org.apache.calcite.rel

Class RelCollations

java.lang.Object

org.apache.calcite.rel.RelCollations

public class RelCollations
extends Object

Utilities concerning RelCollation and RelFieldCollation.

Field Summary

Fields

Modifier and Type	Field and Description
static RelCollation	EMPTY A collation indicating that a relation is not sorted.
static RelCollation	PRESERVE A collation that cannot be replicated by applying a sort.

Method Summary

Methods

Modifier and Type	Method and Description
static boolean	contains(List<RelCollation> collations, ImmutableIntList keys) Returns whether one of a list of collations indicates that the collection is sorted on the given list of keys.
static boolean	contains(RelCollation collation, Iterable<Integer> keys) Returns whether a collation indicates that the collection is sorted on a given list of keys.
static List<RelCollation>	createSingleton(int fieldIndex) Creates a list containing one collation containing one field.
static boolean	equal(List<RelCollation> collationList1, List<RelCollation> collationList2)
static boolean	isValid(RelDataType rowType, List<RelCollation> collationList, boolean fail) Checks that a collection of collations is valid.
static RelCollation	of(List<RelFieldCollation> fieldCollations)
static RelCollation	of(RelFieldCollation... fieldCollations)
static List<Integer>	ordinals(RelCollation collation) Returns the indexes of the field collations in a given collation.
static RelCollation	shift(RelCollation collation, int offset)

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY

public static final RelCollation EMPTY

A collation indicating that a relation is not sorted. Ordering by no columns.

PRESERVE

public static final RelCollation PRESERVE

A collation that cannot be replicated by applying a sort. The only implementation choice is to apply operations that preserve order.

Method Detail

of

public static RelCollation of(RelFieldCollation... fieldCollations)

of

public static RelCollation of(List<RelFieldCollation> fieldCollations)

createSingleton

public static List<RelCollation> createSingleton(int fieldIndex)

Creates a list containing one collation containing one field.

isValid

public static boolean isValid(RelDataType rowType,
              List<RelCollation> collationList,
              boolean fail)

Checks that a collection of collations is valid.

Parameters:

rowType - Row type of the relational expression

collationList - List of collations

fail - Whether to fail if invalid

Returns:

Whether valid

equal

public static boolean equal(List<RelCollation> collationList1,
            List<RelCollation> collationList2)

ordinals

public static List<Integer> ordinals(RelCollation collation)

Returns the indexes of the field collations in a given collation.

contains

public static boolean contains(RelCollation collation,
               Iterable<Integer> keys)

Returns whether a collation indicates that the collection is sorted on a given list of keys.

Parameters:

collation - Collation

keys - List of keys

Returns:

Whether the collection is sorted on the given keys

contains

public static boolean contains(List<RelCollation> collations,
               ImmutableIntList keys)

Returns whether one of a list of collations indicates that the collection is sorted on the given list of keys.

shift

public static RelCollation shift(RelCollation collation,
                 int offset)