code: public static boolean isPureAscii(byte[] data) {
  		if (data == null) {
  			return false;
  		}
  		for (byte b : data) {
  			if (b < 0x20) {
  				return false;
  			}
  		}
  		return true;
  	}
docs: Test if the data in the array is pure ASCII
  @param data data to check
  @return true if there are only ASCII characters