org.apache.flink.streaming.api.windowing.policy

Interface CentralActiveTrigger<DATA>

All Superinterfaces:

Cloneable, CloneableTriggerPolicy<DATA>, Serializable, TriggerPolicy<DATA>

All Known Implementing Classes:

TimeTriggerPolicy

public interface CentralActiveTrigger<DATA>
extends CloneableTriggerPolicy<DATA>

Interface for defining grouped windowing policies which can interact with other groups to trigger on the latest available information globally available to all groups.

At predefined time intervals the discretizers takes the last globally seen element, and notifies all groups (but the one that already have seen the object). This allows to trigger before an element comes from the next window for a specific group. This pattern can be used for instance in time policies to regularly broadcast the current time to all groups.

Method Summary

Modifier and Type	Method and Description
Object[]	notifyOnLastGlobalElement(DATA datapoint) This method is called to broadcast information about the last globally seen data point to all triggers.

Methods inherited from interface org.apache.flink.streaming.api.windowing.policy.CloneableTriggerPolicy

clone

Methods inherited from interface org.apache.flink.streaming.api.windowing.policy.TriggerPolicy

notifyTrigger

Method Detail

notifyOnLastGlobalElement

Object[] notifyOnLastGlobalElement(DATA datapoint)

This method is called to broadcast information about the last globally seen data point to all triggers. The number of elements returned in the array will determine the number of triggers at that point, while the elements themselves are used only for active eviction.

Parameters:

datapoint - The last globally seen data

Returns:

An object of fake elements. If returned null or empty list, no triggers will occur.