Package org.apache.druid.math.expr

Interface Function

All Superinterfaces:

NamedFunction

All Known Implementing Classes:

Function.Abs, Function.Acos, Function.ArrayAddElementFunction, Function.ArrayAppendFunction, Function.ArrayConcatFunction, Function.ArrayConstructorFunction, Function.ArrayContainsFunction, Function.ArrayLengthFunction, Function.ArrayOffsetFunction, Function.ArrayOffsetOfFunction, Function.ArrayOrdinalFunction, Function.ArrayOrdinalOfFunction, Function.ArrayOverlapFunction, Function.ArrayPrependFunction, Function.ArrayScalarFunction, Function.ArraySetAddAllFunction, Function.ArraySetAddFunction, Function.ArraysFunction, Function.ArraySliceFunction, Function.ArraysMergeFunction, Function.ArrayToMultiValueStringFunction, Function.ArrayToStringFunction, Function.Asin, Function.Atan, Function.Atan2, Function.BitwiseAnd, Function.BitwiseComplement, Function.BitwiseConvertDoubleToLongBits, Function.BitwiseConvertLongBitsToDouble, Function.BitwiseOr, Function.BitwiseShiftLeft, Function.BitwiseShiftRight, Function.BitwiseXor, Function.BivariateBitwiseMathFunction, Function.BivariateFunction, Function.BivariateMathFunction, Function.CaseSearchedFunc, Function.CaseSimpleFunc, Function.CastFunc, Function.Cbrt, Function.Ceil, Function.CoalesceFunc, Function.ConcatFunc, Function.ConditionFunc, Function.CopySign, Function.Cos, Function.Cosh, Function.Cot, Function.Div, Function.DoubleBivariateMathFunction, Function.DoubleUnivariateMathFunction, Function.Exp, Function.Expm1, Function.Floor, Function.GetExponent, Function.GreatestFunc, Function.HumanReadableBinaryByteFormatFunc, Function.HumanReadableDecimalByteFormatFunc, Function.HumanReadableDecimalFormatFunc, Function.Hypot, Function.IsDistinctFromFunc, Function.IsFalseFunc, Function.IsNotDistinctFromFunc, Function.IsNotFalseFunc, Function.IsNotNullFunc, Function.IsNotTrueFunc, Function.IsNullFunc, Function.IsTrueFunc, Function.LeastFunc, Function.LeftFunc, Function.Log, Function.Log10, Function.Log1p, Function.LowerFunc, Function.LpadFunc, Function.Max, Function.Min, Function.MultiValueStringHarmonizeNullsFunction, Function.MultiValueStringToArrayFunction, Function.MvContainsFunction, Function.MvOverlapFunction, Function.NextAfter, Function.NextUp, Function.NvlFunc, Function.ParseLong, Function.Pi, Function.Pow, Function.ReduceFunction, Function.Remainder, Function.RepeatFunc, Function.ReplaceFunc, Function.ReverseFunc, Function.RightFunc, Function.Rint, Function.Round, Function.RpadFunc, Function.SafeDivide, Function.ScalarInArrayFunction, Function.Scalb, Function.Signum, Function.Sin, Function.Sinh, Function.SizeFormatFunc, Function.Sqrt, Function.StringFormatFunc, Function.StringLongFunction, Function.StringToArrayFunction, Function.StrlenFunc, Function.StrposFunc, Function.SubMonthFunc, Function.SubstringFunc, Function.Tan, Function.Tanh, Function.TimestampFromEpochFunc, Function.ToDegrees, Function.ToRadians, Function.Ulp, Function.UnivariateFunction, Function.UnivariateMathFunction, Function.UnixTimestampFunc, Function.UpperFunc

public interface Function
extends NamedFunction

Base interface describing the mechanism used to evaluate a FunctionExpr. All Function implementations are immutable. Do NOT remove "unused" members in this class. They are used by generated Antlr

