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.slf4j.helpers;
018
019 import org.apache.logging.log4j.LogManager;
020 import org.apache.logging.log4j.spi.AbstractLogger;
021 import org.apache.logging.log4j.spi.LoggerContext;
022 import org.apache.logging.slf4j.SLF4JLoggingException;
023 import org.slf4j.ILoggerFactory;
024 import org.slf4j.Logger;
025 import org.slf4j.LoggerFactory;
026 import org.slf4j.impl.SLF4JLogger;
027
028 import java.util.Map;
029 import java.util.WeakHashMap;
030 import java.util.concurrent.ConcurrentHashMap;
031 import java.util.concurrent.ConcurrentMap;
032
033 /**
034 *
035 */
036 public class Log4JLoggerFactory implements ILoggerFactory {
037
038 private static final String FQCN = Log4JLoggerFactory.class.getName();
039 private static final String PACKAGE = "org.slf4j";
040
041 private final Map<LoggerContext, ConcurrentMap<String, Logger>> contextMap =
042 new WeakHashMap<LoggerContext, ConcurrentMap<String, Logger>>();
043
044 public Logger getLogger(String name) {
045 LoggerContext context = getContext();
046 ConcurrentMap<String, Logger> loggers = getLoggersMap(context);
047
048 if (loggers.containsKey(name)) {
049 return loggers.get(name);
050 }
051 String key = Logger.ROOT_LOGGER_NAME.equals(name) ? LogManager.ROOT_LOGGER_NAME : name;
052 org.apache.logging.log4j.Logger logger = context.getLogger(key);
053 if (logger instanceof AbstractLogger) {
054 loggers.putIfAbsent(name, new SLF4JLogger((AbstractLogger) logger, name));
055 return loggers.get(name);
056 }
057 throw new SLF4JLoggingException("SLF4J Adapter requires base logging system to extend Log4J AbstractLogger");
058 }
059
060 private ConcurrentMap<String, Logger> getLoggersMap(LoggerContext context) {
061 synchronized (contextMap) {
062 ConcurrentMap<String, Logger> map = contextMap.get(context);
063 if (map == null) {
064 map = new ConcurrentHashMap<String, Logger>();
065 contextMap.put(context, map);
066 }
067 return map;
068 }
069 }
070 private LoggerContext getContext() {
071 Throwable t = new Throwable();
072 boolean next = false;
073 boolean pkg = false;
074 String fqcn = LoggerFactory.class.getName();
075 for (StackTraceElement element : t.getStackTrace()) {
076 if (FQCN.equals(element.getClassName())) {
077 next = true;
078 continue;
079 }
080 if (next && element.getClassName().startsWith(PACKAGE)) {
081 fqcn = element.getClassName();
082 pkg = true;
083 continue;
084 }
085 if (pkg) {
086 break;
087 }
088 }
089 return PrivateManager.getContext(fqcn);
090 }
091
092 /**
093 * The real bridge between SLF4J and Log4j.
094 */
095 private static class PrivateManager extends LogManager {
096 private static final String FQCN = LoggerFactory.class.getName();
097
098 public static LoggerContext getContext() {
099 return getContext(FQCN, false);
100 }
101
102 public static LoggerContext getContext(String fqcn) {
103 return getContext(fqcn, false);
104 }
105
106 public static org.apache.logging.log4j.Logger getLogger(String name) {
107 return getLogger(FQCN, name);
108 }
109 }
110
111 }