Source code: nextapp/echoservlet/util/Version.java
1 /*
2 * This file is part of the Echo Web Application Framework (hereinafter "Echo").
3 * Copyright (C) 2002-2004 NextApp, Inc.
4 *
5 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
6 *
7 * The contents of this file are subject to the Mozilla Public License Version
8 * 1.1 (the "License"); you may not use this file except in compliance with
9 * the License. You may obtain a copy of the License at
10 * http://www.mozilla.org/MPL/
11 *
12 * Software distributed under the License is distributed on an "AS IS" basis,
13 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
14 * for the specific language governing rights and limitations under the
15 * License.
16 *
17 * Alternatively, the contents of this file may be used under the terms of
18 * either the GNU General Public License Version 2 or later (the "GPL"), or
19 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
20 * in which case the provisions of the GPL or the LGPL are applicable instead
21 * of those above. If you wish to allow use of your version of this file only
22 * under the terms of either the GPL or the LGPL, and not to allow others to
23 * use your version of this file under the terms of the MPL, indicate your
24 * decision by deleting the provisions above and replace them with the notice
25 * and other provisions required by the GPL or the LGPL. If you do not delete
26 * the provisions above, a recipient may use your version of this file under
27 * the terms of any one of the MPL, the GPL or the LGPL.
28 */
29
30 package nextapp.echoservlet.util;
31
32 import java.util.StringTokenizer;
33
34 /**
35 * Utility class for comparing version numbers in String format. This class
36 * may be used to determine if a version number is greater than another to
37 * make a hypothesis about whether the version is compatible with a
38 * requirement.
39 */
40 public final class Version {
41
42 /**
43 * Tests to see if a version number meets or exceeds a requirement.
44 * For example, if version 1.4 is required, 1.4, 1.4.0, 1.4.1, 1.5,
45 * and 2.0 would meet the requirement. 0.7, 1, 1.0, 1.3, and
46 * 1.3.5 would not. Warning: At this time all versions must be numeric and
47 * separated by periods. Any deviation will result in .0 versions, such as
48 * 1.5.3b being calculated as 1.5.0.
49 *
50 * @param requiredVersion The version number that is required.
51 * @param testVersion The version number that is available.
52 * @return True if the tested version is equal to or higher than the
53 * requirement.
54 */
55 public static final boolean meetsRequirement(String requiredVersion, String testVersion) {
56 StringTokenizer reqTokenizer = new StringTokenizer(requiredVersion, ".");
57 StringTokenizer testTokenizer = new StringTokenizer(testVersion, ".");
58 boolean value = true;
59
60 int reqValue;
61 int testValue;
62
63 while (value && (reqTokenizer.hasMoreTokens() || testTokenizer.hasMoreTokens())) {
64 if (reqTokenizer.hasMoreTokens()) {
65 reqValue = getTokenValue(reqTokenizer.nextToken());
66 } else {
67 reqValue = 0;
68 }
69 if (testTokenizer.hasMoreTokens()) {
70 testValue = getTokenValue(testTokenizer.nextToken());
71 } else {
72 testValue = 0;
73 }
74
75 if (testValue > reqValue) {
76 break;
77 } else if (testValue < reqValue) {
78 value = false;
79 }
80 }
81
82 return value;
83 }
84
85 /**
86 * Returns a best guess translation of a string to an integer.
87 * If the string is not numeric, zero is returned.
88 *
89 * @param token A string that may or may not contain a number.
90 * @return The string's value, forcibly converted into a number.
91 */
92 private static final int getTokenValue(String token) {
93 int value;
94
95 try {
96 value = Integer.parseInt(token);
97 } catch (NumberFormatException ex) {
98 value = 0;
99 }
100
101 return value;
102 }
103
104 /** Non-instantiable class. */
105 private Version() { }
106 }