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
018package org.apache.logging.log4j.core.config;
019
020import java.util.Objects;
021import java.util.concurrent.locks.ReadWriteLock;
022import java.util.concurrent.locks.ReentrantReadWriteLock;
023
024import org.apache.logging.log4j.Level;
025import org.apache.logging.log4j.Marker;
026import org.apache.logging.log4j.core.LogEvent;
027import org.apache.logging.log4j.message.Message;
028import org.apache.logging.log4j.util.Supplier;
029
030/**
031 * ReliabilityStrategy that uses read/write locks to prevent the LoggerConfig from stopping while it is in use.
032 */
033public class LockingReliabilityStrategy implements ReliabilityStrategy {
034    private final LoggerConfig loggerConfig;
035    private final ReadWriteLock reconfigureLock = new ReentrantReadWriteLock();
036    private volatile boolean isStopping = false;
037
038    public LockingReliabilityStrategy(final LoggerConfig loggerConfig) {
039        this.loggerConfig = Objects.requireNonNull(loggerConfig, "loggerConfig was null");
040    }
041
042    /* (non-Javadoc)
043     * @see org.apache.logging.log4j.core.config.ReliabilityStrategy#log(org.apache.logging.log4j.util.Supplier, java.lang.String, java.lang.String, org.apache.logging.log4j.Marker, org.apache.logging.log4j.Level, org.apache.logging.log4j.message.Message, java.lang.Throwable)
044     */
045    @Override
046    public void log(final Supplier<LoggerConfig> reconfigured, final String loggerName, final String fqcn,
047            final Marker marker, final Level level, final Message data, final Throwable t) {
048
049        final LoggerConfig config = getActiveLoggerConfig(reconfigured);
050        try {
051            config.log(loggerName, fqcn, marker, level, data, t);
052        } finally {
053            config.getReliabilityStrategy().afterLogEvent();
054        }
055    }
056
057    /* (non-Javadoc)
058     * @see org.apache.logging.log4j.core.config.ReliabilityStrategy#log(org.apache.logging.log4j.util.Supplier, org.apache.logging.log4j.core.LogEvent)
059     */
060    @Override
061    public void log(final Supplier<LoggerConfig> reconfigured, final LogEvent event) {
062        final LoggerConfig config = getActiveLoggerConfig(reconfigured);
063        try {
064            config.log(event);
065        } finally {
066            config.getReliabilityStrategy().afterLogEvent();
067        }
068    }
069
070    /* (non-Javadoc)
071     * @see org.apache.logging.log4j.core.config.ReliabilityStrategy#beforeLogEvent(org.apache.logging.log4j.core.config.LoggerConfig, org.apache.logging.log4j.util.Supplier)
072     */
073    @Override
074    public LoggerConfig getActiveLoggerConfig(final Supplier<LoggerConfig> next) {
075        LoggerConfig result = this.loggerConfig;
076        if (!beforeLogEvent()) {
077            result = next.get();
078            return result.getReliabilityStrategy().getActiveLoggerConfig(next);
079        }
080        return result;
081    }
082
083    private boolean beforeLogEvent() {
084        reconfigureLock.readLock().lock();
085        if (isStopping) {
086            reconfigureLock.readLock().unlock();
087            return false;
088        }
089        return true;
090    }
091
092    public void afterLogEvent() {
093        reconfigureLock.readLock().unlock();
094    }
095
096    /* (non-Javadoc)
097     * @see org.apache.logging.log4j.core.config.ReliabilityStrategy#beforeStopAppenders()
098     */
099    @Override
100    public void beforeStopAppenders() {
101        reconfigureLock.writeLock().lock();
102        try {
103            isStopping = true;
104        } finally {
105            reconfigureLock.writeLock().unlock();
106        }
107    }
108
109    /* (non-Javadoc)
110     * @see org.apache.logging.log4j.core.config.ReliabilityStrategy#beforeStopConfiguration(org.apache.logging.log4j.core.config.Configuration)
111     */
112    @Override
113    public void beforeStopConfiguration(Configuration configuration) {
114        // no action
115    }
116
117}