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Type:
Improvement
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Resolution: Done
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Priority:
Unknown
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None
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Affects Version/s: None
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Component/s: None
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None
https://github.com/mongodb/mongo-java-driver/pull/1164 added TimePoint1, which implements Comparable<TimePoint>, as a tool to measure elapsed time:
TimePoint start = TimePoint.now(); ... Duration elapsed1 = start.elapsed(); Duration elapsed2 = TimePoint.now().durationSince(start);
maxim.katcharov@mongodb.com suggested in that PR that the driver can use deadlines internally instead of timeouts. If we do this, we won't need to have two APIs, Timeout and TimePoint, we will only need TimePoint. I like this idea.
The following table shows how usage may change as a result (the examples assume that the operation we are doing is acquiring a Lock):
| timeouts | deadlines |
|---|---|
// results in calling `tryLock(...)` Timeout timeout1 = Timeout.startNow(1, SECONDS); Timeout timeout2 = Timeout.started(1, SECONDS, t); // results in calling `tryLock(0, ...)`/`tryLock()` Timeout expiredTimeout = Timeout.expired(); // results in calling `lock()` Timeout noTimeout = Timeout.infinite(); |
// results in calling `tryLock(...)` TimePoint deadline1 = TimePoint.now().add(Duration.ofSeconds(1)); TimePoint deadline2 = t.add(Duration.ofSeconds(1)); // results in calling `tryLock(0, ...)`/`tryLock()` TimePoint missedDeadline = TimePoint.now(); // results in calling `lock()` TimePoint noDeadline = TimePoint.infinity(); |
tryLock(
timeout.remaining(NANOSECONDS),
NANOSECONDS);
|
tryLock(
deadline.saturatingDurationSince(TimePoint.now()).toNanos(),
NANOSECONDS);
|
timeout.expired(); |
deadline.isNotAfter(TimePoint.now()); deadline.compareTo(TimePoint.now()) <= 0; |
timeout.isInfinite(); |
deadline.isInfinity(); deadline.equals(TimePoint.infinite()); deadline.compareTo(TimePoint.infinity()) == 0; TimePoint.infinity().isNotAfter(deadline); |
1 TimePoint is, of course, implemented via System.nanoTime, but it is better to have a tool that
- exposes types less generic than long
- and values that are meaningful on their own (a value returned by System.nanoTime is meaningless on its own).