Reconfiguring Distributed Reo Connectors [chapter]

Christian Koehler, Farhad Arbab, Erik de Vink
2009 Lecture Notes in Computer Science  
The coordination language Reo defines circuit-like connectors to steer the collaboration of independent components. In this paper, we present a framework for the modeling of distributed, self-reconfigurable connectors based on algebraic graph transformations. Reconfiguring a connector that is composed with others, may involve a change of shared interfaces and may therefore require a reconfiguration of the surrounding connectors as well. We present a method of synchronized local reconfigurations
more » ... in this setting and discuss a bottom-up strategy for coordinating synchronized reconfigurations in a connector network. We exploit the double-pushout approach for the modeling of reconfigurations, and propose an adaptation of the concept of amalgamation for synchronizing reconfigurations. We use a nondeterministic scheduler as our running example. Introduction Building software systems using an exogenous coordination language, such as Reo [1], is done by (i) implementing a set of (wrappers for existing) components or services and (ii) composing these entities using a kind of glue code. In the case of Reo, circuit-like connectors constitute the glue code. Connectors may consist of other connectors, but are elementarily composed from channels and nodes. Every connector implements a protocol defined by the semantics of its constituents, and the topology of the connector. Reconfiguring a connector means to change its topology and thereby the coordination protocol that it implements. Reconfiguration arises from the need to dynamically adapt the behavior of a system, e.g., in response to a change in its environment, to cope with altered resource availability or to retrofit it for a modified mission. The need for considering distributed connectors arises from two concerns. On the one hand, connectors are decomposed into logically separate parts, each of which defines a specific subprotocol. On the other hand, connectors can be deployed on different physical locations in a network. In both cases, the concept of distribution facilitates and promotes the use of black-boxed subconnectors in a larger context. In this paper, we propose a framework for modeling reconfigurable, distributed Reo connectors. We consider connectors that are distributed over a network and are encapsulated, i.e. their internals are hidden from the outside Supported by NWO GLANCE project WoMaLaPaDiA and SYANCO.
doi:10.1007/978-3-642-03429-9_15 fatcat:6keafxuuv5gxjanss74meyd43y