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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.filter; | |
19 | ||
20 | import org.lttng.ust.agent.session.EventRule; | |
21 | ||
22 | /** | |
23 | * Filter notification listener interface. | |
24 | * <p> | |
25 | * Applications wanting to be notified of event filtering rule changes should | |
26 | * implement this interface, then register their listener using | |
27 | * {@link FilterChangeNotifier#registerListener}. | |
28 | * </p> | |
29 | * <p> | |
30 | * The callbacks defined in this interface will be called whenever an event rule | |
31 | * is added or removed. The manager will take care of the reference-counting in | |
32 | * case multiple tracing sessions enable the exact same rules. For example, the | |
33 | * {@link #eventRuleRemoved} callback is only called when there are no more | |
34 | * session interested into it. | |
35 | * </p> | |
36 | * <p> | |
37 | * Do not forget to unregister the listener after use, using | |
38 | * {@link FilterChangeNotifier#unregisterListener}. If you do not, or if | |
39 | * you use an anonymous listener for example, these will remain attached until | |
40 | * the complete shutdown of the application. | |
41 | * </p> | |
42 | * <p> | |
43 | * Only one thread is used to dispatch notifications, sequentially. This means | |
44 | * that if a callback hangs it will prevent other listeners from receiving | |
45 | * notifications. Please take care of not blocking inside the listener | |
46 | * callbacks, and use separate threads for potentially long or blocking | |
47 | * operations. | |
48 | * </p> | |
49 | * | |
50 | * @author Alexandre Montplaisir | |
51 | */ | |
52 | public interface IFilterChangeListener { | |
53 | ||
54 | /** | |
55 | * Notification that a new event rule is now enabled in the tracing | |
56 | * sessions. | |
57 | * | |
58 | * @param rule | |
59 | * The event rule that was enabled | |
60 | */ | |
61 | void eventRuleAdded(EventRule rule); | |
62 | ||
63 | /** | |
64 | * Notification that an existing event rule is now disabled in the tracing | |
65 | * sessions. | |
66 | * | |
67 | * @param rule | |
68 | * The event rule that was disabled | |
69 | */ | |
70 | void eventRuleRemoved(EventRule rule); | |
71 | } |