Java example source code file (SessionId.java)

This example Java source code file (SessionId.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

object, override, randomcookie, securerandom, security, sessionid, stringbuffer

The SessionId.java Java example source code

/*
 * Copyright (c) 1996, 2012, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */


package sun.security.ssl;

import java.security.SecureRandom;

/**
 * Encapsulates an SSL session ID.  SSL Session IDs are not reused by
 * servers during the lifetime of any sessions it created.  Sessions may
 * be used by many connections, either concurrently (for example, two
 * connections to a web server at the same time) or sequentially (over as
 * long a time period as is allowed by a given server).
 *
 * @author Satish Dharmaraj
 * @author David Brownell
 */
final
class SessionId
{
    private byte sessionId [];          // max 32 bytes

    /** Constructs a new session ID ... perhaps for a rejoinable session */
    SessionId (boolean isRejoinable, SecureRandom generator)
    {
        if (isRejoinable)
            // this will be unique, it's a timestamp plus much randomness
            sessionId = new RandomCookie (generator).random_bytes;
        else
            sessionId = new byte [0];
    }

    /** Constructs a session ID from a byte array (max size 32 bytes) */
    SessionId (byte sessionId [])
        { this.sessionId = sessionId; }

    /** Returns the length of the ID, in bytes */
    int length ()
        { return sessionId.length; }

    /** Returns the bytes in the ID.  May be an empty array.  */
    byte [] getId ()
    {
        return sessionId.clone ();
    }

    /** Returns the ID as a string */
    @Override
    public String toString ()
    {
        int             len = sessionId.length;
        StringBuffer    s = new StringBuffer (10 + 2 * len);

        s.append ("{");
        for (int i = 0; i < len; i++) {
            s.append (0x0ff & sessionId [i]);
            if (i != (len - 1))
                s.append (", ");
        }
        s.append ("}");
        return s.toString ();
    }


    /** Returns a value which is the same for session IDs which are equal */
    @Override
    public int hashCode ()
    {
        int     retval = 0;

        for (int i = 0; i < sessionId.length; i++)
            retval += sessionId [i];
        return retval;
    }

    /** Returns true if the parameter is the same session ID */
    @Override
    public boolean equals (Object obj)
    {
        if (!(obj instanceof SessionId))
            return false;

        SessionId s = (SessionId) obj;
        byte b [] = s.getId ();

        if (b.length != sessionId.length)
            return false;
        for (int i = 0; i < sessionId.length; i++) {
            if (b [i] != sessionId [i])
                return false;
        }
        return true;
    }
}