/>
045     * This function depends on <code>MidFunction</code>.
046     *
047     * @see MidFunction
048     *
049     * @author Cedric Pronzato
050     *
051     */
052    public class RightFunction implements Function
053    {
054      public RightFunction()
055      {
056      }
057    
058      public TypeValuePair evaluate(final FormulaContext context,
059                                    final ParameterCallback parameters) throws EvaluationException
060      {
061        final int parameterCount = parameters.getParameterCount();
062        if (parameterCount < 1 || parameterCount > 2)
063        {
064          throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
065        }
066        final TypeRegistry typeRegistry = context.getTypeRegistry();
067    
068        final Type textType = parameters.getType(0);
069        final Object textValue = parameters.getValue(0);
070    
071        final String text = typeRegistry.convertToText(textType, textValue);
072        final int length;
073        if(parameterCount == 2)
074        {
075          final Number lengthVal = typeRegistry.convertToNumber(parameters.getType(1), parameters.getValue(1));
076          if (lengthVal.doubleValue() < 0)
077          {
078            throw new EvaluationException(LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
079          }
080          length = lengthVal.intValue();
081        }
082        else
083        {
084          length = 1;
085        }
086    
087        if(text == null || length < 0)
088        {
089          throw new EvaluationException(LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
090        }
091    
092        int s = text.length()-length +1;
093        if(s < 1)
094        {
095          s = 1;
096        }
097        final MidFunction function = new MidFunction();
098        return new TypeValuePair(TextType.TYPE, function.process(text, new Integer(s), new Integer(length)));
099      }
100    
101      public String getCanonicalName()
102      {
103        return "RIGHT";
104      }
105    
106    }