Interface Automata for Choreographies

Formal choreographic models yield a suitable frameworks to specify, analyse, and develop message-passing applications. In this application domain, orchestration has so far been preferred to choreography because the former offers a simpler approach to tame the complexity of developing distributed applications. On the one hand, orchestration yields a toolbox of handy and relatively simple solutions to practitioners. However, orchestration shows scalability limitations that choreographies seem able to tackle. Another key advantage of choreographies is the possibility of guaranteeing behavioural properties of applications “by construction”. Correct components can be (semi)automatically derived from correct global specifications. In this context it is crucial to verify the correctness of global specifications. In this thesis, we adopt the global choreographies of Guanciale and Tuosto to specify global views while we abstract components as special automata. More precisely, we generalise the class of interface automata of de Alfaro and Henzinger to group interface automata and equip them with two internal products, instrumental to the verification of “sound” global specifications. In particular, these products allow us to characterise erroneous states that potentially spoil interactions. A main result of our approach is that the absence of those erroneous state is equivalent to well-formedness of global choreographies, that is a sufficient property guaranteeing well-behaviour of local components projected from the global specification.