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 */ 017package org.apache.logging.log4j.core.impl; 018 019import java.util.List; 020 021import org.apache.logging.log4j.Level; 022import org.apache.logging.log4j.Marker; 023import org.apache.logging.log4j.ThreadContext; 024import org.apache.logging.log4j.core.ContextDataInjector; 025import org.apache.logging.log4j.core.LogEvent; 026import org.apache.logging.log4j.core.async.ThreadNameCachingStrategy; 027import org.apache.logging.log4j.core.config.Property; 028import org.apache.logging.log4j.core.util.Clock; 029import org.apache.logging.log4j.core.util.ClockFactory; 030import org.apache.logging.log4j.message.Message; 031import org.apache.logging.log4j.util.StringMap; 032 033/** 034 * Garbage-free LogEventFactory that reuses a single mutable log event. 035 * @since 2.6 036 */ 037public class ReusableLogEventFactory implements LogEventFactory, LocationAwareLogEventFactory { 038 private static final ThreadNameCachingStrategy THREAD_NAME_CACHING_STRATEGY = ThreadNameCachingStrategy.create(); 039 private static final Clock CLOCK = ClockFactory.getClock(); 040 041 private static ThreadLocal<MutableLogEvent> mutableLogEventThreadLocal = new ThreadLocal<>(); 042 private final ContextDataInjector injector = ContextDataInjectorFactory.createInjector(); 043 044 /** 045 * Creates a log event. 046 * 047 * @param loggerName The name of the Logger. 048 * @param marker An optional Marker. 049 * @param fqcn The fully qualified class name of the caller. 050 * @param level The event Level. 051 * @param message The Message. 052 * @param properties Properties to be added to the log event. 053 * @param t An optional Throwable. 054 * @return The LogEvent. 055 */ 056 @Override 057 public LogEvent createEvent(final String loggerName, final Marker marker, 058 final String fqcn, final Level level, final Message message, 059 final List<Property> properties, final Throwable t) { 060 return createEvent(loggerName, marker, fqcn, null, level, message, properties, t); 061 } 062 063 /** 064 * Creates a log event. 065 * 066 * @param loggerName The name of the Logger. 067 * @param marker An optional Marker. 068 * @param fqcn The fully qualified class name of the caller. 069 * @param location The location of the caller. 070 * @param level The event Level. 071 * @param message The Message. 072 * @param properties Properties to be added to the log event. 073 * @param t An optional Throwable. 074 * @return The LogEvent. 075 */ 076 @Override 077 public LogEvent createEvent(final String loggerName, final Marker marker, final String fqcn, 078 final StackTraceElement location, final Level level, final Message message, 079 final List<Property> properties, final Throwable t) { 080 MutableLogEvent result = mutableLogEventThreadLocal.get(); 081 if (result == null || result.reserved) { 082 final boolean initThreadLocal = result == null; 083 result = new MutableLogEvent(); 084 085 // usually no need to re-initialize thread-specific fields since the event is stored in a ThreadLocal 086 result.setThreadId(Thread.currentThread().getId()); 087 result.setThreadName(Thread.currentThread().getName()); // Thread.getName() allocates Objects on each call 088 result.setThreadPriority(Thread.currentThread().getPriority()); 089 if (initThreadLocal) { 090 mutableLogEventThreadLocal.set(result); 091 } 092 } 093 result.reserved = true; 094 result.clear(); // ensure any previously cached values (thrownProxy, source, etc.) are cleared 095 096 result.setLoggerName(loggerName); 097 result.setMarker(marker); 098 result.setLoggerFqcn(fqcn); 099 result.setLevel(level == null ? Level.OFF : level); 100 result.setMessage(message); 101 result.initTime(CLOCK, Log4jLogEvent.getNanoClock()); 102 result.setThrown(t); 103 result.setSource(location); 104 result.setContextData(injector.injectContextData(properties, (StringMap) result.getContextData())); 105 result.setContextStack(ThreadContext.getDepth() == 0 ? ThreadContext.EMPTY_STACK : ThreadContext.cloneStack());// mutable copy 106 107 if (THREAD_NAME_CACHING_STRATEGY == ThreadNameCachingStrategy.UNCACHED) { 108 result.setThreadName(Thread.currentThread().getName()); // Thread.getName() allocates Objects on each call 109 result.setThreadPriority(Thread.currentThread().getPriority()); 110 } 111 return result; 112 } 113 114 /** 115 * Switches the {@code reserved} flag off if the specified event is a MutableLogEvent, otherwise does nothing. 116 * This flag is used internally to verify that a reusable log event is no longer in use and can be reused. 117 * @param logEvent the log event to make available again 118 * @since 2.7 119 */ 120 public static void release(final LogEvent logEvent) { // LOG4J2-1583 121 if (logEvent instanceof MutableLogEvent) { 122 final MutableLogEvent mutableLogEvent = (MutableLogEvent) logEvent; 123 mutableLogEvent.clear(); 124 mutableLogEvent.reserved = false; 125 } 126 } 127}