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 import java.io.ByteArrayOutputStream;

    28 import java.io.DataOutputStream;

    29 import java.io.IOException;

    30 

    31 /**

    32  * JdpPacketWriter responsible for writing a packet

    33  * <p>This class assembles a set of key/value pairs to valid JDP packet,

    34  * ready to be sent across a Net</p>

    35  */

    36 public final class JdpPacketWriter {

    37 

    38     private final ByteArrayOutputStream baos;

    39     private final DataOutputStream pkt;

    40 

    41     /**

    42      * Create a JDP packet, add mandatory magic and version headers

    43      *

    44      * @throws IOException

    45      */

    46     public JdpPacketWriter()

    47             throws IOException {

    48         baos = new ByteArrayOutputStream();

    49         pkt = new DataOutputStream(baos);

    50 

    51         pkt.writeInt(JdpGenericPacket.getMagic());

    52         pkt.writeShort(JdpGenericPacket.getVersion());

    53     }

    54 

    55     /**

    56      * Put string entry to packet

    57      *

    58      * @param entry - string to put (utf-8 encoded)

    59      * @throws IOException

    60      */

    61     public void addEntry(String entry)

    62             throws IOException {

    63         /* DataOutputStream.writeUTF() do essentially

    64          *  the same as:

    65          *    pkt.writeShort(entry.getBytes("UTF-8").length);

    66          *    pkt.write(entry.getBytes("UTF-8"));

    67          */

    68         pkt.writeUTF(entry);

    69     }

    70 

    71     /**

    72      * Put key/value pair to packet

    73      *

    74      * @param key - key to put (utf-8 encoded)

    75      * @param val - value to put (utf-8 encoded)

    76      * @throws IOException

    77      */

    78     public void addEntry(String key, String val)

    79             throws IOException {

    80         /* Silently skip key if value is null.

    81          * We don't need to distinguish between key missing

    82          * and key has no value cases

    83          */

    84         if (val != null) {

    85             addEntry(key);

    86             addEntry(val);

    87         }

    88     }

    89 

    90     /**

    91      * Return assembled packet as a byte array

    92      *

    93      * @return packet bytes

    94      */

    95     public byte[] getPacketBytes() {

    96         return baos.toByteArray();

    97     }

    98 }