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 */ JdpGenericPacket()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 */ checkMagic(int magic)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 */ checkVersion(short version)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 */ getMagic()86 public static int getMagic() { 87 return MAGIC; 88 } 89 90 /** 91 * 92 * @return current protocol version 93 */ getVersion()94 public static short getVersion() { 95 return PROTOCOL_VERSION; 96 } 97 } 98