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Conference pamsrc::objectbroker

Title:ObjectBroker - BEA Systems' CORBA
Notice:See note 3 for kits; note 5 for training; note 1134 for releases
Moderator:TLE::PARODId
Created:Tue Jul 11 1989
Last Modified:Thu Jun 05 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1413
Total number of notes:6391

1367.0. "How to develop a "Callback Interface"" by HYDRA::SCHAFER (Mark Schafer, SPE MRO) Thu Feb 13 1997 09:44

    I have a request for documentation from an ISV that's trying to use
    ObjectBroker.  Could you suggest what publication he needs?
    
    Thank you,
    
    Mark Schafer
    SPE MRO
    297-3524       
From: Esi Technology Corp <[email protected]>
To: Mark Schafer <[email protected]>
Subject: corba help
Message-ID: <[email protected]>
                             
ESI Technology Corp.
5 Commonwealth Rd. Natic, MA
Feb. 11. 97

Dear Mark Schafer:

We are  having  a difficulty in creating a callback procedure with Object
Broker. What we are trying to realize is that while an operation on the server
side is invoked , this operation can invoke an operation of  an object  (that
is passed over ) on client side.

It would  greatly appreciated if you can give us some introduction to  how  to
write a "Callback Interface".

We are looking forward to hearing from you.
Thank you very much.

Hanlin Weng
ESI Technology Corp.

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1367.1Both sides act as serversCFSCTC::HUSTONSteve HustonThu Feb 13 1997 12:0329
To do this in CORBA, both "client" and "server" need to implement an
interface.  So, both sides act as both server and client.  You'll also
need to use DII to avoid deadlocks.

I've just finished implementing a system that does exactly this.  Generally,
this is what needs to happen:

- "Client" creates an object ref for the interface/implementation it supports.
- Client gets an objref for something implemented by the "server".
- Client invokes (using DII) an operation on the server's objref.
- Server, using the objref that the client passed as an argument to its
  method, invokes an operation back on the "client".  Depending on the
  design and constraints, this may need to be DII also.

You need to take a look at the design and constraints to properly design the
interfaces.  For example, it may be that one (or both) of the methods may
need to return from the method invoke before what was requested can be
done (say, if you need to use X windows stuff to respond to the request).
In this case, the operation can't really use "out" arguments or a return
value, but invoke another operation on the original requester to give
results back.

I am out the door today (this is my last day on this contract).  If you find
that you or the customer needs more help than the above, feel free to call
me (508-384-5708) or email me ([email protected]) and talk about it.

Good luck,

-Steve Huston
1367.2why not implementing as COSS Event ServiceEMNTAL::STADELMANNSepp @ZUO 760-2609Fri Feb 14 1997 02:5412
    Calling back ocures on a event, i.e. something has finished, is done,
    yet ready, burning, or diverting abnormaly ....
    
    May you have a look at the COSS Event Service, and then implement it.
    An Event Service provides a Push/Pull Consumer/Provider Model via an
    Event Channel.
    
    There are excat IDL specifications available from OMG for all this COSS
    Services and the full COSS Services Specification is available as .PDF
    and .PS on the OMG WWW (world wide waiting) Page
    
    Sepp,