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5b5ffa03 | 1 | /* |
d60dfbe4 | 2 | * Copyright (C) 2015 - EfficiOS Inc., Alexandre Montplaisir <alexmonthy@efficios.com> |
5b5ffa03 DG |
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 | ||
d60dfbe4 AM |
18 | package org.lttng.ust.agent.log4j; |
19 | ||
68a1ef73 AM |
20 | import java.util.Collection; |
21 | import java.util.Collections; | |
a548b3c1 | 22 | import java.util.Enumeration; |
68a1ef73 | 23 | import java.util.List; |
46070114 AM |
24 | import java.util.Set; |
25 | import java.util.TreeSet; | |
68a1ef73 AM |
26 | |
27 | import org.apache.log4j.Appender; | |
46070114 | 28 | import org.apache.log4j.Category; |
68a1ef73 AM |
29 | import org.apache.log4j.LogManager; |
30 | import org.apache.log4j.Logger; | |
d60dfbe4 AM |
31 | import org.lttng.ust.agent.AbstractLttngAgent; |
32 | ||
33 | /** | |
34 | * Agent implementation for using the Log4j logger, connecting to a root session | |
35 | * daemon. | |
36 | * | |
37 | * @author Alexandre Montplaisir | |
38 | */ | |
39 | class LttngLog4jAgent extends AbstractLttngAgent<LttngLogAppender> { | |
40 | ||
41 | private static LttngLog4jAgent instance = null; | |
42 | ||
43 | private LttngLog4jAgent() { | |
44 | super(Domain.LOG4J); | |
45 | } | |
5b5ffa03 | 46 | |
d60dfbe4 AM |
47 | public static synchronized LttngLog4jAgent getInstance() { |
48 | if (instance == null) { | |
49 | instance = new LttngLog4jAgent(); | |
50 | } | |
51 | return instance; | |
52 | } | |
5b5ffa03 | 53 | |
68a1ef73 AM |
54 | @Override |
55 | public Collection<String> listAvailableEvents() { | |
46070114 | 56 | Set<String> ret = new TreeSet<String>(); |
68a1ef73 AM |
57 | |
58 | @SuppressWarnings("unchecked") | |
59 | List<Logger> loggers = Collections.list(LogManager.getCurrentLoggers()); | |
60 | for (Logger logger : loggers) { | |
2b218c9a AM |
61 | if (logger == null) { |
62 | continue; | |
63 | } | |
64 | ||
68a1ef73 AM |
65 | /* |
66 | * Check if that logger has at least one LTTng log4j appender | |
67 | * attached. | |
68 | */ | |
69 | if (hasLttngAppenderAttached(logger)) { | |
70 | ret.add(logger.getName()); | |
71 | } | |
72 | } | |
73 | ||
74 | return ret; | |
75 | } | |
76 | ||
46070114 | 77 | private static boolean hasLttngAppenderAttached(Category logger) { |
68a1ef73 | 78 | @SuppressWarnings("unchecked") |
a548b3c1 AM |
79 | Enumeration<Appender> appenders = logger.getAllAppenders(); |
80 | if (appenders != null) { | |
81 | for (Appender appender : Collections.list(appenders)) { | |
82 | if (appender instanceof LttngLogAppender) { | |
83 | return true; | |
84 | } | |
68a1ef73 AM |
85 | } |
86 | } | |
46070114 AM |
87 | |
88 | /* | |
89 | * A parent logger, if any, may be connected to an LTTng handler. In | |
90 | * this case, we will want to include this child logger in the output, | |
91 | * since it will be accessible by LTTng. | |
92 | */ | |
93 | Category parent = logger.getParent(); | |
94 | if (parent != null) { | |
95 | return hasLttngAppenderAttached(parent); | |
96 | } | |
97 | ||
98 | /* | |
99 | * We have reached the root logger and have not found any LTTng handler, | |
100 | * this event will not be accessible. | |
101 | */ | |
68a1ef73 AM |
102 | return false; |
103 | } | |
46070114 | 104 | |
5b5ffa03 | 105 | } |