Re: Local ECs (was Re: Can't modify EO objects! ARGH! =()
Re: Local ECs (was Re: Can't modify EO objects! ARGH! =()
- Subject: Re: Local ECs (was Re: Can't modify EO objects! ARGH! =()
- From: Art Isbell <email@hidden>
- Date: Tue, 22 Jul 2003 13:59:02 -1000
On Tuesday, July 22, 2003, at 06:01 AM, Jonathan Rochkind wrote:
At 02:55 PM 7/21/2003 -1000, Art Isbell wrote:
Also, unfortunately, once you start using multiple ECs, you need to
take care of LOCKING them all.
Only if one uses concurrent request handling, right?
I think I can explain at least ONE reason why this assumption is not
true: When an EC receives a notification, it is important that it
process the notification at the proper time. For some types of
notifications, the EC should not be handling them in the middle of
other stuff. The way the EC keeps from doing this is by delaying
processing of the notification if the EC is lock()ed, waiting until
the lock is released. If you do not lock your ECs, notifications sent
will be processed at improper times---in a
non-concurrent-request-handling app, this can still occur,
notifications can be sent as a result of some action in the very same
session, which still causes problems when the notifications are
received by other ECs assigned to that same session, if those ECs have
not been locked.
I don't think this is true. In the past for desktop apps,
notifications received by editing contexts were sent at the end of the
event loop. For a desktop app, the event loop is very short, but for a
Web app, it's very long (the request-response loop). So I expect that
these notifications will all be sent at the same point in the
request-response loop. With only a single WO thread active when
concurrent request handling isn't being used, there is no other WO
thread to send such notifications at an unexpected time. I have never
heard that EOF creates its own threads for these notifications, so I
can't see how an editing context could possibly receive a notification
at an unexpected time.
Aloha,
Art
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