2 * Copyright (C) 2015-2016 - EfficiOS Inc., Alexandre Montplaisir <alexmonthy@efficios.com>
3 * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
5 * This library is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU Lesser General Public License, version 2.1 only,
7 * as published by the Free Software Foundation.
9 * This library is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
14 * You should have received a copy of the GNU Lesser General Public License
15 * along with this library; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 package org
.lttng
.ust
.agent
.client
;
21 import java
.nio
.ByteBuffer
;
22 import java
.nio
.charset
.Charset
;
25 * Base class to represent all commands sent from the session daemon to the Java
26 * agent. The agent is then expected to execute the command and provide a
29 * @author Alexandre Montplaisir
31 abstract class SessiondCommand
{
34 * Encoding that should be used for the strings in the sessiond agent
35 * protocol on the socket.
37 protected static final Charset SESSIOND_PROTOCOL_CHARSET
= Charset
.forName("UTF-8");
40 /** List logger(s). */
42 /** Enable logger by name. */
44 /** Disable logger by name. */
46 /** Registration done */
48 /** Enable application context */
49 CMD_APP_CTX_ENABLE(5),
50 /** Disable application context */
51 CMD_APP_CTX_DISABLE(6);
55 private CommandType(int c
) {
59 public int getCommandType() {
65 * Execute the command handler's action on the specified tracing agent.
68 * The agent on which to execute the command
69 * @return If the command completed successfully or not
71 public abstract LttngAgentResponse
execute(ILttngTcpClientListener agent
);
74 * Utility method to read agent-protocol strings passed on the socket. The
75 * buffer will contain a 32-bit integer representing the length, immediately
76 * followed by the string itself.
79 * The ByteBuffer from which to read. It should already be setup
80 * and positioned where the read should begin.
81 * @return The string that was read, or <code>null</code> if it was badly
84 protected static String
readNextString(ByteBuffer buffer
) {
85 int nbBytes
= buffer
.getInt();
87 /* The string length should be positive */
91 /* The string is explicitly an empty string */
95 byte[] stringBytes
= new byte[nbBytes
];
96 buffer
.get(stringBytes
);
97 return new String(stringBytes
, SESSIOND_PROTOCOL_CHARSET
).trim();