Composition and Self-Adaptation of Service-Based Systems with Feature Models

The adoption of mechanisms for reusing software in pervasive systems has not yet become standard practice. This is because the use of pre-existing software requires the selection, composition and adaptation of prefabricated software parts, as well as the management of some complex problems such as guaranteeing high levels of efficiency and safety in critical domains. In addition to the wide variety of services, pervasive systems are composed of many networked heterogeneous devices with embedded software. In this work, we promote the safe reuse of services in service-based systems using two complementary technologies, Service-Oriented Architecture and Software Product Lines. In order to do this, we extend both the service discovery and composition processes defined in the DAMASCo framework, which currently does not deal with the service variability that constitutes pervasive systems. We use feature models to represent the variability and to self-adapt the services during the composition in a safe way taking context changes into consideration. We illustrate our proposal with a case study related to the driving domain of an Intelligent Transportation System, handling the context information of the environment.Work partially supported by the projects TIN2008-05932, TIN2008-01942, TIN2012-35669, TIN2012-34840 and CSD2007-0004 funded by Spanish Ministry of Economy and Competitiveness and FEDER; P09-TIC-05231 and P11-TIC-7659 funded by Andalusian Government; and FP7-317731 funded by EU. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Statistical Model Checking for Product Lines

International audienceWe report on the suitability of statistical model checking forthe analysis of quantitative properties of product line models by an extendedtreatment of earlier work by the authors. The type of analysis thatcan be performed includes the likelihood of specific product behaviour,the expected average cost of products (in terms of the attributes of theproducts’ features) and the probability of features to be (un)installed atruntime. The product lines must be modelled in QFLan, which extendsthe probabilistic feature-oriented language PFLan with novel quantitativeconstraints among features and on behaviour and with advancedfeature installation options. QFLan is a rich process-algebraic specifi-cation language whose operational behaviour interacts with a store ofconstraints, neatly separating product configuration from product behaviour.The resulting probabilistic configurations and probabilistic behaviourconverge in a discrete-time Markov chain semantics, enablingthe analysis of quantitative properties. Technically, a Maude implementationof QFLan, integrated with Microsoft’s SMT constraint solver Z3,is combined with the distributed statistical model checker MultiVeStA,developed by one of the authors. We illustrate the feasibility of our frameworkby applying it to a case study of a product line of bikes

Foundations of Coloring Algebra with Consequences for Feature-Oriented Programming

Abstract. In 2011, simple and concise axioms for feature compositions, interactions and products have been proposed by Batory et al. They were mainly inspired by Kästner’s Colored IDE (CIDE) as well as by experience in feature oriented programming over the last decades. However, so far only axioms were proposed; consequences of these axioms such as variability in models have not been studied. In this paper we discuss the proposed axioms from a theoretical point of view, which yields a much better understanding of the proposed algebra and therefore of feature oriented programming. For example, we show that the axioms characterising feature composition are isomorphic to set-theoretic models.

Use Case Level Pointcuts

Software developers create a variety of artifacts that model the behaviour of applications at di#erent levels of abstraction; e.g. use cases, sequence diagrams, and source code. Aspect-oriented programming languages, such as AspectJ, support the modularization of crosscutting concerns at the source code level. However, crosscutting concerns also arise in other behavioural models of software systems. We provide a new aspect language, AspectU, which supports modularization of crosscutting concerns in the use-case model. Further, we provide a prototype tool that partially translates AspectU aspects into AspectJ aspects. To facilitate this translation we introduce a third aspect language, AspectSD, which targets the sequence-diagram model. AspectU together with our translation tool allows developers to express advice using use case level concepts while still a#ecting the runtime behaviour of a system, yielding a natural and intensional expression of some concerns

Structured document algebra in action

A Structured Document Algebra (SDA) defines modules with variation points and how such modules compose. The basic operations are module addition and replacement. Repeated addition can create nested module structures. SDA also allows the decomposition of modules into smaller parts. In this paper we show how SDA modules can be used to deal algebraically with Software Product Lines (SPLs). In particular, we treat some fundamental concepts of SPLs, such as refinement and refactoring. This leads to mathematically precise formalization of fundamental concepts used in SPLs, which can be used for improved Feature-Oriented Software Development (FOSD) tooling