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Java > Open Source Codes > org > mr > api > jms > selector > syntax > RegexpFactory


1 /*
2  * Copyright 2002 by
3  * <a HREF="http://www.coridan.com">Coridan</a>
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6  * The contents of this file are subject to the Mozilla Public License Version
7  * 1.1 (the "License"); you may not use this file except in compliance with the
8  * License. You may obtain a copy of the License at
9  * http://www.mozilla.org/MPL/
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11  * Software distributed under the License is distributed on an "AS IS" basis,
12  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
13  * for the specific language governing rights and limitations under the
14  * License.
15  *
16  * The Original Code is "MantaRay" (TM).
17  *
18  * The Initial Developer of the Original Code is Coridan.
19  * Portions created by the Initial Developer are Copyright (C) 2006
20  * Coridan Inc. All Rights Reserved.
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23  * code where applicable.
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25  * Alternatively, the contents of this file may be used under the terms of the
26  * LGPL license (the "GNU LESSER GENERAL PUBLIC LICENSE"), in which case the
27  * provisions of LGPL are applicable instead of those above. If you wish to
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32  * If you do not delete the provisions above, a recipient may use your version
33  * of this file under either the MPL or the GNU LESSER GENERAL PUBLIC LICENSE.
34  
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36  * This library is free software; you can redistribute it and/or modify it
37  * under the terms of the MPL as stated above or under the terms of the GNU
38  * Lesser General Public License as published by the Free Software Foundation;
39  * either version 2.1 of the License, or any later version.
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41  * This library is distributed in the hope that it will be useful, but WITHOUT
42  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
43  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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45  */
46 package org.mr.api.jms.selector.syntax;
47
48
49 import java.util.regex.Pattern JavaDoc;
50 import java.util.regex.PatternSyntaxException JavaDoc;
51
52
53 /**
54  * Regular expression factory. This creates a regular expression for a given
55  * SQL92 pattern and escape character.
56  *
57  */
58 final class RegexpFactory {
59
60     /**
61      * Private constructor,we don't want to create a new RegexpFactory
62      */
63     private RegexpFactory() {
64     }//RegexpFactory
65
66
67     /**
68      * Converts the pattern and escape to an ORO Pattern
69      *
70      * @param pattern the pattern
71      * @param escape the escape character. May be null
72      * @return an ORO Pattern corresponding to pattern and escape
73      * @throws InvalidRegexpException if pattern or escape are invalid
74      */
75     public static Pattern JavaDoc create(final String JavaDoc pattern, final Character JavaDoc escape) throws InvalidRegexpException {
76
77         StringBuffer JavaDoc buff = new StringBuffer JavaDoc();
78         buff.append('^');
79
80         for (int i = 0; i < pattern.length(); ++i) {
81             boolean escaped = false;
82             char ch = pattern.charAt(i);
83             if (escape != null && ch == escape.charValue()) {
84                 if (++i < pattern.length()) {
85                     ch = pattern.charAt(i);
86                     escaped = true;
87                 }//if
88 else {
89                     throw new InvalidRegexpException(pattern);
90                 }//else
91 }//if
92
93             switch (ch) {
94                 case '_':
95                     if (escaped) {
96                         buff.append(ch);
97                     }//if
98 else {
99                         buff.append('.');
100                     }//else
101 break;
102                 case '%':
103                     if (escaped) {
104                         buff.append(ch);
105                     }//if
106 else {
107                         buff.append(".*");
108                     }//else
109 break;
110                 case '.':
111                 case '[':
112                 case ']':
113                 case '\\':
114                 case '+':
115                 case '?':
116                 case '{':
117                 case '}':
118                 case '$':
119                 case '^':
120                 case '|':
121                 case '(':
122                 case ')':
123                     // the above are all special characters that need to be
124 // escaped.
125 buff.append('\\');
126                     buff.append(ch);
127                     break;
128                 default:
129                     buff.append(ch);
130             }//switch
131 }//for
132 buff.append('$');
133
134         Pattern JavaDoc result = null;
135         try {
136             //Perl5Compiler compiler = new Perl5Compiler();
137 //result = compiler.compile(buff.toString());
138 result = Pattern.compile(buff.toString());
139         }//try
140 catch (PatternSyntaxException JavaDoc exception) {
141             // coding error if this gets thrown here...
142 throw new InvalidRegexpException(pattern);
143         }//catch
144 return result;
145     }//create
146 }//RegexpFactory
147
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