Inserts an element into the array at the specified index, growing the array if there is no more room. - Android java.lang

Android examples for java.lang:array

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Description

Inserts an element into the array at the specified index, growing the array if there is no more room.

Demo Code

/*//from   ww w.ja  v  a  2s .  co  m
 * Copyright (C) 2014 The Android Open Source Project
 *
 * 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
 *
 *      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.
 */
//package com.java2s;

import java.util.Arrays;

public class Main {
    /**
     * Inserts an element into the array at the specified index, growing the array if there is no
     * more room.
     *
     * @param array The array to which to append the element. Must NOT be null.
     * @param currentSize The number of elements in the array. Must be less than or equal to
     *                    array.length.
     * @param element The element to insert.
     * @return the array to which the element was appended. This may be different than the given
     *         array.
     */
    public static <T> T[] insert(T[] array, int currentSize, int index,
            T element) {
        assert currentSize <= array.length;

        if (currentSize + 1 <= array.length) {
            System.arraycopy(array, index, array, index + 1, currentSize
                    - index);
            array[index] = element;
            return array;
        }

        @SuppressWarnings("unchecked")
        int newLength = growSize(currentSize);
        T[] newArray = Arrays.copyOf(array, newLength);
        // ArrayUtils.newUnpaddedArray((Class<T>)array.getClass().getComponentType(),
        //        growSize(currentSize));
        // System.arraycopy(array, 0, newArray, 0, index);
        newArray[index] = element;
        System.arraycopy(array, index, newArray, index + 1, array.length
                - index);
        return newArray;
    }

    /**
     * Primitive int version of {@link #insert(Object[], int, int, Object)}.
     */
    public static int[] insert(int[] array, int currentSize, int index,
            int element) {
        assert currentSize <= array.length;

        if (currentSize + 1 <= array.length) {
            System.arraycopy(array, index, array, index + 1, currentSize
                    - index);
            array[index] = element;
            return array;
        }

        int[] newArray = new int[growSize(currentSize)];
        System.arraycopy(array, 0, newArray, 0, index);
        newArray[index] = element;
        System.arraycopy(array, index, newArray, index + 1, array.length
                - index);
        return newArray;
    }

    /**
     * Primitive long version of {@link #insert(Object[], int, int, Object)}.
     */
    public static long[] insert(long[] array, int currentSize, int index,
            long element) {
        assert currentSize <= array.length;

        if (currentSize + 1 <= array.length) {
            System.arraycopy(array, index, array, index + 1, currentSize
                    - index);
            array[index] = element;
            return array;
        }

        long[] newArray = new long[growSize(currentSize)];
        System.arraycopy(array, 0, newArray, 0, index);
        newArray[index] = element;
        System.arraycopy(array, index, newArray, index + 1, array.length
                - index);
        return newArray;
    }

    /**
     * Primitive boolean version of {@link #insert(Object[], int, int, Object)}.
     */
    public static boolean[] insert(boolean[] array, int currentSize,
            int index, boolean element) {
        assert currentSize <= array.length;

        if (currentSize + 1 <= array.length) {
            System.arraycopy(array, index, array, index + 1, currentSize
                    - index);
            array[index] = element;
            return array;
        }

        boolean[] newArray = new boolean[growSize(currentSize)];
        System.arraycopy(array, 0, newArray, 0, index);
        newArray[index] = element;
        System.arraycopy(array, index, newArray, index + 1, array.length
                - index);
        return newArray;
    }

    /**
     * Given the current size of an array, returns an ideal size to which the array should grow.
     * This is typically double the given size, but should not be relied upon to do so in the
     * future.
     */
    public static int growSize(int currentSize) {
        return currentSize <= 4 ? 8 : currentSize * 2;
    }
}

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