liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/client/SessiondListLoggersCommand.java

   1 /*
   2  * Copyright (C) 2015 - EfficiOS Inc., Alexandre Montplaisir <alexmonthy@efficios.com>
   3  * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
   4  *
   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.
   8  *
   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
  12  * for more details.
  13  *
  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
  17  */
  18
  19 package org.lttng.ust.agent.client;
  20
  21 import java.nio.ByteBuffer;
  22 import java.nio.ByteOrder;
  23 import java.util.ArrayList;
  24 import java.util.List;
  25
  26 /**
  27  * Session daemon command asking the Java agent to list its registered loggers,
  28  * which corresponds to event names in the tracing session.
  29  *
  30  * @author Alexandre Montplaisir
  31  * @author David Goulet
  32  */
  33 class SessiondListLoggersCommand implements ISessiondCommand {
  34
  35         @Override
  36         public LttngAgentResponse execute(ILttngTcpClientListener agent) {
  37                 final List<String> loggerList = new ArrayList<String>();
  38                 int dataSize = 0;
  39
  40                 for (String event : agent.listEnabledEvents()) {
  41                         loggerList.add(event);
  42                         dataSize += event.length() + 1;
  43                 }
  44
  45                 return new SessiondListLoggersResponse(loggerList, dataSize);
  46         }
  47
  48         private static class SessiondListLoggersResponse extends LttngAgentResponse {
  49
  50                 private final static int SIZE = 12;
  51
  52                 private final List<String> loggers;
  53                 private final int dataSize;
  54
  55                 public SessiondListLoggersResponse(List<String> loggers, int dataSize) {
  56                         this.loggers = loggers;
  57                         this.dataSize = dataSize;
  58                 }
  59
  60                 @Override
  61                 public ReturnCode getReturnCode() {
  62                         /* This command can't really fail */
  63                         return ReturnCode.CODE_SUCCESS_CMD;
  64                 }
  65
  66                 @Override
  67                 public byte[] getBytes() {
  68                         byte data[] = new byte[SIZE + dataSize];
  69                         ByteBuffer buf = ByteBuffer.wrap(data);
  70                         buf.order(ByteOrder.BIG_ENDIAN);
  71
  72                         /* Returned code */
  73                         buf.putInt(getReturnCode().getCode());
  74                         buf.putInt(dataSize);
  75                         buf.putInt(loggers.size());
  76
  77                         for (String logger : loggers) {
  78                                 buf.put(logger.getBytes());
  79                                 /* NULL terminated byte after the logger name. */
  80                                 buf.put((byte) 0x0);
  81                         }
  82                         return data;
  83                 }
  84         }
  85
  86 }