[JDEV] jabber extensions available for handling location information

[Ralph Meijer]

On Mon, Nov 25, 2002 at 05:46:29PM +0100, Arjan Peddemors wrote:
> We had two main reasons for having the location element at the 
> same level as the presence element. First, we are considering 
> presence and location (and many other types of information) as
> independent parameters that define the context of a user (or
> other non-human entity).  Second, we want the user to control
> the distribution of his/her context information in a flexible
> manner: the user must be able to allow subscription to this
> information an a per-item basis. This means that subscription
> to presence and location, although essentially based on the
> same mechanism, is completely independent.

Arjan, thanks for explaination. I had assumed exactly these reasons
for choosing for a <location/> top-level element.

> In the end, this translated to having a top-level location
> element. The location subscription mechanism is more or less
> copy-past from the presence handling. I think, if there was
> a generic and flexible publish/subscribe mechanism available as 
> part of the jabber server at the time we started the development,
> we would have used that (I didn't really follow the discussion
> on what here is called pub/sub, but at first glance it looks 
> promising).

What we call pub/sub here is a generic framework for communication
by the publish/subscribe design pattern (also known as the Observer
pattern). Presence is a specialisation of this pattern, and so is
your implementation of communication location information. I think
it would go to far to go into this further in this thread, but I
can give you some pointers out-of-band if you like. My JID is
ralphm at ik.nu.


Ralphm