Java tutorial
/** * Copyright 2016 Yahoo Inc. * * Licensed 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 com.yahoo.pulsar.client.impl; import java.io.Closeable; import java.util.ArrayList; import java.util.HashSet; import java.util.List; import java.util.Set; import java.util.concurrent.TimeUnit; import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReentrantReadWriteLock; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.yahoo.pulsar.common.util.collections.ConcurrentOpenHashSet; import io.netty.util.Timeout; import io.netty.util.TimerTask; public class UnAckedMessageTracker implements Closeable { private static final Logger log = LoggerFactory.getLogger(UnAckedMessageTracker.class); private ConcurrentOpenHashSet<MessageIdImpl> currentSet; private ConcurrentOpenHashSet<MessageIdImpl> oldOpenSet; private final ReentrantReadWriteLock readWriteLock; private final Lock readLock; private final Lock writeLock; private Timeout timeout; public static final UnAckedMessageTrackerDisabled UNACKED_MESSAGE_TRACKER_DISABLED = new UnAckedMessageTrackerDisabled(); private static class UnAckedMessageTrackerDisabled extends UnAckedMessageTracker { @Override public void clear() { } @Override public boolean add(MessageIdImpl m) { return true; } @Override public boolean remove(MessageIdImpl m) { return true; } @Override public int removeMessagesTill(MessageIdImpl msgId) { return 0; } @Override public void close() { } } public UnAckedMessageTracker() { readWriteLock = null; readLock = null; writeLock = null; } public UnAckedMessageTracker(PulsarClientImpl client, ConsumerBase consumerBase, long ackTimeoutMillis) { currentSet = new ConcurrentOpenHashSet<MessageIdImpl>(); oldOpenSet = new ConcurrentOpenHashSet<MessageIdImpl>(); readWriteLock = new ReentrantReadWriteLock(); readLock = readWriteLock.readLock(); writeLock = readWriteLock.writeLock(); start(client, consumerBase, ackTimeoutMillis); } public void start(PulsarClientImpl client, ConsumerBase consumerBase, long ackTimeoutMillis) { this.stop(); timeout = client.timer().newTimeout(new TimerTask() { @Override public void run(Timeout t) throws Exception { if (isAckTimeout()) { log.warn("[{}] {} messages have timed-out", consumerBase, oldOpenSet.size()); Set<MessageIdImpl> messageIds = new HashSet<>(); oldOpenSet.forEach(messageIds::add); oldOpenSet.clear(); consumerBase.redeliverUnacknowledgedMessages(messageIds); } toggle(); timeout = client.timer().newTimeout(this, ackTimeoutMillis, TimeUnit.MILLISECONDS); } }, ackTimeoutMillis, TimeUnit.MILLISECONDS); } void toggle() { writeLock.lock(); try { ConcurrentOpenHashSet<MessageIdImpl> temp = currentSet; currentSet = oldOpenSet; oldOpenSet = temp; } finally { writeLock.unlock(); } } public void clear() { readLock.lock(); try { currentSet.clear(); oldOpenSet.clear(); } finally { readLock.unlock(); } } public boolean add(MessageIdImpl m) { readLock.lock(); try { oldOpenSet.remove(m); return currentSet.add(m); } finally { readLock.unlock(); } } boolean isEmpty() { readLock.lock(); try { return currentSet.isEmpty() && oldOpenSet.isEmpty(); } finally { readLock.unlock(); } } public boolean remove(MessageIdImpl m) { readLock.lock(); try { return currentSet.remove(m) || oldOpenSet.remove(m); } finally { readLock.unlock(); } } long size() { readLock.lock(); try { return currentSet.size() + oldOpenSet.size(); } finally { readLock.unlock(); } } private boolean isAckTimeout() { readLock.lock(); try { return !oldOpenSet.isEmpty(); } finally { readLock.unlock(); } } public int removeMessagesTill(MessageIdImpl msgId) { readLock.lock(); try { int currentSetRemovedMsgCount = currentSet.removeIf(m -> ((m.getLedgerId() < msgId.getLedgerId() || (m.getLedgerId() == msgId.getLedgerId() && m.getEntryId() <= msgId.getEntryId())) && m.getPartitionIndex() == msgId.getPartitionIndex())); int oldSetRemovedMsgCount = oldOpenSet.removeIf(m -> ((m.getLedgerId() < msgId.getLedgerId() || (m.getLedgerId() == msgId.getLedgerId() && m.getEntryId() <= msgId.getEntryId())) && m.getPartitionIndex() == msgId.getPartitionIndex())); return currentSetRemovedMsgCount + oldSetRemovedMsgCount; } finally { readLock.unlock(); } } private void stop() { writeLock.lock(); try { if (timeout != null && !timeout.isCancelled()) { timeout.cancel(); } this.clear(); } finally { writeLock.unlock(); } } @Override public void close() { stop(); } }