Contract Based Multi-party Service Composition

Choreographies in the wild

“…In [25] contracts are considered compliant when their composition may always reach success (so guaranteeing progress until success). In our work, progress is provided by the synthesis of a global type.…”

Towards a Unifying Theory for Choreography Conformance and Contract Compliance

“…The theory of contracts that we discuss in Section 3 is an extension of the theory reported in our paper [BZ06a]. More precisely, Section 3 is a revisitation of that theory in a slightly different context.…”

“…This notion is the same as in [BZ06a]. Intuitively, a system composed of contracts is correct if all possible computations may guarantee completion; this means that the system is both deadlock and livelock free (there could be an infinite computation, but given any possible prefix of this infinite computation, it can be extended to reach a successfully completed computation).…”

“…In fact, if we consider mixed choice it is easy to prove that there exists no maximal subcontract preorder family (see [BZ06a]). We will show that the maximal subcontract pre-order family can be achieved defining a more coarse form of refinement in which, given any system composed of a set of contracts, refinement is applied to one contract only (thus leaving the other unchanged).…”

“…This section is essentially an extension of our previous work [BZ06a]; the main novelty is that in the contract calculus we associate to contracts also an additional information indicating the location where the corresponding service is located. The presence of locations permits to prove new interesting results that did not hold in the theory reported in [BZ06a] (for this reason we need to completely revisit and extend the results already proved in [BZ06a]). Section 4 describes the exploitation of the theory of contract refinement in the context of choreography-based service composition.…”