@Internal public final class BuiltInFunctionDefinition extends Object implements SpecializedFunction
Compared to regular FunctionDefinition
, built-in functions have a default name. This
default name is used to look up the function in a catalog during resolution. However, note that
every built-in function is actually fully qualified by a name and a version. Internal functions
are required to have a name that includes the version (e.g. $REPLICATE_ROWS$1
). The most
recent version of a regular function is picked during a lookup if a call does not reference an
internal function.
Equality is defined by reference equality.
Modifier and Type | Class and Description |
---|---|
static class |
BuiltInFunctionDefinition.Builder
Builder for fluent definition of built-in functions.
|
SpecializedFunction.ExpressionEvaluator, SpecializedFunction.ExpressionEvaluatorFactory, SpecializedFunction.SpecializedContext
Modifier and Type | Field and Description |
---|---|
static int |
DEFAULT_VERSION |
Modifier and Type | Method and Description |
---|---|
FunctionKind |
getKind()
Returns the kind of function this definition describes.
|
String |
getName() |
String |
getQualifiedName() |
Optional<String> |
getRuntimeClass() |
TypeInference |
getTypeInference(DataTypeFactory typeFactory)
Returns the logic for performing type inference of a call to this function definition.
|
Optional<Integer> |
getVersion() |
boolean |
hasRuntimeImplementation() |
boolean |
isDeterministic()
Returns information about the determinism of the function's results.
|
boolean |
isInternal() |
static BuiltInFunctionDefinition.Builder |
newBuilder()
Builder for configuring and creating instances of
BuiltInFunctionDefinition . |
static String |
qualifyFunctionName(String name,
int version) |
UserDefinedFunction |
specialize(SpecializedFunction.SpecializedContext context)
Provides a runtime implementation that is specialized for the given call and session.
|
String |
toString() |
static void |
validateFunction(String name,
Integer version,
boolean isInternal) |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
getRequirements
public static final int DEFAULT_VERSION
public static BuiltInFunctionDefinition.Builder newBuilder()
BuiltInFunctionDefinition
.public String getName()
public boolean hasRuntimeImplementation()
public boolean isInternal()
public String getQualifiedName()
public UserDefinedFunction specialize(SpecializedFunction.SpecializedContext context)
SpecializedFunction
The method must return an instance of UserDefinedFunction
or throw a TableException
if the given call is not supported. The returned instance must have the same
FunctionDefinition
semantics but can have a different FunctionDefinition.getTypeInference(DataTypeFactory)
implementation.
specialize
in interface SpecializedFunction
public FunctionKind getKind()
FunctionDefinition
getKind
in interface FunctionDefinition
public TypeInference getTypeInference(DataTypeFactory typeFactory)
FunctionDefinition
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.
getTypeInference
in interface FunctionDefinition
public boolean isDeterministic()
FunctionDefinition
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.
isDeterministic
in interface FunctionDefinition
public static void validateFunction(String name, @Nullable Integer version, boolean isInternal)
Copyright © 2014–2024 The Apache Software Foundation. All rights reserved.