org.apache.kafka.streams.kstream

Class Windows<W extends Window>

java.lang.Object

org.apache.kafka.streams.kstream.Windows<W>

Type Parameters:

W - type of the window instance

Direct Known Subclasses:

JoinWindows, TimeWindows, UnlimitedWindows

public abstract class Windows<W extends Window>
extends Object

The window specification for fixed size windows that is used to define window boundaries and grace period.

Grace period defines how long to wait on out-of-order events. That is, windows will continue to accept new records until stream_time >= window_end + grace_period. Records that arrive after the grace period passed are considered late and will not be processed but are dropped.

Warning: It may be unsafe to use objects of this class in set- or map-like collections, since the equals and hashCode methods depend on mutable fields.

See Also:

TimeWindows, UnlimitedWindows, JoinWindows, SessionWindows, TimestampExtractor

Method Summary

Modifier and Type	Method and Description
abstract long	gracePeriodMs() Return the window grace period (the time to admit out-of-order events after the end of the window.)
abstract long	size() Return the size of the specified windows in milliseconds.
abstract Map<Long,W>	windowsFor(long timestamp) Create all windows that contain the provided timestamp, indexed by non-negative window start timestamps.

Methods inherited from class java.lang.Object

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

Method Detail

windowsFor

public abstract Map<Long,W> windowsFor(long timestamp)

Create all windows that contain the provided timestamp, indexed by non-negative window start timestamps.

Parameters:

timestamp - the timestamp window should get created for

Returns:

a map of windowStartTimestamp -> Window entries

size

public abstract long size()

Return the size of the specified windows in milliseconds.

Returns:

the size of the specified windows

gracePeriodMs

public abstract long gracePeriodMs()

Return the window grace period (the time to admit out-of-order events after the end of the window.) Delay is defined as (stream_time - record_timestamp).