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.async;
018
019import com.lmax.disruptor.Sequence;
020import com.lmax.disruptor.SequenceReportingEventHandler;
021
022/**
023 * This event handler gets passed messages from the RingBuffer as they become
024 * available. Processing of these messages is done in a separate thread,
025 * controlled by the {@code Executor} passed to the {@code Disruptor}
026 * constructor.
027 */
028public class RingBufferLogEventHandler implements
029        SequenceReportingEventHandler<RingBufferLogEvent> {
030
031    private static final int NOTIFY_PROGRESS_THRESHOLD = 50;
032    private Sequence sequenceCallback;
033    private int counter;
034
035    @Override
036    public void setSequenceCallback(final Sequence sequenceCallback) {
037        this.sequenceCallback = sequenceCallback;
038    }
039
040    @Override
041    public void onEvent(final RingBufferLogEvent event, final long sequence,
042            final boolean endOfBatch) throws Exception {
043        event.execute(endOfBatch);
044        event.clear();
045
046        // notify the BatchEventProcessor that the sequence has progressed.
047        // Without this callback the sequence would not be progressed
048        // until the batch has completely finished.
049        if (++counter > NOTIFY_PROGRESS_THRESHOLD) {
050            sequenceCallback.set(sequence);
051            counter = 0;
052        }
053    }
054
055}