A JMS provider will only invoke a MessageListener on a JMS MessageConsumer by one thread at once. Indeed; a JMS provider will invoke the MessageListener on all MessageConsumer's in a given Session by a single thread at once.
On 4/15/07, robr <[EMAIL PROTECTED]> wrote:
i read the post at : http://www.nabble.com/-activemq-user--two-threads-per-session-tf476901s2354.html#a1298138 which suggests an extra thread around the onMessage dispatcher. We have occaisional issues in the scope of our 3.1 implementation of "onMessage()" that could be cause by non-thread-safe code on a file Access. These could be issues that only come up when the broker gets very busy as they affect only 5 - 10% of our message flow. I dont completely understand whether there are , in fact , multiple threads that call onMessage? The javax.jms api says there is only 1. http://java.sun.com/javaee/5/docs/api/javax/jms/MessageListener.html Other posts suggest that when using listeners and ASYNC that you should be prepared to have a 2nd onMessage call dispatched before the prior call has finished. So , your call stak from onMessage should be thread-safe. I've decided to review the code and to make sure that we are not throwing exceptions in the scope of "onMessage" and to protect the obvious objects in case there is m-thread issue... but i dont really know... comments appreciated -- View this message in context: http://www.nabble.com/messageListener%2C-ASYNC%2C-and-threads-in-%22onMessage%28%29%22-tf3579500s2354.html#a10002299 Sent from the ActiveMQ - User mailing list archive at Nabble.com.
-- James ------- http://radio.weblogs.com/0112098/
