Package org.apache.flink.table.types.inference

Interface CallContext

All Known Implementing Classes:

CastCallContext, UnknownCallContext

@PublicEvolving
public interface CallContext

Provides details about a function call during TypeInference.

Method Summary

Modifier and Type	Method	Description
default <T> Optional<T>	fail(boolean throwOnFailure, String message, Object... args)	Helper method for handling failures during the type inference process while considering the throwOnFailure flag.
List<DataType>	getArgumentDataTypes()	Returns a resolved list of the call's argument types.
<T> Optional<T>	getArgumentValue(int pos, Class<T> clazz)	Returns the literal value of the argument at the given position, given that the argument is a literal, is not null, and can be expressed as an instance of the provided class.
DataTypeFactory	getDataTypeFactory()	Enables to lookup types in a catalog and resolve RAW types.
FunctionDefinition	getFunctionDefinition()	Returns the function definition that defines the function currently being called.
String	getName()	Returns the function's name usually referencing the function in a catalog.
default Optional<ChangelogMode>	getOutputChangelogMode()	Returns the ChangelogMode that the framework requires from the function.
Optional<DataType>	getOutputDataType()	Returns the inferred output data type of the function call.
default Optional<TableSemantics>	getTableSemantics(int pos)	Returns information about the table that has been passed to a table argument.
boolean	isArgumentLiteral(int pos)	Returns whether the argument at the given position is a value literal.
boolean	isArgumentNull(int pos)	Returns true if the argument at the given position is a literal and null, false otherwise.
boolean	isGroupedAggregation()	Returns whether the function call happens as part of an aggregation that defines grouping columns.
default ValidationException	newValidationError(String message, Object... args)	Creates a validation exception for exiting the type inference process with a meaningful exception.

Method Detail

getDataTypeFactory

DataTypeFactory getDataTypeFactory()

Enables to lookup types in a catalog and resolve RAW types.

getFunctionDefinition

FunctionDefinition getFunctionDefinition()

Returns the function definition that defines the function currently being called.

isArgumentLiteral

boolean isArgumentLiteral(int pos)

Returns whether the argument at the given position is a value literal.

isArgumentNull

boolean isArgumentNull(int pos)

Returns true if the argument at the given position is a literal and null, false otherwise. If the argument is declared as optional and has no value, true is returned.

Use isArgumentLiteral(int) before to check if the argument is actually a literal.

getArgumentValue

<T> Optional<T> getArgumentValue(int pos,
                                 Class<T> clazz)

Returns the literal value of the argument at the given position, given that the argument is a literal, is not null, and can be expressed as an instance of the provided class.

It supports conversions to default conversion classes of LogicalTypes. This method should not be called with other classes.

Use isArgumentLiteral(int) before to check if the argument is actually a literal.

getTableSemantics

default Optional<TableSemantics> getTableSemantics(int pos)

Returns information about the table that has been passed to a table argument.

This method applies only to ProcessTableFunctions.

Semantics are only available for table arguments that are annotated with @ArgumentHint(SET_SEMANTIC_TABLE) or @ArgumentHint(ROW_SEMANTIC_TABLE)).

getOutputChangelogMode

default Optional<ChangelogMode> getOutputChangelogMode()

Returns the ChangelogMode that the framework requires from the function.

This method applies only to ProcessTableFunction.

Returns empty during type inference phase as the changelog mode is still unknown. Returns an actual changelog mode, when the PTF implements the ChangelogFunction interface.

getName

String getName()

Returns the function's name usually referencing the function in a catalog.

Note: The name is meant for debugging purposes only.

getArgumentDataTypes

List<DataType> getArgumentDataTypes()

Returns a resolved list of the call's argument types. It also includes a type for every argument in a vararg function call.

getOutputDataType

Optional<DataType> getOutputDataType()

Returns the inferred output data type of the function call.

It does this by inferring the input argument data type using ArgumentTypeStrategy.inferArgumentType(CallContext, int, boolean) of a wrapping call (if available) where this function call is an argument. For example, takes_string(this_function(NULL)) would lead to a DataTypes.STRING() because the wrapping call expects a string argument.

newValidationError

default ValidationException newValidationError(String message,
                                               Object... args)

Creates a validation exception for exiting the type inference process with a meaningful exception.

fail

default <T> Optional<T> fail(boolean throwOnFailure,
                             String message,
                             Object... args)

Helper method for handling failures during the type inference process while considering the throwOnFailure flag.

Shorthand for if (throwOnFailure) throw ValidationException(...) else return Optional.empty().

isGroupedAggregation

boolean isGroupedAggregation()

Returns whether the function call happens as part of an aggregation that defines grouping columns.

E.g. SELECT COUNT(*) FROM t is not a grouped aggregation but SELECT COUNT(*) FROM t GROUP BY k is.