blob: 74925f6cb90a292182455ae6184a58516565156d [file] [log] [blame]
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache license, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the license for the specific language governing permissions and
* limitations under the license.
*/
package org.apache.logging.log4j.core.impl;
import org.apache.logging.log4j.ThreadContext;
import org.apache.logging.log4j.core.ContextDataInjector;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.util.Loader;
import org.apache.logging.log4j.spi.CopyOnWrite;
import org.apache.logging.log4j.spi.DefaultThreadContextMap;
import org.apache.logging.log4j.spi.ReadOnlyThreadContextMap;
import org.apache.logging.log4j.status.StatusLogger;
import org.apache.logging.log4j.util.PropertiesUtil;
import org.apache.logging.log4j.util.ReadOnlyStringMap;
/**
* Factory for ContextDataInjectors. Returns a new {@code ContextDataInjector} instance based on the value of system
* property {@code log4j2.ContextDataInjector}. Users may use this system property to specify the fully qualified class
* name of a class that implements the {@code ContextDataInjector} interface.
* If no value was specified this factory method returns one of the injectors defined in
* {@code ThreadContextDataInjector}.
*
* @see ContextDataInjector
* @see ReadOnlyStringMap
* @see ThreadContextDataInjector
* @see LogEvent#getContextData()
* @since 2.7
*/
public class ContextDataInjectorFactory {
/**
* Returns a new {@code ContextDataInjector} instance based on the value of system property
* {@code log4j2.ContextDataInjector}. If no value was specified this factory method returns one of the
* {@code ContextDataInjector} classes defined in {@link ThreadContextDataInjector} which is most appropriate for
* the ThreadContext implementation.
* <p>
* <b>Note:</b> It is no longer recommended that users provide a custom implementation of the ContextDataInjector.
* Instead, provide a {@code ContextDataProvider}.
* </p>
* <p>
* Users may use this system property to specify the fully qualified class name of a class that implements the
* {@code ContextDataInjector} interface.
* </p><p>
* When providing a custom {@code ContextDataInjector}, be aware that this method may be invoked multiple times by
* the various components in Log4j that need access to context data.
* This includes the object(s) that populate log events, but also various lookups and filters that look at
* context data to determine whether an event should be logged.
* </p>
*
* @return a ContextDataInjector that populates the {@code ReadOnlyStringMap} of all {@code LogEvent} objects
* @see LogEvent#getContextData()
* @see ContextDataInjector
*/
public static ContextDataInjector createInjector() {
final String className = PropertiesUtil.getProperties().getStringProperty("log4j2.ContextDataInjector");
if (className == null) {
return createDefaultInjector();
}
try {
final Class<? extends ContextDataInjector> cls = Loader.loadClass(className).asSubclass(
ContextDataInjector.class);
return cls.newInstance();
} catch (final Exception dynamicFailed) {
final ContextDataInjector result = createDefaultInjector();
StatusLogger.getLogger().warn(
"Could not create ContextDataInjector for '{}', using default {}: {}",
className, result.getClass().getName(), dynamicFailed);
return result;
}
}
private static ContextDataInjector createDefaultInjector() {
final ReadOnlyThreadContextMap threadContextMap = ThreadContext.getThreadContextMap();
// note: map may be null (if legacy custom ThreadContextMap was installed by user)
if (threadContextMap instanceof DefaultThreadContextMap || threadContextMap == null) {
return new ThreadContextDataInjector.ForDefaultThreadContextMap(); // for non StringMap-based context maps
}
if (threadContextMap instanceof CopyOnWrite) {
return new ThreadContextDataInjector.ForCopyOnWriteThreadContextMap();
}
return new ThreadContextDataInjector.ForGarbageFreeThreadContextMap();
}
}