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 */ JdpPacketWriter()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 */ addEntry(String entry)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 */ addEntry(String key, String val)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 */ getPacketBytes()95 public byte[] getPacketBytes() { 96 return baos.toByteArray(); 97 } 98 } 99