com.google.cloud.dataflow.sdk.transforms.windowing

Class AfterFirst<W extends BoundedWindow>

java.lang.Object

com.google.cloud.dataflow.sdk.transforms.windowing.Trigger<W>

com.google.cloud.dataflow.sdk.transforms.windowing.Trigger.OnceTrigger<W>

com.google.cloud.dataflow.sdk.transforms.windowing.AfterFirst<W>

Type Parameters:

W - BoundedWindow subclass used to represent the windows used by this Trigger

All Implemented Interfaces:

TriggerBuilder<W>, Serializable

@Experimental(value=TRIGGER)
public class AfterFirst<W extends BoundedWindow>
extends Trigger.OnceTrigger<W>

Create a composite Trigger that fires once after at least one of its sub-triggers have fired.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class com.google.cloud.dataflow.sdk.transforms.windowing.Trigger

Trigger.MergeResult, Trigger.MergingTriggerInfo<W extends BoundedWindow>, Trigger.OnceTrigger<W extends BoundedWindow>, Trigger.OnElementContext, Trigger.OnMergeContext, Trigger.OnTimerContext, Trigger.TriggerContext, Trigger.TriggerInfo<W extends BoundedWindow>, Trigger.TriggerResult

Field Summary

Fields inherited from class com.google.cloud.dataflow.sdk.transforms.windowing.Trigger

subTriggers

Method Summary

Modifier and Type	Method and Description
Trigger.OnceTrigger<W>	getContinuationTrigger(List<Trigger<W>> continuationTriggers) Return the Trigger.getContinuationTrigger() of this Trigger.
org.joda.time.Instant	getWatermarkThatGuaranteesFiring(W window) Returns a bound in watermark time by which this trigger would have fired at least once for a given window had there been input data.
static <W extends BoundedWindow> Trigger.OnceTrigger<W>	of(Trigger.OnceTrigger<W>... triggers)
Trigger.TriggerResult	onElement(Trigger.OnElementContext c) Called immediately after an element is first incorporated into a window.
Trigger.MergeResult	onMerge(Trigger.OnMergeContext c) Called immediately after windows have been merged.
Trigger.TriggerResult	onTimer(Trigger.OnTimerContext c) Called when a timer has fired for the current window.

Methods inherited from class com.google.cloud.dataflow.sdk.transforms.windowing.Trigger.OnceTrigger

getContinuationTrigger

Methods inherited from class com.google.cloud.dataflow.sdk.transforms.windowing.Trigger

buildTrigger, clear, equals, hashCode, isCompatible, orFinally, prefetchOnElement, prefetchOnMerge, prefetchOnTimer, subTriggers, toString

Methods inherited from class java.lang.Object

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

Method Detail

of

@SafeVarargs
public static <W extends BoundedWindow> Trigger.OnceTrigger<W> of(Trigger.OnceTrigger<W>... triggers)

onElement

public Trigger.TriggerResult onElement(Trigger.OnElementContext c)
                                throws Exception

Description copied from class: Trigger

Called immediately after an element is first incorporated into a window.

Specified by:

onElement in class Trigger<W extends BoundedWindow>

Throws:

Exception

onMerge

public Trigger.MergeResult onMerge(Trigger.OnMergeContext c)
                            throws Exception

Description copied from class: Trigger

Called immediately after windows have been merged.

Leaf triggers should determine their result by inspecting their status and any state in the merging windows. Composite triggers should determine their result by calling ExecutableTrigger.invokeMerge(com.google.cloud.dataflow.sdk.transforms.windowing.Trigger<W>.OnMergeContext) on their sub-triggers, and applying appropriate logic.

A trigger can only return Trigger.MergeResult.ALREADY_FINISHED if it is marked as finished in at least one of the windows being merged.

The implementation does not need to clear out any state associated with the old windows.

Specified by:

onMerge in class Trigger<W extends BoundedWindow>

Throws:

Exception

onTimer

public Trigger.TriggerResult onTimer(Trigger.OnTimerContext c)
                              throws Exception

Description copied from class: Trigger

Called when a timer has fired for the current window. Composite triggers should pass the event to all sub-triggers. Triggers that set timers should verify the timer matches what they set before processing the firing.

Specified by:

onTimer in class Trigger<W extends BoundedWindow>

Throws:

Exception

getWatermarkThatGuaranteesFiring

public org.joda.time.Instant getWatermarkThatGuaranteesFiring(W window)

Description copied from class: Trigger

Returns a bound in watermark time by which this trigger would have fired at least once for a given window had there been input data. This is a static property of a trigger that does not depend on its state.

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

This estimate is used 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<W extends BoundedWindow>

getContinuationTrigger

public Trigger.OnceTrigger<W> getContinuationTrigger(List<Trigger<W>> continuationTriggers)

Description copied from class: Trigger

Return the Trigger.getContinuationTrigger() of this Trigger. For convenience, this is provided the continuation trigger of each of the sub-triggers.

Specified by:

getContinuationTrigger in class Trigger<W extends BoundedWindow>