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

@InterfaceStability.Unstable
public abstract class Windows<W extends Window>
extends Object

The window specification interface for fixed size windows that is used to define window boundaries and window maintain duration.

If not explicitly specified, the default maintain duration is 1 day. For time semantics, see TimestampExtractor.

See Also:

TimeWindows, UnlimitedWindows, JoinWindows, SessionWindows, TimestampExtractor

Field Summary

Fields

Modifier and Type	Field and Description
int	segments

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Windows()

Method Summary

Methods

Modifier and Type	Method and Description
long	maintainMs() Return the window maintain duration (retention time) in milliseconds.
protected Windows<W>	segments(int segments) Set the number of segments to be used for rolling the window store.
abstract long	size() Return the size of the specified windows in milliseconds.
Windows<W>	until(long durationMs) Set the window maintain duration (retention time) 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

segments

public int segments

Constructor Detail

Windows

protected Windows()

Method Detail

until

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

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

public long maintainMs()

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

Returns:

the window maintain duration

segments

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

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