Package org.apache.storm.windowing

Class StatefulWindowManager<T>

java.lang.Object

org.apache.storm.windowing.WindowManager<T>

org.apache.storm.windowing.StatefulWindowManager<T>

All Implemented Interfaces:

TriggerHandler

public class StatefulWindowManager<T>
extends WindowManager<T>

Window manager that handles windows with state persistence.

Field Summary

Fields inherited from class org.apache.storm.windowing.WindowManager

evictionPolicy, EXPIRE_EVENTS_THRESHOLD, queue, triggerPolicy, windowLifecycleListener

Constructor Summary

Constructors

Constructor	Description
StatefulWindowManager(WindowLifecycleListener<T> lifecycleListener)
StatefulWindowManager(WindowLifecycleListener<T> lifecycleListener, Collection<Event<T>> queue)	Constructs a StatefulWindowManager.

Method Summary

Modifier and Type	Method	Description
protected void	compactWindow()	expires events that fall out of the window every EXPIRE_EVENTS_THRESHOLD so that the window does not grow too big.
boolean	onTrigger()	The callback invoked by the trigger policy.

Methods inherited from class org.apache.storm.windowing.WindowManager

add, add, add, getEarliestEventTs, getEventCount, getSlidingCountTimestamps, getState, restoreState, setEvictionPolicy, setTriggerPolicy, shutdown, toString

Methods inherited from class java.lang.Object

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

Constructor Details

StatefulWindowManager

public StatefulWindowManager(WindowLifecycleListener<T> lifecycleListener)

StatefulWindowManager

public StatefulWindowManager(WindowLifecycleListener<T> lifecycleListener,
 Collection<Event<T>> queue)

Constructs a StatefulWindowManager.

Parameters:

lifecycleListener - the WindowLifecycleListener

queue - a collection where the events in the window can be enqueued.
Note: This collection has to be thread safe.

Method Details

compactWindow

protected void compactWindow()

Description copied from class: WindowManager

expires events that fall out of the window every EXPIRE_EVENTS_THRESHOLD so that the window does not grow too big.

Overrides:

compactWindow in class WindowManager<T>

onTrigger

public boolean onTrigger()

Description copied from class: WindowManager

The callback invoked by the trigger policy.

Specified by:

onTrigger in interface TriggerHandler

Overrides:

onTrigger in class WindowManager<T>

Returns:

true if the window was evaluated with at least one event in the window, false otherwise