Integrated Structure and Semantics for Reo Connectors and Petri Nets

In this paper, we present an integrated structural and behavioral model of Reo connectors and Petri nets, allowing a direct comparison of the two concurrency models. For this purpose, we introduce a notion of connectors which consist of a number of interconnected, user-defined primitives with fixed behavior. While the structure of connectors resembles hypergraphs, their semantics is given in terms of so-called port automata. We define both models in a categorical setting where composition operations can be elegantly defined and integrated. Specifically, we formalize structural gluings of connectors as pushouts, and joins of port automata as pullbacks. We then define a semantical functor from the connector to the port automata category which preserves this composition. We further show how to encode Reo connectors and Petri nets into this model and indicate applications to dynamic reconfigurations modeled using double pushout graph transformation

Towards an engine for coordination-based architectural reconfigurations

Software reconfigurability became increasingly relevant to the architectural process due to the crescent dependency of modern societies on reliable and adaptable systems. Such systems are supposed to adapt themselves to surrounding environmental changes with minimal service disruption, if any. This paper introduces an engine that statically applies reconfigurations to (formal) models of software architectures. Reconfigurations are specified using a domain specific language— ReCooPLa—which targets the manipulation of software coordinationstructures,typicallyusedinservice-orientedarchitectures(soa).Theengine is responsible for the compilation of ReCooPLa instances and their application to the relevant coordination structures. The resulting configurations are amenable to formal analysis of qualitative and quantitative (probabilistic) properties.This work is partly funded by ERDF - European Regional Development Fund through the COMPETE Programme (operational programme for competitiveness) and by National Funds through the FCT, the Portuguese Foundation for Science and Technology, within project FCOMP-01-0124-FEDER-028923. The second author is supported by an Individual Doctoral Grant from FCT, with reference SFRH/BD/71475/2010

Reconfiguration mechanisms for service coordination

Serie : Lecture notes in computer science, ISSN 0302-9743, vol. 7843Models for exogenous coordination provide powerful glue- code, in the form of software connectors, to express interaction protocols between services in distributed applications. Connector reconfiguration mechanisms play, in this setting, a major role to deal with change and adaptation of interaction protocols. This paper introduces a model for connector reconfiguration, based on a collection of primitives as well as a language to specify connectors and their reconfigurations.Fundação para a Ciência e a Tecnologia (FCT

Reconfiguration of Reo Connectors Triggered by Dataflow

Reo is a language for coordinating autonomous components in distributed environments. Coordination in Reo is performed by circuit-like connectors, which are constructed from primitive, mobile channels with well-defined behaviour. While the structure of a connector can be modeled as a graph, its behaviour is compositionally defined using that of its primitive constituents. In previous work, we showed that graph transformation techniques are well-suited to model reconfigurations of connectors. In this paper, we investigate how the connector colouring semantics can be used to perform dynamic reconfigurations. Dynamic reconfigurations are triggered by dataflow in the connector at runtime, when certain structural patterns enriched with dataflow annotations occur. For instance we are able to elegantly model dynamic Reo circuits, such as just-in-time augmentation of single-b

Distributed Port Automata

Dynamic reconfigurations are a powerful approach for the adaption of component-based or service-oriented software systems at runtime. Important issues in this area are the problems of state transfer and state consistency, i.e., to determine the system state after a reconfiguration and to ensure that it is valid. To deal with these problems, we introduce distributed port automata in this paper. Distributed port automata combine structural and behavioral system properties and therefore allow to reason about dynamic reconfigurations. In our approach, we use an automata-based model for describing the behavior of the primitive building blocks in a system, and a graph-based model for describing its structure in terms of a network. We demonstrate how to derive the system semantics of a distributed port automaton and show that it is compositional. We consider an encoding of the coordination language Reo and show a new result on compositionality of flattening for distributed graphs

Modelling and Analysis Using GROOVE

In this paper we present case studies that describe how the graph transformation tool GROOVE has been used to model problems from a wide variety of domains. These case studies highlight the wide applicability of GROOVE in particular, and of graph transformation in general. They also give concrete templates for using GROOVE in practice. Furthermore, we use the case studies to analyse the main strong and weak points of GROOVE