Hi all, I would like to propose a change to make the Java clients session Dispatcher thread be set non-daemon if a MessageListener is present on the session, with a new configuration option to allow manipulating this behaviour.
Historically, for the 0-8/0-9/0-9-1 client the use of Mina kept the JVM alive when a MessageListener was set, allowing asynchronous delivery to continue without the user having taken any explicit action to keep the JVM alive. Since we removed Mina this is no longer the case, and if there are no non-daemon threads then the JVM will now exit even though the user has set a MessageListener set. Investigating other providers suggests the typical behaviour is to make use of non-daemon threads by default, preventing this happening, but allowing users who desire that behaviour to configure it as such. For example, tibco seem to do exactly what I am proposing with their Dispatcher threads: https://docs.tibco.com/pub/enterprise_message_service/6.1.0-august-2011/doc/html/tib_ems_api_reference/api/javadoc/com/tibco/tibjms/Tibjms.html#PROP_DAEMON_DISPATCHER ActiveMQ seems to control this through transport options, defaulting to non-daemon threads with an option to reconfigure it: http://activemq.apache.org/tcp-transport-reference.html Given this seems to be the adopted practice for other JMS providers it would seem like a good thing to standardise on, making it easier for people to pick up Qpid and try it with existing code they might have. Making this change is basically noticable to anyone already working round the all-daemon-thread behaviour of the client, but not making it could be fairly dissruptive for anyone looking to upgrade and running into it for the first time. Thoughts? Robbie. --------------------------------------------------------------------- Apache Qpid - AMQP Messaging Implementation Project: http://qpid.apache.org Use/Interact: mailto:[email protected]
