Interface WatermarkEstimator<WatermarkEstimatorStateT>
- All Known Subinterfaces:
ManualWatermarkEstimator<WatermarkEstimatorStateT>
,TimestampObservingWatermarkEstimator<WatermarkEstimatorStateT>
,WatermarkEstimators.WatermarkAndStateObserver<WatermarkEstimatorStateT>
- All Known Implementing Classes:
WatermarkEstimators.Manual
,WatermarkEstimators.MonotonicallyIncreasing
,WatermarkEstimators.WallTime
public interface WatermarkEstimator<WatermarkEstimatorStateT>
A
WatermarkEstimator
which is used for estimating output watermarks of a splittable
DoFn
. See WatermarkEstimators
for commonly used watermark estimators.-
Method Summary
Modifier and TypeMethodDescriptionReturn estimated output watermark.getState()
Get current state of theWatermarkEstimator
instance, which can be used to recreate theWatermarkEstimator
when processing the restriction.
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Method Details
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currentWatermark
Instant currentWatermark()Return estimated output watermark. This method must return monotonically increasing watermarks across instances that are constructed from prior state. -
getState
WatermarkEstimatorStateT getState()Get current state of theWatermarkEstimator
instance, which can be used to recreate theWatermarkEstimator
when processing the restriction. SeeDoFn.NewWatermarkEstimator
for additional details.The internal state of the estimator must not be mutated by this method.
The state returned must not be mutated.
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