[MUD-Dev] Room-based vs. coordinate-based
malachai at iname.com
Fri Jun 13 09:34:16 New Zealand Standard Time 1997
clawrenc at cup.hp.com wrote:
> Shawn Halpenny <malachai at iname.com> said:
> > clawrenc at cup.hp.com wrote:
[ any change in object sends notification ]
> >> This allows a watcher to trigger on a state change for a private data
> >> member in an object. Depending on the strictness of your views on
> >> data encapsulation, this can be thought of as a Good Thing, or a Bad
> >> Thing.
> >Watchers can trigger on private data changes by not defining exactly
> >what they're watching, but choosing to watch for a change in any
> >property. So I still maintain the low message traffic for watchers
> >waiting on a few properties, and don't have to cheat my encapsulation
> >by allowing watching on the entire object if desired.
> This raises an implementation question:
> if your watchers are specified with a definition of what they are
> watching, this suggests that a single watcher could be watching
> several attributes at the same time.
That's correct. A single watcher can wait on any number of attributes
in a single object.
> Does this mean that an entry is made on the "watch list" for each of
> those attributes, or does it mean that upon a change, that change is
> compared to the object's list of watcher filters, and the approriate
> messages sent? The latter case seems wasteful (tho better than the
> broadcast everything approach) if true. The former gets data space
It is the latter. There is, of course, a point where it is cheaper to
for change on the entire object, rather than changes in many
attributes. I haven't defined the actual implementation yet, but I
anticipate these watcher filters to be somewhat wildcard-able (ATM all
my attributes are defined by string names), so a single watcher can
easily and efficiently monitor a number of related attributes. This
optimization will depend on the composition of the attribute names, but
those are something that can be easily tweaked.
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