id = null; } /** * Get the ID. The ID can be zero, or even negative (for virtual elements). If an element is virtual, can be * checked with isVirtualElement(). * * Returns null, if the element is not saved to the DB yet. * * @return int|null the ID of this element */ final public function getID(): ?int { return $this->id; } /** * Returns the ID as an string, defined by the element class. * This should have a form like P000014, for a part with ID 14. * * @return string The ID as a string; */ abstract public function getIDString(): string; }