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.core.async;
18
19 import com.lmax.disruptor.LifecycleAware;
20 import com.lmax.disruptor.Sequence;
21 import com.lmax.disruptor.SequenceReportingEventHandler;
22
23 /**
24 * This event handler gets passed messages from the RingBuffer as they become
25 * available. Processing of these messages is done in a separate thread,
26 * controlled by the {@code Executor} passed to the {@code Disruptor}
27 * constructor.
28 */
29 public class RingBufferLogEventHandler implements
30 SequenceReportingEventHandler<RingBufferLogEvent>, LifecycleAware {
31
32 private static final int NOTIFY_PROGRESS_THRESHOLD = 50;
33 private Sequence sequenceCallback;
34 private int counter;
35 private long threadId = -1;
36
37 @Override
38 public void setSequenceCallback(final Sequence sequenceCallback) {
39 this.sequenceCallback = sequenceCallback;
40 }
41
42 @Override
43 public void onEvent(final RingBufferLogEvent event, final long sequence,
44 final boolean endOfBatch) throws Exception {
45 try {
46 event.execute(endOfBatch);
47 }
48 finally {
49 event.clear();
50 // notify the BatchEventProcessor that the sequence has progressed.
51 // Without this callback the sequence would not be progressed
52 // until the batch has completely finished.
53 notifyCallback(sequence);
54 }
55 }
56
57 private void notifyCallback(long sequence) {
58 if (++counter > NOTIFY_PROGRESS_THRESHOLD) {
59 sequenceCallback.set(sequence);
60 counter = 0;
61 }
62 }
63
64 /**
65 * Returns the thread ID of the background consumer thread, or {@code -1} if the background thread has not started
66 * yet.
67 * @return the thread ID of the background consumer thread, or {@code -1}
68 */
69 public long getThreadId() {
70 return threadId;
71 }
72
73 @Override
74 public void onStart() {
75 threadId = Thread.currentThread().getId();
76 }
77
78 @Override
79 public void onShutdown() {
80 }
81 }