Package org.apache.commons.collections4

Class ArrayUtils

java.lang.Object

org.apache.commons.collections4.ArrayUtils

class ArrayUtils
extends Object

Operations on arrays, primitive arrays (like int[]) and primitive wrapper arrays (like Integer[]).

This class tries to handle null input gracefully. An exception will not be thrown for a null array input. However, an Object array that contains a null element may throw an exception. Each method documents its behaviour.

Package private, might move to an internal package if this needs to be public.

#ThreadSafe#

Since:

4.2 (Copied from Apache Commons Lang.)

Field Summary

Fields

Modifier and Type	Field	Description
(package private) static int	INDEX_NOT_FOUND	The index value when an element is not found in a list or array: -1.

Constructor Summary

Constructors

Constructor	Description
ArrayUtils()

Method Summary

Modifier and Type	Method	Description
(package private) static boolean	contains(Object[] array, Object objectToFind)	Checks if the object is in the given array.
(package private) static int	indexOf(Object[] array, Object objectToFind, int startIndex)	Finds the index of the given object in the array starting at the given index.
(package private) static <T> int	indexOf(T[] array, Object objectToFind)	Finds the index of the given object in the array.

Methods inherited from class java.lang.Object

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

Field Detail

INDEX_NOT_FOUND

static final int INDEX_NOT_FOUND

The index value when an element is not found in a list or array: -1. This value is returned by methods in this class and can also be used in comparisons with values returned by various method from List.

See Also:

Constant Field Values

Constructor Detail

ArrayUtils

ArrayUtils()

Method Detail

contains

static boolean contains(Object[] array,
                        Object objectToFind)

Checks if the object is in the given array.

The method returns false if a null array is passed in.

Parameters:

array - the array to search through

objectToFind - the object to find

Returns:

true if the array contains the object

indexOf

static <T> int indexOf(T[] array,
                       Object objectToFind)

Finds the index of the given object in the array.

This method returns INDEX_NOT_FOUND (-1) for a null input array.

Parameters:

array - the array to search through for the object, may be null

objectToFind - the object to find, may be null

Returns:

the index of the object within the array, INDEX_NOT_FOUND (-1) if not found or null array input

indexOf

static int indexOf(Object[] array,
                   Object objectToFind,
                   int startIndex)

Finds the index of the given object in the array starting at the given index.

This method returns INDEX_NOT_FOUND (-1) for a null input array.

A negative startIndex is treated as zero. A startIndex larger than the array length will return INDEX_NOT_FOUND (-1).

Parameters:

array - the array to search through for the object, may be null

objectToFind - the object to find, may be null

startIndex - the index to start searching at

Returns:

the index of the object within the array starting at the index, INDEX_NOT_FOUND (-1) if not found or null array input