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.jul;
018    
019    import java.util.Collections;
020    import java.util.Enumeration;
021    import java.util.logging.Logger;
022    
023    import org.apache.logging.log4j.LoggingException;
024    import org.apache.logging.log4j.status.StatusLogger;
025    import org.apache.logging.log4j.util.LoaderUtil;
026    import org.apache.logging.log4j.util.PropertiesUtil;
027    
028    /**
029     * Log4j implementation of {@link java.util.logging.LogManager}. Note that the system property
030     * {@code java.util.logging.manager} must be set to {@code org.apache.logging.log4j.jul.LogManager} in order to use
031     * this adaptor. This LogManager requires the {@code log4j-api} library to be available. If {@code log4j-core} is
032     * also available, then more features of {@link java.util.logging.Logger} are supported.
033     *
034     * <p>To override the default {@link AbstractLoggerAdapter} that is used, specify the Log4j property
035     * {@code log4j.jul.LoggerAdapter} and set it to the fully qualified class name of a custom
036     * implementation. All implementations must have a default constructor.</p>
037     *
038     * @since 2.1
039     */
040    public class LogManager extends java.util.logging.LogManager {
041    
042        private static final org.apache.logging.log4j.Logger LOGGER = StatusLogger.getLogger();
043        private final AbstractLoggerAdapter loggerAdapter;
044    
045        public LogManager() {
046            super();
047            AbstractLoggerAdapter adapter = null;
048            final String overrideAdaptorClassName =
049                PropertiesUtil.getProperties().getStringProperty(Constants.LOGGER_ADAPTOR_PROPERTY);
050            if (overrideAdaptorClassName != null) {
051                try {
052                    LOGGER.info("Trying to use LoggerAdaptor [{}] specified by Log4j property.", overrideAdaptorClassName);
053                    adapter = LoaderUtil.newCheckedInstanceOf(overrideAdaptorClassName, AbstractLoggerAdapter.class);
054                } catch (final Exception e) {
055                    LOGGER.error("Specified LoggerAdapter [{}] is incompatible.", overrideAdaptorClassName, e);
056                }
057            }
058            if (adapter == null) {
059                // default adapter
060                String adapterClassName;
061                try {
062                    // find out if log4j-core is available
063                    LoaderUtil.loadClass(Constants.CORE_LOGGER_CLASS_NAME);
064                    adapterClassName = Constants.CORE_LOGGER_ADAPTER_CLASS_NAME;
065                } catch (final ClassNotFoundException ignored) {
066                    adapterClassName = Constants.API_LOGGER_ADAPTER_CLASS_NAME;
067                }
068                LOGGER.debug("Attempting to use {}", adapterClassName);
069                try {
070                    adapter = LoaderUtil.newCheckedInstanceOf(adapterClassName, AbstractLoggerAdapter.class);
071                } catch (final Exception e) {
072                    throw LOGGER.throwing(new LoggingException(e));
073                }
074            }
075            loggerAdapter = adapter;
076            LOGGER.info("Registered Log4j as the java.util.logging.LogManager.");
077        }
078    
079        @Override
080        public boolean addLogger(final Logger logger) {
081            // in order to prevent non-bridged loggers from being registered, we always return false to indicate that
082            // the named logger should be obtained through getLogger(name)
083            return false;
084        }
085    
086        @Override
087        public Logger getLogger(final String name) {
088            LOGGER.trace("Call to LogManager.getLogger({})", name);
089            return loggerAdapter.getLogger(name);
090        }
091    
092        @Override
093        public Enumeration<String> getLoggerNames() {
094            return Collections.enumeration(loggerAdapter.getLoggersInContext(loggerAdapter.getContext()).keySet());
095        }
096    
097    }