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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).
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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