Class DefaultTrigger
- java.lang.Object
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- org.apache.beam.sdk.transforms.windowing.Trigger
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- org.apache.beam.sdk.transforms.windowing.DefaultTrigger
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- All Implemented Interfaces:
java.io.Serializable
@Experimental(TRIGGER) public class DefaultTrigger extends Trigger
A trigger that is equivalent toRepeatedly.forever(AfterWatermark.pastEndOfWindow())
. SeeRepeatedly.forever(org.apache.beam.sdk.transforms.windowing.Trigger)
andAfterWatermark.pastEndOfWindow()
for more details.This is a distinguished class to make it easy for runners to optimize for this common case.
- See Also:
- Serialized Form
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Nested Class Summary
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Nested classes/interfaces inherited from class org.apache.beam.sdk.transforms.windowing.Trigger
Trigger.OnceTrigger
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Field Summary
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Fields inherited from class org.apache.beam.sdk.transforms.windowing.Trigger
subTriggers
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description protected Trigger
getContinuationTrigger(java.util.List<Trigger> continuationTriggers)
Subclasses should override this to return theTrigger.getContinuationTrigger()
of thisTrigger
.org.joda.time.Instant
getWatermarkThatGuaranteesFiring(BoundedWindow window)
For internal use only; no backwards-compatibility guarantees.boolean
isCompatible(Trigger other)
For internal use only; no backwards-compatibility guarantees.boolean
mayFinish()
For internal use only; no backwards-compatibility guarantees.static DefaultTrigger
of()
Returns the default trigger.-
Methods inherited from class org.apache.beam.sdk.transforms.windowing.Trigger
equals, getContinuationTrigger, hashCode, orFinally, subTriggers, toString
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Method Detail
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of
public static DefaultTrigger of()
Returns the default trigger.
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getWatermarkThatGuaranteesFiring
public org.joda.time.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 classTrigger
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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.
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isCompatible
public boolean isCompatible(Trigger other)
Description copied from class:Trigger
For internal use only; no backwards-compatibility guarantees.Returns whether this performs the same triggering as the given
Trigger
.- Overrides:
isCompatible
in classTrigger
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getContinuationTrigger
protected Trigger getContinuationTrigger(java.util.List<Trigger> continuationTriggers)
Description copied from class:Trigger
Subclasses should override this to return theTrigger.getContinuationTrigger()
of thisTrigger
. For convenience, this is provided the continuation trigger of each of the sub-triggers in the same order asTrigger.subTriggers
.- Specified by:
getContinuationTrigger
in classTrigger
- Parameters:
continuationTriggers
- contains the result ofTrigger.getContinuationTrigger()
on each of thesubTriggers
in the same order.
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