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
int	segments Deprecated.

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).
long	maintainMs() Deprecated. since 2.1. Use Materialized.retention instead.
protected Windows<W>	segments(int segments) Deprecated. since 2.1 Override segmentInterval() instead.
abstract long	size() Return the size of the specified windows in milliseconds.
Windows<W>	until(long durationMs) Deprecated. since 2.1. Use Materialized.withRetention(Duration) or directly configure the retention in a store supplier and use Materialized.as(WindowBytesStoreSupplier).
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

segments

@Deprecated
public int segments

Deprecated.

Constructor Detail

Windows

protected Windows()

Method Detail

until

@Deprecated
public Windows<W> until(long durationMs)
                             throws IllegalArgumentException

Deprecated. since 2.1. Use Materialized.withRetention(Duration) or directly configure the retention in a store supplier and use Materialized.as(WindowBytesStoreSupplier).

Set the window maintain duration (retention time) in milliseconds. This retention time is a guaranteed lower bound for how long a window will be maintained.

Parameters:

durationMs - the window retention time in milliseconds

Returns:

itself

Throws:

IllegalArgumentException - if durationMs is negative

maintainMs

@Deprecated
public long maintainMs()

Deprecated. since 2.1. Use Materialized.retention instead.

Return the window maintain duration (retention time) in milliseconds.

Returns:

the window maintain duration

segments

@Deprecated
protected Windows<W> segments(int segments)
                                   throws IllegalArgumentException

Deprecated. since 2.1 Override segmentInterval() instead.

Set the number of segments to be used for rolling the window store. This function is not exposed to users but can be called by developers that extend this class.

Parameters:

segments - the number of segments to be used

Returns:

itself

Throws:

IllegalArgumentException - if specified segments is small than 2

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).