Java example source code file (ArrayUtils.java)

This example Java source code file (ArrayUtils.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

arrayutils, reflection, suppresswarnings

The ArrayUtils.java Java example source code

/*
 * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package com.sun.tools.javac.util;

import java.lang.reflect.Array;

/** <p>This is NOT part of any supported API.
 *  If you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 */
public class ArrayUtils {

    private static int calculateNewLength(int currentLength, int maxIndex) {
        while (currentLength < maxIndex + 1)
            currentLength = currentLength * 2;
        return currentLength;
    }

    public static <T> T[] ensureCapacity(T[] array, int maxIndex) {
        if (maxIndex < array.length) {
            return array;
        } else {
            int newLength = calculateNewLength(array.length, maxIndex);
            @SuppressWarnings("unchecked")
            T[] result = (T[]) Array.newInstance(array.getClass().getComponentType(), newLength);
            System.arraycopy(array, 0, result, 0, array.length);
            return result;
        }
    }

    public static byte[] ensureCapacity(byte[] array, int maxIndex) {
        if (maxIndex < array.length) {
            return array;
        } else {
            int newLength = calculateNewLength(array.length, maxIndex);
            byte[] result = new byte[newLength];
            System.arraycopy(array, 0, result, 0, array.length);
            return result;
        }
    }

    public static char[] ensureCapacity(char[] array, int maxIndex) {
        if (maxIndex < array.length) {
            return array;
        } else {
            int newLength = calculateNewLength(array.length, maxIndex);
            char[] result = new char[newLength];
            System.arraycopy(array, 0, result, 0, array.length);
            return result;
        }
    }

    public static int[] ensureCapacity(int[] array, int maxIndex) {
        if (maxIndex < array.length) {
            return array;
        } else {
            int newLength = calculateNewLength(array.length, maxIndex);
            int[] result = new int[newLength];
            System.arraycopy(array, 0, result, 0, array.length);
            return result;
        }
    }

}