Towards OCL/RT

An extension of the “Object Constraint Language” (OCL) for modeling real-time and reactive systems in the “Unified Modeling Language” (UML) is proposed, called OCL/RT. A general notion of events that may carry time stamps is introduced providing means to describe the detailed dynamic and timing behaviour of UML software models. OCL is enriched by satisfaction operators @η for referring to the value in the history of an expression at the instant when event η occurred, as well as the modalities always and sometime. The approach is illustrated by several examples. Finally, an operational semantics of OCL/RT is given.