com.rabbitmq.jms.client.RMQMessageConsumer Maven / Gradle / Ivy
/* Copyright (c) 2013 Pivotal Software, Inc. All rights reserved. */
package com.rabbitmq.jms.client;
import java.io.IOException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import javax.jms.IllegalStateException;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageListener;
import javax.jms.Queue;
import javax.jms.QueueReceiver;
import javax.jms.Session;
import javax.jms.Topic;
import javax.jms.TopicSubscriber;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Consumer;
import com.rabbitmq.client.GetResponse;
import com.rabbitmq.client.ShutdownSignalException;
import com.rabbitmq.jms.admin.RMQDestination;
import com.rabbitmq.jms.util.AbortableHolder;
import com.rabbitmq.jms.util.AbortedException;
import com.rabbitmq.jms.util.EntryExitManager;
import com.rabbitmq.jms.util.TimeTracker;
import com.rabbitmq.jms.util.Util;
/**
* The implementation of {@link MessageConsumer} in the RabbitMQ JMS Client.
*
* Single message {@link #receive receive()}s are implemented by abortable polling in {@link DelayedReceiver}.
*
*
* {@link MessageListener#onMessage} calls are implemented with a more conventional {@link Consumer}.
*
*/
public class RMQMessageConsumer implements MessageConsumer, QueueReceiver, TopicSubscriber {
private final Logger logger = LoggerFactory.getLogger(RMQMessageConsumer.class);
private static final int DEFAULT_BATCHING_SIZE = 5;
private static final long STOP_TIMEOUT_MS = 1000; // ONE SECOND
/** The destination that this consumer belongs to */
private final RMQDestination destination;
/** The session that this consumer was created under */
private final RMQSession session;
/** Unique tag, used when creating AMQP queues for a consumer that thinks it's a topic */
private final String uuidTag;
/** The selector used to filter messages consumed */
private final String messageSelector;
/** The {@link Consumer} that we use to subscribe to Rabbit messages which drives {@link MessageListener#onMessage}. */
private final AtomicReference listenerConsumer = new AtomicReference();
/** Entry and exit of application threads calling {@link #receive} are managed by an {@link EntryExitManager}. */
private final EntryExitManager receiveManager = new EntryExitManager();
/** We track things that need to be aborted (for a Connection.close()). Typically these are waits. */
private final AbortableHolder abortables = new AbortableHolder();
/** Is this consumer closed? This value can change to true, but never changes back. */
private volatile boolean closed = false;
/** If this consumer is in the process of closing. */
private volatile boolean closing = false;
/** {@link MessageListener}, set by the user. */
private volatile MessageListener messageListener;
/** Flag to check if we are a durable subscription. */
private volatile boolean durable = false;
/** Flag to check if we have noLocal set */
private volatile boolean noLocal = false;
/** For getting messages from {@link #receive} queues. */
private final DelayedReceiver delayedReceiver;
/** Record and preserve the need to acknowledge automatically */
private final boolean autoAck;
/** Track how this consumer is being used. */
private final AtomicInteger numberOfReceives = new AtomicInteger(0);
/**
* Whether requeue message on {@link RuntimeException} in the
* {@link javax.jms.MessageListener} or not.
*/
private final boolean requeueOnMessageListenerException;
/**
* Creates a RMQMessageConsumer object. Internal constructor used by {@link RMQSession}
*
* @param session - the session object that created this consume
* @param destination - the destination for this consumer
* @param uuidTag - when creating queues to a topic, we need a unique queue name for each consumer. This is the
* unique name.
* @param paused - true if the connection is {@link javax.jms.Connection#stop}ped, false otherwise.
