[Exist-development] Data Change notifications (i.e. push)

[The A. <Ans...@gm...>]

Hi,

Might be a newb question, but I'm curious if there is an XML-RPC-based standard and servlet for signing up to receive change notifications to a given document (or something more deep, like XPath match - although that would be pretty heavy), and whether it is implemented/intended/thought about as an extension to eXists. 

For my purposes, almost any level of granularity of change notification could be workable for my application (the finer the better in terms of depth: knowing whether a given node or it's children was updated, rather than something like "any updates to an attribute named 'blah' anywhere in any document"), I just don't see it. I could work around it with a side-band message queue, but I was wondering if there was something more elegant I'm missing. 

I'm just beginning to play around with eXists now, and you've done some great work - thank you for it,

TA