001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache license, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the license for the specific language governing permissions and
015 * limitations under the license.
016 */
017 package org.apache.logging.log4j.core.selector;
018
019 import java.net.URI;
020 import java.util.ArrayList;
021 import java.util.Collections;
022 import java.util.List;
023 import java.util.Map;
024 import java.util.concurrent.ConcurrentHashMap;
025 import java.util.concurrent.ConcurrentMap;
026 import javax.naming.NamingException;
027
028 import org.apache.logging.log4j.core.LoggerContext;
029 import org.apache.logging.log4j.core.impl.ContextAnchor;
030 import org.apache.logging.log4j.core.net.JndiManager;
031 import org.apache.logging.log4j.core.util.Constants;
032 import org.apache.logging.log4j.status.StatusLogger;
033
034 /**
035 * This class can be used to define a custom logger repository. It makes use of the fact that in J2EE environments, each
036 * web-application is guaranteed to have its own JNDI context relative to the <code>java:comp/env</code> context. In
037 * EJBs, each enterprise bean (albeit not each application) has its own context relative to the
038 * <code>java:comp/env</code> context. An <code>env-entry</code> in a deployment descriptor provides the information to
039 * the JNDI context. Once the <code>env-entry</code> is set, a repository selector can query the JNDI application
040 * context to look up the value of the entry. The logging context of the web-application will depend on the value the
041 * env-entry. The JNDI context which is looked up by this class is <code>java:comp/env/log4j/context-name</code>.
042 *
043 * <p>
044 * Here is an example of an <code>env-entry</code>:
045 * </p>
046 * <blockquote>
047 *
048 * <pre>
049 * <env-entry>
050 * <description>JNDI logging context name for this app</description>
051 * <env-entry-name>log4j/context-name</env-entry-name>
052 * <env-entry-value>aDistinctiveLoggingContextName</env-entry-value>
053 * <env-entry-type>java.lang.String</env-entry-type>
054 * </env-entry>
055 * </pre>
056 *
057 * </blockquote>
058 *
059 * <p>
060 * <em>If multiple applications use the same logging context name, then they
061 * will share the same logging context.</em>
062 * </p>
063 *
064 * <p>
065 * You can also specify the URL for this context's configuration resource. This repository selector
066 * (ContextJNDISelector) will use this resource to automatically configure the log4j repository.
067 * </p>
068 ** <blockquote>
069 *
070 * <pre>
071 * <env-entry>
072 * <description>URL for configuring log4j context</description>
073 * <env-entry-name>log4j/configuration-resource</env-entry-name>
074 * <env-entry-value>urlOfConfigurationResource</env-entry-value>
075 * <env-entry-type>java.lang.String</env-entry-type>
076 * </env-entry>
077 * </pre>
078 *
079 * </blockquote>
080 *
081 * <p>
082 * It usually good practice for configuration resources of distinct applications to have distinct names. However, if
083 * this is not possible Naming
084 * </p>
085 */
086 public class JndiContextSelector implements NamedContextSelector {
087
088 private static final LoggerContext CONTEXT = new LoggerContext("Default");
089
090 private static final ConcurrentMap<String, LoggerContext> CONTEXT_MAP =
091 new ConcurrentHashMap<String, LoggerContext>();
092
093 private static final StatusLogger LOGGER = StatusLogger.getLogger();
094
095 @Override
096 public LoggerContext getContext(final String fqcn, final ClassLoader loader, final boolean currentContext) {
097 return getContext(fqcn, loader, currentContext, null);
098 }
099
100 @Override
101 public LoggerContext getContext(final String fqcn, final ClassLoader loader, final boolean currentContext,
102 final URI configLocation) {
103
104 final LoggerContext lc = ContextAnchor.THREAD_CONTEXT.get();
105 if (lc != null) {
106 return lc;
107 }
108
109 String loggingContextName = null;
110
111 final JndiManager jndiManager = JndiManager.getDefaultManager();
112 try {
113 loggingContextName = jndiManager.lookup(Constants.JNDI_CONTEXT_NAME);
114 } catch (final NamingException ne) {
115 LOGGER.error("Unable to lookup {}", Constants.JNDI_CONTEXT_NAME, ne);
116 } finally {
117 jndiManager.release();
118 }
119
120 return loggingContextName == null ? CONTEXT : locateContext(loggingContextName, null, configLocation);
121 }
122
123 @Override
124 public LoggerContext locateContext(final String name, final Object externalContext, final URI configLocation) {
125 if (name == null) {
126 LOGGER.error("A context name is required to locate a LoggerContext");
127 return null;
128 }
129 if (!CONTEXT_MAP.containsKey(name)) {
130 final LoggerContext ctx = new LoggerContext(name, externalContext, configLocation);
131 CONTEXT_MAP.putIfAbsent(name, ctx);
132 }
133 return CONTEXT_MAP.get(name);
134 }
135
136 @Override
137 public void removeContext(final LoggerContext context) {
138
139 for (final Map.Entry<String, LoggerContext> entry : CONTEXT_MAP.entrySet()) {
140 if (entry.getValue().equals(context)) {
141 CONTEXT_MAP.remove(entry.getKey());
142 }
143 }
144 }
145
146 @Override
147 public LoggerContext removeContext(final String name) {
148 return CONTEXT_MAP.remove(name);
149 }
150
151 @Override
152 public List<LoggerContext> getLoggerContexts() {
153 final List<LoggerContext> list = new ArrayList<LoggerContext>(CONTEXT_MAP.values());
154 return Collections.unmodifiableList(list);
155 }
156
157 }