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

Class TimeTrigger<W extends BoundedWindow,T extends TimeTrigger<W,T>>

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,T>

Type Parameters:

W - BoundedWindow subclass used to represent the windows used.

T - TimeTrigger subclass produced by modifying the current TimeTrigger.

All Implemented Interfaces:

java.io.Serializable

Direct Known Subclasses:

AfterProcessingTime, AfterWatermark

@Experimental(value=TRIGGER)
public abstract class TimeTrigger<W extends BoundedWindow,T extends TimeTrigger<W,T>>
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.OnceTrigger<W extends BoundedWindow>, Trigger.OnElementEvent<W>, Trigger.OnMergeEvent<W>, Trigger.OnTimerEvent<W extends BoundedWindow>, Trigger.TimeDomain, Trigger.TriggerContext<W extends BoundedWindow>, Trigger.TriggerId<W extends BoundedWindow>, Trigger.TriggerResult, Trigger.WindowStatus

Field Summary

Fields

Modifier and Type	Field and Description
protected static com.google.common.collect.ImmutableList<SerializableFunction<Instant,Instant>>	IDENTITY

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	TimeTrigger(com.google.common.collect.ImmutableList<SerializableFunction<Instant,Instant>> timestampMappers)

Method Summary

Methods

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

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

clear, getWatermarkCutoff, onElement, onMerge, onTimer, orFinally, willNeverFinish

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

IDENTITY

protected static final com.google.common.collect.ImmutableList<SerializableFunction<Instant,Instant>> IDENTITY

Constructor Detail

TimeTrigger

protected TimeTrigger(com.google.common.collect.ImmutableList<SerializableFunction<Instant,Instant>> timestampMappers)

Method Detail

computeTargetTimestamp

protected Instant computeTargetTimestamp(Instant time)

plusDelayOf

public T plusDelayOf(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 T alignedTo(Duration size,
          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 T alignedTo(Duration size)

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

mappedTo

public T mappedTo(SerializableFunction<Instant,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.

Specified by:

isCompatible in class Trigger<W extends BoundedWindow>

newWith

protected abstract T newWith(com.google.common.collect.ImmutableList<SerializableFunction<Instant,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.