1 /***
2 * Redistribution and use of this software and associated documentation
3 * ("Software"), with or without modification, are permitted provided
4 * that the following conditions are met:
5 *
6 * 1. Redistributions of source code must retain copyright
7 * statements and notices. Redistributions must also contain a
8 * copy of this document.
9 *
10 * 2. Redistributions in binary form must reproduce the
11 * above copyright notice, this list of conditions and the
12 * following disclaimer in the documentation and/or other
13 * materials provided with the distribution.
14 *
15 * 3. The name "Exolab" must not be used to endorse or promote
16 * products derived from this Software without prior written
17 * permission of Exoffice Technologies. For written permission,
18 * please contact info@exolab.org.
19 *
20 * 4. Products derived from this Software may not be called "Exolab"
21 * nor may "Exolab" appear in their names without prior written
22 * permission of Exoffice Technologies. Exolab is a registered
23 * trademark of Exoffice Technologies.
24 *
25 * 5. Due credit should be given to the Exolab Project
26 * (http://www.exolab.org/).
27 *
28 * THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS
29 * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
30 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
31 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
32 * EXOFFICE TECHNOLOGIES OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
33 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
34 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
35 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
37 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
38 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
39 * OF THE POSSIBILITY OF SUCH DAMAGE.
40 *
41 * Copyright 2000-2001,2003 (C) Exoffice Technologies Inc. All Rights Reserved.
42 */
43
44 package org.exolab.jms.selector.parser;
45
46 import org.exolab.jms.selector.SelectorException;
47
48
49 /***
50 * This class validates the format of patterns and escape characters used
51 * in 'like' expressions.
52 *
53 * @version $Revision: 1.1 $ $Date: 2004/11/26 01:50:45 $
54 * @author <a href="mailto:tma@netspace.net.au">Tim Anderson</a>
55 * @see SelectorAST
56 * @see SelectorParser
57 */
58 final class PatternValidator {
59
60 /***
61 * Private constructor
62 */
63 private PatternValidator() {
64 }
65
66 /***
67 * Validate a pattern and escape
68 *
69 * @param patternNode the pattern node
70 * @param escapeNode the escape node. May be null.
71 * @throws SelectorException if the pattern or escape node are invalid
72 */
73 public static void validate(final SelectorAST patternNode,
74 final SelectorAST escapeNode)
75 throws SelectorException {
76
77 String pattern = patternNode.getText();
78
79 if (escapeNode != null) {
80 String escape = escapeNode.getText();
81 if (escape.length() != 1) {
82 String msg = "escape must be a single character";
83 throw new SelectorException(escapeNode.getContext(), msg);
84 }
85
86 char esc = escape.charAt(0);
87 for (int i = 0; i < pattern.length(); ++i) {
88 char ch = pattern.charAt(i);
89 if (pattern.charAt(i) == esc) {
90 if (++i >= pattern.length()) {
91 String msg = "invalid pattern: no character "
92 + "following last escape character";
93 throw new SelectorException(patternNode.getContext(),
94 msg);
95 }
96 }
97 }
98 }
99 }
100
101 }