queue裏面send方法
@Override
public void send(final ProducerBrokerExchange producerExchange, final Message message) throws Exception {
final ConnectionContext context = producerExchange.getConnectionContext();
// There is delay between the client sending it and it arriving at the
// destination.. it may have expired.
message.setRegionDestination(this);
ProducerState state = producerExchange.getProducerState();
if (state == null) {
LOG.warn("Send failed for: {}, missing producer state for: {}", message, producerExchange);
throw new JMSException("Cannot send message to " + getActiveMQDestination() + " with invalid (null) producer state");
}
final ProducerInfo producerInfo = producerExchange.getProducerState().getInfo();
final boolean sendProducerAck = !message.isResponseRequired() && producerInfo.getWindowSize() > 0
&& !context.isInRecoveryMode();
if (message.isExpired()) {
// message not stored - or added to stats yet - so chuck here
broker.getRoot().messageExpired(context, message, null);
if (sendProducerAck) {
ProducerAck ack = new ProducerAck(producerInfo.getProducerId(), message.getSize());
context.getConnection().dispatchAsync(ack);
}
return;
}
if (memoryUsage.isFull()) {
isFull(context, memoryUsage);
fastProducer(context, producerInfo);
if (isProducerFlowControl() && context.isProducerFlowControl()) {
if (warnOnProducerFlowControl) {
warnOnProducerFlowControl = false;
LOG.info("Usage Manager Memory Limit ({}) reached on {}, size {}. Producers will be throttled to the rate at which messages are removed from this destination to prevent flooding it. See http://activemq.apache.org/producer-flow-control.html for more info.",
memoryUsage.getLimit(), getActiveMQDestination().getQualifiedName(), destinationStatistics.getMessages().getCount());
}
if (!context.isNetworkConnection() && systemUsage.isSendFailIfNoSpace()) {
throw new ResourceAllocationException("Usage Manager Memory Limit reached. Stopping producer ("
+ message.getProducerId() + ") to prevent flooding "
+ getActiveMQDestination().getQualifiedName() + "."
+ " See http://activemq.apache.org/producer-flow-control.html for more info");
}
// We can avoid blocking due to low usage if the producer is
// sending
// a sync message or if it is using a producer window
if (producerInfo.getWindowSize() > 0 || message.isResponseRequired()) {
// copy the exchange state since the context will be
// modified while we are waiting
// for space.
final ProducerBrokerExchange producerExchangeCopy = producerExchange.copy();
synchronized (messagesWaitingForSpace) {
// Start flow control timeout task
// Prevent trying to start it multiple times
if (!flowControlTimeoutTask.isAlive()) {
flowControlTimeoutTask.setName(getName()+" Producer Flow Control Timeout Task");
flowControlTimeoutTask.start();
}
messagesWaitingForSpace.put(message.getMessageId(), new Runnable() {
@Override
public void run() {
try {
// While waiting for space to free up... the
// message may have expired.
if (message.isExpired()) {
LOG.error("expired waiting for space..");
broker.messageExpired(context, message, null);
destinationStatistics.getExpired().increment();
} else {
doMessageSend(producerExchangeCopy, message);
}
if (sendProducerAck) {
ProducerAck ack = new ProducerAck(producerInfo.getProducerId(), message
.getSize());
context.getConnection().dispatchAsync(ack);
} else {
Response response = new Response();
response.setCorrelationId(message.getCommandId());
context.getConnection().dispatchAsync(response);
}
} catch (Exception e) {
if (!sendProducerAck && !context.isInRecoveryMode() && !brokerService.isStopping()) {
ExceptionResponse response = new ExceptionResponse(e);
response.setCorrelationId(message.getCommandId());
context.getConnection().dispatchAsync(response);
} else {
LOG.debug("unexpected exception on deferred send of: {}", message, e);
}
}
}
});
if (!context.isNetworkConnection() && systemUsage.getSendFailIfNoSpaceAfterTimeout() != 0) {
flowControlTimeoutMessages.add(new TimeoutMessage(message, context, systemUsage
.getSendFailIfNoSpaceAfterTimeout()));
}
registerCallbackForNotFullNotification();
context.setDontSendReponse(true);
return;
}
} else {
if (memoryUsage.isFull()) {
waitForSpace(context, producerExchange, memoryUsage, "Usage Manager Memory Limit reached. Producer ("
+ message.getProducerId() + ") stopped to prevent flooding "
+ getActiveMQDestination().getQualifiedName() + "."
+ " See http://activemq.apache.org/producer-flow-control.html for more info");
}
// The usage manager could have delayed us by the time
// we unblock the message could have expired..
if (message.isExpired()) {
LOG.debug("Expired message: {}", message);
broker.getRoot().messageExpired(context, message, null);
return;
}
}
}
}
doMessageSend(producerExchange, message);
if (sendProducerAck) {
ProducerAck ack = new ProducerAck(producerInfo.getProducerId(), message.getSize());
context.getConnection().dispatchAsync(ack);
}
}
看memoryUsage.isFull的if判斷裏面
DelayQueue<TimeoutMessage> flowControlTimeoutMessages = new DelayQueue<TimeoutMessage>();
class FlowControlTimeoutTask extends Thread {
@Override
public void run() {
TimeoutMessage timeout;
try {
while (true) {
timeout = flowControlTimeoutMessages.take();
if (timeout != null) {
synchronized (messagesWaitingForSpace) {
if (messagesWaitingForSpace.remove(timeout.message.getMessageId()) != null) {
ExceptionResponse response = new ExceptionResponse(
new ResourceAllocationException(
"Usage Manager Memory Limit reached. Stopping producer ("
+ timeout.message.getProducerId()
+ ") to prevent flooding "
+ getActiveMQDestination().getQualifiedName()
+ "."
+ " See http://activemq.apache.org/producer-flow-control.html for more info"));
response.setCorrelationId(timeout.message.getCommandId());
timeout.context.getConnection().dispatchAsync(response);
}
}
}
}
} catch (InterruptedException e) {
LOG.debug(getName() + "Producer Flow Control Timeout Task is stopping");
}
}
};
如果設置了等待有空閒空間的時間，會等待timeout的時間，然後拋出一個ResourceAllocationException的異常