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

   1 /*
   2  * Copyright (C) 2015 - EfficiOS Inc., Alexandre Montplaisir <alexmonthy@efficios.com>
   3  *
   4  * This library is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU Lesser General Public License, version 2.1 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This library is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
  11  * for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public License
  14  * along with this library; if not, write to the Free Software Foundation,
  15  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  16  */
  17
  18 package org.lttng.ust.agent.client;
  19
  20 import java.util.Collection;
  21
  22 import org.lttng.ust.agent.session.EventRule;
  23
  24 /**
  25  * TCP client listener interface.
  26  *
  27  * This interface contains callbacks that are called when the TCP client
  28  * receives commands from the session daemon. These callbacks will define what
  29  * do to with each command.
  30  *
  31  * @author Alexandre Montplaisir
  32  */
  33 public interface ILttngTcpClientListener {
  34
  35         /**
  36          * Callback for the TCP client to notify the listener agent that a request
  37          * for enabling an event rule was sent from the session daemon.
  38          *
  39          * @param eventRule
  40          *            The event rule that was requested to be enabled
  41          * @return Since we do not track individual sessions, right now this command
  42          *         cannot fail. It will always return true.
  43          */
  44         boolean eventEnabled(EventRule eventRule);
  45
  46         /**
  47          * Callback for the TCP client to notify the listener agent that a request
  48          * for disabling an event was sent from the session daemon.
  49          *
  50          * @param eventName
  51          *            The name of the event that was requested to be disabled.
  52          * @return True if the command completed successfully, false if we should
  53          *         report an error (event was not enabled, etc.)
  54          */
  55         boolean eventDisabled(String eventName);
  56
  57         /**
  58          * Callback for the TCP client to notify the listener agent that a request
  59          * for enabling an application-specific context was sent from the session
  60          * daemon.
  61          *
  62          * @param contextRetrieverName
  63          *            The name of the retriever in which the context is present.
  64          *            This is used to namespace the contexts.
  65          * @param contextName
  66          *            The name of the context that was requested to be enabled
  67          * @return Since we do not track individual sessions, right now this command
  68          *         cannot fail. It will always return true.
  69          */
  70         boolean appContextEnabled(String contextRetrieverName, String contextName);
  71
  72         /**
  73          * Callback for the TCP client to notify the listener agent that a request
  74          * for disabling an application-specific context was sent from the session
  75          * daemon.
  76          *
  77          * @param contextRetrieverName
  78          *            The name of the retriever in which the context is present.
  79          *            This is used to namespace the contexts.
  80          * @param contextName
  81          *            The name of the context that was requested to be disabled.
  82          * @return True if the command completed successfully, false if we should
  83          *         report an error (context was not previously enabled for example)
  84          */
  85         boolean appContextDisabled(String contextRetrieverName, String contextName);
  86
  87         /**
  88          * List the events that are available in the agent's tracing domain.
  89          *
  90          * In Java terms, this means loggers that have at least one LTTng log
  91          * handler of their corresponding domain attached.
  92          *
  93          * @return The list of available events
  94          */
  95         Collection<String> listAvailableEvents();
  96 }