@Internal public abstract class BuiltInSpecializedFunction extends Object implements SpecializedFunction
SpecializedFunction.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.
SpecializedFunction.ExpressionEvaluator, SpecializedFunction.ExpressionEvaluatorFactory, SpecializedFunction.SpecializedContext
Modifier | Constructor and Description |
---|---|
protected |
BuiltInSpecializedFunction(BuiltInFunctionDefinition definition) |
Modifier and Type | Method and 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.
|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
specialize
protected BuiltInSpecializedFunction(BuiltInFunctionDefinition definition)
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 Set<FunctionRequirement> getRequirements()
FunctionDefinition
getRequirements
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
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