org.apache.storm.windowing

Class CountEvictionPolicy<T>

java.lang.Object

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

All Implemented Interfaces:

EvictionPolicy<T>

Direct Known Subclasses:

WatermarkCountEvictionPolicy

public class CountEvictionPolicy<T>
extends Object
implements EvictionPolicy<T>

An eviction policy that tracks event counts and can evict based on a threshold count.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.storm.windowing.EvictionPolicy

EvictionPolicy.Action

Field Summary

Fields

Modifier and Type	Field and Description
protected AtomicLong	currentCount
protected int	threshold

Constructor Summary

Constructors

Constructor and Description
CountEvictionPolicy(int count)

Method Summary

Modifier and Type	Method and Description
EvictionPolicy.Action	evict(org.apache.storm.windowing.Event<T> event) Decides if an event should be expired from the window, processed in the current window or kept for later processing.
void	setContext(EvictionContext context) Sets a context in the eviction policy that can be used while evicting the events.
String	toString()
void	track(org.apache.storm.windowing.Event<T> event) Tracks the event to later decide whether EvictionPolicy.evict(Event) should evict it or not.

Methods inherited from class java.lang.Object

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

Field Detail

threshold

protected final int threshold

currentCount

protected final AtomicLong currentCount

Constructor Detail

CountEvictionPolicy

public CountEvictionPolicy(int count)

Method Detail

evict

public EvictionPolicy.Action evict(org.apache.storm.windowing.Event<T> event)

Description copied from interface: EvictionPolicy

Decides if an event should be expired from the window, processed in the current window or kept for later processing.

Specified by:

evict in interface EvictionPolicy<T>

Parameters:

event - the input event

Returns:

the EvictionPolicy.Action to be taken based on the input event

track

public void track(org.apache.storm.windowing.Event<T> event)

Description copied from interface: EvictionPolicy

Tracks the event to later decide whether EvictionPolicy.evict(Event) should evict it or not.

Specified by:

track in interface EvictionPolicy<T>

Parameters:

event - the input event to be tracked

setContext

public void setContext(EvictionContext context)

Description copied from interface: EvictionPolicy

Sets a context in the eviction policy that can be used while evicting the events. E.g. For TimeEvictionPolicy, this could be used to set the reference timestamp.

Specified by:

setContext in interface EvictionPolicy<T>

toString

public String toString()

Overrides:

toString in class Object