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.
Adds all the elements of the given arrays into a new array.
*The new array contains all of the element of array1
followed
* by all of the elements array2
. When an array is returned, it is always
* a new array.
* ArrayUtils.addAll(null, null) = null * ArrayUtils.addAll(array1, null) = cloned copy of array1 * ArrayUtils.addAll(null, array2) = cloned copy of array2 * ArrayUtils.addAll([], []) = [] * ArrayUtils.addAll([null], [null]) = [null, null] * ArrayUtils.addAll(["a", "b", "c"], ["1", "2", "3"]) = ["a", "b", "c", "1", "2", "3"] ** * @param array1 the first array whose elements are added to the new array, may be
null
* @param array2 the second array whose elements are added to the new array, may be null
* @return The new array, null
if null
array inputs.
* The type of the new array is the type of the first array.
* @since 2.1
*/
public static Object[] addAll(Object[] array1, Object[] array2) {
if (array1 == null) {
return clone(array2);
} else if (array2 == null) {
return clone(array1);
}
Object[] joinedArray = (Object[]) Array.newInstance(array1.getClass().getComponentType(),
array1.length + array2.length);
System.arraycopy(array1, 0, joinedArray, 0, array1.length);
System.arraycopy(array2, 0, joinedArray, array1.length, array2.length);
return joinedArray;
}
/**
* Shallow clones an array returning a typecast result and handling
* null
.
The objects in the array are not cloned, thus there is no special * handling for multi-dimensional arrays.
* *This method returns null
for a null
input array.
null
* @return the cloned array, null
if null
input
*/
public static Object[] clone(Object[] array) {
if (array == null) {
return null;
}
return (Object[]) array.clone();
}
}