Utility method used to ensure the capacity of byte array. - Java java.lang

Java examples for java.lang:byte Array

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Description

Utility method used to ensure the capacity of byte array.

Demo Code


//package com.java2s;

import java.util.Arrays;

public class Main {
    public static void main(String[] argv) throws Exception {
        byte[] bytes = new byte[] { 34, 35, 36, 37, 37, 37, 67, 68, 69 };
        int capacity = 2;
        System.out.println(java.util.Arrays.toString(ensureCapacity(bytes,
                capacity)));/*from w  w  w  .  j  a va2  s .c o  m*/
    }

    /**
     * Utility method used to ensure the capacity of byte array.
     * 
     * @param bytes
     * @param size
     * @param factor
     * @return
     */
    private static byte[] ensureCapacity(byte[] bytes, int capacity) {
        if (bytes.length < capacity) {
            int newsize = Math.max(1, bytes.length) << 1;
            bytes = Arrays.copyOf(bytes, newsize);
        }
        return bytes;
    }

    /**
     * Concatenate strings with the given separator char.
     * 
     * @param strs
     * @param separator
     * @return
     */
    public static String toString(String[] strs, char separator) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < strs.length; i++) {
            sb.append(strs[i]);
            if (i + 1 < strs.length) {
                sb.append(separator);
            }
        }
        return sb.toString();
    }

    /**
     * Convert the bytes starting at the given index to a string of
     * the given length.
     * 
     * @param bytes
     * @param index
     * @param strLeng
     * @return
     */
    public static String toString(byte[] bytes, int index, int strLeng) {
        int typeBytes = Character.SIZE / Byte.SIZE;
        checkBounds(bytes, index, typeBytes * strLeng);
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < strLeng; i++) {
            int c = 0;
            for (int j = 0; j < typeBytes; j++) {
                int b = bytes[index++];
                b = (b < 0) ? b + 256 : b;
                int shiftBits = Byte.SIZE * j;
                c = (c << shiftBits) + b;
            }
            sb.append((char) c);
        }
        return sb.toString();
    }

    /**
     * Utility method used to bounds check the byte array
     * and requested offset & length values.
     * 
     * @param bytes
     * @param offset
     * @param length
     */
    public static void checkBounds(byte[] bytes, int offset, int length) {
        if (length < 0)
            throw new IndexOutOfBoundsException("Index out of range: "
                    + length);
        if (offset < 0)
            throw new IndexOutOfBoundsException("Index out of range: "
                    + offset);
        if (offset > bytes.length - length)
            throw new IndexOutOfBoundsException("Index out of range: "
                    + (offset + length));
    }
}

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