org.grouplens.lenskit.collections

Class LongUtils

java.lang.Object

org.grouplens.lenskit.collections.LongUtils

public final class LongUtils
extends Object

Utilities for working with longs and collections of them from Fastutil.

Since:

2.0

Author:

GroupLens Research

Method Summary

Methods

Modifier and Type	Method and Description
static it.unimi.dsi.fastutil.longs.LongCollection	asLongCollection(Collection<Long> longs) Get a Fastutil LongCollection from a Collection of longs.
static it.unimi.dsi.fastutil.longs.LongSet	asLongSet(Set<Long> longs) Get a Fastutil LongSet from a Set of longs.
static it.unimi.dsi.fastutil.longs.LongSortedSet	packedSet(Collection<Long> longs) Pack longs into a sorted set.
static it.unimi.dsi.fastutil.longs.LongSortedSet	packedSet(long... longs) Pack longs into a sorted set.
static it.unimi.dsi.fastutil.longs.LongSortedSet	setDifference(it.unimi.dsi.fastutil.longs.LongSet items, it.unimi.dsi.fastutil.longs.LongSet exclude) Compute the set difference of two sets.
static it.unimi.dsi.fastutil.longs.LongSortedSet	setUnion(it.unimi.dsi.fastutil.longs.LongSortedSet a, it.unimi.dsi.fastutil.longs.LongSortedSet b) Compute the union of two sets.
static int	unionSize(it.unimi.dsi.fastutil.longs.LongSortedSet a, it.unimi.dsi.fastutil.longs.LongSortedSet b) Compute the size of the union of two sets.

Methods inherited from class java.lang.Object

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

Method Detail

packedSet

public static it.unimi.dsi.fastutil.longs.LongSortedSet packedSet(Collection<Long> longs)

Pack longs into a sorted set.

Parameters:

longs - A collection of longs.

Returns:

An efficient sorted set containing the numbers in longs.

packedSet

public static it.unimi.dsi.fastutil.longs.LongSortedSet packedSet(long... longs)

Pack longs into a sorted set.

Parameters:

longs - An array of longs. This array is copied, not wrapped.

Returns:

An efficient sorted set containing the numbers in longs.

asLongCollection

public static it.unimi.dsi.fastutil.longs.LongCollection asLongCollection(Collection<Long> longs)

Get a Fastutil LongCollection from a Collection of longs. This method simply casts the collection, if possible, and returns a wrapper otherwise.

Parameters:

longs - A collection of longs.

Returns:

The collection as a LongCollection.

asLongSet

public static it.unimi.dsi.fastutil.longs.LongSet asLongSet(Set<Long> longs)

Get a Fastutil LongSet from a Set of longs.

Parameters:

longs - The set of longs.

Returns:

longs as a fastutil LongSet. If longs is already a LongSet, it is cast.

setDifference

public static it.unimi.dsi.fastutil.longs.LongSortedSet setDifference(it.unimi.dsi.fastutil.longs.LongSet items,
                                                      it.unimi.dsi.fastutil.longs.LongSet exclude)

Compute the set difference of two sets.

Parameters:

items - The initial set

exclude - The items to remove

Returns:

The elements of that are not in .

unionSize

public static int unionSize(it.unimi.dsi.fastutil.longs.LongSortedSet a,
            it.unimi.dsi.fastutil.longs.LongSortedSet b)

Compute the size of the union of two sets.

Parameters:

a - The first set.

b - The second set.

Returns:

The size of the union of the two sets.

setUnion

public static it.unimi.dsi.fastutil.longs.LongSortedSet setUnion(it.unimi.dsi.fastutil.longs.LongSortedSet a,
                                                 it.unimi.dsi.fastutil.longs.LongSortedSet b)

Compute the union of two sets.

Parameters:

a - The first set.

b - The second set.

Returns:

The elements of that are not in .