PartKeepr\CategoryBundle\EventListener\RootCategoryListener::checkForRoot PHP Method

    protected function checkForRoot(AbstractCategory $category)
    {
        if ($category->getParent() === null) {
            try {
                $rootNode = $this->container->get($this->service)->getRootNode();
                if ($rootNode->getId() != $category->getId()) {
                    throw new OnlySingleRootNodeAllowedException();
                }
            } catch (RootNodeNotFoundException $e) {
            }
        }
    }