Package org.apache.druid.math.expr

Class ApplyFunction.FoldFunction

java.lang.Object

org.apache.druid.math.expr.ApplyFunction.BaseFoldFunction

org.apache.druid.math.expr.ApplyFunction.FoldFunction

All Implemented Interfaces:

ApplyFunction, NamedFunction

Enclosing interface:

ApplyFunction

public static class ApplyFunction.FoldFunction
extends ApplyFunction.BaseFoldFunction

Accumulate a value for a single array input with a 2 argument LambdaExpr. The 'array' input expression is the first argument, the initial value for the accumulator expression is the 2nd argument.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.druid.math.expr.ApplyFunction

ApplyFunction.AllMatchFunction, ApplyFunction.AnyMatchFunction, ApplyFunction.BaseFoldFunction, ApplyFunction.BaseMapFunction, ApplyFunction.CartesianFoldFunction, ApplyFunction.CartesianFoldLambdaBinding, ApplyFunction.CartesianMapFunction, ApplyFunction.CartesianMapLambdaBinding, ApplyFunction.FilterFunction, ApplyFunction.FoldFunction, ApplyFunction.FoldLambdaBinding, ApplyFunction.IndexableFoldLambdaBinding, ApplyFunction.IndexableMapLambdaObjectBinding, ApplyFunction.LambdaInputBindingInspector, ApplyFunction.MapFunction, ApplyFunction.MapLambdaBinding, ApplyFunction.MatchFunction, ApplyFunction.SettableLambdaBinding

Constructor Summary

Constructors

Constructor	Description
FoldFunction()

Method Summary

Modifier and Type	Method	Description
ExprEval	apply(LambdaExpr lambdaExpr, List<Expr> argsExpr, Expr.ObjectBinding bindings)	Apply LambdaExpr to argument list of Expr given a set of outer Expr.ObjectBinding.
Set<Expr>	getArrayInputs(List<Expr> args)	Get list of input arguments which must evaluate to an array ExprType
String	name()	Name of the function
void	validateArguments(LambdaExpr lambdaExpr, List<Expr> args)	Validate function arguments.

Methods inherited from class org.apache.druid.math.expr.ApplyFunction.BaseFoldFunction

getOutputType, hasArrayOutput

Methods inherited from class java.lang.Object

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

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

asVectorProcessor, canVectorize

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

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

Constructor Details

FoldFunction

public FoldFunction()

Method Details

name

public String name()

Description copied from interface: NamedFunction

Name of the function

apply

public ExprEval apply(LambdaExpr lambdaExpr,
 List<Expr> argsExpr,
 Expr.ObjectBinding bindings)

Description copied from interface: ApplyFunction

Apply LambdaExpr to argument list of Expr given a set of outer Expr.ObjectBinding. These outer bindings will be used to form the scope for the bindings used to evaluate the LambdaExpr, which use the array inputs to supply scalar values to use as bindings for IdentifierExpr in the lambda body.

getArrayInputs

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

Description copied from interface: ApplyFunction

Get list of input arguments which must evaluate to an array ExprType

validateArguments

public void validateArguments(LambdaExpr lambdaExpr,
 List<Expr> args)

Description copied from interface: ApplyFunction

Validate function arguments. This method is called whenever a ApplyFunctionExpr 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.