No abstract

No abstract

No abstract

The effective (re)use of components requires languages for the precise description of observable behaviour, along with methods for checking the compatibility of component interfaces in a design. This is even more challenging in the presence of concurrency. In previous work we have considered a set-based model of components and their composition, in a concurrent setting. In this paper, we present a class of automata, called Σ-automata, in which true-concurrency is treated as an explicit structural property. We show how an automaton can be derived from a component and that every such automaton generates back a component. Apart from determining a usage protocol for the underlying component, this extension to our model provides useful insights on component composition.

We describe a translation of scenarios given in UML 2.0 sequence diagrams into a tuples-based behavioural model that considers multiple access points for a participating instance and exhibits true-concurrency. This is important in a component setting since different access points are connected to different instances, which have no knowledge of each other. Interactions specified in a scenario are modelled using tuples of sequences, one sequence for each access point. The proposed unfolding of the sequence diagram involves mapping each location (graphical position) onto the so-called component vectors. The various modes of interaction (sequential, alternative, concurrent) manifest themselves in the order structure of the resulting set of component vectors, which captures the dependencies between participating instances. In previous work, we have described how (sets of) vectors generate concurrent automata. The extension to our model with sequence diagrams in this paper provides a way to verify the diagram against the state-based model