* @param requeueOnMessageListenerException true to requeue message on RuntimeException in listener, false otherwise
*/
RMQMessageConsumer(RMQSession session, RMQDestination destination, String uuidTag, boolean paused, String messageSelector, boolean requeueOnMessageListenerException) {
this.session = session;
this.destination = destination;
this.uuidTag = uuidTag;
this.delayedReceiver = new DelayedReceiver(DEFAULT_BATCHING_SIZE, this);
this.messageSelector = messageSelector;
if (!paused)
this.receiveManager.openGate();
this.autoAck = session.isAutoAck();
this.requeueOnMessageListenerException = requeueOnMessageListenerException;
}
/**
* {@inheritDoc}
*/
@Override
public Queue getQueue() throws JMSException {
return this.destination;
}
/**
* {@inheritDoc}
*/
@Override
public String getMessageSelector() throws JMSException {
return this.messageSelector;
}
/**
* {@inheritDoc}
*/
@Override
public MessageListener getMessageListener() throws JMSException {
return this.messageListener;
}
/**
* @return whether this Consumer is being used asynchronously
*/
boolean messageListenerIsSet() {
return (null != this.messageListener);
}
/**
* Dispose of any Rabbit Consumer that may be active and tracked.
*/
private void removeListenerConsumer() {
MessageListenerConsumer listConsumer = this.listenerConsumer.getAndSet(null);
if (listConsumer != null) {
this.abortables.remove(listConsumer);
listConsumer.stop(); // orderly stop
}
}
/**
* From the on-line JavaDoc:
*
* Sets the message consumer's {@link MessageListener}.
*
*
* Setting the message listener to null is the equivalent of clearing the message listener for the
* message consumer.
*
*
* The effect of calling {@link #setMessageListener} while messages are being consumed by an existing listener or
* the consumer is being used to consume messages synchronously is undefined.
*
*
*
* Notwithstanding, we attempt to clear the previous listener gracefully (by cancelling the Consumer) if there is
* one.
*
* {@inheritDoc}
*/
@Override
public void setMessageListener(MessageListener messageListener) throws JMSException {
if (messageListener == this.messageListener) { // no change, so do nothing
logger.info("MessageListener({}) already set", messageListener);
return;
}
if (!this.session.aSyncAllowed()) {
throw new IllegalStateException("A MessageListener cannot be set if receive() is outstanding on a session. (See JMS 1.1 §4.4.6.)");
}
logger.trace("setting MessageListener({})", messageListener);
this.removeListenerConsumer(); // if there is any
this.messageListener = messageListener;
this.setNewListenerConsumer(messageListener); // if needed
}
/**
* Create a new RabitMQ Consumer, if necessary.
* @param messageListener to drive from Consumer; no Consumer is created if this is null.
* @throws IllegalStateException
*/
private void setNewListenerConsumer(MessageListener messageListener) throws IllegalStateException {
if (messageListener != null) {
MessageListenerConsumer mlConsumer =
new MessageListenerConsumer(this,
getSession().getChannel(),
messageListener,
TimeUnit.MILLISECONDS.toNanos(this.session.getConnection()
.getTerminationTimeout()),
this.requeueOnMessageListenerException);
if (this.listenerConsumer.compareAndSet(null, mlConsumer)) {
this.abortables.add(mlConsumer);
if (!this.getSession().getConnection().isStopped()) {
mlConsumer.start();
}
} else {
mlConsumer.abort();
throw new IllegalStateException(String.format("MessageListener concurrently set on Consumer [%s].", this));
}
}
}
/**
* {@inheritDoc}
*/
@Override
public Message receive() throws JMSException {
if (this.closed || this.closing)
throw new IllegalStateException("Consumer is closed or closing.");
logger.trace("receive (wait forever)");
return receive(new TimeTracker());
}
/**
* Receive a single message from the destination, waiting for up to timeout milliseconds if necessary.
*
* The JMS 1.1 specification for {@link javax.jms.Connection#stop()} says:
*
*
*
* When the connection is stopped, delivery to all the connection's message consumers is inhibited: synchronous
* receives block, and messages are not delivered to message listeners. {@link javax.jms.Connection#stop()} blocks until
* receives and/or message listeners in progress have completed.
*
*
*
* For synchronous gets, we potentially have to block on the way in.
*
* {@inheritDoc}
*
* @param timeout - (in milliseconds) zero means wait forever; {@inheritDoc}
*/
@Override
public Message receive(long timeout) throws JMSException {
if (this.closed || this.closing)
throw new IllegalStateException("Consumer is closed or closing.");
logger.trace("receive(timeout={}ms)", timeout);
return receive(timeout==0 ? new TimeTracker() : new TimeTracker(timeout, TimeUnit.MILLISECONDS));
}
/**
* Returns true if messages should be automatically acknowledged upon arrival
*
* @return true if {@link Session#getAcknowledgeMode()}=={@link Session#DUPS_OK_ACKNOWLEDGE} or
* {@link Session#getAcknowledgeMode()}=={@link Session#AUTO_ACKNOWLEDGE} or transacted.
