1 /* 2 * Copyright (c) 1997, 2013, 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 */ 25 26 /* 27 * @(#)UniqueValue.java 1.6 02/03/27 28 */ 29 30 31 32 package com.sun.xml.internal.messaging.saaj.packaging.mime.internet; 33 34 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 */ 46 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; 54 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(); 64 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 }