Package org.apache.flink.table.runtime.operators.window.slicing

Class SliceAssigners.HoppingSliceAssigner

java.lang.Object

org.apache.flink.table.runtime.operators.window.slicing.SliceAssigners.HoppingSliceAssigner

All Implemented Interfaces:

Serializable, SliceAssigner, SliceSharedAssigner

Enclosing class:

SliceAssigners

public static final class SliceAssigners.HoppingSliceAssigner
extends Object
implements SliceSharedAssigner

The SliceAssigner for hopping windows.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.flink.table.runtime.operators.window.slicing.SliceSharedAssigner

SliceSharedAssigner.MergeCallback

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	HoppingSliceAssigner(int rowtimeIndex, java.time.ZoneId shiftTimeZone, long size, long slide, long offset)

Method Summary

Modifier and Type	Method	Description
long	assignSliceEnd(long timestamp)
Iterable<Long>	expiredSlices(long windowEnd)	Returns an iterator of slices to expire when the given window is emitted.
long	getLastWindowEnd(long sliceEnd)	Returns the last window which the slice belongs to.
long	getSliceEndInterval()	Returns the interval of slice ends, i.e.
long	getWindowStart(long windowEnd)	Returns the corresponding window start timestamp of the given window end timestamp.
void	mergeSlices(long sliceEnd, SliceSharedAssigner.MergeCallback callback)	Determines which slices (if any) should be merged.
Optional<Long>	nextTriggerWindow(long windowEnd, java.util.function.Supplier<Boolean> isWindowEmpty)	Returns the optional end timestamp of next window which should be triggered.
SliceAssigners.HoppingSliceAssigner	withOffset(java.time.Duration offset)	Creates a new SliceAssigners.HoppingSliceAssigner with a new specified offset.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.flink.table.runtime.operators.window.slicing.SliceAssigner

assignSliceEnd, isEventTime

Constructor Detail

HoppingSliceAssigner

protected HoppingSliceAssigner(int rowtimeIndex,
                               java.time.ZoneId shiftTimeZone,
                               long size,
                               long slide,
                               long offset)

Method Detail

withOffset

public SliceAssigners.HoppingSliceAssigner withOffset(java.time.Duration offset)

Creates a new SliceAssigners.HoppingSliceAssigner with a new specified offset.

assignSliceEnd

public long assignSliceEnd(long timestamp)

getLastWindowEnd

public long getLastWindowEnd(long sliceEnd)

Description copied from interface: SliceAssigner

Returns the last window which the slice belongs to. The window and slices are both identified by the end timestamp.

Specified by:

getLastWindowEnd in interface SliceAssigner

getWindowStart

public long getWindowStart(long windowEnd)

Description copied from interface: SliceAssigner

Returns the corresponding window start timestamp of the given window end timestamp.

Specified by:

getWindowStart in interface SliceAssigner

expiredSlices

public Iterable<Long> expiredSlices(long windowEnd)

Description copied from interface: SliceAssigner

Returns an iterator of slices to expire when the given window is emitted. The window and slices are both identified by the end timestamp.

Specified by:

expiredSlices in interface SliceAssigner

Parameters:

windowEnd - the end timestamp of window emitted.

getSliceEndInterval

public long getSliceEndInterval()

Description copied from interface: SliceAssigner

Returns the interval of slice ends, i.e. the step size to advance of the slice end when a new slice assigned.

Specified by:

getSliceEndInterval in interface SliceAssigner

mergeSlices

public void mergeSlices(long sliceEnd,
                        SliceSharedAssigner.MergeCallback callback)
                 throws Exception

Description copied from interface: SliceSharedAssigner

Determines which slices (if any) should be merged.

Specified by:

mergeSlices in interface SliceSharedAssigner

Parameters:

sliceEnd - the triggered slice, identified by end timestamp

callback - a callback that can be invoked to signal which slices should be merged.

Throws:

Exception

nextTriggerWindow

public Optional<Long> nextTriggerWindow(long windowEnd,
                                        java.util.function.Supplier<Boolean> isWindowEmpty)

Description copied from interface: SliceSharedAssigner

Returns the optional end timestamp of next window which should be triggered. Empty if no following window to trigger for now.

The purpose of this method is avoid register too many timers for each hopping and cumulative slice, e.g. HOP(1day, 10s) needs register 8640 timers for every slice. In order to improve this, we only register one timer for the next window. For hopping windows we don't register next window if current window is empty (i.e. no records in current window). That means we will have one more unnecessary window triggered for hopping windows if no elements arrives for a key for a long time. We will skip to emit window result for the triggered empty window, see SliceSharedWindowAggProcessor.fireWindow(Long).

Specified by:

nextTriggerWindow in interface SliceSharedAssigner

Parameters:

windowEnd - the current triggered window, identified by end timestamp

isWindowEmpty - a supplier that can be invoked to get whether the triggered window is empty (i.e. no records in the window).