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: ReplaceFunction.java 2785 2007-05-08 11:12:25Z 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 text where an old text is substituted with a new text.
045     *
046     * @author Cedric Pronzato
047     */
048    public class ReplaceFunction implements Function
049    {
050      public ReplaceFunction()
051      {
052      }
053    
054      public TypeValuePair evaluate(final FormulaContext context,
055                                    final ParameterCallback parameters) throws EvaluationException
056      {
057        final int parameterCount = parameters.getParameterCount();
058        if (parameterCount != 4)
059        {
060          throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
061        }
062        final TypeRegistry typeRegistry = context.getTypeRegistry();
063    
064        final Type newTextType = parameters.getType(3);
065        final Object newTextValue = parameters.getValue(3);
066        final Type textType = parameters.getType(0);
067        final Object textValue = parameters.getValue(0);
068        final Type startType = parameters.getType(1);
069        final Object startValue = parameters.getValue(1);
070        final Type lengthType = parameters.getType(2);
071        final Object lengthValue = parameters.getValue(2);
072    
073        final String newText = typeRegistry.convertToText(newTextType, newTextValue);
074        final String text = typeRegistry.convertToText(textType, textValue);
075        final Number start = typeRegistry.convertToNumber(startType, startValue);
076        final Number length = typeRegistry.convertToNumber(lengthType, lengthValue);
077        
078        final MidFunction function = new MidFunction();
079        final String result1 = function.process(text, new Integer(1), new Integer(start.intValue() - 1));
080        final String result2 = function.process(text,
081            new Integer(start.intValue() + length.intValue()), new Integer(text.length()));
082    
083    
084        final StringBuffer buffer = new StringBuffer();
085        buffer.append(result1);
086        buffer.append(newText);
087        buffer.append(result2);
088        return new TypeValuePair(TextType.TYPE, buffer.toString());
089      }
090    
091      public String getCanonicalName()
092      {
093        return "REPLACE";
094      }
095    
096    }