Marco Antonio Barbosa

Specifying software connectors

Orchestrating software components, often from independent suppliers, became a central concern in software construction. Actually, as relevant as components themselves, are the ways in which they can be put together to interact and cooperate in order to achieve some common goal. Such is the role of the so-called software connectors: external coordination devices which ensure the flow of data and enforce synchronization constraints within a component’s network. This paper introduces a new model for software connectors, based on relations extended in time, which aims to provide support for light inter-component dependency and effective external control.

An Orchestrator for Dynamic Interconnection of Software Components

Composing and orchestrating software components is a fundamental concern in modern software engineering. This paper addresses the possibility of such orchestration being dynamic, in the sense that the structure of components interconnection patterns can change at run-time. The envisaged approach extends previous work by the authors on the use of coalgebraic models for the specification of software connectors.

A coordination model for interactive components

Although presented with a variety of ‘flavours’, the notion of an interactor, as an abstract characterisation of an interactive component, is well-known in the area of formal modelling techniques for interactive systems. This paper replaces traditional, hierarchical, ‘tree-like’ composition of interactors in the specification of complex interactive systems, by their exogenous coordination through general-purpose software connectors which assure the flow of data and the meet of synchronisation constraints. The paper’s technical contribution is twofold. First a modal logic is defined to express behavioural properties of both interactors and connectors. The logic is new in the sense that its modalities are indexed by fragments of sets of actions to cater for action co-occurrence. Then, this logic is used in the specification of both interactors and coordination layers which orchestrate their interconnection.

Towards a Coordination Model for Interactive Systems

When modelling complex interactive systems, traditional interactor-based approaches suffer from lack of expressiveness regarding the composition of the different interactors present in the user interface model into a coherent system. In this paper we investigate an alternative approach to the composition of interactors for the specification of complex interactive systems which is based on the coordination paradigm. We layout the fundations for the work and present an illustrative example. Lines for future work are identified.

Configurations of Web Services

The quest for sound foundations for the orchestration of web services is still open. To a great extent its relevance comes from the possibility of defining formal semantics for new language standards (like BPEL4WS or WS-CDL) in this emerging and challenging technology. As a step in that direction, this paper resorts to a notion of configuration, developed by the authors in the context of a Reo-like exogenous coordination model for software components, to formally express service orchestration. The latter is regarded as involving both the architectural assembly of independent services and the description of their interactions.

Revisiting Context-Aware Component Interconnection

Software connectors are external coordination devices which ensure the flow of data and enforce synchronization constraints within a component’s network. The specification of software connectors through which context dependent behaviour is correctly propagated remains an open, non trivial issue in their semantics. This paper, building on previous work by the authors, revisits this problem and introduces a model in which context awareness is suitably handled.