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Manoj,
The
person you're quoting seems to be saying that you can't convert a Service Object
to an EJB because a Service Object "can handle many objects"? I'm not even
sure what that means! :) A Service Object, as I explained previously, is
created from a single Forte TOOL class, just as an EJB has a single bean class
(plus home/remote interfaces, obviously). I worked on two porting efforts,
and as I said before, as long as you understand the assumptions being made
by the Service Objects, and how those assumptions translate to EJB, then there's
no reason why it can't be done. In some instances, some re-design may
have to occur - for example, in the batch mode scenario that I described - but
I'm not sure what your other source was concerned
about.
On
your other question - if I remember correctly (and it's been about 3 years
since I did any Forte work!), setting the Distributed property to true is essentially the equivalent
of implementing the Serializable interface in Java. If the Distributed
property is false, then the object cannot be sent across partitions.
Partitions are interpreter processes, similar to the Java Virtual Machine.
Attempting to send an object to another partition when Distributed is false will
throw an exception, just as trying to send an object across JVMs will throw an
exception in Java if the Serializable interface is not implemented.
Hope
this helps.
Dale
Dale V.
Georg
Technical Manager
Indus Consultancy
Services
(201)
261-3100 x229
Hi George,
Thanks for ur detailed description...
Unfortunately no one in my team is having working
exp with Forte and we are waiting for the details of the application. So
in between we have to deliver some tech comparison matrix between Forte
Service object and Java technologies(J2EE) to our client. Based on our study
and understanding we have prepared one comparision matrix but from one
source we got the response like "No one cannot map service objects to ejbs if you are trying to convert
a forte application to j2ee, because a servce object can handle many oebject
and when you want to convert a Forte object to Java, you usually convert a
object to a EJB. And because a service object could handle many objects
you can end up with making many EJBs" and now we are in
confusion. will you pls comment on this.
Also I would very much appreciate
if someone elaborates on the difference between a TOOL class
with distributed property isAllowed and a
Service Object. Can we access a TOOL class
with distributed property isAllowed
from other server/client partitions
Regards,
Manoj
----- Original Message -----
Sent: Friday, July 05, 2002 9:51
PM
Subject: RE: [jdjlist] Service Objects
in Forte !!
Manoj,
That's essentially correct. In Forte, Service Objects are
created from classes (typically application business classes) and are then
deployed to one or more servers. They are called Service Objects
because they are objects whose purpose is to provide services to
clients. Deployed Service Objects can be replicated for load balancing
and failover as well.
One of the key differences between Service Objects in Forte and
Session Beans in J2EE is that Service Objects are instantiated when the
Forte server starts running, and they remain in memory until the server is
stopped. Therefore, it was not uncommon to have a Service Object
that started separate threads on start-up to perform batch-type tasks, or a
Service Object that was completely server-based and never required any
client interaction. Contrast this with Session Beans, whose life
cycle is very much tied to the client.
In
general, you should be able to port Service Objects to Stateless Session
Beans without too much difficulty. But it will be important for you to
understand the purpose of each of the Service Objects you port, and what
types of assumptions were made regarding client access, transaction
management, etc in order to be successful. Are you working with anyone
who is familiar with Forte and the particular application you're
porting? If not, you may want to invest some time learning the basic
Forte concepts first.
Good luck!!
Dale
Dale V.
Georg
Technical
Manager
Indus
Consultancy Services
(201) 261-3100 x229
Hi All,
I am working on a migration project (from
Forte 4GL to J2EE)..... I have one basic doubt regarding the concept and
usage of Service Objects in Forte, that is, to perform any
business/logical operation based on a client request do we compulsarily
need to create a service object for a class ?
Is this Service Object is something
like wrapper to a business class to achieve distributed computing in
Forte?
Thanks & Regards,
Manoj
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