Clocks should provide wall clock time, obtained from a reasonable clock source, such as the local system clock.
MonotonicClocks provide the following behavior, with the assertion always
being true if
org. is
used:
MonotonicClock clk = ...;
long r1;
try (ProposedTimestamp t1 = clk.propose()) {
r1 = t1.millis();
t1.blockUntil(...);
}
try (ProposedTimestamp t2 = clk.propose()) {
assert t2.millis() > r1;
}
| Modifier and Type | Method and Description |
|---|---|
| public ProposedTimestamp | Returns: aorg. object.Obtain a timestamp close to "now". |
| propose | back to summary |
|---|---|
| public ProposedTimestamp propose() Obtain a timestamp close to "now". 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
| |