org.apache.logging.log4j.spi.AbstractLoggerAdapter Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to you under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.logging.log4j.spi;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.util.LoaderUtil;
/**
* Provides an abstract base class to use for implementing LoggerAdapter.
*
* @param the Logger class to adapt
* @since 2.1
*/
public abstract class AbstractLoggerAdapter implements LoggerAdapter, LoggerContextShutdownAware {
/**
* A map to store loggers for their given LoggerContexts.
*/
protected final Map> registry = new ConcurrentHashMap<>();
private final ReadWriteLock lock = new ReentrantReadWriteLock(true);
@Override
public L getLogger(final String name) {
final LoggerContext context = getContext();
final ConcurrentMap loggers = getLoggersInContext(context);
final L logger = loggers.get(name);
if (logger != null) {
return logger;
}
loggers.putIfAbsent(name, newLogger(name, context));
return loggers.get(name);
}
@Override
public void contextShutdown(final LoggerContext loggerContext) {
registry.remove(loggerContext);
}
/**
* Gets or creates the ConcurrentMap of named loggers for a given LoggerContext.
*
* @param context the LoggerContext to get loggers for
* @return the map of loggers for the given LoggerContext
*/
public ConcurrentMap getLoggersInContext(final LoggerContext context) {
ConcurrentMap loggers;
lock.readLock().lock();
try {
loggers = registry.get(context);
} finally {
lock.readLock().unlock();
}
if (loggers != null) {
return loggers;
}
lock.writeLock().lock();
try {
loggers = registry.get(context);
if (loggers == null) {
loggers = new ConcurrentHashMap<>();
registry.put(context, loggers);
if (context instanceof LoggerContextShutdownEnabled) {
((LoggerContextShutdownEnabled) context).addShutdownListener(this);
}
}
return loggers;
} finally {
lock.writeLock().unlock();
}
}
/**
* For unit testing. Consider to be private.
*/
public Set getLoggerContexts() {
return new HashSet<>(registry.keySet());
}
/**
* Creates a new named logger for a given {@link LoggerContext}.
*
* @param name the name of the logger to create
* @param context the LoggerContext this logger will be associated with
* @return the new named logger
*/
protected abstract L newLogger(final String name, final LoggerContext context);
/**
* Gets the {@link LoggerContext} that should be used to look up or create loggers. This is similar in spirit to the
* {@code ContextSelector} class in {@code log4j-core}. However, implementations can rely on their own framework's
* separation of contexts instead (or simply use a singleton).
*
* @return the LoggerContext to be used for lookup and creation purposes
* @see org.apache.logging.log4j.LogManager#getContext(ClassLoader, boolean)
* @see org.apache.logging.log4j.LogManager#getContext(String, boolean)
*/
protected abstract LoggerContext getContext();
/**
* Gets the {@link LoggerContext} associated with the given caller class.
*
* @param callerClass the caller class
* @return the LoggerContext for the calling class
*/
protected LoggerContext getContext(final Class callerClass) {
ClassLoader cl = null;
if (callerClass != null) {
cl = callerClass.getClassLoader();
}
if (cl == null) {
cl = LoaderUtil.getThreadContextClassLoader();
}
return LogManager.getContext(cl, false);
}
@Override
public void close() {
lock.writeLock().lock();
try {
registry.clear();
} finally {
lock.writeLock().unlock();
}
}
}