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	Function.Abs
static class	Function.Acos
static class	Function.ArrayAddElementFunction	Scaffolding for a 2 argument Function which accepts one array and one scalar input and adds the scalar input to the array in some way.
static class	Function.ArrayAppendFunction
static class	Function.ArrayConcatFunction
static class	Function.ArrayConstructorFunction
static class	Function.ArrayContainsFunction
static class	Function.ArrayLengthFunction
static class	Function.ArrayOffsetFunction
static class	Function.ArrayOffsetOfFunction
static class	Function.ArrayOrdinalFunction
static class	Function.ArrayOrdinalOfFunction
static class	Function.ArrayOverlapFunction
static class	Function.ArrayPrependFunction
static class	Function.ArrayScalarFunction	Function that takes 1 array operand and 1 scalar operand
static class	Function.ArraySetAddAllFunction
static class	Function.ArraySetAddFunction
static class	Function.ArraysFunction	Function that takes 2 array operands
static class	Function.ArraySliceFunction
static class	Function.ArraysMergeFunction	Base scaffolding for functions which accept 2 array arguments and combine them in some way
static class	Function.ArrayToMultiValueStringFunction
static class	Function.ArrayToStringFunction
static class	Function.Asin
static class	Function.Atan
static class	Function.Atan2
static class	Function.BitwiseAnd
static class	Function.BitwiseComplement
static class	Function.BitwiseConvertDoubleToLongBits
static class	Function.BitwiseConvertLongBitsToDouble
static class	Function.BitwiseOr
static class	Function.BitwiseShiftLeft
static class	Function.BitwiseShiftRight
static class	Function.BitwiseXor
static class	Function.BivariateBitwiseMathFunction
static class	Function.BivariateFunction	Base class for a 2 variable input Function implementation
static class	Function.BivariateMathFunction	Base class for a 2 variable input mathematical Function, with specialized 'eval' implementations that operate on primitive number types
static class	Function.CaseSearchedFunc	"Searched CASE" function, similar to CASE WHEN boolean_expr THEN result [ELSE else_result] END in SQL.
static class	Function.CaseSimpleFunc	"Simple CASE" function, similar to CASE expr WHEN value THEN result [ELSE else_result] END in SQL.
static class	Function.CastFunc
static class	Function.Cbrt
static class	Function.Ceil
static class	Function.CoalesceFunc
static class	Function.ConcatFunc
static class	Function.ConditionFunc
static class	Function.CopySign
static class	Function.Cos
static class	Function.Cosh
static class	Function.Cot
static class	Function.Div
static class	Function.DoubleBivariateMathFunction	Many math functions always output a Double primitive, regardless of input type.
static class	Function.DoubleUnivariateMathFunction	Many math functions always output a Double primitive, regardless of input type.
static class	Function.Exp
static class	Function.Expm1
static class	Function.Floor
static class	Function.GetExponent
static class	Function.GreatestFunc
static class	Function.HumanReadableBinaryByteFormatFunc
static class	Function.HumanReadableDecimalByteFormatFunc
static class	Function.HumanReadableDecimalFormatFunc
static class	Function.Hypot
static class	Function.IsDistinctFromFunc	SQL function "x IS DISTINCT FROM y".
static class	Function.IsFalseFunc	SQL function "IS FALSE".
static class	Function.IsNotDistinctFromFunc	SQL function "x IS NOT DISTINCT FROM y".
static class	Function.IsNotFalseFunc	SQL function "IS NOT FALSE".
static class	Function.IsNotNullFunc
static class	Function.IsNotTrueFunc	SQL function "IS NOT TRUE".
static class	Function.IsNullFunc
static class	Function.IsTrueFunc	SQL function "IS TRUE".
static class	Function.LeastFunc
static class	Function.LeftFunc
static class	Function.Log
static class	Function.Log10
static class	Function.Log1p
static class	Function.LowerFunc
static class	Function.LpadFunc
static class	Function.Max
static class	Function.Min
static class	Function.MultiValueStringHarmonizeNullsFunction	Primarily internal helper function used to coerce null, [], and [null] into [null], similar to the logic done by ExpressionSelectors.supplierFromDimensionSelector(org.apache.druid.segment.DimensionSelector, boolean, boolean) when the 3rd argument is true, which is done when implicitly mapping scalar functions over mvd values.
static class	Function.MultiValueStringToArrayFunction
static class	Function.MvContainsFunction
static class	Function.MvOverlapFunction
static class	Function.NextAfter
static class	Function.NextUp
static class	Function.NvlFunc	nvl is like coalesce, but accepts exactly two arguments.
static class	Function.ParseLong
static class	Function.Pi
static class	Function.Pow
static class	Function.ReduceFunction
static class	Function.Remainder
static class	Function.RepeatFunc
static class	Function.ReplaceFunc
static class	Function.ReverseFunc
static class	Function.RightFunc
static class	Function.Rint
static class	Function.Round
static class	Function.RpadFunc
static class	Function.SafeDivide
static class	Function.ScalarInArrayFunction
static class	Function.Scalb
static class	Function.Signum
static class	Function.Sin
static class	Function.Sinh
static class	Function.SizeFormatFunc
static class	Function.Sqrt
static class	Function.StringFormatFunc
static class	Function.StringLongFunction	Base class for a 2 variable input Function whose first argument is a ExprType.STRING and second argument is ExprType.LONG.
static class	Function.StringToArrayFunction
static class	Function.StrlenFunc
static class	Function.StrposFunc
static class	Function.SubMonthFunc
static class	Function.SubstringFunc
static class	Function.Tan
static class	Function.Tanh
static class	Function.TimestampFromEpochFunc
static class	Function.ToDegrees
static class	Function.ToRadians
static class	Function.Ulp
static class	Function.UnivariateFunction	Base class for a single variable input Function implementation
static class	Function.UnivariateMathFunction	Base class for a single variable input mathematical Function, with specialized 'eval' implementations that that operate on primitive number types
static class	Function.UnixTimestampFunc
static class	Function.UpperFunc

