slate comments

Alexandre Oliva
22 Mar 2000 17:40:20 -0300

On Mar 21, 2000, "Brian T. Rice" <> wrote:

> Of course, I'd like to know if there are any interesting
> applications of the architecture that you've found useful that
> aren't outlined in the papers, since I'm relatively new to this
> idea.

There certainly are.  Besides MOLDS, the Meta-Object Library for
Distributed Systems, that is going to be the main subject of my PhD,
Nadia implemented a transparent persistence-by-reachability system.
Luciane implemented a reflective variant of the state pattern.
Alexandre Braga implemented Tropyc, that introduces security through
criptography into inter-object communication.  Alessandro implemented
an exception handling framework for fault-tolerant applications, that
Delano is using for his PhD research in coordinated actions.  Nelson
is working on testing by fault-injection.  Rodrigo is working on
GDK/Dejavu, a tool that can be used for debugging, reverse
engineering, monitoring and meta-configuration management in general.
You can get an idea of where he's heading to at  (BTW, Rodrigo, I still
owe you a reply, sorry :-(  Hopefully, later today.

> Okay, well I plan to use the Guaranį by having the composers essentially
> contain the composed meta-objects within its slots.

Yep.  That's essentially what our general-purpose SequentialComposer
does (except that it contains just one slot, that refers to an array
of MetaObjects :-), but that's the idea.  It's worth pointing out,
however, that it's not always as simple as that.  Sometimes, you have
to add intelligence to a composer because their components have
behaviors that conflict, so you may have to use the composer to
resolve them.  But I believe general-purpose composers can be used
most of the time and, in the cases they can't, you can always isolate
conflicting meta-objects you want to use together by means of a
specialized composer, and compose this specialized composers with
other meta-objects by means of general-purpose composers.

> Thanks for the tip. :)

You're welcome :-)

Alexandre Oliva    Enjoy Guaranį, see
Cygnus Solutions, a Red Hat company        aoliva@{redhat, cygnus}.com
Free Software Developer and Evangelist    CS PhD student at IC-Unicamp
oliva@{,}   Write to mailing lists, not to me