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: SubstituteFunction.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 text where an old text is substituted with a new text.
045 *
046 * @author Cedric Pronzato
047 */
048 public class SubstituteFunction implements Function
049 {
050 public SubstituteFunction()
051 {
052 }
053
054 public TypeValuePair evaluate(final FormulaContext context,
055 final ParameterCallback parameters)
056 throws EvaluationException
057 {
058 final int parameterCount = parameters.getParameterCount();
059 if (parameterCount < 3 || parameterCount > 4)
060 {
061 throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
062 }
063 final TypeRegistry typeRegistry = context.getTypeRegistry();
064
065 final Type newTextType = parameters.getType(2);
066 final Object newTextValue = parameters.getValue(2);
067 final Type textType = parameters.getType(0);
068 final Object textValue = parameters.getValue(0);
069 final Type oldTextType = parameters.getType(1);
070 final Object oldTextValue = parameters.getValue(1);
071
072 final String newText = typeRegistry.convertToText(newTextType, newTextValue);
073 final String text = typeRegistry.convertToText(textType, textValue);
074 final String oldText = typeRegistry.convertToText(oldTextType, oldTextValue);
075
076 if (parameterCount == 3)
077 {
078 int index = text.indexOf(oldText);
079 if (index == -1)
080 {
081 return new TypeValuePair(TextType.TYPE, text);
082 }
083
084 String result = text;
085 while (index >= 0)
086 {
087 final StringBuffer buffer = new StringBuffer(result);
088 buffer.replace(index, index + oldText.length(), newText);
089 result = buffer.toString();
090 index = result.indexOf(oldText, index + newText.length());
091 }
092 return new TypeValuePair(TextType.TYPE, result);
093 }
094
095 // Instead of replacing all occurences, the user only requested to replace
096 // a specific one.
097 final Type whichType = parameters.getType(3);
098 final Object whichValue = parameters.getValue(3);
099 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
139 }