org.apache.flink.streaming.api.windowing.evictors

Class CountEvictor<W extends Window>

java.lang.Object

org.apache.flink.streaming.api.windowing.evictors.CountEvictor<W>

Type Parameters:

W - The type of Windows on which this Evictor can operate.

All Implemented Interfaces:

Serializable, Evictor<Object,W>

@PublicEvolving
public class CountEvictor<W extends Window>
extends Object
implements Evictor<Object,W>

An Evictor that keeps up to a certain amount of elements.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.flink.streaming.api.windowing.evictors.Evictor

Evictor.EvictorContext

Method Summary

Modifier and Type	Method and Description
void	evictAfter(Iterable<TimestampedValue<Object>> elements, int size, W window, Evictor.EvictorContext ctx) Optionally evicts elements.
void	evictBefore(Iterable<TimestampedValue<Object>> elements, int size, W window, Evictor.EvictorContext ctx) Optionally evicts elements.
static <W extends Window> CountEvictor<W>	of(long maxCount) Creates a CountEvictor that keeps the given number of elements.
static <W extends Window> CountEvictor<W>	of(long maxCount, boolean doEvictAfter) Creates a CountEvictor that keeps the given number of elements in the pane Eviction is done before/after the window function based on the value of doEvictAfter.

Methods inherited from class java.lang.Object

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

Method Detail

evictBefore

public void evictBefore(Iterable<TimestampedValue<Object>> elements,
                        int size,
                        W window,
                        Evictor.EvictorContext ctx)

Description copied from interface: Evictor

Optionally evicts elements. Called before windowing function.

Specified by:

evictBefore in interface Evictor<Object,W extends Window>

Parameters:

elements - The elements currently in the pane.

size - The current number of elements in the pane.

window - The Window

ctx - The context for the Evictor

evictAfter

public void evictAfter(Iterable<TimestampedValue<Object>> elements,
                       int size,
                       W window,
                       Evictor.EvictorContext ctx)

Description copied from interface: Evictor

Optionally evicts elements. Called after windowing function.

Specified by:

evictAfter in interface Evictor<Object,W extends Window>

Parameters:

elements - The elements currently in the pane.

size - The current number of elements in the pane.

window - The Window

ctx - The context for the Evictor

of

public static <W extends Window> CountEvictor<W> of(long maxCount)

Creates a CountEvictor that keeps the given number of elements. Eviction is done before the window function.

Parameters:

maxCount - The number of elements to keep in the pane.

of

public static <W extends Window> CountEvictor<W> of(long maxCount,
                                                    boolean doEvictAfter)

Creates a CountEvictor that keeps the given number of elements in the pane Eviction is done before/after the window function based on the value of doEvictAfter.

Parameters:

maxCount - The number of elements to keep in the pane.

doEvictAfter - Whether to do eviction after the window function.