*/
final boolean isAutoAck() {
return this.autoAck;
}
/**
* Register a {@link Consumer} with the Rabbit API to receive messages
*
* @param consumer the SynchronousConsumer being registered
* @param consTag the ConsumerTag to use for RabbitMQ callbacks
* @throws IOException from RabbitMQ calls
* @see Channel#basicConsume(String, boolean, String, boolean, boolean, java.util.Map, Consumer)
*/
void basicConsume(Consumer consumer, String consTag) throws IOException {
String name = rmqQueueName();
// never ack async messages automatically, only when we can deliver them
// to the actual consumer so we pass in false as the auto ack mode
// we must support setMessageListener(null) while messages are arriving
// and those message we NACK
logger.debug("consuming from queue '{}' with tag '{}'", name, consTag);
getSession().getChannel()
.basicConsume(name, /* the name of the queue */
false, /* autoack is ALWAYS false, otherwise we risk acking messages that are received
* to the client but the client listener(onMessage) has not yet been invoked */
consTag, /* the consumer tag to use */
this.noLocal, /* RabbitMQ accepts but does not support noLocal=true for subscriptions */
false, /* exclusive will always be false: exclusive consumer access true means only this
* consumer can access the queue. */
null, /* there are no custom arguments for the subscription */
consumer /* the callback object for handleDelivery(), etc. */
);
}
/**
* RabbitMQ {@link Channel#basicConsume} should accept a {@link null} consumer-tag, to cause it to generate a new,
* unique one for us; but it doesn't :-(
*/
static final String newConsumerTag() {
return Util.generateUUID("jms-consumer-");
// return null;
}
String rmqQueueName() {
if (this.destination.isQueue()) {
/* javax.jms.Queue we share a single AMQP queue among all consumers hence the name will the the name of the
* destination */
return this.destination.getAmqpQueueName();
} else {
/* javax.jms.Topic we created a unique AMQP queue for each consumer and that name is unique for this
* consumer alone */
return this.getUUIDTag();
}
}
int getNumberOfReceives() {
return this.numberOfReceives.get();
}
private RMQMessage receive(TimeTracker tt) throws JMSException {
/* Pseudocode:
* get (synchronous read)
* if something return it;
* if nothing, then poll (intervals up to time limit given)
* if still nothing return nothing.
*/
if (!this.session.syncAllowed()) {
throw new IllegalStateException("A session may not receive() when a MessageListener is set. (See JMS 1.1 §4.4.6.)");
}
this.numberOfReceives.incrementAndGet();
try {
if (!this.receiveManager.enter(tt)) // stopped?
return null; // timed out while stopped
/* Try to receive a message, there's some time left! */
try {
GetResponse resp = this.delayedReceiver.get(tt);
if (resp == null) return null; // nothing received in time or aborted
this.dealWithAcknowledgements(this.isAutoAck(), resp.getEnvelope().getDeliveryTag());
return RMQMessage.convertMessage(this.session, this.destination, resp);
} finally {
this.receiveManager.exit();
}
} catch (AbortedException e) {
/* If we were aborted (closed) we return null, too. */
return null;
} catch (InterruptedException e) {
/* Someone interrupted us -- we ought to terminate */
Thread.currentThread().interrupt(); // reset interrupt status
return null;
} finally {
this.numberOfReceives.decrementAndGet();
}
}
void dealWithAcknowledgements(boolean ack, long dtag) {
if (ack) {
this.session.explicitAck(dtag);
} else {
this.session.unackedMessageReceived(dtag);
}
}
/**
* {@inheritDoc}
*/
@Override
public Message receiveNoWait() throws JMSException {
logger.trace("receive without waiting");
if (this.closed || this.closing)
throw new IllegalStateException("Consumer is closed or closing.");
return receive(TimeTracker.ZERO);
}
/**
* JMS Spec:
*
* Closes the message consumer. Since a provider may allocate some resources on behalf of a
* MessageConsumer outside the Java virtual machine, clients should close them when they are not needed. Relying on
* garbage collection to eventually reclaim these resources may not be timely enough. This call blocks until a
* receive or message listener in progress has completed.
