@Experimental(value=TIMERS) public interface Timer
See TimeDomain for details on the time domains available.
In a DoFn, a Timer is specified by a TimerSpec annotated with DoFn.TimerId.
An implementation of Timer is implicitly scoped - it may be scoped to a key and
window, or a key, window, and trigger, etc.
A timer exists in one of two states: set or unset. A timer can be set only for a single time per scope.
Timer callbacks are not guaranteed to be called immediately according to the local view of the
TimeDomain, but will be called at some time after the requested time, in timestamp order.
| Modifier and Type | Method and Description |
|---|---|
Timer |
align(Duration period)
Aligns the target timestamp used by
setRelative() to the next boundary of period. |
Timer |
offset(Duration offset)
Offsets the target timestamp used by
setRelative() by the given duration. |
void |
set(Instant absoluteTime)
Sets or resets the time in the timer's
TimeDomain at which it should fire. |
void |
setRelative()
Sets the timer relative to the current time, according to any offset and alignment specified.
|
void set(Instant absoluteTime)
TimeDomain at which it should fire. If the timer
was already set, resets it to the new requested time.
For TimeDomain.PROCESSING_TIME, the behavior is be unpredictable, since processing
time timers are ignored after a window has expired. Instead, it is recommended to use setRelative().
void setRelative()
offset(Duration) and align(Duration).Timer offset(Duration offset)
setRelative() by the given duration.Timer align(Duration period)
setRelative() to the next boundary of period.