Fredrik Bromee ([EMAIL PROTECTED]) wrote:
> Suppose that your application server has some of the services you need,
> but not all. Suppose that there is an implementation of a CORBA service
> that I would like to use, for example the Notification service (included in
> CORBA 2.2). Problem is, I don't see how I could reach these services
> from within an EJB.
>
> What I'd like to do is implement or buy implementations of the CORBA
> services I need, deploy them on an ORB either running in my application
> server or 'besides' it. Either way I would like to somehow access these
> services from an EJB. I don't know if this is possible or even smart, so I
> turn to you:
>
> Is this possible?
> How would I call my CORBA service from my EJB?
An EJB can be a CORBA client. In fact, the J2EE specification requires that
compliant servers provide the JavaIDL CORBA client APIs for use by EJB
code.
> Does this imply any restrictions on my choice of application server?
> Would I need a separate ORB?
Some application servers provide built-in CORBA server ORBs. Some don't. If
you're using one that doesn't, you'll need to acquire a server ORB and run
your CORBA server objects manually, or through means other than those used
to run EJBs.
> Another question I have is related to my first one. The way I have
> understood it (please correct me if I'm wrong), all Enterprise JavaBeans are
> idle between method calls. Couldn't there be situations when you would
> like to have a running process on the server? I have seen postings to this
> list about some kind of batch job scheduling service. I think that in the
> end
> they came to the conclusion that it was best to put this service in a thread
> of its own. Would this be a general solution to the situation when you want
> to have a running process on the server? Isn't this a bit of an 'unclean'
> solution?
It seems like a good approach, and isn't at all "unclean". Nobody is trying
to claim that all computing operations in a system have to be implemented
as EJBs. EJB defines the rules and framework for transactional session and
entity objects. It doesn't preclude application servers from providing
additional external services that are orthogonal to EJB operations. Most of
the application servers I'm aware of that support EJB also allow you to run
other kinds of objects using other programming models.
Marc San Soucie
GemStone Systems, Inc.
Beaverton, Oregon
[EMAIL PROTECTED]
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