1,发送消息入口
Message message = messageBean.getMessageCreator().createMessage(session);
producer.send(message);2,调用ActiveMQMessageProducerSupport的send方法。该类实现了MessageProducer接口
public void send(Message message) throws JMSException {
this.send(this.getDestination(),
message,
this.defaultDeliveryMode,
this.defaultPriority,
this.defaultTimeToLive);
}
public void send(Destination destination, Message message, int deliveryMode, int priority, long timeToLive, AsyncCallback onComplete) throws JMSException {
checkClosed();
if (destination == null) {
if (info.getDestination() == null) {
throw new UnsupportedOperationException("A destination must be specified.");
}
throw new InvalidDestinationException("Don't understand null destinations");
}
ActiveMQDestination dest;
if (destination.equals(info.getDestination())) {
dest = (ActiveMQDestination)destination;
} else if (info.getDestination() == null) {
dest = ActiveMQDestination.transform(destination);
} else {
throw new UnsupportedOperationException("This producer can only send messages to: " + this.info.getDestination().getPhysicalName());
}
if (dest == null) {
throw new JMSException("No destination specified");
}
if (transformer != null) {
Message transformedMessage = transformer.producerTransform(session, this, message);
if (transformedMessage != null) {
message = transformedMessage;
}
}
if (producerWindow != null) {
try {
producerWindow.waitForSpace();
} catch (InterruptedException e) {
throw new JMSException("Send aborted due to thread interrupt.");
}
}
this.session.send(this, dest, message, deliveryMode, priority, timeToLive, producerWindow, sendTimeout, onComplete);
stats.onMessage();
}3调用ActiveMQSession的send接口进行消息发送
protected void send(ActiveMQMessageProducer producer, ActiveMQDestination destination, Message message, int deliveryMode, int priority, long timeToLive,
MemoryUsage producerWindow, int sendTimeout, AsyncCallback onComplete) throws JMSException {
checkClosed();
if (destination.isTemporary() && connection.isDeleted(destination)) {
throw new InvalidDestinationException("Cannot publish to a deleted Destination: " + destination);
}
synchronized (sendMutex) {
// tell the Broker we are about to start a new transaction
doStartTransaction();
TransactionId txid = transactionContext.getTransactionId();
long sequenceNumber = producer.getMessageSequence();
//Set the "JMS" header fields on the original message, see 1.1 spec section 3.4.11
message.setJMSDeliveryMode(deliveryMode);
long expiration = 0L;
if (!producer.getDisableMessageTimestamp()) {
long timeStamp = System.currentTimeMillis();
message.setJMSTimestamp(timeStamp);
if (timeToLive > 0) {
expiration = timeToLive + timeStamp;
}
}
message.setJMSExpiration(expiration);
message.setJMSPriority(priority);
message.setJMSRedelivered(false);
// transform to our own message format here
ActiveMQMessage msg = ActiveMQMessageTransformation.transformMessage(message, connection);
// Set the message id.
if (msg == message) {
msg.setMessageId(new MessageId(producer.getProducerInfo().getProducerId(), sequenceNumber));
} else {
msg.setMessageId(new MessageId(producer.getProducerInfo().getProducerId(), sequenceNumber));
message.setJMSMessageID(msg.getMessageId().toString());
}
//clear the brokerPath in case we are re-sending this message
msg.setBrokerPath(null);
// destination format is provider specific so only set on transformed message
msg.setJMSDestination(destination);
msg.setTransactionId(txid);
if (connection.isCopyMessageOnSend()) {
msg = (ActiveMQMessage)msg.copy();
}
msg.setConnection(connection);
msg.onSend();
msg.setProducerId(msg.getMessageId().getProducerId());
if (LOG.isTraceEnabled()) {
LOG.trace(getSessionId() + " sending message: " + msg);
}
if (onComplete==null && sendTimeout 0 && onComplete==null) {
this.connection.syncSendPacket(msg,sendTimeout);
}else {
this.connection.syncSendPacket(msg, onComplete);
}
}
}
}4,ActiveMQConnection发送消息
public Response syncSendPacket(Command command) throws JMSException {
if (isClosed()) {
throw new ConnectionClosedException();
} else {
try {
Response response = (Response)this.transport.request(command);
if (response.isException()) {
ExceptionResponse er = (ExceptionResponse)response;
if (er.getException() instanceof JMSException) {
throw (JMSException)er.getException();
} else {
if (isClosed()||closing.get()) {
LOG.debug("Received an exception but connection is closing");
}
JMSException jmsEx = null;
try {
jmsEx = JMSExceptionSupport.create(er.getException());
} catch(Throwable e) {
LOG.error("Caught an exception trying to create a JMSException for " +er.getException(),e);
}
//dispose of transport for security exceptions
if (er.getException() instanceof SecurityException && command instanceof ConnectionInfo){
