Pierre-Charles David

FPath and FScript: Language support for navigation and reliable reconfiguration of Fractal architectures

Component-based systems must support dynamic reconfigurations to adapt to their execution context, but not at the cost of reliability. Fractal provides intrinsic support for dynamic reconfiguration, but its definition in terms of low-level APIs makes it complex to write reconfigurations and to ensure their reliability. This article presents a language-based approach to solve these issues: direct and focused language support for architecture navigation and reconfiguration make it easier both to write the reconfigurations and to ensure their reliability. Concretely, this article presents two languages: (1) FPath, a domain-specific language that provides a concise yet powerful notation to navigate inside and query Fractal architectures, and (2) FScript, a scripting language that embeds FPath and supports the definition of complex reconfigurations. FScript ensures the reliability of these reconfigurations thanks to sophisticated run-time control, which provides transactional semantics (ACID properties) to the reconfigurations.

An Infrastructure for Adaptable Middleware

Todays software systems have to deal with an increasing diversity and complexity of execution environments. Next generation applications will have to deal with the unknown, with execution conditions which can not be predicted at the time they are written: they must be adaptable. In this paper, we present our current answer to this problem, in the form of an infrastructure for adaptable middleware. This infrastructure distinguishes functional components from non-functional services and enables dynamic reconfiguration of the associations between them. These associations are controlled by an adaptation engine which monitors both the execution environment and the application, and adapts the associations according to adaptation policies.

A multi-stage approach for reliable dynamic reconfigurations of component-based systems

In this paper we present an end-to-end solution to define and execute reliable dynamic reconfigurations of open component-based systems while guaranteeing their continuity of service. It uses a multi-stage approach in order to deal with the different kinds of possible errors in the most appropriate way; in particular, the goal is to detect errors as early as possible to minimize their impact on the target system. Reconfigurations are expressed in a restricted, domain-specific language in order to allow different levels of static and dynamic validation, thus detecting errors before executing the reconfiguration where possible. For errors that can not be detected early (including software and hardware faults), a runtime environment provides transactional semantics to the reconfigurations.