1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache license, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the license for the specific language governing permissions and
15 * limitations under the license.
16 */
17 package org.apache.logging.log4j.spi;
18
19 import java.util.Map;
20 import java.util.WeakHashMap;
21 import java.util.concurrent.ConcurrentHashMap;
22 import java.util.concurrent.ConcurrentMap;
23
24 import org.apache.logging.log4j.LogManager;
25 import org.apache.logging.log4j.util.LoaderUtil;
26
27 /**
28 * Provides an abstract base class to use for implementing LoggerAdapter.
29 * @param <L> the Logger class to adapt
30 * @since 2.1
31 */
32 public abstract class AbstractLoggerAdapter<L> implements LoggerAdapter<L> {
33
34 /**
35 * A map to store loggers for their given LoggerContexts.
36 */
37 protected final Map<LoggerContext, ConcurrentMap<String, L>> registry =
38 new WeakHashMap<LoggerContext, ConcurrentMap<String, L>>();
39
40 @Override
41 public L getLogger(final String name) {
42 final LoggerContext context = getContext();
43 final ConcurrentMap<String, L> loggers = getLoggersInContext(context);
44 if (loggers.containsKey(name)) {
45 return loggers.get(name);
46 }
47 loggers.putIfAbsent(name, newLogger(name, context));
48 return loggers.get(name);
49 }
50
51 /**
52 * Gets or creates the ConcurrentMap of named loggers for a given LoggerContext.
53 *
54 * @param context the LoggerContext to get loggers for
55 * @return the map of loggers for the given LoggerContext
56 */
57 public ConcurrentMap<String, L> getLoggersInContext(final LoggerContext context) {
58 synchronized (registry) {
59 ConcurrentMap<String, L> loggers = registry.get(context);
60 if (loggers == null) {
61 loggers = new ConcurrentHashMap<String, L>();
62 registry.put(context, loggers);
63 }
64 return loggers;
65 }
66 }
67
68 /**
69 * Creates a new named logger for a given {@link LoggerContext}.
70 *
71 * @param name the name of the logger to create
72 * @param context the LoggerContext this logger will be associated with
73 * @return the new named logger
74 */
75 protected abstract L newLogger(final String name, final LoggerContext context);
76
77 /**
78 * Gets the {@link LoggerContext} that should be used to look up or create loggers. This is similar in spirit to
79 * the {@code ContextSelector} class in {@code log4j-core}. However, implementations can rely on their own
80 * framework's separation of contexts instead (or simply use a singleton).
81 *
82 * @return the LoggerContext to be used for lookup and creation purposes
83 * @see org.apache.logging.log4j.LogManager#getContext(ClassLoader, boolean)
84 * @see org.apache.logging.log4j.LogManager#getContext(String, boolean)
85 */
86 protected abstract LoggerContext getContext();
87
88 /**
89 * Gets the {@link LoggerContext} associated with the given caller class.
90 *
91 * @param callerClass the caller class
92 * @return the LoggerContext for the calling class
93 */
94 protected LoggerContext getContext(final Class<?> callerClass) {
95 ClassLoader cl = null;
96 if (callerClass != null) {
97 cl = callerClass.getClassLoader();
98 }
99 if (cl == null) {
100 cl = LoaderUtil.getThreadContextClassLoader();
101 }
102 return LogManager.getContext(cl, false);
103 }
104
105 @Override
106 public void close() {
107 registry.clear();
108 }
109 }