Package org.apache.flink.table.runtime.functions

Class BuiltInSpecializedFunction

java.lang.Object

org.apache.flink.table.runtime.functions.BuiltInSpecializedFunction

All Implemented Interfaces:

FunctionDefinition, SpecializedFunction

Direct Known Subclasses:

UnnestRowsFunction

@Internal
public abstract class BuiltInSpecializedFunction
extends Object
implements SpecializedFunction

Base class for built-in functions that need another level of specialization via BuiltInFunctionDefinition.specialize(SpecializedContext).

Subclasses can create a specific UDF runtime implementation targeted to the given (fully known) arguments and derived output type. Subclasses must provide a default constructor.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.flink.table.functions.SpecializedFunction

SpecializedFunction.ExpressionEvaluator, SpecializedFunction.ExpressionEvaluatorFactory, SpecializedFunction.SpecializedContext

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	BuiltInSpecializedFunction(BuiltInFunctionDefinition definition)

Method Summary

Modifier and Type	Method	Description
FunctionKind	getKind()	Returns the kind of function this definition describes.
Set<FunctionRequirement>	getRequirements()	Returns the set of requirements this definition demands.
TypeInference	getTypeInference(DataTypeFactory typeFactory)	Returns the logic for performing type inference of a call to this function definition.
boolean	isDeterministic()	Returns information about the determinism of the function's results.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.flink.table.functions.FunctionDefinition

supportsConstantFolding

Methods inherited from interface org.apache.flink.table.functions.SpecializedFunction

specialize

Constructor Detail

BuiltInSpecializedFunction

protected BuiltInSpecializedFunction(BuiltInFunctionDefinition definition)

Method Detail

getKind

public FunctionKind getKind()

Description copied from interface: FunctionDefinition

Returns the kind of function this definition describes.

Specified by:

getKind in interface FunctionDefinition

getTypeInference

public TypeInference getTypeInference(DataTypeFactory typeFactory)

Description copied from interface: FunctionDefinition

Returns the logic for performing type inference of a call to this function definition.

The type inference process is responsible for inferring unknown types of input arguments, validating input arguments, and producing result types. The type inference process happens independent of a function body. The output of the type inference is used to search for a corresponding runtime implementation.

Instances of type inference can be created by using TypeInference.newBuilder().

See BuiltInFunctionDefinitions for concrete usage examples.

Specified by:

getTypeInference in interface FunctionDefinition

getRequirements

public Set<FunctionRequirement> getRequirements()

Description copied from interface: FunctionDefinition

Returns the set of requirements this definition demands.

Specified by:

getRequirements in interface FunctionDefinition

isDeterministic

public boolean isDeterministic()

Description copied from interface: FunctionDefinition

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 purely functional like random(), date(), now(), ... this method must return false.

Furthermore, return false if the planner should always execute this function on the cluster side. In other words: the planner should not perform constant expression reduction during planning for constant calls to this function.

Specified by:

isDeterministic in interface FunctionDefinition