Thu, 31 Aug 2017 15:18:52 +0800
merge
1 /*
2 * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
26 /*
27 * @(#)UniqueValue.java 1.6 02/03/27
28 */
32 package com.sun.xml.internal.messaging.saaj.packaging.mime.internet;
35 /**
36 * This is a utility class that generates unique values. The generated
37 * String contains only US-ASCII characters and hence is safe for use
38 * in RFC822 headers. <p>
39 *
40 * This is a package private class.
41 *
42 * @author John Mani
43 * @author Max Spivak
44 * @author Bill Shannon
45 */
47 class UniqueValue {
48 /**
49 * A global part number. Access is not synchronized because the
50 * value is only one part of the unique value and so doesn't need
51 * to be accurate.
52 */
53 private static int part = 0;
55 /**
56 * Get a unique value for use in a multipart boundary string.
57 *
58 * This implementation generates it by concatenating a global
59 * part number, a newly created object's <code>hashCode()</code>,
60 * and the current time (in milliseconds).
61 */
62 public static String getUniqueBoundaryValue() {
63 StringBuffer s = new StringBuffer();
65 // Unique string is ----=_Part_<part>_<hashcode>.<currentTime>
66 s.append("----=_Part_").append(part++).append("_").
67 append(s.hashCode()).append('.').
68 append(System.currentTimeMillis());
69 return s.toString();
70 }
71 }