pyflink.table.udf.AggregateFunction

class AggregateFunction(*args, **kwds)

Base interface for user-defined aggregate function. A user-defined aggregate function maps scalar values of multiple rows to a new scalar value.

New in version 1.12.0.

Methods

accumulate(accumulator, *args)	Processes the input values and updates the provided accumulator instance.
close()	Tear-down method for the user code.
create_accumulator()	Creates and initializes the accumulator for this AggregateFunction.
get_accumulator_type()	Returns the DataType of the AggregateFunction's accumulator.
get_result_type()	Returns the DataType of the AggregateFunction's result.
get_value(accumulator)	Called every time when an aggregation result should be materialized.
is_deterministic()	Returns information about the determinism of the function's results.
merge(accumulator, accumulators)	Merges a group of accumulator instances into one accumulator instance.
open(function_context)	Initialization method for the function.
retract(accumulator, *args)	Retracts the input values from the accumulator instance.The current design assumes the inputs are the values that have been previously accumulated.