* A blocked message consumer receive call returns null when
* this message consumer is closed.
*
* {@inheritDoc}
*/
@Override
public void close() throws JMSException {
this.getSession().consumerClose(this);
}
/**
* @return true if {@link #close()} has been invoked and the call has completed, or false
* if {@link #close()} has not been called or is in progress
*/
boolean isClosed() {
return this.closed;
}
/**
* Method called when message consumer is closed
*/
void internalClose() throws JMSException {
logger.trace("close consumer({})", this);
this.closing = true;
/* If we are stopped, we must break that. This will release all threads waiting on the gate and effectively
* disable the use of the gate */
this.receiveManager.closeGate(); // stop any more entering receive region
this.receiveManager.abortWaiters(); // abort any that arrive now
this.delayedReceiver.close(); // close the synchronous receive, if any
/* stop and remove any active subscription - waits for onMessage processing to finish */
this.removeListenerConsumer();
this.abortables.abort(); // abort Consumers of both types that remain
this.closed = true;
this.closing = false;
}
/**
* Returns the destination this message consumer is registered with
*
* @return the destination this message consumer is registered with
*/
RMQDestination getDestination() {
return this.destination;
}
/**
* Returns the session this consumer was created by
*
* @return the session this consumer was created by
*/
RMQSession getSession() {
return this.session;
}
/**
* The unique tag that this consumer holds
*
* @return unique tag that this consumer holds
*/
private String getUUIDTag() {
return this.uuidTag;
}
/**
* {@inheritDoc}
*/
@Override
public Topic getTopic() throws JMSException {
if (this.getDestination().isQueue()) {
throw new JMSException("Destination is not of type Topic");
}
return this.getDestination();
}
/**
* {@inheritDoc}
*/
@Override
public boolean getNoLocal() throws JMSException {
return getNoLocalNoException();
}
/**
* @see #getNoLocal()
* @return true if the noLocal variable was set
*/
private boolean getNoLocalNoException() {
return this.noLocal;
}
/**
* Stops this consumer from receiving messages. This is called by the session indirectly when
* {@link javax.jms.Connection#stop()} is invoked. In this implementation, any async consumers will be cancelled,
* only to be re-subscribed when resume()d.
*
* @throws InterruptedException if the thread is interrupted
*/
void pause() throws InterruptedException {
this.receiveManager.closeGate();
this.receiveManager.waitToClear(new TimeTracker(STOP_TIMEOUT_MS, TimeUnit.MILLISECONDS));
this.abortables.stop();
}
/**
* Resubscribes all async listeners and continues to receive messages
*
* @see javax.jms.Connection#start()
* @throws javax.jms.JMSException if the thread is interrupted
*/
void resume() throws JMSException {
this.abortables.start(); // async listener restarted
this.receiveManager.openGate(); // sync listener allowed to run
}
/**
* @return true if durable
*/
public boolean isDurable() {
return this.durable;
}
/**
* Set durable status
*
* @param durable
*/
void setDurable(boolean durable) {
this.durable = durable;
}
/**
* Configures the no local for this consumer. This is currently only used when subscribing an async consumer.
*
* @param noLocal - if true, and the destination is a {@link Topic}, inhibits the delivery of messages published by its own
* connection. The behaviour for noLocal is not specified if the destination is a {@link Queue}.
*/
void setNoLocal(boolean noLocal) {
this.noLocal = noLocal;
}
GetResponse getFromRabbitQueue() {
String qN = rmqQueueName();
try {
return getSession().getChannel().basicGet(qN, false);
} catch (Exception e) { // includes unchecked exceptions, e.g. ShutdownSignalException
if (!(e instanceof ShutdownSignalException) && !(e.getCause() instanceof ShutdownSignalException)) {
logger.error("basicGet for queue '{}' threw unexpected exception", qN, e);
}
}
return null;
}
}