1 /*

     2  * Copyright (c) 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 package sun.management.jdp;

    26 

    27 /**

    28  * JdpGenericPacket responsible to provide fields

    29  * common for all Jdp packets

    30  */

    31 public abstract class JdpGenericPacket implements JdpPacket {

    32 

    33     /**

    34      * JDP protocol magic. Magic allows a reader to quickly select

    35      * JDP packets from a bunch of broadcast packets addressed to the same port

    36      * and broadcast group. Any packet intended to be parsed by JDP client

    37      * has to start from this  magic.

    38      */

    39     private static final int MAGIC = 0xC0FFEE42;

    40 

    41     /**

    42      * Current version of protocol. Any implementation of this protocol has to

    43      * conform with the packet structure and the flow described in JEP-168

    44      */

    45     private static final short PROTOCOL_VERSION = 1;

    46 

    47     /**

    48      * Default do-nothing constructor

    49      */

    50     protected  JdpGenericPacket(){

    51         // do nothing

    52     }

    53 

    54 

    55     /**

    56      * Validate protocol header magic field

    57      *

    58      * @param magic - value to validate

    59      * @throws JdpException

    60      */

    61     public static void checkMagic(int magic)

    62             throws JdpException {

    63         if (magic != MAGIC) {

    64             throw new JdpException("Invalid JDP magic header: " + magic);

    65         }

    66     }

    67 

    68     /**

    69      * Validate protocol header version field

    70      *

    71      * @param version - value to validate

    72      * @throws JdpException

    73      */

    74     public static void checkVersion(short version)

    75             throws JdpException {

    76 

    77         if (version > PROTOCOL_VERSION) {

    78             throw new JdpException("Unsupported protocol version: " + version);

    79         }

    80     }

    81 

    82     /**

    83      *

    84      * @return protocol magic

    85      */

    86     public static int getMagic() {

    87         return MAGIC;

    88     }

    89 

    90     /**

    91      *

    92      * @return current protocol version

    93      */

    94     public static short getVersion() {

    95         return PROTOCOL_VERSION;

    96     }

    97 }