org.hibernate.internal.util.collections

Class CollectionHelper

java.lang.Object

org.hibernate.internal.util.collections.CollectionHelper

public final class CollectionHelper
extends Object

Various help for handling collections.

Field Summary

Fields

Modifier and Type	Field and Description
static Collection	EMPTY_COLLECTION Deprecated. use Collections.EMPTY_LIST or Collections.emptyList() instead
static List	EMPTY_LIST Deprecated. use Collections.EMPTY_LIST or Collections.emptyList() instead
static Map	EMPTY_MAP Deprecated. use Collections.EMPTY_MAP or Collections.emptyMap() instead
static float	LOAD_FACTOR
static int	MINIMUM_INITIAL_CAPACITY

Method Summary

Methods

Modifier and Type	Method and Description
static <T> List<T>	arrayList(int anticipatedSize)
static <K,V> ConcurrentHashMap<K,V>	concurrentMap(int expectedNumberOfElements) Create a properly sized ConcurrentHashMap based on the given expected number of elements.
static <K,V> ConcurrentHashMap<K,V>	concurrentMap(int expectedNumberOfElements, float loadFactor) Create a properly sized ConcurrentHashMap based on the given expected number of elements and an explicit load factor
static int	determineProperSizing(int numberOfElements) Determine the proper initial size for a new collection in order for it to hold the given a number of elements.
static int	determineProperSizing(Map original) Given a map, determine the proper initial size for a new Map to hold the same number of values.
static int	determineProperSizing(Set original) Given a set, determine the proper initial size for a new set to hold the same number of values.
static boolean	isEmpty(Collection collection)
static boolean	isEmpty(Map map)
static boolean	isEmpty(Object[] objects)
static boolean	isNotEmpty(Collection collection)
static boolean	isNotEmpty(Map map)
static <X,Y> Map<X,Y>	makeCopy(Map<X,Y> map)
static <T> Set<T>	makeCopy(Set<T> source)
static <K,V> Map<K,V>	mapOfSize(int size) Build a properly sized map, especially handling load size and load factor to prevent immediate resizing.

Methods inherited from class java.lang.Object

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

Field Detail

MINIMUM_INITIAL_CAPACITY

public static final int MINIMUM_INITIAL_CAPACITY

See Also:

Constant Field Values

LOAD_FACTOR

public static final float LOAD_FACTOR

See Also:

Constant Field Values

EMPTY_LIST

@Deprecated
public static final List EMPTY_LIST

Deprecated. use Collections.EMPTY_LIST or Collections.emptyList() instead

EMPTY_COLLECTION

@Deprecated
public static final Collection EMPTY_COLLECTION

Deprecated. use Collections.EMPTY_LIST or Collections.emptyList() instead

EMPTY_MAP

@Deprecated
public static final Map EMPTY_MAP

Deprecated. use Collections.EMPTY_MAP or Collections.emptyMap() instead

Method Detail

mapOfSize

public static <K,V> Map<K,V> mapOfSize(int size)

Build a properly sized map, especially handling load size and load factor to prevent immediate resizing.

Especially helpful for copy map contents.

Parameters:

size - The size to make the map.

Returns:

The sized map.

determineProperSizing

public static int determineProperSizing(Map original)

Given a map, determine the proper initial size for a new Map to hold the same number of values. Specifically we want to account for load size and load factor to prevent immediate resizing.

Parameters:

original - The original map

Returns:

The proper size.

determineProperSizing

public static int determineProperSizing(Set original)

Given a set, determine the proper initial size for a new set to hold the same number of values. Specifically we want to account for load size and load factor to prevent immediate resizing.

Parameters:

original - The original set

Returns:

The proper size.

determineProperSizing

public static int determineProperSizing(int numberOfElements)

Determine the proper initial size for a new collection in order for it to hold the given a number of elements. Specifically we want to account for load size and load factor to prevent immediate resizing.

Parameters:

numberOfElements - The number of elements to be stored.

Returns:

The proper size.

concurrentMap

public static <K,V> ConcurrentHashMap<K,V> concurrentMap(int expectedNumberOfElements)

Create a properly sized ConcurrentHashMap based on the given expected number of elements.

Type Parameters:

K - The map key type

V - The map value type

Parameters:

expectedNumberOfElements - The expected number of elements for the created map

Returns:

The created map.

concurrentMap

public static <K,V> ConcurrentHashMap<K,V> concurrentMap(int expectedNumberOfElements,
                                         float loadFactor)

Create a properly sized ConcurrentHashMap based on the given expected number of elements and an explicit load factor

Type Parameters:

K - The map key type

V - The map value type

Parameters:

expectedNumberOfElements - The expected number of elements for the created map

loadFactor - The collection load factor

Returns:

The created map.

arrayList

public static <T> List<T> arrayList(int anticipatedSize)

makeCopy

public static <T> Set<T> makeCopy(Set<T> source)

isEmpty

public static boolean isEmpty(Collection collection)

isEmpty

public static boolean isEmpty(Map map)

isNotEmpty

public static boolean isNotEmpty(Collection collection)

isNotEmpty

public static boolean isNotEmpty(Map map)

isEmpty

public static boolean isEmpty(Object[] objects)

makeCopy

public static <X,Y> Map<X,Y> makeCopy(Map<X,Y> map)