URLConnection from MDB

Question

I am working on an application where the MDB (configurable value) will pick up message from IBM MQ, process these messages and post them out to a URI and handle the response back and put them to MQ. I am trying to use HttpClient instead of URLConnection. My question is,
1) What is the best practice to open this (rather say these) external connection (s) and post message to them?
2) How to do the house keeping (managing resources)
3) Is it good to use SessionBean (Stateful, Stateless?)
Any ideas appreciated

Answer 1

1) What is the best practice to open this (rather say these) external connection (s) and post message to them?
The biggest problem you'll have is figuring out how (and if) to handle errors. Since HTTP POSTS aren't transactional you can get the situation where the POST succeeds, but your server dies before the JMS session is commited. Since the JMS session didn't commit, the message will still be on the queue and be picked up next time your MDB starts, leading to a duplicate post. One way to resovle this is if the message contains a unique id, the recipient can discard duplicates.
An alternative scenario where there is something wrong with the message. In this situation you need to agree with the recipient whether they will handle the error or whether the MDB should.
There's no best practice for this sort of thing, as it depends on how valuable the message is, whether duplicates matter, whether bad messages can be fixed, or need to be corrected at source etc.
2) How to do the house keeping (managing resources)
Do you mean TCP/IP connections? I haven't done much work with HttpClient but it looks as though you can share connections using the HttpConnectionManager.
3) Is it good to use SessionBean (Stateful, Stateless?)
I would delegate the http work to another class, but don't see any benefit in making it a session bean.