org.agrona.collections

Class ArrayUtil

java.lang.Object

org.agrona.collections.ArrayUtil

public final class ArrayUtil
extends java.lang.Object

Utility class for operating on arrays as if they were collections. This is useful for critical paths where operations like add and remove are seldom used, but iterating is common and checkcast and indirection are comparatively expensive. In all cases the array being mutated is assumed to be full. In all cases reference equality is used.

Field Summary

Fields

Modifier and Type	Field and Description
static int	UNKNOWN_INDEX

Constructor Summary

Constructors

Constructor and Description
ArrayUtil()

Method Summary

Modifier and Type	Method and Description
static <T> T[]	add(T[] oldElements, T elementToAdd) Add an element to an array resulting in a new array.
static <T> T[]	ensureCapacity(T[] oldElements, int requiredLength) Ensure an array has the required capacity.
static <T> T[]	newArray(T[] oldElements, int length) Allocate a new array of the same type as another array.
static <T> T[]	remove(T[] oldElements, int index)
static <T> T[]	remove(T[] oldElements, T elementToRemove) Remove an element from an array resulting in a new array if the element was found otherwise the old array.

Methods inherited from class java.lang.Object

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

Field Detail

UNKNOWN_INDEX

public static final int UNKNOWN_INDEX

See Also:

Constant Field Values

Constructor Detail

ArrayUtil

public ArrayUtil()

Method Detail

add

public static <T> T[] add(T[] oldElements,
                          T elementToAdd)

Add an element to an array resulting in a new array.

Type Parameters:

T - type of the array.

Parameters:

oldElements - to have the new element added.

elementToAdd - for the new array.

Returns:

a new array that is one bigger and containing the new element at the end.

remove

public static <T> T[] remove(T[] oldElements,
                             T elementToRemove)

Remove an element from an array resulting in a new array if the element was found otherwise the old array. Returns its input parameter if the element to remove isn't a member.

Type Parameters:

T - type of the array.

Parameters:

oldElements - to have the element removed from.

elementToRemove - being searched for by identity semantics.

Returns:

a new array without the element if found otherwise the original array.

remove

public static <T> T[] remove(T[] oldElements,
                             int index)

newArray

public static <T> T[] newArray(T[] oldElements,
                               int length)

Allocate a new array of the same type as another array.

Type Parameters:

T - type of the array.

Parameters:

oldElements - on which the new array is based.

length - of the new array.

Returns:

the new array of requested length.

ensureCapacity

public static <T> T[] ensureCapacity(T[] oldElements,
                                     int requiredLength)

Ensure an array has the required capacity. Resizing only if needed.

Type Parameters:

T - type of the array.

Parameters:

oldElements - to ensure that are long enough.

requiredLength - to ensure.

Returns:

an array of the required length.