Main.java Source code

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//package com.java2s;
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * 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.
 */

import java.lang.reflect.Array;

public class Main {
    /**
     * The index value when an element is not found in a list or array: <code>-1</code>.
     * This value is returned by methods in this class and can also be used in comparisons with values returned by
     * various method from {@link java.util.List}.
     */
    public static final int INDEX_NOT_FOUND = -1;

    /**
     * <p>Removes the first occurrence of the specified element from the
     * specified array. All subsequent elements are shifted to the left
     * (substracts one from their indices). If the array doesn't contains
     * such an element, no elements are removed from the array.</p>
     * <p/>
     * <p>This method returns a new array with the same elements of the input
     * array except the first occurrence of the specified element. The component
     * type of the returned array is always the same as that of the input
     * array.</p>
     * <p/>
     * <pre>
     * ArrayUtils.removeElement(null, "a")            = null
     * ArrayUtils.removeElement([], "a")              = []
     * ArrayUtils.removeElement(["a"], "b")           = ["a"]
     * ArrayUtils.removeElement(["a", "b"], "a")      = ["b"]
     * ArrayUtils.removeElement(["a", "b", "a"], "a") = ["b", "a"]
     * </pre>
     *
     * @param array   the array to remove the element from, may be <code>null</code>
     * @param element the element to be removed
     * @return A new array containing the existing elements except the first
     *         occurrence of the specified element.
     * @since 2.1
     */
    public static Object[] removeElement(Object[] array, Object element) {
        int index = indexOf(array, element);
        if (index == INDEX_NOT_FOUND) {
            return clone(array);
        }
        return remove(array, index);
    }

    /**
     * <p>Finds the index of the given object in the array.</p>
     * <p/>
     * <p>This method returns {@link #INDEX_NOT_FOUND} (<code>-1</code>) for a <code>null</code> input array.</p>
     *
     * @param array        the array to search through for the object, may be <code>null</code>
     * @param objectToFind the object to find, may be <code>null</code>
     * @return the index of the object within the array,
     *         {@link #INDEX_NOT_FOUND} (<code>-1</code>) if not found or <code>null</code> array input
     */
    public static int indexOf(Object[] array, Object objectToFind) {
        return indexOf(array, objectToFind, 0);
    }

    /**
     * <p>Finds the index of the given object in the array starting at the given index.</p>
     * <p/>
     * <p>This method returns {@link #INDEX_NOT_FOUND} (<code>-1</code>) for a <code>null</code> input array.</p>
     * <p/>
     * <p>A negative startIndex is treated as zero. A startIndex larger than the array
     * length will return {@link #INDEX_NOT_FOUND} (<code>-1</code>).</p>
     *
     * @param array        the array to search through for the object, may be <code>null</code>
     * @param objectToFind the object to find, may be <code>null</code>
     * @param startIndex   the index to start searching at
     * @return the index of the object within the array starting at the index,
     *         {@link #INDEX_NOT_FOUND} (<code>-1</code>) if not found or <code>null</code> array input
     */
    public static int indexOf(Object[] array, Object objectToFind, int startIndex) {
        if (array == null) {
            return INDEX_NOT_FOUND;
        }
        if (startIndex < 0) {
            startIndex = 0;
        }
        if (objectToFind == null) {
            for (int i = startIndex; i < array.length; i++) {
                if (array[i] == null) {
                    return i;
                }
            }
        } else {
            for (int i = startIndex; i < array.length; i++) {
                if (objectToFind.equals(array[i])) {
                    return i;
                }
            }
        }
        return INDEX_NOT_FOUND;
    }

    /**
     * <p>Finds the index of the given value in the array.</p>
     * <p/>
     * <p>This method returns {@link #INDEX_NOT_FOUND} (<code>-1</code>) for a <code>null</code> input array.</p>
     *
     * @param array       the array to search through for the object, may be <code>null</code>
     * @param valueToFind the value to find
     * @return the index of the value within the array,
     *         {@link #INDEX_NOT_FOUND} (<code>-1</code>) if not found or <code>null</code> array input
     * @since 2.1
     */
    public static int indexOf(char[] array, char valueToFind) {
        return indexOf(array, valueToFind, 0);
    }

    /**
     * <p>Finds the index of the given value in the array starting at the given index.</p>
     * <p/>
     * <p>This method returns {@link #INDEX_NOT_FOUND} (<code>-1</code>) for a <code>null</code> input array.</p>
     * <p/>
     * <p>A negative startIndex is treated as zero. A startIndex larger than the array
     * length will return {@link #INDEX_NOT_FOUND} (<code>-1</code>).</p>
     *
     * @param array       the array to search through for the object, may be <code>null</code>
     * @param valueToFind the value to find
     * @param startIndex  the index to start searching at
     * @return the index of the value within the array,
     *         {@link #INDEX_NOT_FOUND} (<code>-1</code>) if not found or <code>null</code> array input
     * @since 2.1
     */
    public static int indexOf(char[] array, char valueToFind, int startIndex) {
        if (array == null) {
            return INDEX_NOT_FOUND;
        }
        if (startIndex < 0) {
            startIndex = 0;
        }
        for (int i = startIndex; i < array.length; i++) {
            if (valueToFind == array[i]) {
                return i;
            }
        }
        return INDEX_NOT_FOUND;
    }

