2 * Copyright (C) 2015 - EfficiOS Inc., Alexandre Montplaisir <alexmonthy@efficios.com>
3 * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
5 * Permission is hereby granted, free of charge, to any person obtaining a copy
6 * of this software and associated documentation files (the "Software"), to
7 * deal in the Software without restriction, including without limitation the
8 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
9 * sell copies of the Software, and to permit persons to whom the Software is
10 * furnished to do so, subject to the following conditions:
12 * The above copyright notice and this permission notice shall be included in
13 * all copies or substantial portions of the Software.
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
24 import java
.io
.IOException
;
25 import java
.util
.logging
.Handler
;
26 import java
.util
.logging
.Logger
;
28 import org
.lttng
.ust
.agent
.jul
.LttngLogHandler
;
31 * Example application using the LTTng-UST Java JUL agent.
34 * Basically all that is required is to instantiate a {@link LttngLogHandler}
35 * and to attach it to a JUL {@link Logger}. Then use the Logger normally to log
36 * messages, which will be sent to UST as trace events.
39 * {@link Logger} names are used as event names on the UST side. This means that
40 * by enabling/disabling certain events in the tracing session, you are
41 * effectively enabling and disabling Loggers on the Java side. Note that this
42 * applies only to {@link LttngLogHandler}'s. If other handlers are attached to
43 * the Logger, those will continue logging events normally.
46 * @author Alexandre Montplaisir
47 * @author David Goulet
51 /** Class-wide JUL logger object */
52 private static final Logger LOGGER
= Logger
.getLogger(Hello
.class.getName());
58 * Command-line arguments
60 * @throws InterruptedException
62 public static void main(String args
[]) throws IOException
, InterruptedException
{
64 /* Instantiate a LTTngLogHandler object, and attach it to our logger */
65 Handler lttngHandler
= new LttngLogHandler();
66 LOGGER
.addHandler(lttngHandler
);
69 * Gives you time to do some lttng commands before any event is hit.
73 /* Trigger a tracing event using the JUL Logger created before. */
74 LOGGER
.info("Hello World, the answer is " + 42);
77 * From this point on, the above message will be collected in the trace
78 * if the event "Hello" is enabled for the JUL domain using the lttng
79 * command line or the lttng-ctl API. For instance:
81 * $ lttng enable-event -j Hello
85 * A new logger is created here and fired after. Typically with JUL, you
86 * use one static Logger per class. This example here can represent a
87 * class being lazy-loaded later in the execution of the application.
89 * The agent has an internal timer that is fired every 5 seconds in
90 * order to enable events that were not found at first but might need to
91 * be enabled when a new Logger appears. Unfortunately, there is no way
92 * right now to get notified of that so we have to actively poll.
94 * Using the --all command for instance, it will make this Logger
95 * available in a LTTng trace after the internal agent's timer is fired.
96 * (lttng enable-event -j -a).
98 Logger helloLogDelayed
= Logger
.getLogger("hello_delay");
101 * Attach a handler to this new logger.
103 * Using the same handler as before would also work.
105 Handler lttngHandler2
= new LttngLogHandler();
106 helloLogDelayed
.addHandler(lttngHandler2
);
108 System
.out
.println("Firing hello delay in 10 seconds...");
110 helloLogDelayed
.info("Hello World delayed...");
112 System
.out
.println("Cleaning Hello");
115 * Do not forget to close() all handlers so that the agent can shutdown
116 * and the session daemon socket gets cleaned up explicitly.
118 lttngHandler
.close();
119 lttngHandler2
.close();
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