org.apache.logging.log4j.core.async.RingBufferLogEventHandler4 Maven / Gradle / Ivy
/*
* 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.async;
import com.lmax.disruptor.EventHandler;
import com.lmax.disruptor.Sequence;
/**
* This event handler gets passed messages from the RingBuffer as they become
* available. Processing of these messages is done in a separate thread,
* controlled by the {@code Executor} passed to the {@code Disruptor}
* constructor.
* *
* * Warning: this class only works with Disruptor 4.x.
* *
*/
class RingBufferLogEventHandler4 implements EventHandler {
private static final int NOTIFY_PROGRESS_THRESHOLD = 50;
private Sequence sequenceCallback;
private int counter;
private long threadId = -1;
/*
* Overrides a method from Disruptor 4.x. Do not remove.
*/
public void setSequenceCallback(final Sequence sequenceCallback) {
this.sequenceCallback = sequenceCallback;
}
@Override
public void onEvent(final RingBufferLogEvent event, final long sequence, final boolean endOfBatch)
throws Exception {
try {
// RingBufferLogEvents are populated by an EventTranslator. If an exception is thrown during event
// translation, the event may not be fully populated, but Disruptor requires that the associated sequence
// still be published since a slot has already been claimed in the ring buffer. Ignore any such unpopulated
// events. The exception that occurred during translation will have already been propagated.
if (event.isPopulated()) {
event.execute(endOfBatch);
}
} finally {
event.clear();
// notify the BatchEventProcessor that the sequence has progressed.
// Without this callback the sequence would not be progressed
// until the batch has completely finished.
notifyCallback(sequence);
}
}
private void notifyCallback(final long sequence) {
if (++counter > NOTIFY_PROGRESS_THRESHOLD) {
sequenceCallback.set(sequence);
counter = 0;
}
}
/**
* Returns the thread ID of the background consumer thread, or {@code -1} if the background thread has not started
* yet.
*
* @return the thread ID of the background consumer thread, or {@code -1}
*/
public long getThreadId() {
return threadId;
}
/*
* Overrides a method from Disruptor 4.x. Do not remove.
*/
public void onStart() {
threadId = Thread.currentThread().getId();
}
/*
* Overrides a method from Disruptor 4.x. Do not remove.
*/
public void onShutdown() {}
}