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

Class TimeTrigger<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.TimeTrigger<W>

Type Parameters:

W - BoundedWindow subclass used to represent the windows used.

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

AfterProcessingTime

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

Support for manipulating the time at which time-based Triggers fire.

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

Modifier and Type	Field and Description
protected static StateTag<CombiningValueState<org.joda.time.Instant,org.joda.time.Instant>>	DELAYED_UNTIL_TAG
protected static List<SerializableFunction<org.joda.time.Instant,org.joda.time.Instant>>	IDENTITY
protected List<SerializableFunction<org.joda.time.Instant,org.joda.time.Instant>>	timestampMappers A list of timestampMappers m1, m2, m3, ...

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

subTriggers

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	TimeTrigger(List<SerializableFunction<org.joda.time.Instant,org.joda.time.Instant>> timestampMappers)

Method Summary

Modifier and Type	Method and Description
TimeTrigger<W>	alignedTo(org.joda.time.Duration size) Aligns the time to be the smallest multiple of size greater than the timestamp since the epoch.
TimeTrigger<W>	alignedTo(org.joda.time.Duration size, org.joda.time.Instant offset) Aligns timestamps to the smallest multiple of size since the offset greater than the timestamp.
protected org.joda.time.Instant	computeTargetTimestamp(org.joda.time.Instant time)
boolean	isCompatible(Trigger<?> other) Returns whether this performs the same triggering as the given Trigger.
TimeTrigger<W>	mappedTo(SerializableFunction<org.joda.time.Instant,org.joda.time.Instant> timestampMapper) Adjust the time at which the trigger will fire.
protected abstract TimeTrigger<W>	newWith(List<SerializableFunction<org.joda.time.Instant,org.joda.time.Instant>> transform) Method to create an updated version of this TimeTrigger modified to use the specified transform.
TimeTrigger<W>	plusDelayOf(org.joda.time.Duration delay) Adds some delay to the original target time.

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

clear, equals, getContinuationTrigger, getWatermarkThatGuaranteesFiring, hashCode, onElement, onMerge, onTimer, orFinally, prefetchOnElement, prefetchOnMerge, prefetchOnTimer, subTriggers, toString

Methods inherited from class java.lang.Object

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

Field Detail

DELAYED_UNTIL_TAG

protected static final StateTag<CombiningValueState<org.joda.time.Instant,org.joda.time.Instant>> DELAYED_UNTIL_TAG

IDENTITY

protected static final List<SerializableFunction<org.joda.time.Instant,org.joda.time.Instant>> IDENTITY

timestampMappers

protected final List<SerializableFunction<org.joda.time.Instant,org.joda.time.Instant>> timestampMappers

A list of timestampMappers m1, m2, m3, ... m_n considered to be composed in sequence. The overall mapping for an instance `instance` is `m_n(... m3(m2(m1(instant))`, implemented via #computeTargetTimestamp

Constructor Detail

TimeTrigger

protected TimeTrigger(List<SerializableFunction<org.joda.time.Instant,org.joda.time.Instant>> timestampMappers)

Method Detail

computeTargetTimestamp

protected org.joda.time.Instant computeTargetTimestamp(org.joda.time.Instant time)

plusDelayOf

public TimeTrigger<W> plusDelayOf(org.joda.time.Duration delay)

Adds some delay to the original target time.

Parameters:

delay - the delay to add

Returns:

An updated time trigger that will wait the additional time before firing.

alignedTo

public TimeTrigger<W> alignedTo(org.joda.time.Duration size,
                                org.joda.time.Instant offset)

Aligns timestamps to the smallest multiple of size since the offset greater than the timestamp.

TODO: Consider sharing this with FixedWindows, and bring over the equivalent of CalendarWindows.

alignedTo

public TimeTrigger<W> alignedTo(org.joda.time.Duration size)

Aligns the time to be the smallest multiple of size greater than the timestamp since the epoch.

mappedTo

public TimeTrigger<W> mappedTo(SerializableFunction<org.joda.time.Instant,org.joda.time.Instant> timestampMapper)

Adjust the time at which the trigger will fire.

The timestampMapper function must have the following properties for all values a and b:

• Deterministic: If a = b then timestampMapper(a) = timestampMapper(b)
• Monotonicity: If a < b then timestampMapper(a) <= timestampMapper(b)

Parameters:

timestampMapper - Function that will be invoked on the proposed trigger time to determine the time at which the trigger should actually fire.

isCompatible

public boolean isCompatible(Trigger<?> other)

Description copied from class: Trigger

Returns whether this performs the same triggering as the given Trigger.

Overrides:

isCompatible in class Trigger<W extends BoundedWindow>

newWith

protected abstract TimeTrigger<W> newWith(List<SerializableFunction<org.joda.time.Instant,org.joda.time.Instant>> transform)

Method to create an updated version of this TimeTrigger modified to use the specified transform.

Parameters:

transform - The new transform to apply to target times.

Returns:

a new TimeTrigger.