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5b5ffa03 | 1 | /* |
c0c0989a | 2 | * SPDX-License-Identifier: LGPL-2.1-only |
5b5ffa03 | 3 | * |
c0c0989a MJ |
4 | * Copyright (C) 2015 EfficiOS Inc. |
5 | * Copyright (C) 2015 Alexandre Montplaisir <alexmonthy@efficios.com> | |
5b5ffa03 DG |
6 | */ |
7 | ||
d60dfbe4 AM |
8 | package org.lttng.ust.agent.log4j; |
9 | ||
68a1ef73 AM |
10 | import java.util.Collection; |
11 | import java.util.Collections; | |
a548b3c1 | 12 | import java.util.Enumeration; |
68a1ef73 | 13 | import java.util.List; |
46070114 AM |
14 | import java.util.Set; |
15 | import java.util.TreeSet; | |
68a1ef73 AM |
16 | |
17 | import org.apache.log4j.Appender; | |
46070114 | 18 | import org.apache.log4j.Category; |
68a1ef73 AM |
19 | import org.apache.log4j.LogManager; |
20 | import org.apache.log4j.Logger; | |
d60dfbe4 AM |
21 | import org.lttng.ust.agent.AbstractLttngAgent; |
22 | ||
23 | /** | |
24 | * Agent implementation for using the Log4j logger, connecting to a root session | |
25 | * daemon. | |
26 | * | |
27 | * @author Alexandre Montplaisir | |
28 | */ | |
29 | class LttngLog4jAgent extends AbstractLttngAgent<LttngLogAppender> { | |
30 | ||
31 | private static LttngLog4jAgent instance = null; | |
32 | ||
33 | private LttngLog4jAgent() { | |
34 | super(Domain.LOG4J); | |
35 | } | |
5b5ffa03 | 36 | |
d60dfbe4 AM |
37 | public static synchronized LttngLog4jAgent getInstance() { |
38 | if (instance == null) { | |
39 | instance = new LttngLog4jAgent(); | |
40 | } | |
41 | return instance; | |
42 | } | |
5b5ffa03 | 43 | |
68a1ef73 AM |
44 | @Override |
45 | public Collection<String> listAvailableEvents() { | |
46070114 | 46 | Set<String> ret = new TreeSet<String>(); |
68a1ef73 AM |
47 | |
48 | @SuppressWarnings("unchecked") | |
49 | List<Logger> loggers = Collections.list(LogManager.getCurrentLoggers()); | |
50 | for (Logger logger : loggers) { | |
2b218c9a AM |
51 | if (logger == null) { |
52 | continue; | |
53 | } | |
54 | ||
68a1ef73 AM |
55 | /* |
56 | * Check if that logger has at least one LTTng log4j appender | |
57 | * attached. | |
58 | */ | |
59 | if (hasLttngAppenderAttached(logger)) { | |
60 | ret.add(logger.getName()); | |
61 | } | |
62 | } | |
63 | ||
64 | return ret; | |
65 | } | |
66 | ||
46070114 | 67 | private static boolean hasLttngAppenderAttached(Category logger) { |
68a1ef73 | 68 | @SuppressWarnings("unchecked") |
a548b3c1 AM |
69 | Enumeration<Appender> appenders = logger.getAllAppenders(); |
70 | if (appenders != null) { | |
71 | for (Appender appender : Collections.list(appenders)) { | |
72 | if (appender instanceof LttngLogAppender) { | |
73 | return true; | |
74 | } | |
68a1ef73 AM |
75 | } |
76 | } | |
46070114 AM |
77 | |
78 | /* | |
79 | * A parent logger, if any, may be connected to an LTTng handler. In | |
80 | * this case, we will want to include this child logger in the output, | |
81 | * since it will be accessible by LTTng. | |
82 | */ | |
83 | Category parent = logger.getParent(); | |
84 | if (parent != null) { | |
85 | return hasLttngAppenderAttached(parent); | |
86 | } | |
87 | ||
88 | /* | |
89 | * We have reached the root logger and have not found any LTTng handler, | |
90 | * this event will not be accessible. | |
91 | */ | |
68a1ef73 AM |
92 | return false; |
93 | } | |
46070114 | 94 | |
5b5ffa03 | 95 | } |