Array helper
/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2008, Red Hat Middleware LLC or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Middleware LLC.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*
*/
import java.lang.reflect.Array;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
public final class ArrayHelper {
public static int indexOf(Object[] array, Object object) {
for (int i = 0; i < array.length; i++) {
if (array[i].equals(object))
return i;
}
return -1;
}
public static String[] toStringArray(Object[] objects) {
int length = objects.length;
String[] result = new String[length];
for (int i = 0; i < length; i++) {
result[i] = objects[i].toString();
}
return result;
}
public static String[] fillArray(String value, int length) {
String[] result = new String[length];
Arrays.fill(result, value);
return result;
}
public static int[] fillArray(int value, int length) {
int[] result = new int[length];
Arrays.fill(result, value);
return result;
}
public static String[] toStringArray(Collection coll) {
return (String[]) coll.toArray(EMPTY_STRING_ARRAY);
}
public static String[][] to2DStringArray(Collection coll) {
return (String[][]) coll.toArray(new String[coll.size()][]);
}
public static int[][] to2DIntArray(Collection coll) {
return (int[][]) coll.toArray(new int[coll.size()][]);
}
public static Type[] toTypeArray(Collection coll) {
return (Type[]) coll.toArray(EMPTY_TYPE_ARRAY);
}
public static int[] toIntArray(Collection coll) {
Iterator iter = coll.iterator();
int[] arr = new int[coll.size()];
int i = 0;
while (iter.hasNext()) {
arr[i++] = ((Integer) iter.next()).intValue();
}
return arr;
}
public static boolean[] toBooleanArray(Collection coll) {
Iterator iter = coll.iterator();
boolean[] arr = new boolean[coll.size()];
int i = 0;
while (iter.hasNext()) {
arr[i++] = ((Boolean) iter.next()).booleanValue();
}
return arr;
}
public static Object[] typecast(Object[] array, Object[] to) {
return java.util.Arrays.asList(array).toArray(to);
}
// Arrays.asList doesn't do primitive arrays
public static List toList(Object array) {
if (array instanceof Object[])
return Arrays.asList((Object[]) array); // faster?
int size = Array.getLength(array);
ArrayList list = new ArrayList(size);
for (int i = 0; i < size; i++) {
list.add(Array.get(array, i));
}
return list;
}
public static String[] slice(String[] strings, int begin, int length) {
String[] result = new String[length];
for (int i = 0; i < length; i++) {
result[i] = strings[begin + i];
}
return result;
}
public static Object[] slice(Object[] objects, int begin, int length) {
Object[] result = new Object[length];
for (int i = 0; i < length; i++) {
result[i] = objects[begin + i];
}
return result;
}
public static List toList(Iterator iter) {
List list = new ArrayList();
while (iter.hasNext()) {
list.add(iter.next());
}
return list;
}
public static String[] join(String[] x, String[] y) {
String[] result = new String[x.length + y.length];
for (int i = 0; i < x.length; i++)
result[i] = x[i];
for (int i = 0; i < y.length; i++)
result[i + x.length] = y[i];
return result;
}
public static String[] join(String[] x, String[] y, boolean[] use) {
String[] result = new String[x.length + countTrue(use)];
for (int i = 0; i < x.length; i++)
result[i] = x[i];
int k = x.length;
for (int i = 0; i < y.length; i++) {
if (use[i])
result[k++] = y[i];
}
return result;
}
public static int[] join(int[] x, int[] y) {
int[] result = new int[x.length + y.length];
for (int i = 0; i < x.length; i++)
result[i] = x[i];
for (int i = 0; i < y.length; i++)
result[i + x.length] = y[i];
return result;
}
public static final boolean[] TRUE = { true };
public static final boolean[] FALSE = { false };
private ArrayHelper() {
}
public static String toString(Object[] array) {
StringBuffer sb = new StringBuffer();
sb.append("[");
