org.apache.calcite.config

Enum NullCollation

java.lang.Object

java.lang.Enum<NullCollation>

org.apache.calcite.config.NullCollation

All Implemented Interfaces:

Serializable, Comparable<NullCollation>

public enum NullCollation
extends Enum<NullCollation>

Strategy for how NULL values are to be sorted if NULLS FIRST or NULLS LAST are not specified in an item in the ORDER BY clause.

Enum Constant Summary

Enum Constants

Enum Constant and Description
FIRST Nulls first for DESC and ASC.
HIGH Nulls first for DESC, nulls last for ASC.
LAST Nulls last for DESC and ASC.
LOW Nulls last for DESC, nulls first for ASC.

Method Summary

Modifier and Type	Method and Description
boolean	isDefaultOrder(boolean nullsFirst, boolean desc) Returns whether a given combination of null direction and sort order is the default order of nulls returned in the ORDER BY clause.
boolean	last(boolean desc) Returns whether NULL values should appear last.
static NullCollation	valueOf(String name) Returns the enum constant of this type with the specified name.
static NullCollation[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

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

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

HIGH

public static final NullCollation HIGH

Nulls first for DESC, nulls last for ASC.

LOW

public static final NullCollation LOW

Nulls last for DESC, nulls first for ASC.

FIRST

public static final NullCollation FIRST

Nulls first for DESC and ASC.

LAST

public static final NullCollation LAST

Nulls last for DESC and ASC.

Method Detail

values

public static NullCollation[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (NullCollation c : NullCollation.values())
    System.out.println(c);

Returns:

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

valueOf

public static NullCollation valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (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 type has no constant with the specified name

NullPointerException - if the argument is null

last

public boolean last(boolean desc)

Returns whether NULL values should appear last.

Parameters:

desc - Whether sort is descending

isDefaultOrder

public boolean isDefaultOrder(boolean nullsFirst,
                              boolean desc)

Returns whether a given combination of null direction and sort order is the default order of nulls returned in the ORDER BY clause.