Package org.apache.beam.sdk.transforms

Class PeriodicImpulse

java.lang.Object

org.apache.beam.sdk.transforms.PTransform<PBegin,PCollection<Instant>>

org.apache.beam.sdk.transforms.PeriodicImpulse

All Implemented Interfaces:

Serializable, HasDisplayData

public class PeriodicImpulse
extends PTransform<PBegin,PCollection<Instant>>

A PTransform which produces a sequence of elements at fixed runtime intervals.

If applyWindowing() is specified, each element will be assigned to its own fixed window.

See PeriodicSequence.

See Also:

• Serialized Form

Field Summary

Fields inherited from class org.apache.beam.sdk.transforms.PTransform

annotations, displayData, name, resourceHints

Method Summary

Modifier and Type	Method	Description
PeriodicImpulse	applyWindowing()
PeriodicImpulse	catchUpToNow(boolean catchUpToNow)	For internal use only; no backwards-compatibility guarantees.
static PeriodicImpulse	create()
PCollection<Instant>	expand(PBegin input)	Override this method to specify how this PTransform should be expanded on the given InputT.
PeriodicImpulse	startAt(Instant startTime)	Assign a timestamp when the pipeliene starts to produce data.
PeriodicImpulse	stopAfter(Duration duration)	For internal use only; no backwards-compatibility guarantees.
PeriodicImpulse	stopAt(Instant stopTime)	Assign a timestamp when the pipeliene stops producing data.
PeriodicImpulse	withInterval(Duration interval)

Methods inherited from class org.apache.beam.sdk.transforms.PTransform

addAnnotation, compose, compose, getAdditionalInputs, getAnnotations, getDefaultOutputCoder, getDefaultOutputCoder, getDefaultOutputCoder, getKindString, getName, getResourceHints, populateDisplayData, setDisplayData, setResourceHints, toString, validate, validate

Methods inherited from class java.lang.Object

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

Method Details

create

public static PeriodicImpulse create()

startAt

public PeriodicImpulse startAt(Instant startTime)

Assign a timestamp when the pipeliene starts to produce data.

Cannot be used along with stopAfter(org.joda.time.Duration).

stopAt

public PeriodicImpulse stopAt(Instant stopTime)

Assign a timestamp when the pipeliene stops producing data.

Cannot be used along with stopAfter(org.joda.time.Duration).

stopAfter

@Internal
public PeriodicImpulse stopAfter(Duration duration)

For internal use only; no backwards-compatibility guarantees.

Assign a time interval at which the pipeliene produces data. This is different from setting startAt(org.joda.time.Instant) and stopAt(org.joda.time.Instant), as the first timestamp is determined at run time (pipeline starts processing).

withInterval

public PeriodicImpulse withInterval(Duration interval)

applyWindowing

public PeriodicImpulse applyWindowing()

catchUpToNow

@Internal
public PeriodicImpulse catchUpToNow(boolean catchUpToNow)

For internal use only; no backwards-compatibility guarantees.

The default behavior is that PeriodicImpulse emits all instants until Instant.now(), then starts firing at the specified interval. If this is set to false, the PeriodicImpulse will perform the interval wait before firing each instant.

expand

public PCollection<Instant> expand(PBegin input)

Description copied from class: PTransform

Override this method to specify how this PTransform should be expanded on the given InputT.

NOTE: This method should not be called directly. Instead apply the PTransform should be applied to the InputT using the apply method.

Composite transforms, which are defined in terms of other transforms, should return the output of one of the composed transforms. Non-composite transforms, which do not apply any transforms internally, should return a new unbound output and register evaluators (via backend-specific registration methods).

Specified by:

expand in class PTransform<PBegin,PCollection<Instant>>