    /**
     * <p>Shallow clones an array returning a typecast result and handling
     * <code>null</code>.</p>
     * <p/>
     * <p>The objects in the array are not cloned, thus there is no special
     * handling for multi-dimensional arrays.</p>
     * <p/>
     * <p>This method returns <code>null</code> for a <code>null</code> input array.</p>
     *
     * @param array the array to shallow clone, may be <code>null</code>
     * @return the cloned array, <code>null</code> if <code>null</code> input
     */
    public static Object[] clone(Object[] array) {
        if (array == null) {
            return null;
        }
        return (Object[]) array.clone();
    }

    /**
     * <p>Removes the element at the specified position from the specified array.
     * All subsequent elements are shifted to the left (substracts one from
     * their indices).</p>
     * <p/>
     * <p>This method returns a new array with the same elements of the input
     * array except the element on the specified position. The component
     * type of the returned array is always the same as that of the input
     * array.</p>
     * <p/>
     * <p>If the input array is <code>null</code>, an IndexOutOfBoundsException
     * will be thrown, because in that case no valid index can be specified.</p>
     * <p/>
     * <pre>
     * ArrayUtils.remove(["a"], 0)           = []
     * ArrayUtils.remove(["a", "b"], 0)      = ["b"]
     * ArrayUtils.remove(["a", "b"], 1)      = ["a"]
     * ArrayUtils.remove(["a", "b", "c"], 1) = ["a", "c"]
     * </pre>
     *
     * @param array the array to remove the element from, may not be <code>null</code>
     * @param index the position of the element to be removed
     * @return A new array containing the existing elements except the element
     *         at the specified position.
     * @throws IndexOutOfBoundsException if the index is out of range
     *                                   (index < 0 || index >= array.length), or if the array is <code>null</code>.
     * @since 2.1
     */
    public static Object[] remove(Object[] array, int index) {
        return (Object[]) remove((Object) array, index);
    }

    /**
     * <p>Removes the element at the specified position from the specified array.
     * All subsequent elements are shifted to the left (substracts one from
     * their indices).</p>
     * <p/>
     * <p>This method returns a new array with the same elements of the input
     * array except the element on the specified position. The component
     * type of the returned array is always the same as that of the input
     * array.</p>
     * <p/>
     * <p>If the input array is <code>null</code>, an IndexOutOfBoundsException
     * will be thrown, because in that case no valid index can be specified.</p>
     *
     * @param array the array to remove the element from, may not be <code>null</code>
     * @param index the position of the element to be removed
     * @return A new array containing the existing elements except the element
     *         at the specified position.
     * @throws IndexOutOfBoundsException if the index is out of range
     *                                   (index < 0 || index >= array.length), or if the array is <code>null</code>.
     * @since 2.1
     */
    private static Object remove(Object array, int index) {
        int length = getLength(array);
        if (index < 0 || index >= length) {
            throw new IndexOutOfBoundsException("Index: " + index + ", Length: " + length);
        }

        Object result = Array.newInstance(array.getClass().getComponentType(), length - 1);
        System.arraycopy(array, 0, result, 0, index);
        if (index < length - 1) {
            System.arraycopy(array, index + 1, result, index, length - index - 1);
        }

        return result;
    }

    /**
     * <p>Returns the length of the specified array.
     * This method can deal with <code>Object</code> arrays and with primitive arrays.</p>
     * <p/>
     * <p>If the input array is <code>null</code>, <code>0</code> is returned.</p>
     * <p/>
     * <pre>
     * ArrayUtils.getLength(null)            = 0
     * ArrayUtils.getLength([])              = 0
     * ArrayUtils.getLength([null])          = 1
     * ArrayUtils.getLength([true, false])   = 2
     * ArrayUtils.getLength([1, 2, 3])       = 3
     * ArrayUtils.getLength(["a", "b", "c"]) = 3
     * </pre>
     *
     * @param array the array to retrieve the length from, may be null
     * @return The length of the array, or <code>0</code> if the array is <code>null</code>
     * @throws IllegalArgumentException if the object arguement is not an array.
     * @since 2.1
     */
    public static int getLength(Object array) {
        if (array == null) {
            return 0;
        }
        return Array.getLength(array);
    }
}