1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache license, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the license for the specific language governing permissions and 15 * limitations under the license. 16 */ 17 package org.apache.logging.log4j.spi; 18 19 import java.util.Map; 20 import java.util.WeakHashMap; 21 import java.util.concurrent.ConcurrentHashMap; 22 import java.util.concurrent.ConcurrentMap; 23 24 import org.apache.logging.log4j.LogManager; 25 import org.apache.logging.log4j.util.LoaderUtil; 26 27 /** 28 * Provides an abstract base class to use for implementing LoggerAdapter. 29 * @param <L> the Logger class to adapt 30 * @since 2.1 31 */ 32 public abstract class AbstractLoggerAdapter<L> implements LoggerAdapter<L> { 33 34 /** 35 * A map to store loggers for their given LoggerContexts. 36 */ 37 protected final Map<LoggerContext, ConcurrentMap<String, L>> registry = 38 new WeakHashMap<>(); 39 40 @Override 41 public L getLogger(final String name) { 42 final LoggerContext context = getContext(); 43 final ConcurrentMap<String, L> loggers = getLoggersInContext(context); 44 final L logger = loggers.get(name); 45 if (logger != null) { 46 return logger; 47 } 48 loggers.putIfAbsent(name, newLogger(name, context)); 49 return loggers.get(name); 50 } 51 52 /** 53 * Gets or creates the ConcurrentMap of named loggers for a given LoggerContext. 54 * 55 * @param context the LoggerContext to get loggers for 56 * @return the map of loggers for the given LoggerContext 57 */ 58 public ConcurrentMap<String, L> getLoggersInContext(final LoggerContext context) { 59 synchronized (registry) { 60 ConcurrentMap<String, L> loggers = registry.get(context); 61 if (loggers == null) { 62 loggers = new ConcurrentHashMap<>(); 63 registry.put(context, loggers); 64 } 65 return loggers; 66 } 67 } 68 69 /** 70 * Creates a new named logger for a given {@link LoggerContext}. 71 * 72 * @param name the name of the logger to create 73 * @param context the LoggerContext this logger will be associated with 74 * @return the new named logger 75 */ 76 protected abstract L newLogger(final String name, final LoggerContext context); 77 78 /** 79 * Gets the {@link LoggerContext} that should be used to look up or create loggers. This is similar in spirit to 80 * the {@code ContextSelector} class in {@code log4j-core}. However, implementations can rely on their own 81 * framework's separation of contexts instead (or simply use a singleton). 82 * 83 * @return the LoggerContext to be used for lookup and creation purposes 84 * @see org.apache.logging.log4j.LogManager#getContext(ClassLoader, boolean) 85 * @see org.apache.logging.log4j.LogManager#getContext(String, boolean) 86 */ 87 protected abstract LoggerContext getContext(); 88 89 /** 90 * Gets the {@link LoggerContext} associated with the given caller class. 91 * 92 * @param callerClass the caller class 93 * @return the LoggerContext for the calling class 94 */ 95 protected LoggerContext getContext(final Class<?> callerClass) { 96 ClassLoader cl = null; 97 if (callerClass != null) { 98 cl = callerClass.getClassLoader(); 99 } 100 if (cl == null) { 101 cl = LoaderUtil.getThreadContextClassLoader(); 102 } 103 return LogManager.getContext(cl, false); 104 } 105 106 @Override 107 public void close() { 108 registry.clear(); 109 } 110 }