/**
* Obtain a queue message synchronously.
*
* @param queueName Name of the queue from where to retrieve a message
* @param timeout Timeout, in milliseconds. When timeout is reached a TimeoutException is thrown.
* Zero means that the client wants to wait forever. A negative value means that the client
* doesn't want to wait if there are no messages is local agent's queue.
* @param reserveTime Message reserve time, in milliseconds. Polled messages are reserved, by
* default, for 15 minutes. If clients prefer a different reserve time , bigger or small, they
* can specify it.
* @param acceptRequest An AcceptRequest object used handling Accept messages.
* @return A notification containing the queue message. Or null if timeout was a negative value
* and there was no message in local agent's queue.
*/
public NetNotification poll(
String queueName, long timeout, long reserveTime, AcceptRequest acceptRequest)
throws Throwable {
if (StringUtils.isBlank(queueName))
throw new IllegalArgumentException("Mal-formed Poll request. queueName is blank.");
NetPoll poll = new NetPoll(queueName, timeout);
NetAction action = new NetAction(ActionType.POLL);
action.setPollMessage(poll);
NetMessage message = buildMessage(action);
SynchronousQueue<NetMessage> synQueue = new SynchronousQueue<NetMessage>();
synchronized (_syncSubscriptions) {
if (_syncSubscriptions.containsKey(queueName))
throw new IllegalArgumentException("Queue " + queueName + " has already a poll runnig.");
_syncSubscriptions.put(queueName, message);
pendingPolls.put(queueName, synQueue);
}
if (reserveTime > 0) {
message.getHeaders().put(Headers.RESERVE_TIME, reserveTime + "");
}
if (acceptRequest != null) {
poll.setActionId(acceptRequest.getActionId());
PendingAcceptRequestsManager.addAcceptRequest(acceptRequest);
}
getNetHandler().sendMessage(message);
NetMessage receivedMsg = synQueue.take();
synchronized (_syncSubscriptions) {
_syncSubscriptions.remove(queueName);
pendingPolls.remove(queueName);
}
if (receivedMsg == BrokerProtocolHandler.TimeoutUnblockNotification)
throw new TimeoutException();
if (receivedMsg == BrokerProtocolHandler.NoMessageUnblockNotification) return null;
NetNotification m = null;
if (receivedMsg.getAction().getActionType().equals(ActionType.NOTIFICATION)) {
m = receivedMsg.getAction().getNotificationMessage();
} else {
log.error(
"Poll unbloqued by a message that wasn't of any of the expeceted error nor a notification.");
return null;
}
return m;
}
