Long-running Batch eWay JCD - threading and stopping

Question

I have a requirement to poll for files on a remote server, every few seconds, almost continuously. Furthermore, without making a connections every polling interval. In other words, connect once and stay running, If a file is found, send a JMS message to another service that will process the file, but keep polling for more files. Thus, a long-running service. This will tie up the thread?
Can I have an array of BatchFTP instances, and in each loop of the long-running process, check each connected instance for incoming files? Or can I only have one instance?
If the domain is shutdown, will this service shutdown nicely, if it is still in its looping process? If not, I could check another 'command queue' for a shutdown command, but now I have to add code to the domain shutdown script to send that shutdown message to the command queue. Could I instead, somehow check the status of another service in the same project to see if it is shutdown, and therefore know to stop the loop and allow it to be shutdown? I saw an example of a JMX command to check the status of an object. Is that the best way to check the status of a jcd from inside another jcd?
thanks, Pete

Answer 1

Hi Chris and thank you,
I also do not want to build and manage a long-running service, from a performance point of view. The owners of the target server want a file to be picked up as soon as it arrives (within 5 seconds), but they don't want FTP connections created and deleted every 5 seconds. They expect that we will make a connect() call, and then continually loop / poll using dirlist() method.
When I look at this requirement I also think of re-using it as a generic service - as long as I have a long-running service, I might as well use it for any other long-running, open FTP connections to other servers/userids. So in the same jcd instance, I would connect to multiple FTP servers and execute a loop where I go through a list of FTP connections, and for each, I would go through a list of folders that should be polled (using dirlist method). So I only have one JCD running for a long time but it could have multiple FTP connections open. That is why I am thinking of using an array of BatchFTP objects.
When your code shows a Scheduler eWay input, do you mean that the JCD will triggered by the first Scheduler message, but would then go into a loop, doing work, and performing a JMS.receive on that Scheduler queue for the 2dn, 3rd, .. nth Scheduler message? So because the jcd is still running, it still had all its objects and FTP connections (open), but its looping is controlled by the Scheduler message?
I'm running 513u3. I am worried about shutdown. I think it might not listen to a shutdown command. So that is why I was thinking about putting in some code at the bottom of the loop that would check, somehow, if a shutdown is in progress.
Peter