com.sun.xml.messaging.saaj.packaging.mime.internet.UniqueValue Maven / Gradle / Ivy
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/*
* Copyright (c) 1997, 2020 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0, which is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
/*
* @(#)UniqueValue.java 1.6 02/03/27
*/
package com.sun.xml.messaging.saaj.packaging.mime.internet;
/**
* This is a utility class that generates unique values. The generated
* String contains only US-ASCII characters and hence is safe for use
* in RFC822 headers.
*
* This is a package private class.
*
* @author John Mani
* @author Max Spivak
* @author Bill Shannon
*/
class UniqueValue {
/**
* A global part number. Access is not synchronized because the
* value is only one part of the unique value and so doesn't need
* to be accurate.
*/
private static int part = 0;
/**
* Get a unique value for use in a multipart boundary string.
*
* This implementation generates it by concatenating a global
* part number, a newly created object's hashCode(),
* and the current time (in milliseconds).
*/
public static String getUniqueBoundaryValue() {
StringBuilder s = new StringBuilder();
// Unique string is ----=_Part__.
s.append("----=_Part_").append(part++).append("_").
append(s.hashCode()).append('.').
append(System.currentTimeMillis());
return s.toString();
}
}