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Re: object change notification

Hi Falko, Ann, and all ozonies,

What kind of notification would you like to do?
I mean we could think about a notification on change,
on delete, on new object creation, etc...
Here is how Jini Remote Events are working together
with JavaSpaces. Here we could associate Ozone
with the JavaSpaces cause they both are kind of
repositories.

With JavaSpaces you can register a listener for a
special type, with eventually some specified fields
values, so when an Object matching this type and
eventually the specified fields values is written into
the repository, you can fire an event. Same for the
delete approach. When an object is deleted from
the repository, we can fire an event. I wont speak
for notification on update cause...there is no update
in Javaspaces ;-) Anyway the line of thought is the
same. Now my question is, what kind of granularity
should we put into this notification system (on object,
fields?) I dunno how JSDT handle remote events but
I think an implementation in RMI wouldn t be too
hard to do. We have to do such implementation for
our JavaSpaces/Jini project but I dont know really
when it would be done. What I can tell is that it will
follow the Jini Specs.

Anyway, Falko, would it be possible to have some
kind of draft explaining in just a page or two the main
architecture of Ozone, cause I really think that people
needs something on which they can begin before
hacking some code. My feelings are that people may
be are scared to put their hands in an ODBMS because
the name itself is scaring, and because of a lack of
reference and standards.  I know you are busy, but just
one page or two, or a beautiful schema :-)

Regards,

Johann




----- Original Message -----
From: Falko Braeutigam <falko@softwarebuero.de>
To: Ann Tecklenburg <tcklnbrg@promonium.com>
Cc: <ozone-users@ozone-db.org>
Sent: Friday, June 23, 2000 2:22 PM
Subject: Re: object change notification


> Ann, I Cc: this to the list. I hope this is okay.
>
> On Fri, 23 Jun 2000, Ann Tecklenburg wrote:
> > Well, to some extent, JSDT adds a separate server
> > to handle the object change stuff.
> >
> >  I suspect there is some overhead to assuming that every object is
> > interested in being handled by the JSDT.
> >
> > So some thought must be given as to
> > whether or not the JSDT should be at the core
> > of Ozone so that all objects automatically get this
> > feature or whether objects can merely be externally
> > enabled for this feature, if desired.
> The proposed plug-in architecture could be fine for this. A special
plug-in
> could integrate a JSDT based notification system. Maybe this could also be
the
> default notification system of ozone. However, other implementations could
be
> integrated very easy.
>
> > I can tell you for sure that few (none?) databases at any price
> > have a change notification mechanism built-in.
> Then let's do it!
>
> If anybody is real interested in contributing by writing a notification or
> other plug-ins, then I could put the making of the plug-in system up on my
> todo list.
>
>
> Falko
> --
> ______________________________________________________________________
> Falko Braeutigam                         mailto:falko@softwarebuero.de
> softwarebuero m&b (SMB)                    http://www.softwarebuero.de
>
> l ozone database (using LocalDatabase)
> >
> >     for objects_number = 10,100,1000 do
> >       create(objects_number, size)
> >      read(objects_number)
> >   destroy(objects_number)
> >     end for
> >
> >     close connection
> >
> >   end for
> >
> >
> >   But I think it isn't the correct solution.
> Unfortunately you didn't send the complete code so I have to write my own
to
> check this ;) Anyway, I will do so. Maybe it's a good canditate for a new
> test or sample.
>
> > If transactions that involve a change in the objects state, driven by
the
> > interface marked methods (with /*update*/), how can I manage
transactions
> > involving the creation and destruction of objects?.
> The only way to create and destroy database objects are the API methods
> createObject() and deleteObject(). These methods implicitely have WRITE
lock
> level. Does this answer your question?
>
>
> Falko
> --
> ______________________________________________________________________
> Falko Braeutigam                         mailto:falko@softwarebuero.de
> softwarebuero m&b (SMB)                    http://www.softwarebuero.de
>