protected function get_new_id()
 {
     if (!file_exists("particle/")) {
         return 0;
     }
     $files = array();
     $iterator = new FilesystemIterator("particle/", FilesystemIterator::SKIP_DOTS);
     while ($iterator->valid()) {
         array_push($files, $iterator->getFileName());
         $iterator->next();
     }
     if (sizeof($files) == 0) {
         return 0;
     }
     natsort($files);
     $lastFile = end($files);
     $name = explode(".", $lastFile);
     return intval($name[0]) + 1;
 }