public class MonotonicSystemClock extends java.lang.Object implements MonotonicClock
MonotonicClock
based on
System.currentTimeMillis
.Modifier and Type | Field and Description |
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private static java.util.concurrent.atomic.AtomicLong |
before |
Constructor and Description |
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MonotonicSystemClock() |
Modifier and Type | Method and Description |
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private static long |
nowMicros() |
ProposedTimestamp |
propose()
Obtain a timestamp close to "now".
|
private static long nowMicros()
public ProposedTimestamp propose()
Proposed times are close to "now", but may not yet be certainly in the past. This allows the calling thread to interleave other useful work while waiting for the clock instance to create an assurance it will never in the future propose a time earlier than the returned time.
A hypothetical implementation could read the local system clock (managed
by NTP) and return that proposal, concurrently sending network messages
to closely collaborating peers in the same cluster to also ensure their
system clocks are ahead of this time. In such an implementation the
ProposedTimestamp.blockUntil(Duration)
method would wait for replies from the peers indicating their own system
clocks have moved past the proposed time.
propose
in interface MonotonicClock
ProposedTimestamp
object.