Package org.apache.flink.table.runtime.operators.window.tvf.unslicing

Interface UnsliceAssigner<W extends Window>

All Superinterfaces:

Serializable, WindowAssigner

All Known Implementing Classes:

UnsliceAssigners.SessionUnsliceAssigner, UnsliceAssigners.WindowedUnsliceAssigner

@Internal
public interface UnsliceAssigner<W extends Window>
extends WindowAssigner

A UnsliceAssigner assigns each element into a single window and not divides the window into finite number of non-overlapping slice. Different with SliceAssigner, we use the Window to identifier a window.

UnsliceAssigner is designed for unaligned Windows like session window.

Because unaligned Windows are windows determined dynamically based on elements, and its window boundaries are determined based on the messages timestamps and their correlations, some windows may be merged into one.

See Also:

for more definition of unslice window.

Method Summary

Modifier and Type	Method	Description
Optional<W>	assignActualWindow(org.apache.flink.table.data.RowData element, ClockService clock, MergingWindowProcessFunction<?,W> windowFunction)	Returns the Window that the given element should belong to be used to trigger on.
Optional<W>	assignStateNamespace(org.apache.flink.table.data.RowData element, ClockService clock, MergingWindowProcessFunction<?,W> windowFunction)	Returns the Window that the given element should belong to be used as a namespace to restore the state.
MergingWindowAssigner<W>	getMergingWindowAssigner()	Currently, unslice assigner has an inner MergingWindowAssigner to reuse the logic in GroupWindowAssigner to merge windows.

Methods inherited from interface org.apache.flink.table.runtime.operators.window.tvf.common.WindowAssigner

getDescription, isEventTime

Method Detail

assignActualWindow

Optional<W> assignActualWindow(org.apache.flink.table.data.RowData element,
                               ClockService clock,
                               MergingWindowProcessFunction<?,W> windowFunction)
                        throws Exception

Returns the Window that the given element should belong to be used to trigger on.

See more details in MergingWindowProcessFunction.assignActualWindows(org.apache.flink.table.data.RowData, long).

Parameters:

element - the element to which slice should belong to.

clock - the service to get current processing time.

Returns:

if empty, that means the element is late.

Throws:

Exception

assignStateNamespace

Optional<W> assignStateNamespace(org.apache.flink.table.data.RowData element,
                                 ClockService clock,
                                 MergingWindowProcessFunction<?,W> windowFunction)
                          throws Exception

Returns the Window that the given element should belong to be used as a namespace to restore the state.

See more details in MergingWindowProcessFunction.assignStateNamespace(org.apache.flink.table.data.RowData, long).

Parameters:

element - the element to which slice should belong to.

clock - the service to get current processing time.

Returns:

if empty, that means the element is late.

Throws:

Exception

getMergingWindowAssigner

MergingWindowAssigner<W> getMergingWindowAssigner()

Currently, unslice assigner has an inner MergingWindowAssigner to reuse the logic in GroupWindowAssigner to merge windows.