Reasoning about software reconfigurations: The behavioural and structural perspectives

•An algebra of reconfigurations for software connectors.•Behavioural and structural perspectives to reason about reconfigurations.•A hybrid logic to investigate structural properties of connectors reconfigurations.•A case study on medical domain to show the applicability of the results.

Software connectors encapsulate interaction patterns between services in complex, distributed service-oriented applications. Such patterns encode the interconnection between the architectural elements in a system, which is not necessarily fixed, but often evolves dynamically. This may happen in response to faults, degrading levels of QoS, new enforced requirements or the re-assessment of contextual conditions. To be able to characterise and reason about such changes became a major issue in the project of trustworthy software.This paper discusses what reconfiguration means within coordination-based models of software design. In these models computation and interaction are kept separate: components and services interact anonymously through specific connectors encoding the coordination protocols. In such a setting, of which Reo is a paradigmatic illustration, the paper introduces a model for connector reconfigurations, from both a structural and a behavioural perspective.