com.cedarsoftware.util

Class ArrayUtilities

java.lang.Object

com.cedarsoftware.util.ArrayUtilities

public final class ArrayUtilities
extends Object

Handy utilities for working with Java arrays.

Author:

Ken Partlow, John DeRegnaucourt ([email protected])
Copyright (c) Cedar Software LLC

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

License

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Field Summary

Fields

Modifier and Type	Field and Description
static byte[]	EMPTY_BYTE_ARRAY
static char[]	EMPTY_CHAR_ARRAY
static Character[]	EMPTY_CHARACTER_ARRAY
static Class[]	EMPTY_CLASS_ARRAY
static Object[]	EMPTY_OBJECT_ARRAY Immutable common arrays.

Method Summary

Modifier and Type	Method and Description
static <T> T[]	addAll(T[] array1, T[] array2) Adds all the elements of the given arrays into a new array.
static <T> T[]	getArraySubset(T[] array, int start, int end)
static boolean	isEmpty(Object array) This is a null-safe isEmpty check.
static <T> T[]	removeItem(T[] array, int pos)
static <T> T[]	shallowCopy(T[] array) Shallow copies an array of Objects
static int	size(Object array) This is a null-safe size check.
static <T> T[]	toArray(Class<T> classToCastTo, Collection<?> c) Convert Collection to a Java (typed) array [].

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY_OBJECT_ARRAY

public static final Object[] EMPTY_OBJECT_ARRAY

Immutable common arrays.

EMPTY_BYTE_ARRAY

public static final byte[] EMPTY_BYTE_ARRAY

EMPTY_CHAR_ARRAY

public static final char[] EMPTY_CHAR_ARRAY

EMPTY_CHARACTER_ARRAY

public static final Character[] EMPTY_CHARACTER_ARRAY

EMPTY_CLASS_ARRAY

public static final Class[] EMPTY_CLASS_ARRAY

Method Detail

isEmpty

public static boolean isEmpty(Object array)

This is a null-safe isEmpty check. It uses the Array static class for doing a length check. This check is actually .0001 ms slower than the following typed check:

return array == null || array.length == 0;

but gives you more flexibility, since it checks for all array types.

Parameters:

array - array to check

Returns:

true if empty or null

size

public static int size(Object array)

This is a null-safe size check. It uses the Array static class for doing a length check. This check is actually .0001 ms slower than the following typed check:

return (array == null) ? 0 : array.length;

Parameters:

array - array to check

Returns:

true if empty or null

shallowCopy

public static <T> T[] shallowCopy(T[] array)

Shallow copies an array of Objects

The objects in the array are not cloned, thus there is no special handling for multi-dimensional arrays.

This method returns null if null array input.

Type Parameters:

T - the array type

Parameters:

array - the array to shallow clone, may be null

Returns:

the cloned array, null if null input

addAll

public static <T> T[] addAll(T[] array1,
                             T[] array2)

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.

 ArrayUtilities.addAll(null, null)     = null
 ArrayUtilities.addAll(array1, null)   = cloned copy of array1
 ArrayUtilities.addAll(null, array2)   = cloned copy of array2
 ArrayUtilities.addAll([], [])         = []
 ArrayUtilities.addAll([null], [null]) = [null, null]
 ArrayUtilities.addAll(["a", "b", "c"], ["1", "2", "3"]) = ["a", "b", "c", "1", "2", "3"]
 

Type Parameters:

T - the array type

Parameters:

array1 - the first array whose elements are added to the new array, may be null

array2 - the second array whose elements are added to the new array, may be null

Returns:

The new array, null if null array inputs. The type of the new array is the type of the first array.

removeItem

public static <T> T[] removeItem(T[] array,
                                 int pos)

getArraySubset

public static <T> T[] getArraySubset(T[] array,
                                     int start,
                                     int end)

toArray

public static <T> T[] toArray(Class<T> classToCastTo,
                              Collection<?> c)

Convert Collection to a Java (typed) array [].

Type Parameters:

T - Type of the array

Parameters:

classToCastTo - array type (Object[], Person[], etc.)

c - Collection containing items to be placed into the array.

Returns:

Array of the type (T) containing the items from collection 'c'.