This abstract class contains those properties which are common to all Promise classes (e.g., LabPromise, PharmacyPromise, etc.). A Promise is an intent to perform a service that has the strength of a commitment, i.e., other parties may rely on the originator of such promise that said originator will see to it that the promised act will be fulfilled. A promise can be either solicited or unsolicited. The entity that makes such a promise is also called a "filler", while the entity that requests the service is also called a "placer". The Promise can be looked at as the Order from the filler's point of view. "An order from the perspective of a fulfillment system." - HL7 CIMI, Promise