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

   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: SubstituteFunction.java,v 1.5 2007/04/10 14:10:41 taqua Exp $
  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 text where an old text is substituted with a new text.
  45:  *
  46:  * @author Cedric Pronzato
  47:  */
  48: public class SubstituteFunction implements Function
  49: {
  50:   public SubstituteFunction()
  51:   {
  52:   }
  53: 
  54:   public TypeValuePair evaluate(final FormulaContext context,
  55:                                 final ParameterCallback parameters)
  56:       throws EvaluationException
  57:   {
  58:     final int parameterCount = parameters.getParameterCount();
  59:     if (parameterCount < 3 || parameterCount > 4)
  60:     {
  61:       throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
  62:     }
  63:     final TypeRegistry typeRegistry = context.getTypeRegistry();
  64: 
  65:     final Type newTextType = parameters.getType(2);
  66:     final Object newTextValue = parameters.getValue(2);
  67:     final Type textType = parameters.getType(0);
  68:     final Object textValue = parameters.getValue(0);
  69:     final Type oldTextType = parameters.getType(1);
  70:     final Object oldTextValue = parameters.getValue(1);
  71: 
  72:     final String newText = typeRegistry.convertToText(newTextType, newTextValue);
  73:     final String text = typeRegistry.convertToText(textType, textValue);
  74:     final String oldText = typeRegistry.convertToText(oldTextType, oldTextValue);
  75: 
  76:     if (parameterCount == 3)
  77:     {
  78:       int index = text.indexOf(oldText);
  79:       if (index == -1)
  80:       {
  81:         return new TypeValuePair(TextType.TYPE, text);
  82:       }
  83: 
  84:       String result = text;
  85:       while (index >= 0)
  86:       {
  87:         final StringBuffer buffer = new StringBuffer(result);
  88:         buffer.replace(index, index + oldText.length(), newText);
  89:         result = buffer.toString();
  90:         index = result.indexOf(oldText, index + newText.length());
  91:       }
  92:       return new TypeValuePair(TextType.TYPE, result);
  93:     }
  94: 
  95:     // Instead of replacing all occurences, the user only requested to replace
  96:     // a specific one.
  97:     final Type whichType = parameters.getType(3);
  98:     final Object whichValue = parameters.getValue(3);
  99:     final Number n = typeRegistry.convertToNumber(whichType, whichValue);
 100:     if (n.doubleValue() < 1)
 101:     {
 102:       throw new EvaluationException(
 103:           LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
 104:     }
 105: 
 106:     final int nthOccurence = n.intValue();
 107: 
 108:     int index = text.indexOf(oldText);
 109:     if (index == -1)
 110:     {
 111:       return new TypeValuePair(TextType.TYPE, text);
 112:     }
 113: 
 114:     String result = text;
 115:     int counter = 1;
 116:     while (index >= 0)
 117:     {
 118:       if (counter == nthOccurence)
 119:       {
 120:         final StringBuffer buffer = new StringBuffer(result);
 121:         buffer.replace(index, index + oldText.length(), newText);
 122:         result = buffer.toString();
 123:         index = result.indexOf(oldText, index + newText.length());
 124:       }
 125:       else
 126:       {
 127:         index = result.indexOf(oldText, index + 1);
 128:       }
 129:       counter += 1;
 130:     }
 131:     return new TypeValuePair(TextType.TYPE, result);
 132:   }
 133: 
 134:   public String getCanonicalName()
 135:   {
 136:     return "SUBSTITUTE";
 137:   }
 138: