/*
* Copyright (c) 2008-2017, Hazelcast, Inc. All Rights Reserved.
*
* 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.hazelcast.client.proxy;
import com.hazelcast.client.HazelcastClientNotActiveException;
import com.hazelcast.client.config.ClientReliableTopicConfig;
import com.hazelcast.client.impl.HazelcastClientInstanceImpl;
import com.hazelcast.client.spi.ClientContext;
import com.hazelcast.client.spi.ClientProxy;
import com.hazelcast.core.ExecutionCallback;
import com.hazelcast.core.HazelcastInstanceNotActiveException;
import com.hazelcast.core.ICompletableFuture;
import com.hazelcast.core.ITopic;
import com.hazelcast.core.Member;
import com.hazelcast.core.Message;
import com.hazelcast.core.MessageListener;
import com.hazelcast.logging.ILogger;
import com.hazelcast.monitor.LocalTopicStats;
import com.hazelcast.nio.serialization.Data;
import com.hazelcast.ringbuffer.OverflowPolicy;
import com.hazelcast.ringbuffer.ReadResultSet;
import com.hazelcast.ringbuffer.Ringbuffer;
import com.hazelcast.ringbuffer.StaleSequenceException;
import com.hazelcast.spi.exception.DistributedObjectDestroyedException;
import com.hazelcast.spi.serialization.SerializationService;
import com.hazelcast.topic.ReliableMessageListener;
import com.hazelcast.topic.TopicOverloadException;
import com.hazelcast.topic.TopicOverloadPolicy;
import com.hazelcast.topic.impl.reliable.ReliableMessageListenerAdapter;
import com.hazelcast.topic.impl.reliable.ReliableTopicMessage;
import com.hazelcast.util.UuidUtil;
import com.hazelcast.version.MemberVersion;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.Executor;
import java.util.concurrent.RejectedExecutionException;
import static com.hazelcast.ringbuffer.impl.RingbufferService.TOPIC_RB_PREFIX;
import static com.hazelcast.topic.impl.reliable.ReliableTopicService.SERVICE_NAME;
import static com.hazelcast.util.ExceptionUtil.peel;
import static com.hazelcast.util.Preconditions.checkNotNull;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
/**
* Reliable proxy implementation of {@link ITopic}.
* <p/>
* Unlike other topics, a reliable topic has its own {@link com.hazelcast.ringbuffer.Ringbuffer} to store events and
* has its own executor to process events.
*
* @param <E> message type
*/
public class ClientReliableTopicProxy<E> extends ClientProxy implements ITopic<E> {
private static final int MAX_BACKOFF = 2000;
private static final int INITIAL_BACKOFF_MS = 100;
private final ILogger logger;
private final ConcurrentMap<String, MessageRunner> runnersMap = new ConcurrentHashMap<String, MessageRunner>();
private final Ringbuffer ringbuffer;
private final SerializationService serializationService;
private final ClientReliableTopicConfig config;
private final Executor executor;
private final TopicOverloadPolicy overloadPolicy;
public ClientReliableTopicProxy(String objectId, ClientContext context, HazelcastClientInstanceImpl client) {
super(SERVICE_NAME, objectId, context);
this.ringbuffer = client.getRingbuffer(TOPIC_RB_PREFIX + objectId);
this.serializationService = client.getSerializationService();
this.config = client.getClientConfig().getReliableTopicConfig(objectId);
this.executor = getExecutor(config, client);
this.overloadPolicy = config.getTopicOverloadPolicy();
logger = client.getLoggingService().getLogger(getClass());
}
private Executor getExecutor(ClientReliableTopicConfig config, HazelcastClientInstanceImpl client) {
Executor executor = config.getExecutor();
if (executor == null) {
executor = client.getClientExecutionService().getUserExecutor();
}
return executor;
}
@Override
public void publish(E payload) {
try {
Data data = serializationService.toData(payload);
ReliableTopicMessage message = new ReliableTopicMessage(data, null);
switch (overloadPolicy) {
case ERROR:
addOrFail(message);
break;
case DISCARD_OLDEST:
addOrOverwrite(message);
break;
case DISCARD_NEWEST:
ringbuffer.addAsync(message, OverflowPolicy.FAIL).get();
break;
case BLOCK:
addWithBackoff(message);
break;
default:
throw new IllegalArgumentException("Unknown overloadPolicy:" + overloadPolicy);
}
} catch (Exception e) {
throw (RuntimeException) peel(e, null,
"Failed to publish message: " + payload + " to topic:" + getName());
}
}
private Long addOrOverwrite(ReliableTopicMessage message) throws Exception {
return (Long) ringbuffer.addAsync(message, OverflowPolicy.OVERWRITE).get();
}
private void addOrFail(ReliableTopicMessage message) throws Exception {
long sequenceId = (Long) ringbuffer.addAsync(message, OverflowPolicy.FAIL).get();
if (sequenceId == -1) {
throw new TopicOverloadException("Failed to publish message: " + message + " on topic:" + name);
}
}
private void addWithBackoff(ReliableTopicMessage message) throws Exception {
long timeoutMs = INITIAL_BACKOFF_MS;
for (; ; ) {
long result = (Long) ringbuffer.addAsync(message, OverflowPolicy.FAIL).get();
if (result != -1) {
break;
}
MILLISECONDS.sleep(timeoutMs);
timeoutMs *= 2;
if (timeoutMs > MAX_BACKOFF) {
timeoutMs = MAX_BACKOFF;
}
}
}
@Override
public String addMessageListener(MessageListener<E> listener) {
checkNotNull(listener, "listener can't be null");
String id = UuidUtil.newUnsecureUuidString();
ReliableMessageListener<E> reliableMessageListener = toReliableMessageListener(listener);
MessageRunner runner = new MessageRunner(id, reliableMessageListener);
runnersMap.put(id, runner);
runner.next();
return id;
}
private ReliableMessageListener<E> toReliableMessageListener(MessageListener<E> listener) {
if (listener instanceof ReliableMessageListener) {
return (ReliableMessageListener) listener;
} else {
return new ReliableMessageListenerAdapter<E>(listener);
}
}
@Override
public boolean removeMessageListener(String registrationId) {
checkNotNull(registrationId, "registrationId can't be null");
MessageRunner runner = runnersMap.get(registrationId);
if (runner == null) {
return false;
}
runner.cancel();
return true;
}
@Override
public LocalTopicStats getLocalTopicStats() {
throw new UnsupportedOperationException("Locality is ambiguous for client!");
}
public Ringbuffer getRingbuffer() {
return ringbuffer;
}
@Override
public String toString() {
return "ITopic{" + "name='" + name + '\'' + '}';
}
class MessageRunner implements ExecutionCallback<ReadResultSet<ReliableTopicMessage>> {
final ReliableMessageListener<E> listener;
private final String id;
private long sequence;
private volatile boolean cancelled;
public MessageRunner(String id, ReliableMessageListener<E> listener) {
this.id = id;
this.listener = listener;
// we are going to listen to next publication. We don't care about what already has been published.
long initialSequence = listener.retrieveInitialSequence();
if (initialSequence == -1) {
initialSequence = ringbuffer.tailSequence() + 1;
}
this.sequence = initialSequence;
}
void next() {
if (cancelled) {
return;
}
ICompletableFuture<ReadResultSet<ReliableTopicMessage>> f
= ringbuffer.readManyAsync(sequence, 1, config.getReadBatchSize(), null);
f.andThen(this, executor);
}
// This method is called from the provided executor.
@Override
public void onResponse(ReadResultSet<ReliableTopicMessage> result) {
// we process all messages in batch. So we don't release the thread and reschedule ourselves;
// but we'll process whatever was received in 1 go.
for (Object item : result) {
ReliableTopicMessage message = (ReliableTopicMessage) item;
if (cancelled) {
return;
}
try {
listener.storeSequence(sequence);
process(message);
} catch (Throwable t) {
if (terminate(t)) {
cancel();
return;
}
}
sequence++;
}
next();
}
private void process(ReliableTopicMessage message) throws Throwable {
// proxy.localTopicStats.incrementReceives();
listener.onMessage(toMessage(message));
}
private Message<E> toMessage(ReliableTopicMessage m) {
Member member = null;
if (m.getPublisherAddress() != null) {
member = new com.hazelcast.client.impl.MemberImpl(m.getPublisherAddress(), MemberVersion.UNKNOWN);
}
E payload = serializationService.toObject(m.getPayload());
return new Message<E>(name, payload, m.getPublishTime(), member);
}
// This method is called from the provided executor.
@Override
public void onFailure(Throwable t) {
if (cancelled) {
return;
}
t = peel(t);
if (t instanceof StaleSequenceException) {
// StaleSequenceException.getHeadSeq() is not available on the client-side, see #7317
long remoteHeadSeq = ringbuffer.headSequence();
if (listener.isLossTolerant()) {
if (logger.isFinestEnabled()) {
logger.finest("MessageListener " + listener + " on topic: " + name + " ran into a stale sequence. "
+ "Jumping from oldSequence: " + sequence
+ " to sequence: " + remoteHeadSeq);
}
sequence = remoteHeadSeq;
next();
return;
}
logger.warning("Terminating MessageListener:" + listener + " on topic: " + name + ". "
+ "Reason: The listener was too slow or the retention period of the message has been violated. "
+ "head: " + remoteHeadSeq + " sequence:" + sequence);
} else if (t instanceof HazelcastInstanceNotActiveException) {
if (logger.isFinestEnabled()) {
logger.finest("Terminating MessageListener " + listener + " on topic: " + name + ". "
+ " Reason: HazelcastInstance is shutting down");
}
} else if (t instanceof DistributedObjectDestroyedException) {
if (logger.isFinestEnabled()) {
logger.finest("Terminating MessageListener " + listener + " on topic: " + name + ". "
+ "Reason: Topic is destroyed");
}
} else if (t instanceof HazelcastClientNotActiveException || t instanceof RejectedExecutionException) {
if (logger.isFinestEnabled()) {
logger.finest("Terminating MessageListener " + listener + " on topic: " + name + ". "
+ "Reason: HazelcastClient is shutting down");
}
} else {
logger.warning("Terminating MessageListener " + listener + " on topic: " + name + ". "
+ "Reason: Unhandled exception, message: " + t.getMessage(), t);
}
cancel();
}
void cancel() {
cancelled = true;
runnersMap.remove(id);
}
private boolean terminate(Throwable failure) {
if (cancelled) {
return true;
}
try {
boolean terminate = listener.isTerminal(failure);
if (terminate) {
logger.warning("Terminating MessageListener " + listener + " on topic: " + name + ". "
+ "Reason: Unhandled exception, message: " + failure.getMessage(), failure);
} else {
if (logger.isFinestEnabled()) {
logger.finest("MessageListener " + listener + " on topic: " + name + " ran into an exception:"
+ " message:" + failure.getMessage(), failure);
}
}
return terminate;
} catch (Throwable t) {
logger.warning("Terminating messageListener:" + listener + " on topic: " + name + ". "
+ "Reason: Unhandled exception while calling ReliableMessageListener.isTerminal() method", t);
return true;
}
}
}
}