Hi John,
> >> I can see that not worrying about handover from one hub to another
> >> would simplify things. So we need to decide how to fire up such a
> >> daemon if it's not already running. We could just ask the user to
> >> start it, I guess. No doubt some app authors will still want to make
> >> it seamless by spawning off a hub themselves. In that case we'll
> >> have to rely on good etiquette so that such hubs don't "bump" an
> >> already running hub, and when the user tries to shut them down they
> >> give fair warning if there are applications still using their hub
> >> (and if closing the app implies shutting down the hub).
That's more or less how Aladin is behaving (in the PLASTIC framework). It starts its own hub automatically at startup, only if no other running hub has been detected (this behaviour can be disabled in preferences in order not to automatically launch the embedded hub). If the running hub shuts down, the user is warned, and he can startup manually the embedded hub.
Now, the case of multiple applications already connected to a hub which shuts down is more problematic. You can't just fire up a new hub and assume everything will be ok, as applications would have to re-register with the new hub.
Generally, as Alasdair and you are stating, we should let maximum freedom to the user, as well as imposing as little as possible to developers willing to support the messaging standard in their applications. Embedded hubs should of course not be compulsory, but they can be useful.
Cheers,
Thomas Received on 2007-02-13Z14:20:59