Google Cloud Dataflow SDK for Java, version 1.9.1
Class Repeatedly<W extends BoundedWindow>
- java.lang.Object
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- com.google.cloud.dataflow.sdk.transforms.windowing.Trigger<W>
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- com.google.cloud.dataflow.sdk.transforms.windowing.Repeatedly<W>
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- Type Parameters:
W
-BoundedWindow
subclass used to represent the windows used by thisTrigger
- All Implemented Interfaces:
- TriggerBuilder<W>, Serializable
public class Repeatedly<W extends BoundedWindow> extends Trigger<W>
Repeat a trigger, either until some condition is met or forever.For example, to fire after the end of the window, and every time late data arrives:
Repeatedly.forever(AfterWatermark.isPastEndOfWindow());
Repeatedly.forever(someTrigger)
behaves like an infiniteAfterEach.inOrder(someTrigger, someTrigger, someTrigger, ...)
.- See Also:
- Serialized Form
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Nested Class Summary
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Nested classes/interfaces inherited from class com.google.cloud.dataflow.sdk.transforms.windowing.Trigger
Trigger.MergingTriggerInfo<W extends BoundedWindow>, Trigger.OnceTrigger<W extends BoundedWindow>, Trigger.OnElementContext, Trigger.OnMergeContext, Trigger.TriggerContext, Trigger.TriggerInfo<W extends BoundedWindow>
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Field Summary
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Fields inherited from class com.google.cloud.dataflow.sdk.transforms.windowing.Trigger
subTriggers
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method and Description static <W extends BoundedWindow>
Repeatedly<W>forever(Trigger<W> repeated)
Create a composite trigger that repeatedly executes the triggerrepeated
, firing each time it fires and ignoring any indications to finish.Trigger<W>
getContinuationTrigger(List<Trigger<W>> continuationTriggers)
Return theTrigger.getContinuationTrigger()
of thisTrigger
.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.void
onElement(Trigger.OnElementContext c)
Called immediately after an element is first incorporated into a window.void
onFire(Trigger.TriggerContext context)
Adjusts the state of the trigger to be ready for the next pane.void
onMerge(Trigger.OnMergeContext c)
Called immediately after windows have been merged.boolean
shouldFire(Trigger.TriggerContext context)
Returnstrue
if the current state of the trigger indicates that its condition is satisfied and it is ready to fire.String
toString()
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Methods inherited from class com.google.cloud.dataflow.sdk.transforms.windowing.Trigger
buildTrigger, clear, equals, getContinuationTrigger, hashCode, isCompatible, orFinally, prefetchOnElement, prefetchOnFire, prefetchOnMerge, prefetchShouldFire, subTriggers
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Method Detail
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forever
public static <W extends BoundedWindow> Repeatedly<W> forever(Trigger<W> repeated)
Create a composite trigger that repeatedly executes the triggerrepeated
, firing each time it fires and ignoring any indications to finish.Unless used with
Trigger.orFinally(com.google.cloud.dataflow.sdk.transforms.windowing.Trigger.OnceTrigger<W>)
the composite trigger will never finish.- Parameters:
repeated
- the trigger to execute repeatedly.
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onElement
public void 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 classTrigger<W extends BoundedWindow>
- Throws:
Exception
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onMerge
public void onMerge(Trigger.OnMergeContext c) throws Exception
Description copied from class:Trigger
Called immediately after windows have been merged.Leaf triggers should update their state by inspecting their status and any state in the merging windows. Composite triggers should update their state by calling
ExecutableTrigger.invokeOnMerge(com.google.cloud.dataflow.sdk.transforms.windowing.Trigger<W>.OnMergeContext)
on their sub-triggers, and applying appropriate logic.A trigger such as
AfterWatermark.pastEndOfWindow()
may no longer be finished; it is the responsibility of the trigger itself to record this fact. It is forbidden for a trigger to become finished due toTrigger.onMerge(com.google.cloud.dataflow.sdk.transforms.windowing.Trigger<W>.OnMergeContext)
, as it has not yet fired the pending elements that led to it being ready to fire.The implementation does not need to clear out any state associated with the old windows.
- Specified by:
onMerge
in classTrigger<W extends BoundedWindow>
- Throws:
Exception
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getWatermarkThatGuaranteesFiring
public 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 classTrigger<W extends BoundedWindow>
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getContinuationTrigger
public Trigger<W> getContinuationTrigger(List<Trigger<W>> continuationTriggers)
Description copied from class:Trigger
Return theTrigger.getContinuationTrigger()
of thisTrigger
. For convenience, this is provided the continuation trigger of each of the sub-triggers.- Specified by:
getContinuationTrigger
in classTrigger<W extends BoundedWindow>
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shouldFire
public boolean shouldFire(Trigger.TriggerContext context) throws Exception
Description copied from class:Trigger
Returnstrue
if the current state of the trigger indicates that its condition is satisfied and it is ready to fire.- Specified by:
shouldFire
in classTrigger<W extends BoundedWindow>
- Throws:
Exception
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onFire
public void onFire(Trigger.TriggerContext context) throws Exception
Description copied from class:Trigger
Adjusts the state of the trigger to be ready for the next pane. For example, aRepeatedly
trigger will reset its inner trigger, since it has fired.If the trigger is finished, it is the responsibility of the trigger itself to record that fact via the
context
.- Specified by:
onFire
in classTrigger<W extends BoundedWindow>
- Throws:
Exception
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toString
public String toString()
- Overrides:
toString
in classTrigger<W extends BoundedWindow>
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