org.apache.beam.sdk.transforms.windowing

Class AfterEach

java.lang.Object

org.apache.beam.sdk.transforms.windowing.Trigger

org.apache.beam.sdk.transforms.windowing.AfterEach

All Implemented Interfaces:

java.io.Serializable

@Experimental(value=TRIGGER)
public class AfterEach
extends Trigger

A composite Trigger that executes its sub-triggers in order. Only one sub-trigger is executing at a time, and any time it fires the AfterEach fires. When the currently executing sub-trigger finishes, the AfterEach starts executing the next sub-trigger.

AfterEach.inOrder(t1, t2, ...) finishes when all of the sub-triggers have finished.

The following properties hold:

• AfterEach.inOrder(AfterEach.inOrder(a, b), c) behaves the same as AfterEach.inOrder(a, b, c) and AfterEach.inOrder(a, AfterEach.inOrder(b, c).
• AfterEach.inOrder(Repeatedly.forever(a), b) behaves the same as Repeatedly.forever(a), since the repeated trigger never finishes.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.beam.sdk.transforms.windowing.Trigger

Trigger.OnceTrigger

Field Summary

Fields inherited from class org.apache.beam.sdk.transforms.windowing.Trigger

subTriggers

Method Summary

Modifier and Type	Method and Description
protected Trigger	getContinuationTrigger(java.util.List<Trigger> continuationTriggers) Subclasses should override this to return the Trigger.getContinuationTrigger() of this Trigger.
Instant	getWatermarkThatGuaranteesFiring(BoundedWindow window) For internal use only; no backwards-compatibility guarantees.
static AfterEach	inOrder(java.util.List<Trigger> triggers) Returns an AfterEach Trigger with the given subtriggers.
static AfterEach	inOrder(Trigger... triggers) Returns an AfterEach Trigger with the given subtriggers.
boolean	mayFinish() For internal use only; no backwards-compatibility guarantees.
java.lang.String	toString()

Methods inherited from class org.apache.beam.sdk.transforms.windowing.Trigger

equals, getContinuationTrigger, hashCode, isCompatible, orFinally, subTriggers

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

inOrder

@SafeVarargs
public static AfterEach inOrder(Trigger... triggers)

Returns an AfterEach Trigger with the given subtriggers.

inOrder

public static AfterEach inOrder(java.util.List<Trigger> triggers)

Returns an AfterEach Trigger with the given subtriggers.

getWatermarkThatGuaranteesFiring

public Instant getWatermarkThatGuaranteesFiring(BoundedWindow window)

Description copied from class: Trigger

For internal use only; no backwards-compatibility guarantees.

Returns a bound in event time by which this trigger would have fired at least once for a given window had there been input data.

For triggers that do not fire based on the watermark advancing, returns BoundedWindow.TIMESTAMP_MAX_VALUE.

This estimate may be used, for example, to determine that there are no elements in a side-input window, which causes the default value to be used instead.

Specified by:

getWatermarkThatGuaranteesFiring in class Trigger

mayFinish

public boolean mayFinish()

Description copied from class: Trigger

For internal use only; no backwards-compatibility guarantees.

Indicates whether this trigger may "finish". A top level trigger that finishes can cause data loss, so is rejected by GroupByKey validation.

Specified by:

mayFinish in class Trigger

getContinuationTrigger

protected Trigger getContinuationTrigger(java.util.List<Trigger> continuationTriggers)

Description copied from class: Trigger

Subclasses should override this to return the Trigger.getContinuationTrigger() of this Trigger. For convenience, this is provided the continuation trigger of each of the sub-triggers in the same order as Trigger.subTriggers.

Specified by:

getContinuationTrigger in class Trigger

Parameters:

continuationTriggers - null if Trigger.subTriggers is null, otherwise contains the result of Trigger.getContinuationTrigger() on each of the subTriggers in the same order.

toString

public java.lang.String toString()

Overrides:

toString in class Trigger