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.