private function initTag()
{
$class_name = SwatDBClassMap::get('PinholeTag');
$this->tag = new $class_name();
$this->tag->setDatabase($this->app->db);
$this->tag->setInstance($this->app->getInstance());
if (!$this->tag->load($this->id)) {
throw new AdminNotFoundException(sprintf(Pinhole::_('Tag with id “%s” not found.'), $this->id));
}
}