/**
* Prepare the form for mode delete
*
* Verifies that the repository contains the entry to delete.
*
* @throws NotFoundError In case the entry to delete cannot be found
*/
protected function onDeleteRequest()
{
$count = $this->repository->select()->from($this->getBaseTable())->addFilter($this->createFilter())->count();
if ($count === 0) {
throw new NotFoundError('Entry "%s" not found', $this->getIdentifier());
}
}