Package org.elasticsearch.common.util

Class CollectionUtils

java.lang.Object

org.elasticsearch.common.util.CollectionUtils

public class CollectionUtils
extends Object

Collections-related utility methods.

Constructor Summary

Constructors

Constructor	Description
CollectionUtils()

Method Summary

Modifier and Type	Method	Description
static <E> List<E>	appendToCopy(Collection<E> collection, E element)	Creates a copy of the given collection with the given element appended.
static <E> ArrayList<E>	arrayAsArrayList(E... elements)
static <E> ArrayList<E>	asArrayList(E first, E... other)
static <E> ArrayList<E>	asArrayList(E first, E second, E... other)
static <E> List<E>	concatLists(List<E> listA, List<E> listB)
static <R, T> Map<R,T>	copyMap(Map<R,T> map)	Returns an unmodifiable copy of the given map.
static <E> List<List<E>>	eagerPartition(List<E> list, int size)
static void	ensureNoSelfReferences(Object value, String messageHint)	Deeply inspects a Map, Iterable, or Object array looking for references back to itself.
static boolean	isEmpty(Object[] array)	Checks if the given array contains any elements.
static <E> ArrayList<E>	iterableAsArrayList(Iterable<? extends E> elements)
static <E> ArrayList<E>	newSingletonArrayList(E element)
static <T> List<T>	rotate(List<T> list, int distance)	Return a rotated view of the given list with the given distance.
static void	sort(com.carrotsearch.hppc.ObjectArrayList<byte[]> array)
static void	sort(org.apache.lucene.util.BytesRefArray bytes, int[] indices)
static void	sortAndDedup(com.carrotsearch.hppc.ObjectArrayList<byte[]> array)
static int	sortAndDedup(org.apache.lucene.util.BytesRefArray bytes, int[] indices)
static int[]	toArray(Collection<Integer> ints)
static <E> List<E>	wrapUnmodifiableOrEmptySingleton(List<E> list)

Methods inherited from class java.lang.Object

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

Constructor Details

CollectionUtils

public CollectionUtils()

Method Details

isEmpty

public static boolean isEmpty(Object[] array)

Checks if the given array contains any elements.

Parameters:

array - The array to check

Returns:

false if the array contains an element, true if not or the array is null.

rotate

public static <T> List<T> rotate(List<T> list,
 int distance)

Return a rotated view of the given list with the given distance.

sortAndDedup

public static void sortAndDedup(com.carrotsearch.hppc.ObjectArrayList<byte[]> array)

sort

public static void sort(com.carrotsearch.hppc.ObjectArrayList<byte[]> array)

toArray

public static int[] toArray(Collection<Integer> ints)

ensureNoSelfReferences

public static void ensureNoSelfReferences(Object value,
 String messageHint)

Deeply inspects a Map, Iterable, or Object array looking for references back to itself.

Parameters:

value - The object to evaluate looking for self references

messageHint - A string to be included in the exception message if the call fails, to provide more context to the handler of the exception

Throws:

IllegalArgumentException - if a self-reference is found

copyMap

public static <R,
T> Map<R,T> copyMap(Map<R,T> map)

Returns an unmodifiable copy of the given map.

Parameters:

map - Map to copy

Returns:

unmodifiable copy of the map

sort

public static void sort(org.apache.lucene.util.BytesRefArray bytes,
 int[] indices)

sortAndDedup

public static int sortAndDedup(org.apache.lucene.util.BytesRefArray bytes,
 int[] indices)

iterableAsArrayList

public static <E> ArrayList<E> iterableAsArrayList(Iterable<? extends E> elements)

arrayAsArrayList

@SafeVarargs
public static <E> ArrayList<E> arrayAsArrayList(E... elements)

asArrayList

@SafeVarargs
public static <E> ArrayList<E> asArrayList(E first,
 E... other)

asArrayList

@SafeVarargs
public static <E> ArrayList<E> asArrayList(E first,
 E second,
 E... other)

appendToCopy

public static <E> List<E> appendToCopy(Collection<E> collection,
 E element)

Creates a copy of the given collection with the given element appended.

Parameters:

collection - collection to copy

element - element to append

newSingletonArrayList

public static <E> ArrayList<E> newSingletonArrayList(E element)

eagerPartition

public static <E> List<List<E>> eagerPartition(List<E> list,
 int size)

concatLists

public static <E> List<E> concatLists(List<E> listA,
 List<E> listB)

wrapUnmodifiableOrEmptySingleton

public static <E> List<E> wrapUnmodifiableOrEmptySingleton(List<E> list)