GUI, XML,HTTP and ORBlets (Was Re: GNAT, LINUX, KDE)

["Vladimir Olensky" <vladimir_olensky@yahoo.com>]

David Botton wrote in message <81fcr1$29iq$1@news.gate.net>...

Vladimir Olensky wrote:
>>Idea here is to  use JAVASCRIPT within XML documents to create
>>User Interface and exchange information between user form and Ada
>>application.
>>I think this approach is very good  as along term strategy.

>I agree very much with you. What is needed is a simple HTTP server written
>in Ada so we don't ended up married to Explorer.


>It would also be possible to set up connections between JavaScript and Ada
>using either AdaApplettes or TCP/CORBA/COM connections to Ada code
> from a Java proxy to the JavaScript.


For some reason no one has noticed and reacted to the excellent thing
mentioned here by David.

This thing has to do with CORBA.

The idea to use application embedded HTPP server to supply client  with
XML (HTML) document (which is used to create user GUI) is only initial
part of the task.
The second one is communication between  user GUI and application.
HTTP/SGI approach is not very productive and flexible in this respect.
The more advanced approach is to use  Object WEB model.

XML document uploaded to the client may contain applets that make
use of CORBA IIOP to communicate with CORBA based server
embedded into application or running separately (so called ORBLets).
 In addition soon  almost all browsers will support CORBA ORB that will
make it possible to use  JavaScript  to utilize  CORBA IIOP for
client-server objects  communications.

   Using  such  approach  GUI  (client)  side  of  the  (potentially
distributed) application  may have  direct access to application's
data and invoke application's  procedures/methods directly via
ORB regardless physical location of the client GUI.

In that model HTTP server should have only very limited
functionality which is ability to upload XML(HTML) documents
to the client when needed and nothing else.
All other things are done via ORB IIOP.
In such model this HTTP server could be  very simple.
There may be even no need of  HTTP server at all  (just
simple procedure that sends XML document (which may be
stored separately from application) to the client
using HTTP protocol). There may be even several different
GUIs (XML documents)  for the given application depending on
the authority level of the person who is trying to use that
application.

   I think that such  CORBA orientated approach   is the most
universal  and much more flexible and portable  than use of
Microsoft DCOMs.
   In addition soon we will have the ability to write Java applets
using GNAT for Java ( AppletMagic from Averstar is available
for a long time already but is  commercial product ) .
  As far as CORBA concerned there are already exist CORBA
implementations from Objective Interface entirely written in Ada
( http://www.ois.com/ ).
What's more among them exists Real-Time CORBA
(ORBExpress GT) which may be used for embedded applications.
OIS: "ORBexpress GT was designed with the embedded and
soft real-time programmer in mind".

So described above approach could be successfully used to provide
user GUIs to all kinds of  Ada applications (including embedded
applications) and provide high level of isolation between user GUI and
Ada application.

Regards,
Vladimir Olensky