将无状态bean封装在有状态会话中

Question

I have a Java EE application using EJBs, and perform most of the functions through Stateless EJBs.

I have a requirement for all users to also have an active session, and I'm wondering what the best way of using the beans are.

Currently, I have a command line client which uses the stateless beans directly in addition to logging into the system with the stateful bean.

I'm wondering if I should have the client perform all functions through the stateful bean, that way no functions can be performed unless an active session exists.
This makes more sense to me personally.

I'm just not quite sure what design is 'right' or what is the better design.
If I continue to have the client use the stateless beans, then I'll have to have a way for those stateless beans to check if the client has an active session.

Answer 1

A session exists anyway even if you're only invoking stateless beans. The choice on whether to invoke a stateless or stateful bean should mater only whether you need to keep state between method invocations. Try injecting the SessionContext and notice that there will be a principal, even if it's anonymous.

Answer 2

If your requirement is an authenticated user, a stateless session bean is fine:

• You can call SessionContext.getCallerPrincipal() in the EJB (for logging purposes etc.)
• You can impose authorization declaratively (using the @RolesAllowed annotation on EJB methods)

so I don't see a reason to switch to stateful session beans. It might not be relevant, but a stateful session bean consumes resources on the server side, so there should be a compelling reason to do so.

A related question When to use Stateful session bean over Stateless session bean? received no answers up to today, and I consider no answer in this case to be an answer as well .