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849202d4 | 1 | /* |
d60dfbe4 | 2 | * Copyright (C) 2015 - EfficiOS Inc., Alexandre Montplaisir <alexmonthy@efficios.com> |
849202d4 DG |
3 | * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com> |
4 | * | |
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: | |
11 | * | |
12 | * The above copyright notice and this permission notice shall be included in | |
13 | * all copies or substantial portions of the Software. | |
14 | * | |
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 | |
21 | * IN THE SOFTWARE. | |
22 | */ | |
23 | ||
d60dfbe4 AM |
24 | import java.io.IOException; |
25 | import java.util.logging.Handler; | |
849202d4 DG |
26 | import java.util.logging.Logger; |
27 | ||
d60dfbe4 | 28 | import org.lttng.ust.agent.jul.LttngLogHandler; |
849202d4 | 29 | |
5bfeaeca AM |
30 | /** |
31 | * Example application using the LTTng-UST Java JUL agent. | |
32 | * | |
d60dfbe4 AM |
33 | * <p> |
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. | |
37 | * <p> | |
38 | * </p> | |
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. | |
44 | * </p> | |
45 | * | |
46 | * @author Alexandre Montplaisir | |
5bfeaeca AM |
47 | * @author David Goulet |
48 | */ | |
49 | public class Hello { | |
50 | ||
d60dfbe4 AM |
51 | /** Class-wide JUL logger object */ |
52 | private static final Logger LOGGER = Logger.getLogger(Hello.class.getName()); | |
849202d4 | 53 | |
5bfeaeca AM |
54 | /** |
55 | * Application start | |
56 | * | |
57 | * @param args | |
58 | * Command-line arguments | |
d60dfbe4 AM |
59 | * @throws IOException |
60 | * @throws InterruptedException | |
5bfeaeca | 61 | */ |
d60dfbe4 | 62 | public static void main(String args[]) throws IOException, InterruptedException { |
849202d4 | 63 | |
d60dfbe4 AM |
64 | /* Instantiate a LTTngLogHandler object, and attach it to our logger */ |
65 | Handler lttngHandler = new LttngLogHandler(); | |
66 | LOGGER.addHandler(lttngHandler); | |
849202d4 DG |
67 | |
68 | /* | |
69 | * Gives you time to do some lttng commands before any event is hit. | |
70 | */ | |
71 | Thread.sleep(5000); | |
72 | ||
73 | /* Trigger a tracing event using the JUL Logger created before. */ | |
d60dfbe4 | 74 | LOGGER.info("Hello World, the answer is " + 42); |
849202d4 DG |
75 | |
76 | /* | |
77 | * From this point on, the above message will be collected in the trace | |
d60dfbe4 | 78 | * if the event "Hello" is enabled for the JUL domain using the lttng |
849202d4 DG |
79 | * command line or the lttng-ctl API. For instance: |
80 | * | |
d60dfbe4 AM |
81 | * $ lttng enable-event -j Hello |
82 | */ | |
83 | ||
84 | /* | |
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. | |
849202d4 | 88 | * |
d60dfbe4 AM |
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. | |
849202d4 DG |
93 | * |
94 | * Using the --all command for instance, it will make this Logger | |
d60dfbe4 AM |
95 | * available in a LTTng trace after the internal agent's timer is fired. |
96 | * (lttng enable-event -j -a). | |
849202d4 DG |
97 | */ |
98 | Logger helloLogDelayed = Logger.getLogger("hello_delay"); | |
99 | ||
d60dfbe4 AM |
100 | /* |
101 | * Attach a handler to this new logger. | |
102 | * | |
103 | * Using the same handler as before would also work. | |
104 | */ | |
105 | Handler lttngHandler2 = new LttngLogHandler(); | |
106 | helloLogDelayed.addHandler(lttngHandler2); | |
107 | ||
849202d4 DG |
108 | System.out.println("Firing hello delay in 10 seconds..."); |
109 | Thread.sleep(10000); | |
110 | helloLogDelayed.info("Hello World delayed..."); | |
111 | ||
112 | System.out.println("Cleaning Hello"); | |
113 | ||
114 | /* | |
d60dfbe4 AM |
115 | * Do not forget to close() all handlers so that the agent can shutdown |
116 | * and the session daemon socket gets cleaned up explicitly. | |
849202d4 | 117 | */ |
d60dfbe4 AM |
118 | lttngHandler.close(); |
119 | lttngHandler2.close(); | |
849202d4 DG |
120 | } |
121 | } |