iCONNECT – Emergent Middleware Enablers
Participant : Valérie Issarny [correspondent] .
As part of our research work on Emergent Middleware, we have implemented Enablers (or Enabler functionalities) that make part of the overall Connect architecture realizing Emergent Middleware in practice  . The focus of ARLES work is on the: Discovery enabler that builds on our extensive background in the area of interoperable pervasive service discovery; and Synthesis enabler that synthesizes mediators that allow networked systems that have compatible functionalities to interact despite mismatching interfaces and/or behaviors.
The Connect Discovery Enabler is the component of the overall Connect architecture that handles discovery of networked systems (NSs), stores their descriptions (NS models), and performs an initial phase of matchmaking to determine which pairs of systems are likely to be able to interoperate. Such pairs are then passed to the Synthesis Enabler so that mediators can be generated. The Discovery Enabler is written in Java and implements several legacy discovery protocols including DPWS and UPnP.
The proposed solution to mediator synthesis assumes an ontology-based system description à la OWL-S, which is made available by the Discovery Enabler, possibly helped by machine learning. The semantically-annotated interfaces of systems that need to communicate are then processed to compute the semantic mapping between their respective operations using a constraint solver. The resulting mapping serves generating a mediator process that further coordinates the behaviors of the systems and guarantees their successful interaction. The mediator is deployed on a dedicated engine able to parse and compose middleware messages and convert them to fit each system expectations regarding the type and order of these messages.
The Connect Enablers have been integrated and experimented with by the Connect consortium to effectively enable Emergent Middleware. Part of them are available for download under an open source license at the Connect Web site at https://www.connect-forever.eu/software.html .