org.apache.storm.windowing

Interface EvictionPolicy<T>

All Known Implementing Classes:

CountEvictionPolicy, TimeEvictionPolicy, WatermarkCountEvictionPolicy, WatermarkTimeEvictionPolicy

public interface EvictionPolicy<T>

Eviction policy tracks events and decides whether an event should be evicted from the window or not.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	EvictionPolicy.Action The action to be taken when evict(Event) is invoked.

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.
void	track(org.apache.storm.windowing.Event<T> event) Tracks the event to later decide whether evict(Event) should evict it or not.

Method Detail

evict

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.

Parameters:

event - the input event

Returns:

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

track

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

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

Parameters:

event - the input event to be tracked

setContext

void setContext(EvictionContext context)

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.

Parameters:

context -