W - type of windowpublic static final class ProcessingTimeTriggers.AfterFirstElementPeriodic<W extends Window> extends Trigger<W>
Trigger.OnMergeContext, Trigger.TriggerContext| 限定符和类型 | 方法和说明 |
|---|---|
boolean |
canMerge()
Returns true if this trigger supports merging of trigger state and can therefore.
|
void |
clear(W window)
Clears any state that the trigger might still hold for the given window.
|
boolean |
onElement(Object element,
long timestamp,
W window)
Called for every element that gets added to a pane.
|
boolean |
onEventTime(long time,
W window)
Called when an event-time timer that was set using the trigger context fires.
|
void |
onMerge(W window,
Trigger.OnMergeContext mergeContext)
Called when several windows have been merged into one window by the
WindowAssigner. |
boolean |
onProcessingTime(long time,
W window)
Called when a processing-time timer that was set using the trigger context fires.
|
void |
open(Trigger.TriggerContext ctx)
Initialization method for the trigger.
|
String |
toString() |
public void open(Trigger.TriggerContext ctx) throws Exception
Triggerpublic boolean onElement(Object element, long timestamp, W window) throws Exception
Triggerpublic boolean onProcessingTime(long time,
W window)
throws Exception
TriggerNote: This method is not called in case the window does not contain any elements. Thus,
if you return PURGE from a trigger method and you expect to do cleanup in a future
invocation of a timer callback it might be wise to clean any state that you would clean
in the timer callback.
onProcessingTime 在类中 Trigger<W extends Window>time - The timestamp at which the timer fired.window - The window for which the timer fired.Exceptionpublic boolean onEventTime(long time,
W window)
throws Exception
TriggerNote: This method is not called in case the window does not contain any elements. Thus,
if you return PURGE from a trigger method and you expect to do cleanup in a future
invocation of a timer callback it might be wise to clean any state that you would clean
in the timer callback.
onEventTime 在类中 Trigger<W extends Window>time - The timestamp at which the timer fired.window - The window for which the timer fired.Exceptionpublic boolean canMerge()
TriggerIf this returns true you must properly implement
Trigger.onMerge(Window, OnMergeContext)
public void onMerge(W window, Trigger.OnMergeContext mergeContext) throws Exception
TriggerWindowAssigner.public void clear(W window) throws Exception
TriggerTrigger.TriggerContext.registerEventTimeTimer(long)
and Trigger.TriggerContext.registerProcessingTimeTimer(long) should be deleted here as
well as state acquired using TriggerContext#getPartitionedState(StateDescriptor).Copyright © 2014–2020 The Apache Software Foundation. All rights reserved.