Package org.apache.beam.sdk.transforms.splittabledofn

Class WatermarkEstimators.MonotonicallyIncreasing

java.lang.Object

org.apache.beam.sdk.transforms.splittabledofn.WatermarkEstimators.MonotonicallyIncreasing

All Implemented Interfaces:

TimestampObservingWatermarkEstimator<Instant>, WatermarkEstimator<Instant>

Enclosing class:

WatermarkEstimators

public static class WatermarkEstimators.MonotonicallyIncreasing
extends Object
implements TimestampObservingWatermarkEstimator<Instant>

A watermark estimator that observes timestamps of records output from a DoFn reporting the timestamp of the last element seen as the current watermark.

Note that this watermark estimator expects output timestamps in monotonically increasing order. If they are not, then the watermark will advance based upon the last observed timestamp as long as it is greater then any previously reported watermark.

Constructor Summary

Constructors

Constructor	Description
MonotonicallyIncreasing(Instant watermark)

Method Summary

Modifier and Type	Method	Description
Instant	currentWatermark()	Return estimated output watermark.
Instant	getState()	Get current state of the WatermarkEstimator instance, which can be used to recreate the WatermarkEstimator when processing the restriction.
void	observeTimestamp(Instant timestamp)	Update watermark estimate with latest output timestamp.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

MonotonicallyIncreasing

public MonotonicallyIncreasing(Instant watermark)

Method Details

observeTimestamp

public void observeTimestamp(Instant timestamp)

Description copied from interface: TimestampObservingWatermarkEstimator

Update watermark estimate with latest output timestamp. This is called with the timestamp of every element output from the DoFn.

Specified by:

observeTimestamp in interface TimestampObservingWatermarkEstimator<Instant>

currentWatermark

public Instant currentWatermark()

Description copied from interface: WatermarkEstimator

Return estimated output watermark. This method must return monotonically increasing watermarks across instances that are constructed from prior state.

Specified by:

currentWatermark in interface WatermarkEstimator<Instant>

getState

public Instant getState()

Description copied from interface: WatermarkEstimator

Get current state of the WatermarkEstimator instance, which can be used to recreate the WatermarkEstimator when processing the restriction. See DoFn.NewWatermarkEstimator for additional details.

The internal state of the estimator must not be mutated by this method.

The state returned must not be mutated.

Specified by:

getState in interface WatermarkEstimator<Instant>