On Wed, 12 Mar 2025 00:33:14 GMT, Nir Lisker <nlis...@openjdk.org> wrote:
> > I'm unsure what you are saying here. The common divisor example would not
> > log a warning if I place the warning log in the same location as the SOE.
>
> If you replace the thrown error/exception with logging then the code path
> will continue. What behavior will we get instead? The one before the
> modification where "first listener wins"?
Yeah, if there's disagreement, then the listener earliest in the chain (if it
is persistent) will win, and one of the disagreeing listeners (after setting a
value) will not have been notified of that change (as it was changed back).
Note that there's no inconsistency here; after all notification loops complete,
the last received new value will match the current value of the property. This
goes for **all** listeners, regardless of disagreements. In other words:
(obs, ov, nv) - {
// new value received here is ALWAYS going to be correct after
the full notification completes
// There is no guarantee that after calling set(X) that the
value actually will become X (there
// never was such a guarantee, also not with ExpressionHelper as
other listeners can interfere
// at any time). So if you didn't receive a new value X, it
hasn't actually become X.
property.set(X);
// Calling this afterwards could allow you to see that your
change was "rejected"
if (property.get() != X) {}
}
Realistically, there's not really that much wrong with this. It is just that
listeners should not make assumptions that a value passed to `property.set`
will become the final state. The only way to be sure is to have received a
call back with that value as the new
value.
-------------
PR Comment: https://git.openjdk.org/jfx/pull/1081#issuecomment-2716132609
