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

Field Summary

Fields

Modifier and Type	Field and Description
protected static long	DEPRECATED_DEFAULT_24_HR_GRACE_PERIOD By default grace period is 24 hours for all windows in other words we allow out-of-order data for up to a day This behavior is now deprecated and additional details are available in the motivation for the KIP Check out KIP-633 for more details
protected static long	NO_GRACE_PERIOD This constant is used as the specified grace period where we do not have any grace periods instead of magic constants

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Windows()

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.) Delay is defined as (stream_time - record_timestamp).
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

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

Field Detail

DEPRECATED_DEFAULT_24_HR_GRACE_PERIOD

protected static final long DEPRECATED_DEFAULT_24_HR_GRACE_PERIOD

By default grace period is 24 hours for all windows in other words we allow out-of-order data for up to a day This behavior is now deprecated and additional details are available in the motivation for the KIP Check out KIP-633 for more details

See Also:

Constant Field Values

NO_GRACE_PERIOD

protected static final long NO_GRACE_PERIOD

This constant is used as the specified grace period where we do not have any grace periods instead of magic constants

See Also:

Constant Field Values

Constructor Detail

Windows

protected Windows()

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).