Method Summary

Modifier and Type	Method	Description
ExprEval	apply(List<Expr> args, Expr.ObjectBinding bindings)	Evaluate the function, given a list of arguments and a set of bindings to provide values for IdentifierExpr.
default BitmapColumnIndex	asBitmapColumnIndex(ColumnIndexSelector selector, List<Expr> args)	Allows a Function to be computed into a BitmapColumnIndex.
default ColumnIndexSupplier	asColumnIndexSupplier(ColumnIndexSelector selector, ColumnType outputType, List<Expr> args)	Allows a Function to provide an ColumnIndexSupplier given access to the underlying ColumnIndexSupplier and ColumnHolder of the base table.
default Function	asSingleThreaded(List<Expr> args, Expr.InputBindingInspector inspector)	Possibly convert a Function into an optimized, possibly not thread-safe Function.
default <T> ExprVectorProcessor<T>	asVectorProcessor(Expr.VectorInputBindingInspector inspector, List<Expr> args)	Builds a 'vectorized' function expression processor, that can build vectorized processors for its input values using Expr.asVectorProcessor(org.apache.druid.math.expr.Expr.VectorInputBindingInspector), for use in vectorized query engines.
default boolean	canVectorize(Expr.InputBindingInspector inspector, List<Expr> args)	Check if a function can be 'vectorized', for a given set of Expr inputs.
default Set<Expr>	getArrayInputs(List<Expr> args)	Given a list of arguments to this Function, get the set of arguments that must evaluate to an array value
ExpressionType	getOutputType(Expr.InputBindingInspector inspector, List<Expr> args)	Compute the output type of this function for a given set of argument expression inputs.
default Set<Expr>	getScalarInputs(List<Expr> args)	Given a list of arguments to this Function, get the set of arguments that must evaluate to a scalar value
default boolean	hasArrayInputs()	Returns true if a function expects any array arguments
default boolean	hasArrayOutput()	Returns true if function produces an array.
void	validateArguments(List<Expr> args)	Validate function arguments.

