liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/utils/LttngUstAgentLogger.java

   1 /*
   2  * Copyright (C) 2016 - 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.utils;
  19
  20 /**
  21  * Logging infrastructure for the lttng-ust Java agent. It prints log messages
  22  * to stderr but only when the environment variable LTTNG_UST_DEBUG is defined.
  23  *
  24  * @author Alexandre Montplaisir
  25  */
  26 public class LttngUstAgentLogger {
  27
  28         private static final String ENV_VAR_NAME = "LTTNG_UST_DEBUG";
  29         private static final boolean LOGGING_ENABLED = (System.getenv(ENV_VAR_NAME) == null ? false : true);
  30
  31         /**
  32          * Log event. Will be printed to stderr if the environment variable
  33          * "LTTNG_UST_DEBUG" is defined.
  34          *
  35          * @param c
  36          *            The class logging the message (should normally be called with
  37          *            {@link #getClass()}).
  38          * @param message
  39          *            The message to print
  40          */
  41         public static void log(Class<?> c, String message) {
  42                 if (LOGGING_ENABLED) {
  43                         System.err.println(c.getSimpleName() + ": " + message);
  44                 }
  45         }
  46 }