Milestones: Mythical Signals in UML to Analyze and Monitor Progress

Many applications are evolving towards Service Oriented Architecture (SOA) with technologies such as Web services. Services can be modeled platform independently through UML2 collaborations in the upcoming UML profile for services, SoaML. We observe an increasing need for validation of services. However, such validation is often based on syntactic descriptions of the services and of their interfaces, which are insufficient to ensure that desired liveness properties are satisfied. In this paper, we present a language construct called “milestone” embedded in UML and define its semantics using mythical signals. We show how this interpretation of milestones can be used for liveness analysis and for runtime monitoring of services. The approach is illustrated with a simple bidding service.