I think Ana might be refering to inheritance of Home Interfaces.
public interface SessionAHome extends EJBHome {
public SessionA create() throws CreateException, RemoteException;
}
public interface SessionBHome extends SessionAHome {
public SessionB create() throws CreateException, RemoteException;
}
SessionBHome will not compile. So you are left with either removing the
create method and using the parent version (SessionAHome) or declaring that
SessionBHome extend EJBHome. The first option will mean that your client
will have to perform casting on the object returned from the create method.
The second will mean that your client has to deal with a different home
interface. Remember this relates to when you are extending the remote i.e
SessionA and SessionB interfaces. You might not think this is so bad but
wait until you get to Entity Beans and then things get even more messy i.e.
pks and finders. I think extension of the bean implementations in EJB are
relatively alot easier to deal with than the extension of EJBHome and Remote
interfaces.
Question: Has anybody wrote up a white paper on this. We all know some of
the issues but it would be nice to maybe produce a fully comprehensive
document on this area. The more I think about the possible scenarios the
more I feel compelled to investigate the complexity associated with this
area. Do other people agree on this or see no problems whatsoever?
kind regards,
William Louth
> -----Original Message-----
> From: Sripada Srinivas [SMTP:[EMAIL PROTECTED]]
> Sent: Tuesday, April 11, 2000 7:47 AM
> To: [EMAIL PROTECTED]
> Subject: Re: Migrating from CORBA to EJB
>
> Hi Ana,
>
> I did not understand "U have to be a bit careful in writing the ejb*
> methods in
> the child class" -- I cannot imagine the kind of difficulties one would
> face
> becasue of inheritance.
>
> Regards,
> Sripada
>
> "Bhattacharyya, Ana" wrote:
>
> > Hi Susmita
> > Inheritence is definitely possible in ejb. If u download the Weblogic
> ejb
> > server (free 30 days eval copy) --- u will find one ejb example they
> have
> > done usinf inheritence. U only have to be a bit careful in writing the
> ejb*
> > methods in the child class. I will suggest u to go through the
> child-parent
> > example in Weblogic server 5.1.
> > cheers
> > Anamitra
> >
> > -----Original Message-----
> > From: Susmita Tripathy [mailto:[EMAIL PROTECTED]]
> > Sent: Monday, April 10, 2000 9:28 AM
> > To: [EMAIL PROTECTED]
> > Subject: Re: Migrating from CORBA to EJB
> >
> > Thanks Sripada for your mail.
> > The Corba objects were developed in Java. Actually I
> > did not implement them. They have been implemented
> > before.
> > This application is actually a workflow run time
> > system. which is responsible for enforcing intertask
> > dependencies, scheduling tasks, managing workflow data
> > and ensuring a reliable execution environment.
> >
> > There is some inheritance going on between the CORBA
> > objects, and I do not know if that is possible in EJB.
> > I would imagine most of these CORBA objects could be
> > implemented as Session Beans, but I am not sure how to
> > implement the inheritance part of it.In EJB can we
> > have
> > one session bean inheriting from another. If so how
> > are they deployed.
> > This would be my Masters project and I really need to
> > know if it is feasible so that I could get started.
> > I would really appreciate any suggestions and advise.
> >
> > Thanks a lot again.
> > --- Sripada Srinivas <[EMAIL PROTECTED]>
> > wrote:
> > > Hi Susmita Tripathy,
> > >
> > > 1. You can use j2ee server no problem.
> > > 2. The ease at which you can convert from CORBA to
> > > EJB depends on what sort of
> > > services your CORBA object implements
> > > 3. By the way, in which language did you develop the
> > > CORBA object??
> > >
> > > Regards,
> > > Sripada
> > >
> > > Susmita Tripathy wrote:
> > >
> > > > I am a masters student and I am very new to EJB
> > > and
> > > > j2ee. I need to port a Application developed in
> > > Corba
> > > > and Java to EJB. Basically change the Corba
> > > objects to
> > > > EJb's.
> > > >
> > > > I am not sure how difficult or easy this would be.
> > > I
> > > > would really appreciate any suggestions and advice
> > > on
> > > > this. Any pointers or books I should refer to?
> > > >
> > > > Can I do it using j2ee server or will have to use
> > > some
> > > > other application server(WebLogic)My only
> > > > interaction with EJB has been running some the
> > > > examples that come with j2sdkee1.2. I would really
> > > > appreciate any suggestions, advise and hint.
> > > >
> > > > __________________________________________________
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> > > > http://im.yahoo.com
> > > >
> > > >
> > >
> >
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