Re: [boost] Re: RPC library

From: Iain Hanson (Iain.Hanson_at_[hidden])
Date: 2005-03-03 10:53:17

On Thu, 2005-03-03 at 13:54 +0000, Jarl Lindrud wrote:
> Iain Hanson <Iain.Hanson <at> videonetworks.com> writes:
> 
> >
> 
> So anything less than CORBA should not be considered?

For RPC, Yes.

> 
> My experience with CORBA is that you _do_ pay for things you don't need. Try 
> building a simple server/client app with my RPC library, and then build it with 
> ACE TAO, and I wonder which method you'll find to be simpler/easier/faster... 

Here is an example CORBA client. And it doen not matter which ORB you
use.

#include <iostream>
#include "echoC.hpp" // generated from the idl file

int 
main ( int ArgV , char * ArgV )
{
  try
  {
      // _var types are smart ptrs to ref counted objects.
      CORBA::ORB_var Orb = CORBA::ORB_init ( ArgC , ArgV , "TAO");

      // get IOR from a file so we can talk to server
      CORBA::Object_var Factory_Object = 
                                  Orb->string_to_object ( ArgV [ 1 ] );

      // This is a CORBA safe downcast
      My::Echo_Factory_var Factory = 
                 My::Echo_Factory::_narrow ( Factory_Object.in( ) );

      My::Echo_Server_var EchoServer = 
                              Factory->get_server ( ArgV [ 2 ] );

      CORBA::String_var Echoed = EchoServer-> ( "Hello World" );

  }
  catch ( CORBA::Exception & E )
  {
      std::cerr << "CORBA exception raised!" << std::endl;
  }
}

I don't think 5 lines of code is exactly heavyweight. I could of done it
in 3 lines if I did not use a factory, but that would have been
unrealistic.

I won't show the server but it 2 classes the factory publicly inherits
from Echo_Factory and implements a single function get_server. Likewise
like for EchoServer.

> Which code is less invasive, more intuitive, and more proportional to the task? 
> And oh I forgot, don't forget to first build all of ACE and TAO, and then link 
> the whole shebang to your own 5 lines of code. To me it feels like I'm getting 
> far, far more than I asked for. But that's just me :-)

ACE is nothing to do with CORBA. It just happens to be what TAO uses
internally. Building Open source or installing per build libs has
nothing to do with how easy it is to use. Your comparing apples and
carrots.

>If you need scaleability, then obviously CORBA is one of the few
>options you have. But if you don't need scaleability, or naming
>services, or whatever, what's wrong with using something much simpler?

Because when you app grows you will have to re-write it. More likely, is
that won't happen and people will re-invent the again. Take a look at
the development of SOAP :-(.

/ikh