Module com.darkcollective.relix.function

Package com.darkcollective.relix.function

Enum Class AggregateProperty

java.lang.Object

java.lang.Enum<AggregateProperty>

com.darkcollective.relix.function.AggregateProperty

All Implemented Interfaces:

Serializable, Comparable<AggregateProperty>, Constable

public enum AggregateProperty
extends Enum<AggregateProperty>

A contract an aggregate makes with the optimizer, in the way FunctionProperty does for scalar functions.

Each constant licenses a rewrite that would otherwise be unsound, so declaring one of an aggregate that does not honour it changes results rather than timings.

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Enum

Enum.EnumDesc<E extends Enum<E>>

Enum Constant Summary

Enum Constants

Enum Constant	Description
DUPLICATE_INSENSITIVE	Feeding the same value twice does not change the result, so a duplicate-removing step below the aggregate can be dropped: MIN and MAX do not care how many times they saw a value, while SUM, AVG, COUNT and COLLECT very much do.
ORDER_INSENSITIVE	The result does not depend on the order rows arrive in.

Method Summary

Modifier and Type	Method	Description
static AggregateProperty	valueOf(String name)	Returns the enum constant of this class with the specified name.
static AggregateProperty[]	values()	Returns an array containing the constants of this enum class, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, describeConstable, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Details

DUPLICATE_INSENSITIVE

public static final AggregateProperty DUPLICATE_INSENSITIVE

Feeding the same value twice does not change the result, so a duplicate-removing step below the aggregate can be dropped: MIN and MAX do not care how many times they saw a value, while SUM, AVG, COUNT and COLLECT very much do.

ORDER_INSENSITIVE

public static final AggregateProperty ORDER_INSENSITIVE

The result does not depend on the order rows arrive in. SUM qualifies; COLLECT, which gathers values into an array in row order, does not, and neither does an ARGMAX whose ties resolve to the first matching row.

Method Details

values

public static AggregateProperty[] values()

Returns an array containing the constants of this enum class, in the order they are declared.

Returns:

an array containing the constants of this enum class, in the order they are declared

valueOf

public static AggregateProperty valueOf(String name)

Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum class has no constant with the specified name

NullPointerException - if the argument is null