org.apache.flink.streaming.api.windowing.triggers

Class DeltaTrigger<T extends Serializable,W extends Window>

java.lang.Object

org.apache.flink.streaming.api.windowing.triggers.DeltaTrigger<T,W>

Type Parameters:

W - The type of Windows on which this trigger can operate.

All Implemented Interfaces:

Serializable, Trigger<T,W>

public class DeltaTrigger<T extends Serializable,W extends Window>
extends Object
implements Trigger<T,W>

A Trigger that fires based on a DeltaFunction and a threshold.

This trigger calculates a delta between the data point which triggered last and the currently arrived data point. It triggers if the delta is higher than a specified threshold.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.flink.streaming.api.windowing.triggers.Trigger

Trigger.TriggerContext, Trigger.TriggerResult

Method Summary

Methods

Modifier and Type	Method and Description
static <T extends Serializable,W extends Window> DeltaTrigger<T,W>	of(double threshold, DeltaFunction<T> deltaFunction) Creates a delta trigger from the given threshold and DeltaFunction.
Trigger.TriggerResult	onElement(T element, long timestamp, W window, Trigger.TriggerContext ctx) Called for every element that gets added to a pane.
Trigger.TriggerResult	onEventTime(long time, W window, Trigger.TriggerContext ctx) Called when an event-time timer that was set using the trigger context fires.
Trigger.TriggerResult	onProcessingTime(long time, W window, Trigger.TriggerContext ctx) Called when a processing-time timer that was set using the trigger context fires.
String	toString()

Methods inherited from class java.lang.Object

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

Method Detail

onElement

public Trigger.TriggerResult onElement(T element,
                              long timestamp,
                              W window,
                              Trigger.TriggerContext ctx)
                                throws Exception

Description copied from interface: Trigger

Called for every element that gets added to a pane. The result of this will determine whether the pane is evaluated to emit results.

Specified by:

onElement in interface Trigger<T extends Serializable,W extends Window>

Parameters:

element - The element that arrived.

timestamp - The timestamp of the element that arrived.

window - The window to which this pane belongs.

ctx - A context object that can be used to register timer callbacks.

Throws:

Exception

onEventTime

public Trigger.TriggerResult onEventTime(long time,
                                W window,
                                Trigger.TriggerContext ctx)

Description copied from interface: Trigger

Called when an event-time timer that was set using the trigger context fires.

Specified by:

onEventTime in interface Trigger<T extends Serializable,W extends Window>

Parameters:

time - The timestamp at which the timer fired.

ctx - A context object that can be used to register timer callbacks.

onProcessingTime

public Trigger.TriggerResult onProcessingTime(long time,
                                     W window,
                                     Trigger.TriggerContext ctx)
                                       throws Exception

Description copied from interface: Trigger

Called when a processing-time timer that was set using the trigger context fires.

Specified by:

onProcessingTime in interface Trigger<T extends Serializable,W extends Window>

Parameters:

time - The timestamp at which the timer fired.

ctx - A context object that can be used to register timer callbacks.

Throws:

Exception

toString

public String toString()

Overrides:

toString in class Object

of

public static <T extends Serializable,W extends Window> DeltaTrigger<T,W> of(double threshold,
                                                             DeltaFunction<T> deltaFunction)

Creates a delta trigger from the given threshold and DeltaFunction.

Type Parameters:

T - The type of elements on which this trigger can operate.

W - The type of Windows on which this trigger can operate.

Parameters:

threshold - The threshold at which to trigger.

deltaFunction - The delta function to use