for (int i = 0; i < array.length; i++) {
sb.append(array[i]);
if (i < array.length - 1)
sb.append(",");
}
sb.append("]");
return sb.toString();
}
public static boolean isAllNegative(int[] array) {
for (int i = 0; i < array.length; i++) {
if (array[i] >= 0)
return false;
}
return true;
}
public static boolean isAllTrue(boolean[] array) {
for (int i = 0; i < array.length; i++) {
if (!array[i])
return false;
}
return true;
}
public static int countTrue(boolean[] array) {
int result = 0;
for (int i = 0; i < array.length; i++) {
if (array[i])
result++;
}
return result;
}
/*
* public static int countFalse(boolean[] array) { int result=0; for ( int
* i=0; i<array.length; i++ ) { if ( !array[i] ) result++; } return result; }
*/
public static boolean isAllFalse(boolean[] array) {
for (int i = 0; i < array.length; i++) {
if (array[i])
return false;
}
return true;
}
public static void addAll(Collection collection, Object[] array) {
for (int i = 0; i < array.length; i++) {
collection.add(array[i]);
}
}
public static final String[] EMPTY_STRING_ARRAY = {};
public static final int[] EMPTY_INT_ARRAY = {};
public static final boolean[] EMPTY_BOOLEAN_ARRAY = {};
public static final Class[] EMPTY_CLASS_ARRAY = {};
public static final Object[] EMPTY_OBJECT_ARRAY = {};
public static final Type[] EMPTY_TYPE_ARRAY = {};
public static int[] getBatchSizes(int maxBatchSize) {
int batchSize = maxBatchSize;
int n = 1;
while (batchSize > 1) {
batchSize = getNextBatchSize(batchSize);
n++;
}
int[] result = new int[n];
batchSize = maxBatchSize;
for (int i = 0; i < n; i++) {
result[i] = batchSize;
batchSize = getNextBatchSize(batchSize);
}
return result;
}
private static int getNextBatchSize(int batchSize) {
if (batchSize <= 10) {
return batchSize - 1; // allow 9,8,7,6,5,4,3,2,1
} else if (batchSize / 2 < 10) {
return 10;
} else {
return batchSize / 2;
}
}
private static int SEED = 23;
private static int PRIME_NUMER = 37;
/**
* calculate the array hash (only the first level)
*/
public static int hash(Object[] array) {
int length = array.length;
int seed = SEED;
for (int index = 0; index < length; index++) {
seed = hash(seed, array[index] == null ? 0 : array[index].hashCode());
}
return seed;
}
/**
* calculate the array hash (only the first level)
*/
public static int hash(char[] array) {
int length = array.length;
int seed = SEED;
for (int index = 0; index < length; index++) {
seed = hash(seed, (int) array[index]);
}
return seed;
}
/**
* calculate the array hash (only the first level)
*/
public static int hash(byte[] bytes) {
int length = bytes.length;
int seed = SEED;
for (int index = 0; index < length; index++) {
seed = hash(seed, (int) bytes[index]);
}
return seed;
}
private static int hash(int seed, int i) {
return PRIME_NUMER * seed + i;
}
/**
* Compare 2 arrays only at the first level
*/
public static boolean isEquals(Object[] o1, Object[] o2) {
if (o1 == o2)
return true;
if (o1 == null || o2 == null)
return false;
int length = o1.length;
if (length != o2.length)
return false;
for (int index = 0; index < length; index++) {
if (!o1[index].equals(o2[index]))
return false;
}
return true;
}
/**
* Compare 2 arrays only at the first level
*/
public static boolean isEquals(char[] o1, char[] o2) {
if (o1 == o2)
return true;
if (o1 == null || o2 == null)
return false;
int length = o1.length;
if (length != o2.length)
return false;
for (int index = 0; index < length; index++) {
if (!(o1[index] == o2[index]))
return false;
}
return true;
}
/**
* Compare 2 arrays only at the first level
*/
public static boolean isEquals(byte[] b1, byte[] b2) {
if (b1 == b2)
return true;
if (b1 == null || b2 == null)
return false;
int length = b1.length;
if (length != b2.length)
return false;
for (int index = 0; index < length; index++) {
if (!(b1[index] == b2[index]))
return false;
}
return true;
}
}
Related examples in the same category
