ChecksumHelper.java

package com.dronecontrol.droneapi.helpers;

import java.util.Random;
import java.util.zip.CRC32;
import java.util.zip.Checksum;

public class ChecksumHelper
{

  public static final int RANDOM_STRING_LENGTH = 100;

  public static final String CHARACTERS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

  public static String createRandomCrc32Hex()
  {
    return createCrc32Hex(createRandomString());
  }

  public static String createCrc32Hex(String value)
  {
    byte bytes[] = value.getBytes();
    Checksum checksumCreator = new CRC32();
    checksumCreator.update(bytes, 0, bytes.length);
    long checkSumValue = checksumCreator.getValue();
    return fixLength(Long.toHexString(checkSumValue));
  }

  private static String fixLength(String hexString)
  {
    while (hexString.length() != 8)
    {
      hexString = "0" + hexString;
    }
    return hexString;
  }

  public static String createRandomString()
  {
    Random random = new Random();
    StringBuilder stringBuilder = new StringBuilder(RANDOM_STRING_LENGTH);
    for (int i = 0; i < RANDOM_STRING_LENGTH; i++)
    {
      stringBuilder.append(CHARACTERS.charAt(random.nextInt(CHARACTERS.length())));
    }
    return stringBuilder.toString();
  }
}