protected function getSortableColumn()
    {
        $reader = new AnnotationReader();
        $reflClass = new ReflectionClass($this->getEntityClass());
        foreach ($reflClass->getProperties() as $property) {
            $reflProperty = new ReflectionProperty($this->getEntityClass(), $property->name);
            $annotation = $reader->getPropertyAnnotation($reflProperty, '\Gedmo\Mapping\Annotation\SortablePosition');
            if ($annotation) {
                return $property->name;
            }
        }
    }