Hi Stephen, Peter, I think we should clarify the constructor to indicate that nanoseconds are truncated/ignored. That should be done as a separate request since it is a spec change and needs additional review. Roger On 4/29/2015 5:43 AM, Stephen Colebourne wrote:
On the LocalDateTime being passed in with nanoseconds, that was an unconsidered use case. The whole offset system relies on second based offsets, so it should really be validated/truncated to remove nanos. That way the equals/compareTo could be simplified again. Seems like a separate issue, but perhaps could be tackled here. You need an Oracle sponsor to tell you ;-)
Stephen
On 29 April 2015 at 10:33, Peter Levart <peter.levart@gmail.com> wrote:
On 04/27/2015 06:51 PM, Stephen Colebourne wrote:
One additional change is needed. The compareTo() method can rely on the new epochSecond field as well. Otherwise good! Stephen
Hi Stephen,
LocalDateTime (transition) has nanosecond precision. It may be that transitions loaded from file in ZoneRules only have second precisions, but ZoneOffsetTransition is a public class with public factory method that takes a LocalDateTime transition parameter, so I think compareTo() can't rely on epochSecond alone. But epochSecond can be used as optimization in compareTo() as well as equals():
http://cr.openjdk.java.net/~plevart/jdk9-dev/ZoneOffsetTransition.epochSecon...
An alternative to keeping epochSecond field in ZoneOffsetTransition would be to keep a reference to Instant instead. Instant contains an epochSecond field (as well as nanos) and could be used for both toEpochSecond() and getInstant() methods.
What do you think?
It also occurred to me that serialization format of ZoneOffsetTransition is not adequate currently as it looses nanosecond precision.
Regards, Peter
On 27 April 2015 at 17:24, Peter Levart <peter.levart@gmail.com> wrote:
Hi again,
Here's another optimization to be reviewed that has been discussed a while ago (just rebased from webrev.01) and approved by Stephen:
http://cr.openjdk.java.net/~plevart/jdk9-dev/ZoneOffsetTransition.epochSecon...
The discussion about it is intermingled with the ZoneId.systemDefault() discussion and starts about here:
http://mail.openjdk.java.net/pipermail/core-libs-dev/2015-February/031873.ht...
The rationale for the optimization is speeding-up the conversion from epoch time to LocalDateTime. This conversion uses ZoneRules.getOffset(Instant) where there is a loop over ZoneOffsetTransition[] array that searches for 1st transition that has its toEpochSecond value less than the Instant's epochSecond. This calls ZoneOffsetTransition.toEpochSecond repeatedly, converting ZoneOffsetTransition.transition which is a LocalDateTime to epochSecond. This repeated conversion is unnecessary, as ZoneOffsetTransition[] array is part of ZoneRules which is cached. Optimizing the ZoneOffsetTransition implementation (keeping both LocalDateTime variant and eposhSecond variant of transition time as the object's state) speeds up this conversion.
Regards, Peter