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.jcl;
018    
019    import java.util.Map;
020    import java.util.WeakHashMap;
021    import java.util.concurrent.ConcurrentHashMap;
022    import java.util.concurrent.ConcurrentMap;
023    
024    import org.apache.commons.logging.Log;
025    import org.apache.commons.logging.LogConfigurationException;
026    import org.apache.commons.logging.LogFactory;
027    import org.apache.logging.log4j.LogManager;
028    import org.apache.logging.log4j.spi.AbstractLogger;
029    import org.apache.logging.log4j.spi.LoggerContext;
030    
031    /**
032     *
033     */
034    public class LogFactoryImpl extends LogFactory {
035    
036        private final Map<LoggerContext, ConcurrentMap<String, Log>> contextMap =
037            new WeakHashMap<LoggerContext, ConcurrentMap<String, Log>>();
038    
039        private final ConcurrentMap<String, Object> attributes = new ConcurrentHashMap<String, Object>();
040    
041        @Override
042        public Log getInstance(final String name) throws LogConfigurationException {
043            final LoggerContext context = PrivateManager.getContext();
044            final ConcurrentMap<String, Log> loggers = getLoggersMap();
045            if (loggers.containsKey(name)) {
046                return loggers.get(name);
047            }
048            final org.apache.logging.log4j.Logger logger = PrivateManager.getLogger(name);
049            if (logger instanceof AbstractLogger) {
050                loggers.putIfAbsent(name, new Log4jLog((AbstractLogger) logger, name));
051                return loggers.get(name);
052            }
053            throw new LogConfigurationException(
054                "Commons Logging Adapter requires base logging system to extend Log4j AbstractLogger");
055        }
056    
057        private ConcurrentMap<String, Log> getLoggersMap() {
058            final LoggerContext context = PrivateManager.getContext();
059            synchronized (contextMap) {
060                ConcurrentMap<String, Log> map = contextMap.get(context);
061                if (map == null) {
062                    map = new ConcurrentHashMap<String, Log>();
063                    contextMap.put(context, map);
064                }
065                return map;
066            }
067        }
068    
069        @Override
070        public Object getAttribute(final String name) {
071            return attributes.get(name);
072        }
073    
074        @Override
075        public String[] getAttributeNames() {
076            return attributes.keySet().toArray(new String[attributes.size()]);
077        }
078    
079        @Override
080        public Log getInstance(final Class clazz) throws LogConfigurationException {
081            return getInstance(clazz.getName());
082        }
083    
084        /**
085         * This method is supposed to clear all loggers. In this implementation it will clear all the logger
086         * wrappers but the loggers managed by the underlying logger context will not be.
087         */
088        @Override
089        public void release() {
090            getLoggersMap().clear();
091        }
092    
093        @Override
094        public void removeAttribute(final String name) {
095            attributes.remove(name);
096        }
097    
098        @Override
099        public void setAttribute(final String name, final Object value) {
100            if (value != null) {
101                attributes.put(name, value);
102            } else {
103                removeAttribute(name);
104            }
105        }
106    
107        /**
108         * The real bridge between commons logging and Log4j.
109         */
110        private static class PrivateManager extends LogManager {
111            private static final String FQCN = LogFactory.class.getName();
112    
113            public static LoggerContext getContext() {
114                return getContext(FQCN, false);
115            }
116    
117            public static org.apache.logging.log4j.Logger getLogger(final String name) {
118                return getLogger(FQCN, name);
119            }
120        }
121    
122    }