org.apache.kafka.streams.kstream

Interface EmitStrategy

public interface EmitStrategy

This interface controls the strategy that can be used to control how we emit results in a processor.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	EmitStrategy.StrategyType

Field Summary

Fields

Modifier and Type	Field and Description
static org.slf4j.Logger	log

Method Summary

Modifier and Type	Method and Description
static EmitStrategy	onWindowClose() This strategy indicates that the aggregated result for a window will only be emitted when the window closes instead of when there's an update to the window.
static EmitStrategy	onWindowUpdate() This strategy indicates that the aggregated result for a window will be emitted every time when there's an update to the window instead of when the window closes.
EmitStrategy.StrategyType	type() Returns the strategy type.

Field Detail

log

static final org.slf4j.Logger log

Method Detail

type

EmitStrategy.StrategyType type()

Returns the strategy type.

Returns:

Emit strategy type

onWindowClose

static EmitStrategy onWindowClose()

This strategy indicates that the aggregated result for a window will only be emitted when the window closes instead of when there's an update to the window. Window close means that current event time is larger than (window end time + grace period).

This strategy should only be used for windows which can close. An exception will be thrown if it's used with UnlimitedWindow.

Returns:

"window close" EmitStrategy instance

See Also:

TimeWindows, SlidingWindows, SessionWindows, UnlimitedWindows, WindowUpdateStrategy

onWindowUpdate

static EmitStrategy onWindowUpdate()

This strategy indicates that the aggregated result for a window will be emitted every time when there's an update to the window instead of when the window closes.

Returns:

"window update" EmitStrategy instance

See Also:

TimeWindows, SlidingWindows, SessionWindows, UnlimitedWindows, WindowCloseStrategy