/** {@inheritDoc} */
  @Override
  public Object onReceive(@Nullable Object obj) {
    if (obj instanceof byte[]) {
      X.println(">>> Byte array received over REST: " + Arrays.toString((byte[]) obj));

      BigInteger val = new BigInteger((byte[]) obj);

      X.println(">>> Unpacked a BigInteger from byte array received over REST: " + val);

      return val;
    } else return obj;
  }
  /** {@inheritDoc} */
  @Override
  public Object onSend(Object obj) {
    if (obj instanceof BigInteger) {
      X.println(">>> Creating byte array from BigInteger to send over REST: " + obj);

      byte[] bytes = ((BigInteger) obj).toByteArray();

      X.println(
          ">>> Created byte array from BigInteger to send over REST: " + Arrays.toString(bytes));

      return bytes;
    } else return obj;
  }
  /**
   * Starts up grid and checks all provided values for prime.
   *
   * @param args Command line arguments, none required but if provided first one should point to the
   *     Spring XML configuration file. See {@code "examples/config/"} for configuration file
   *     examples.
   * @throws GridException If example execution failed.
   */
  public static void main(String[] args) throws GridException {
    // Starts grid.
    Grid grid = args.length == 0 ? G.start() : G.start(args[0]);

    // Values we want to check for prime.
    long[] checkVals = {32452841, 32452843, 32452847, 32452849, 236887699, 217645199};

    X.println(">>>");
    X.println(
        ">>> Starting to check the following numbers for primes: " + Arrays.toString(checkVals));

    try {
      long start = System.currentTimeMillis();

      for (long checkVal : checkVals) {
        // This method will be executed on the Grid as it is
        // annotated with @Gridify annotation.
        Long divisor = GridPrimeChecker.checkPrime(checkVal, 2, checkVal);

        // If divisor is null, then the number is prime.
        if (divisor == null) {
          X.println("Value '" + checkVal + "'is a prime number.");
        } else {
          X.println("Value '" + checkVal + "' is divisible by '" + divisor + '\'');
        }
      }

      long totalTime = System.currentTimeMillis() - start;

      X.println(">>> Total time to calculate all primes (milliseconds): " + totalTime);
      X.println(">>>");
    } finally {
      // Stops grid.
      G.stop(grid.name(), true);
    }
  }