Transport t = this.transport;
if (null != t){
ServiceSupport.dispose(t);
}
}
if (jmsEx !=null) {
throw jmsEx;
}
}
}
return response;
} catch (IOException e) {
throw JMSExceptionSupport.create(e);
}
}
}
public Response syncSendPacket(Command command) throws JMSException {
if (isClosed()) {
throw new ConnectionClosedException();
} else {
try {
Response response = (Response)this.transport.request(command);
if (response.isException()) {
ExceptionResponse er = (ExceptionResponse)response;
if (er.getException() instanceof JMSException) {
throw (JMSException)er.getException();
} else {
if (isClosed()||closing.get()) {
LOG.debug("Received an exception but connection is closing");
}
JMSException jmsEx = null;
try {
jmsEx = JMSExceptionSupport.create(er.getException());
} catch(Throwable e) {
LOG.error("Caught an exception trying to create a JMSException for " +er.getException(),e);
}
//dispose of transport for security exceptions
if (er.getException() instanceof SecurityException && command instanceof ConnectionInfo){
Transport t = this.transport;
if (null != t){
ServiceSupport.dispose(t);
}
}
if (jmsEx !=null) {
throw jmsEx;
}
}
}
return response;
} catch (IOException e) {
throw JMSExceptionSupport.create(e);
}
}
}5,ResponseCorrelator发送request
public Object request(Object command) throws IOException {
FutureResponse response = asyncRequest(command, null);
return response.getResult();
}
public FutureResponse asyncRequest(Object o, ResponseCallback responseCallback) throws IOException {
Command command = (Command) o;
command.setCommandId(sequenceGenerator.getNextSequenceId());
command.setResponseRequired(true);
FutureResponse future = new FutureResponse(responseCallback);
IOException priorError = null;
synchronized (requestMap) {
priorError = this.error;
if (priorError == null) {
requestMap.put(new Integer(command.getCommandId()), future);
}
}
if (priorError != null) {
future.set(new ExceptionResponse(priorError));
throw priorError;
}
next.oneway(command);
return future;
}6,调用MutexTransport来发送消息
@Override
public void oneway(Object command) throws IOException {
writeLock.lock();
try {
next.oneway(command);
} finally {
writeLock.unlock();
}
}7,调用AbstractInactivityMonitor完成消息发送准备
public void oneway(Object o) throws IOException {
// To prevent the inactivity monitor from sending a message while we
// are performing a send we take a read lock. The inactivity monitor
// sends its Heart-beat commands under a write lock. This means that
// the MutexTransport is still responsible for synchronizing sends
this.sendLock.readLock().lock();
inSend.set(true);
try {
doOnewaySend(o);
} finally {
commandSent.set(true);
inSend.set(false);
this.sendLock.readLock().unlock();
}
}
private void doOnewaySend(Object command) throws IOException {
if( failed.get() ) {
throw new InactivityIOException("Cannot send, channel has already failed: "+next.getRemoteAddress());
}
if (command.getClass() == WireFormatInfo.class) {
synchronized (this) {
processOutboundWireFormatInfo((WireFormatInfo) command);
}
}
next.oneway(command);
}8，调用TcpTransport，OpenWireFormat，DataOutputStream最终完成通过tcp发送消息
public void oneway(Object command) throws IOException {
checkStarted();
wireFormat.marshal(command, dataOut);
dataOut.flush();
}
public synchronized void marshal(Object o, DataOutput dataOut) throws IOException {
if (cacheEnabled) {
runMarshallCacheEvictionSweep();
}
int size = 1;
if (o != null) {
DataStructure c = (DataStructure)o;
byte type = c.getDataStructureType();
DataStreamMarshaller dsm = (DataStreamMarshaller)dataMarshallers[type & 0xFF];
if (dsm == null) {
throw new IOException("Unknown data type: " + type);
}
if (tightEncodingEnabled) {
BooleanStream bs = new BooleanStream();
size += dsm.tightMarshal1(this, c, bs);
size += bs.marshalledSize();
if (!sizePrefixDisabled) {
dataOut.writeInt(size);
}
dataOut.writeByte(type);
bs.marshal(dataOut);
dsm.tightMarshal2(this, c, dataOut, bs);
} else {
DataOutput looseOut = dataOut;
if (!sizePrefixDisabled) {
bytesOut.restart();
looseOut = bytesOut;
}
looseOut.writeByte(type);
dsm.looseMarshal(this, c, looseOut);
if (!sizePrefixDisabled) {
ByteSequence sequence = bytesOut.toByteSequence();
dataOut.writeInt(sequence.getLength());
dataOut.write(sequence.getData(), sequence.getOffset(), sequence.getLength());
}
}
} else {
if (!sizePrefixDisabled) {
dataOut.writeInt(size);
}
dataOut.writeByte(NULL_TYPE);
}
}
public final void writeInt(int v) throws IOException {
out.write((v >>> 24) & 0xFF);
out.write((v >>> 16) & 0xFF);
out.write((v >>> 8) & 0xFF);
out.write((v >>> 0) & 0xFF);
incCount(4);
}附图
备注:MessageId是通过ProducerId+sequenceNumber来生成的，sequenceNumber通过原子变量的加1完成
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