Functions

RuntimeContext

RuntimeContext.get_task_name()	Returns the name of the task in which the UDF runs, as assigned during plan construction.
RuntimeContext.get_number_of_parallel_subtasks()	Gets the parallelism with which the parallel task runs.
RuntimeContext.get_max_number_of_parallel_subtasks()	Gets the number of max-parallelism with which the parallel task runs.
RuntimeContext.get_index_of_this_subtask()	Gets the number of this parallel subtask.
RuntimeContext.get_attempt_number()	Gets the attempt number of this parallel subtask.
RuntimeContext.get_task_name_with_subtasks()	Returns the name of the task, appended with the subtask indicator, such as "MyTask (3/6)", where 3 would be (get_index_of_this_subtask() + 1), and 6 would be get_number_of_parallel_subtasks().
RuntimeContext.get_job_parameter(key, ...)	Gets the global job parameter value associated with the given key as a string.
RuntimeContext.get_metrics_group()	Gets the metric group.
RuntimeContext.get_state(state_descriptor)	Gets a handle to the system's key/value state.
RuntimeContext.get_list_state(state_descriptor)	Gets a handle to the system's key/value list state.
RuntimeContext.get_map_state(state_descriptor)	Gets a handle to the system's key/value map state.
RuntimeContext.get_reducing_state(...)	Gets a handle to the system's key/value reducing state.
RuntimeContext.get_aggregating_state(...)	Gets a handle to the system's key/value aggregating state.

Function

All user-defined functions.

MapFunction()	Base class for Map functions.
CoMapFunction()	A CoMapFunction implements a map() transformation over two connected streams.
FlatMapFunction()	Base class for flatMap functions.
CoFlatMapFunction()	A CoFlatMapFunction implements a flat-map transformation over two connected streams.
ReduceFunction()	Base interface for Reduce functions.
AggregateFunction()	The AggregateFunction is a flexible aggregation function, characterized by the following features:
ProcessFunction()	A function that process elements of a stream.
KeyedProcessFunction()	A keyed function processes elements of a stream.
CoProcessFunction()	A function that processes elements of two streams and produces a single output one.
KeyedCoProcessFunction()	A function that processes elements of two keyed streams and produces a single output one.
WindowFunction(*args, **kwds)	Base interface for functions that are evaluated over keyed (grouped) windows.
ProcessWindowFunction(*args, **kwds)	Base interface for functions that are evaluated over keyed (grouped) windows using a context for retrieving extra information.
KeySelector()	The KeySelector allows to use deterministic objects for operations such as reduce, reduceGroup, join coGroup, etc.
FilterFunction()	A filter function is a predicate applied individually to each record.
Partitioner()	Function to implement a custom partition assignment for keys.