0) or negative (<0) depending on the Reservation semantic. * * For example, when an Order is placed, a Reservation with negative quantity is appended. * When that Order is processed and the SourceItems related to ordered products are updated, a Reservation with * positive quantity is appended to neglect the first one. * * @return float */ public function getQuantity(): float; /** * Get Reservation Metadata * * Metadata is used to store serialized data that encapsulates the semantic of a Reservation. * * @return string|null */ public function getMetadata(): ?string; }