org.apache.flink.table.functions

Interface FunctionDefinition

All Known Implementing Classes:

AggregateFunction, AggregateFunctionDefinition, AsyncTableFunction, BuiltInFunctionDefinition, ScalarFunction, ScalarFunctionDefinition, TableAggregateFunction, TableAggregateFunctionDefinition, TableFunction, TableFunctionDefinition, TemporalTableFunction, UserDefinedAggregateFunction, UserDefinedFunction

@PublicEvolving
public interface FunctionDefinition

Definition of a function. Instances of this class provide all details necessary to validate a function call and perform planning.

A pure function definition must not contain a runtime implementation. This can be provided by the planner at later stages.

See Also:

UserDefinedFunction

Method Summary

Modifier and Type	Method and Description
FunctionKind	getKind() Returns the kind of function this definition describes.
default Set<FunctionRequirement>	getRequirements() Returns the set of requirements this definition demands.
default boolean	isDeterministic() Returns information about the determinism of the function's results.

Method Detail

getKind

FunctionKind getKind()

Returns the kind of function this definition describes.

getRequirements

default Set<FunctionRequirement> getRequirements()

Returns the set of requirements this definition demands.

isDeterministic

default boolean isDeterministic()

Returns information about the determinism of the function's results.

It returns true if and only if a call to this function is guaranteed to always return the same result given the same parameters. true is assumed by default. If the function is not pure functional like random(), date(), now(), ... this method must return false.