com.intel.gpe.util.arrays
Class ArrayUtil

java.lang.Object
  com.intel.gpe.util.arrays.ArrayUtil

public class ArrayUtil
extends java.lang.Object

Constais some useful library functions related to arrays

Version:

$Id: ArrayUtil.java,v 1.2 2006/05/26 10:30:00 daivanov Exp $

Author:

Dmitry Ivanov

Constructor Summary

ArrayUtil()

Method Summary

static java.lang.Object	castElement2Class(java.lang.Class elClazz, java.lang.Object[] array) Cast every element of array to class elClazz
static byte[][]	divide(byte[] arr, int chunkSize) Divides one big array to a number of smaller arrays, each one with length of chunkSize.
static boolean	equals(byte[][] a1, byte[][] a2) Compares two matrices for equality.
static byte[]	merge(byte[]... arrs) Merges a number of arrays into one big array consequently.
static int[]	searchIndices(java.lang.Object[] arr, java.lang.Object[] toFind) if exists t that arr[t] equals toFind[i] then result[i]=t, otherwise result[i]=-1 t is the smallest one if two such indexes exists.
static byte[]	subarray(byte[] arr, int beginIdx, int endIdx) The same as substring.

Methods inherited from class java.lang.Object

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

Constructor Detail

ArrayUtil

public ArrayUtil()

Method Detail

searchIndices

public static int[] searchIndices(java.lang.Object[] arr,
                                  java.lang.Object[] toFind)

if exists t that arr[t] equals toFind[i] then result[i]=t, otherwise result[i]=-1
t is the smallest one if two such indexes exists. null is equals only with null Method Object.equals(Object) is used as a comparator. An asymptotic complexity is arr.length*toFind.length

Parameters:

arr - - array where search is happening

toFind - - elements which indexes must be found

Returns:

int[tofind.lenght] : res[i] = search(arr, toFind[i]) if any of input array are null then null'll be returned

castElement2Class

public static java.lang.Object castElement2Class(java.lang.Class elClazz,
                                                 java.lang.Object[] array)

Cast every element of array to class elClazz

Parameters:

elClazz - class of elements in the output array

array - input array

Returns:

array with the same elements but it's class is elClazz[] if input array is null then null will be returned

subarray

public static byte[] subarray(byte[] arr,
                              int beginIdx,
                              int endIdx)
                       throws java.lang.IllegalArgumentException

The same as substring. begin - inclusive, end - exclusive

Parameters:

arr - input array

beginIdx - if less then zero then assign to zero

endIdx - if more then arr.length() then assign to length

Returns:

subarray of given array with indexes of range [beginIdx, endIdx) null if input array is null

Throws:

java.lang.IllegalArgumentException - if beginIdx > endIdx

merge

public static byte[] merge(byte[]... arrs)

Merges a number of arrays into one big array consequently. E.g. res = {arrs[0][0],arrs[0][1], ..., arrs[0][arrs[0].length-1], arrs[1][0],arrs[1][1], ..., arrs[1][arrs[1].length-1],... .... ...., arrs[arrs.length-1][0],arrs[arrs.length-1][1], ..., arrs[arrs.length-1][arrs[arrs.length-1].length-1] } Null arrays are threated as empty (0 elements in)

Parameters:

arrs - array of array

Returns:

merge of arrays with length = sum of lengths of arrays null if arrs is null

divide

public static byte[][] divide(byte[] arr,
                              int chunkSize)
                       throws java.lang.IllegalArgumentException

Divides one big array to a number of smaller arrays, each one with length of chunkSize. The length of the last array may be smaller then chunkSize. If you apply merge(byte[][]) to the result of divide(byte[], int) then you obtain the source array. So this method is inverse of merge(byte[][])

Parameters:

arr - big input array

chunkSize - the size of each resulting array (except, maybe, the last one)

Returns:

division of this array into small arrays zero length array if the input array's length is zero null if input array is null

Throws:

java.lang.IllegalArgumentException - if chunkSize isn't positive

equals

public static boolean equals(byte[][] a1,
                             byte[][] a2)

Compares two matrices for equality. Every element of array a1 must be equals to corresponding component in the array a2 as in method Arrays.equals(byte[], byte[]). Also true is returned when both source arrays are null

Parameters:

a1 -

a2 -

Returns:

true if matrices are equals, false otherwise