doc/examples/java-jul/FilterChangeListenerExample.java

   1 /*
   2  * Copyright (C) 2015 - EfficiOS Inc., Alexandre Montplaisir <alexmonthy@efficios.com>
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a copy
   5  * of this software and associated documentation files (the "Software"), to
   6  * deal in the Software without restriction, including without limitation the
   7  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
   8  * sell copies of the Software, and to permit persons to whom the Software is
   9  * furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included in
  12  * all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  17  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  18  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  19  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  20  * IN THE SOFTWARE.
  21  */
  22
  23 import java.io.IOException;
  24 import java.util.logging.Level;
  25
  26 import org.lttng.ust.agent.ILttngHandler;
  27 import org.lttng.ust.agent.filter.FilterChangeNotifier;
  28 import org.lttng.ust.agent.filter.IFilterChangeListener;
  29 import org.lttng.ust.agent.jul.LttngLogHandler;
  30 import org.lttng.ust.agent.session.EventRule;
  31 import org.lttng.ust.agent.session.LogLevelSelector;
  32
  33 /**
  34  * Example usage of a {@link IFilterChangeListener}.
  35  *
  36  * This listener will simply print to stdout the notifications it receives. To
  37  * try it, run the program, then issue "lttng enable-event" and
  38  * "lttng disable-event" commands for the JUL domain.
  39  *
  40  * @author Alexandre Montplaisir
  41  */
  42 public class FilterChangeListenerExample {
  43
  44         private static class ExampleFilterChangeListener implements IFilterChangeListener {
  45
  46                 @Override
  47                 public void eventRuleAdded(EventRule rule) {
  48                         System.out.println();
  49                         System.out.println("New event rule enabled:");
  50                         System.out.println("Event name: " + rule.getEventName());
  51                         System.out.println(printLogLevel(rule.getLogLevelSelector()));
  52                         System.out.println("Filter string: " + rule.getFilterString());
  53                 }
  54
  55                 @Override
  56                 public void eventRuleRemoved(EventRule rule) {
  57                         System.out.println();
  58                         System.out.println("Event rule disabled:");
  59                         System.out.println("Event name: " + rule.getEventName());
  60                         System.out.println(printLogLevel(rule.getLogLevelSelector()));
  61                         System.out.println("Filter string: " + rule.getFilterString());
  62                 }
  63
  64                 /**
  65                  * Convenience method to print integer log level values into their JUL
  66                  * equivalent.
  67                  */
  68                 private static String printLogLevel(LogLevelSelector lls) {
  69                         String llname = Level.parse(String.valueOf(lls.getLogLevel())).getName();
  70                         return "Log level: " + llname + ", filter type: " + lls.getLogLevelType().toString();
  71                 }
  72         }
  73
  74         /**
  75          * Run the program.
  76          *
  77          * @param args
  78          *            Command-line arguments (not used)
  79          * @throws IOException
  80          */
  81         public static void main(String args[]) throws IOException {
  82                 /* We need at least one log handler to activate the LTTng agent */
  83                 ILttngHandler handler = new LttngLogHandler();
  84
  85                 /* Create a listener and register it to the manager */
  86                 IFilterChangeListener listener = new ExampleFilterChangeListener();
  87                 FilterChangeNotifier.getInstance().registerListener(listener);
  88
  89                 System.out.println("Press Enter to finish.");
  90                 System.in.read();
  91
  92                 /* Unregister the listener */
  93                 FilterChangeNotifier.getInstance().unregisterListener(listener);
  94
  95                 /* Cleanup the log handler we created */
  96                 handler.close();
  97         }
  98 }