protected function _beforeInsert()
 {
     parent::_beforeInsert();
     if (!$this->is_home) {
         $this->is_home = 0;
     }
     if (!$this->visible) {
         $this->visible = 0;
     }
     if (!$this->pos) {
         $this->pos = 1;
     }
     //fill parent_subroot_id cache
     $c = Kwf_Component_Data_Root::getInstance()->getComponentById($this->parent_id, array('ignoreVisible' => true));
     $this->parent_subroot_id = $c->getSubroot()->componentId;
 }