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Re: object change notification

On Mon, 19 Jun 2000, Davide Mora wrote:
> Hi Johann,
> i agree with you, keep the notification part outside
> Ozone could be good, a plug-in.
> So we can use only it only when required, and with the
> chance of change how notify the changes.
> About the jms... or other types of notifications,
> well, i think depend very much on the application,
> sometimes sure a "safe" notification system as jms
> make sense... other times no.. this is another reason
> why i prefer a plug-in.
Okay, a plug-in system...?! I like this idea. But keeping notification
completely outside the kernel isn't possible.  The kernel is the only thing
that knows when an object has been changed. So, if the implementation of
the notification logic should be done outside the kernel, then the kernel needs
a general plug-in API. Such architectures are very hip these days. jBoss and
OpenEJB (both EJB servers) provide such plug-in features. jBoss provides so
called 'interceptors'. Every method call is passed to all registered
interceptors. (as far as I understand their system) This way you can add many
different things to the system, like user authentication, transaction
management, notification,.... I'm not sure if jBoss allows to intercept other
things like the store back-end. This could be needed to implement an
notification system for ozone.

Okay, the idea is great. I have to think about this some more. Meanwhile, any
ideas are welcome!

> Falko, i'll send you a "wish list" after fixed a
> problem i have here...
Great, thanks.

Falko Braeutigam                         mailto:falko@softwarebuero.de
softwarebuero m&b (SMB)                    http://www.softwarebuero.de