org.apache.flink.table.types.inference

Interface ArgumentTypeStrategy

All Known Implementing Classes:

AndArgumentTypeStrategy, AnyArgumentTypeStrategy, ExplicitArgumentTypeStrategy, LiteralArgumentTypeStrategy, OrArgumentTypeStrategy, OutputArgumentTypeStrategy

@PublicEvolving
public interface ArgumentTypeStrategy

Strategy for inferring and validating a single input argument type of a function call.

Method Summary

Modifier and Type	Method and Description
Signature.Argument	getExpectedArgument(FunctionDefinition functionDefinition, int argumentPos) Returns a summary of the function's expected argument at argumentPos.
Optional<DataType>	inferArgumentType(CallContext callContext, int argumentPos, boolean throwOnFailure) Main logic for inferring and validating an argument.

Method Detail

inferArgumentType

Optional<DataType> inferArgumentType(CallContext callContext,
                                     int argumentPos,
                                     boolean throwOnFailure)

Main logic for inferring and validating an argument. Returns the data type that is valid for the given call. If the returned type differs from CallContext.getArgumentDataTypes() at argumentPos, a casting operation can be inserted. An empty result means that the given input type could not be inferred.

Parameters:

callContext - provides details about the function call

argumentPos - argument index in the CallContext

throwOnFailure - whether this function is allowed to throw an ValidationException with a meaningful exception in case the inference is not successful or if this function should simply return an empty result.

Returns:

three-state result for either "true, same data type as argument", "true, but argument must be casted to returned data type", or "false, no inferred data type could be found"

See Also:

CallContext.newValidationError(String, Object...)

getExpectedArgument

Signature.Argument getExpectedArgument(FunctionDefinition functionDefinition,
                                       int argumentPos)

Returns a summary of the function's expected argument at argumentPos.

Parameters:

functionDefinition - the function definition that defines the function currently being called.

argumentPos - the position within the function call for which the signature should be retrieved