Real-time constraints with the OCL

The Unified Modeling Language (UML) has received increasing attention from designers of real-time systems. Several approaches apply and enrich the UML notation for modeling of real-time applications. In addition to that, UML modelers can make use of the Object Constraint Language (OCL) to restrict their models by additional constraints. Currently, OCL and real-time extensions of the UML only provide limited means to express temporal constraints. In particular, OCL lacks sufficient means to specify constraints over the dynamic behavior of a UML model, i.e., the evolution of states and state transitions as well as time-bounded constraints. However it is essential to be able to specify such constraints for real-time systems to guarantee correct system behavior We argue for a consistent extension of OCL that enables modelers to express state-related time-bounded constraints