Re: Problems with callbacks

Hi Stefan!

Your mail is very usefull I think! But I have some question and I think I have to get more detailed:

The server is already given I can`t change anything with it, but the idl already defines the callback interface and the register method.(By the way: I use a nameserver to connect to the server). 
The idl: (only a part)

interface CallbackClient
{
  void data(in String data);
  void exit(); 
}


interface Server
{
 boolean register(in CallbackClient client);

};

jidl already creates an _CallbackClientStub from that I inherit in my Client_impl.

My Question: How could I implement Client_impl as server, without be able  to inherit from server relevatet classes? 
First, I`ve think that the jidl has already created the Stub in a way, that make callbacks possible, but sending an reference of Client_impl (or _CallbackClientStub) to the register method, raises an exception (BAD_OPERATION ).

Kind Regards
Manuel Fünfrockne

---
University of Applied Science
Saarland/Germany

---------- Original Message ----------------------------------
From: Stefan Blum <[email protected]>
Date:  Tue, 23 Aug 2005 09:52:30 +0200

>Hi Manuel,
>
>Manuel Fünfrocken wrote:
>
>>I`ve some questions about callbacks: 
>>Is it necessary to implement the client as an server? (with starting a POA, binding to a nameserver etc.) Or does ORBacus handle this?
>>  
>>
>Yes, you have to implement a callback interface resulting in a
>client-server. It seems to be a little bit circumstantial, but keeps
>CORBA flexible.
>
>Do the following:
>
>// the "client"
>interface Callback
>{
>void callback();
>}
>
>
>// the "server"
>interface Server
>{
>void someMethod(); // will invoke Callback::callback() within the
>implementation
>void registerClient(in Callback Cb); // to store the object reference
>}
>
>the implementation class (servant) of Server contains the object
>reference as a member.
>
>within booting the application:
>- start the server
>- start the client
>- register the client to the server before you invoke someMethod();
>
>Alternatively, you may use a nameserver. In this case, you can skip the
>registerCallback() method.
>- start the server
>- start the client
>- register the client to the nameserver
>- in someMethod(): fetch the Callback object reference from  the nameserver.
>
>I prefer the first alternative, because you only need two "instances"
>and no nameserver.
>
>Isn't too complicated, is it?
>
>Best regards,
>  Stefan
>
>
>
>
 
                 

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