Methods inherited from interface org.apache.druid.math.expr.NamedFunction

name, processingFailed, processingFailed, validationFailed, validationFailed, validationHelperCheckAnyOfArgumentCount, validationHelperCheckArgIsLiteral, validationHelperCheckArgumentCount, validationHelperCheckArgumentCount, validationHelperCheckArgumentRange, validationHelperCheckLambaArgumentCount, validationHelperCheckMinArgumentCount, validationHelperCheckMinArgumentCount

Method Details

asSingleThreaded

default Function asSingleThreaded(List<Expr> args,
 Expr.InputBindingInspector inspector)

Possibly convert a Function into an optimized, possibly not thread-safe Function.

apply

ExprEval apply(List<Expr> args,
 Expr.ObjectBinding bindings)

Evaluate the function, given a list of arguments and a set of bindings to provide values for IdentifierExpr.

getScalarInputs

default Set<Expr> getScalarInputs(List<Expr> args)

Given a list of arguments to this Function, get the set of arguments that must evaluate to a scalar value

getArrayInputs

default Set<Expr> getArrayInputs(List<Expr> args)

Given a list of arguments to this Function, get the set of arguments that must evaluate to an array value

hasArrayInputs

default boolean hasArrayInputs()

Returns true if a function expects any array arguments

hasArrayOutput

default boolean hasArrayOutput()

Returns true if function produces an array. All Function implementations are expected to exclusively produce either scalar or array values.

validateArguments

void validateArguments(List<Expr> args)

Validate function arguments. This method is called whenever a FunctionExpr is created, and should validate everything that is feasible up front. Note that input type information is typically unavailable at the time Expr are parsed, and so this method is incapable of performing complete validation.

getOutputType

@Nullable
ExpressionType getOutputType(Expr.InputBindingInspector inspector,
 List<Expr> args)

Compute the output type of this function for a given set of argument expression inputs.

See Also:

• Expr.getOutputType(org.apache.druid.math.expr.Expr.InputBindingInspector)

canVectorize

default boolean canVectorize(Expr.InputBindingInspector inspector,
 List<Expr> args)

Check if a function can be 'vectorized', for a given set of Expr inputs. If this method returns true, asVectorProcessor(org.apache.druid.math.expr.Expr.VectorInputBindingInspector, java.util.List<org.apache.druid.math.expr.Expr>) is expected to produce a ExprVectorProcessor which can evaluate values in batches to use with vectorized query engines.

See Also:

• Expr.canVectorize(Expr.InputBindingInspector)
• ApplyFunction.canVectorize(Expr.InputBindingInspector, LambdaExpr, List)

asVectorProcessor

default <T> ExprVectorProcessor<T> asVectorProcessor(Expr.VectorInputBindingInspector inspector,
 List<Expr> args)

Builds a 'vectorized' function expression processor, that can build vectorized processors for its input values using Expr.asVectorProcessor(org.apache.druid.math.expr.Expr.VectorInputBindingInspector), for use in vectorized query engines.

See Also:

• Expr.asVectorProcessor(Expr.VectorInputBindingInspector)
• ApplyFunction.asVectorProcessor(Expr.VectorInputBindingInspector, LambdaExpr, List)

asColumnIndexSupplier

@Nullable
default ColumnIndexSupplier asColumnIndexSupplier(ColumnIndexSelector selector,
 @Nullable
 ColumnType outputType,
 List<Expr> args)

Allows a Function to provide an ColumnIndexSupplier given access to the underlying ColumnIndexSupplier and ColumnHolder of the base table. Unlike the contracts of other index supplier methods, a null return value for this method is not indicative of anything other than the Function implementation having no specialized index supplier implementation, and so callers can fall back to generic handling as appropriate.

See Also:

• Expr.asColumnIndexSupplier(ColumnIndexSelector, ColumnType)

asBitmapColumnIndex

@Nullable
default BitmapColumnIndex asBitmapColumnIndex(ColumnIndexSelector selector,
 List<Expr> args)

Allows a Function to be computed into a BitmapColumnIndex. The supplied ColumnIndexSelector provides access to underlying ColumnIndexSupplier and even ColumnHolder. Coupled with asColumnIndexSupplier(ColumnIndexSelector, ColumnType, List<Expr>), which allows Function to provide indexes of their own, it allows for a system of composing indexes on top of any base column structures. Unlike Expr.asBitmapColumnIndex(ColumnIndexSelector), a null return value of this method is not indicative of anything other than the Function implementation not having a specialized way to compute into a BitmapColumnIndex, and so callers can fall back to generic handling as appropriate.

See Also:

• Expr.asBitmapColumnIndex(ColumnIndexSelector)