Here's a further revised Schedule for anyone interested. Totally
experimental -- indeed, basically untested. It's been modified in
the following way.
- Any thread can now schedule things on the schedule at any time,
even while schedule.step() is running.
- Any thread can now call reset() or simstate.kill(), but be advised
that other threads could theoretically add new things on the schedule
even after it's been reset, thus nullifying the point of reset() or
- Any thread can call time() (or a new identical method, getTime())
- schedule.step() explicitly looks for reentrancy and denies it
- I've deleted the numOrders constructor. It's time.
- I've deleted the throwsExceptions option. A bit faster and
cleaner. It's time.
I do this by employing two locks: (1) the Schedule itself, whose
synchronization controls access to step() to prevent some race
conditions, and (2) an internal lock which controls access to the
time, steps, shuffling parameter, and heap. Using this second lock
allows some finer control over critical regions and thus makes
possible the "any thread" stuff in the bullets above.
It doesn't look much slower, so I may keep it. But I won't add it to
CVS without some major testing. Anyone up for it?
To be threadsafe, AsynchronousSteppables and ParallelSequence still
shouldn't call reset() or simstate.kill(), but rather should schedule
a Steppable which calls simstate.kill().