Package org.apache.druid.math.expr

Class ExpressionTypeConversion

java.lang.Object

org.apache.druid.math.expr.ExpressionTypeConversion

public class ExpressionTypeConversion
extends Object

Method Summary

Modifier and Type	Method	Description
static ExpressionType	autoDetect(ExprEval eval, ExprEval otherEval)	Given 2 'input' types, which might not be fully trustable, choose the most appropriate combined type for non-vectorized, per-row type detection.
static ExpressionType	conditional(Expr.InputBindingInspector inspector, List<Expr> args)	Infer the output type of a list of possible 'conditional' expression outputs (where any of these could be the output expression if the corresponding case matching expression evaluates to true)
static ExpressionType	function(ExpressionType type, ExpressionType other)	Given 2 'input' types, choose the most appropriate combined type, if possible arrays must be the same type if either type is ExprType.STRING, the output type will be preserved as string if both types are ExprType.LONG, the output type will be preserved as long, otherwise ExprType.DOUBLE
static ExpressionType	integerMathFunction(ExpressionType type, ExpressionType other)	Given 2 'input' types, choose the most appropriate combined type, if possible arrays must be the same type if either type is ExprType.STRING, the output type will be preserved as string any number will be coerced to ExprType.LONG
static ExpressionType	leastRestrictiveType(ExpressionType type, ExpressionType other)	ColumnType.leastRestrictiveType(ColumnType, ColumnType) but for expression types
static ExpressionType	numeric(ExpressionType type, ExpressionType other)	Default best effort numeric type conversion.
static ExpressionType	operator(ExpressionType type, ExpressionType other)	Given 2 'input' types, choose the most appropriate combined type, if possible arrays must be the same type if both types are ExprType.STRING, the output type will be preserved as string if both types are ExprType.LONG, the output type will be preserved as long otherwise, output is ExprType.DOUBLE

Methods inherited from class java.lang.Object

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

Method Details

conditional

public static ExpressionType conditional(Expr.InputBindingInspector inspector,
 List<Expr> args)

Infer the output type of a list of possible 'conditional' expression outputs (where any of these could be the output expression if the corresponding case matching expression evaluates to true)

autoDetect

public static ExpressionType autoDetect(ExprEval eval,
 ExprEval otherEval)

Given 2 'input' types, which might not be fully trustable, choose the most appropriate combined type for non-vectorized, per-row type detection. In this mode, null values are ExprType.STRING typed, despite potentially coming from an underlying numeric column, or when an underlying column was completely missing and so all values are null. This method is not well suited for array handling.

operator

@Nullable
public static ExpressionType operator(@Nullable
 ExpressionType type,
 @Nullable
 ExpressionType other)

Given 2 'input' types, choose the most appropriate combined type, if possible arrays must be the same type if both types are ExprType.STRING, the output type will be preserved as string if both types are ExprType.LONG, the output type will be preserved as long otherwise, output is ExprType.DOUBLE

function

@Nullable
public static ExpressionType function(@Nullable
 ExpressionType type,
 @Nullable
 ExpressionType other)

Given 2 'input' types, choose the most appropriate combined type, if possible arrays must be the same type if either type is ExprType.STRING, the output type will be preserved as string if both types are ExprType.LONG, the output type will be preserved as long, otherwise ExprType.DOUBLE

leastRestrictiveType

@Nullable
public static ExpressionType leastRestrictiveType(@Nullable
 ExpressionType type,
 @Nullable
 ExpressionType other)
                                           throws Types.IncompatibleTypeException

ColumnType.leastRestrictiveType(ColumnType, ColumnType) but for expression types

Throws:

Types.IncompatibleTypeException

integerMathFunction

@Nullable
public static ExpressionType integerMathFunction(@Nullable
 ExpressionType type,
 @Nullable
 ExpressionType other)

Given 2 'input' types, choose the most appropriate combined type, if possible arrays must be the same type if either type is ExprType.STRING, the output type will be preserved as string any number will be coerced to ExprType.LONG

numeric

public static ExpressionType numeric(@Nullable
 ExpressionType type,
 @Nullable
 ExpressionType other)

Default best effort numeric type conversion. If both types are ExprType.LONG, returns ExprType.LONG, else ExprType.DOUBLE