Modeling and Analysis of Self-Adaptive Systems Based on Graph Transformation

Software systems nowadays require continuous operation despite changes both in user needs and in their operational environments. Self-adaptive systems are typically instrumented with tools to autonomously perform adaptation to these changes while maintaining some desired properties. In this paper we model and analyze self-adaptive systems by means of typed, attributed graph grammars. The interplay of different grammars representing the application and the adaptation logic is realized by an adaption manager. Within this formal framework we define consistency and operational properties that are maintained despite adaptations and we give static conditions for their verification. The overall approach is supported by the AGG tool that offers the features for modeling, simulating, and analyzing graph transformation systems. A case study modeling a business process that adapts to changing environment conditions is used to demonstrate and validate the formal framework

Conditions, constraints and contracts: on the use of annotations for policy modeling.

Organisational policies express constraints on generation and processing of resources. However, application domains rely on transformation processes, which are in principle orthogonal to policy specifications and domain rules and policies may evolve in a non-synchronised way. In previous papers, we have proposed annotations as a flexible way to model aspects of some policy, and showed how they could be used to impose constraints on domain configurations, how to derive application conditions on transformations, and how to annotate complex patterns. We extend the approach by: allowing domain model elements to be annotated with collections of elements, which can be collectively applied to individual resources or collections thereof; proposing an original construction to solve the problem of annotations remaining orphan , when annotated resources are consumed; introducing a notion of contract, by which a policy imposes additional pre-conditions and post-conditions on rules for deriving new resources. We discuss a concrete case study of linguistic resources, annotated with information on the licenses under which they can be used. The annotation framework allows forms of reasoning such as identifying conflicts among licenses, enforcing the presence of licenses, or ruling out some modifications of a licence configuration

A requirements engineering approach for the development of web applications

Uno de los problemas más importantes que se propuso solucionar cuando apareció la Ingeniería Web fue la carencia de técnicas para la especificación de requisitos de aplicaciones Web. Aunque se han presentado diversas propuestas que proporcionan soporte metodológico al desarrollo de aplicaciones Web, la mayoría de ellas se centran básicamente en definir modelos conceptuales que permiten representar de forma abstracta una aplicación Web; las actividades relacionadas con la especificación de requisitos son vagamente tratadas por estas propuestas. Además, las técnicas tradicionales para la especificación de requisitos no proporcionan un soporte adecuado para considerar características propias de las aplicaciones Web como la Navegación. En esta tesis, se presenta una aproximación de Ingeniería de Requisitos para especificar los requisitos de las aplicaciones Web. Esta aproximación incluye mecanismos basados en la metáfora de tarea para especificar no sólo los requisitos relacionados con aspectos estructurales y de comportamiento de una aplicación Web sino también los requisitos relacionados con aspectos navegacionales. Sin embargo, una especificación de requisitos es poco útil si no somos capaces de transformarla en los artefactos software adecuados. Este es un problema clásico que la comunidad de Ingeniería del Software ha tratado de resolver desde sus inicios: cómo pasar del espacio del problema (requisitos de usuario) al espacio de la solución (diseño e implementación) siguiendo una guía metodológica clara y precisa. En esta tesis, se presenta una estrategia que, basándose en transformaciones de grafos, y estando soportada por un conjunto de herramientas, nos permite realizar de forma automática transformaciones entre especificaciones de requisitos basadas en tareas y esquemas conceptuales Web. Además, esta estrategia se ha integrado con un método de Ingeniería Web con capacidades de generación automática de código. Esta integración nos permite proporcionar un mecanisValderas Aranda, PJ. (2008). A requirements engineering approach for the development of web applications [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/1997Palanci

A heuristic-based approach to code-smell detection

Encapsulation and data hiding are central tenets of the object oriented paradigm. Deciding what data and behaviour to form into a class and where to draw the line between its public and private details can make the difference between a class that is an understandable, flexible and reusable abstraction and one which is not. This decision is a difficult one and may easily result in poor encapsulation which can then have serious implications for a number of system qualities. It is often hard to identify such encapsulation problems within large software systems until they cause a maintenance problem (which is usually too late) and attempting to perform such analysis manually can also be tedious and error prone. Two of the common encapsulation problems that can arise as a consequence of this decomposition process are data classes and god classes. Typically, these two problems occur together – data classes are lacking in functionality that has typically been sucked into an over-complicated and domineering god class. This paper describes the architecture of a tool which automatically detects data and god classes that has been developed as a plug-in for the Eclipse IDE. The technique has been evaluated in a controlled study on two large open source systems which compare the tool results to similar work by Marinescu, who employs a metrics-based approach to detecting such features. The study provides some valuable insights into the strengths and weaknesses of the two approache

A formal framework for model management

El Desarrollo de Software Dirigido por Modelos es una rama de la Ingeniería del Software en la que los artefactos software se representan como modelos para incrementar la productividad, calidady eficiencia económica en el proceso de desarrollo de software, donde un modelo proporciona una representación abstracta del código final de una aplicación. En este campo, la iniciativa Model-Driven Architecture (MDA), patrocinada por la OMG, está constituida por una familia de estándares industriales, entre los que se destacan: Meta-Object Facility (MOF), Unified Modeling Language (UML), Object Constraint Language (OCL), XML Metadata Interchange (XMI), y Query/Views/Transformations (QVT). Estos estándares proporcionan unas directrices comunes para herramientas basadas en modelos y para procesos de desarrollo de software dirigidos por modelos. Su objetivo consiste en mejorar la interoperabilidad entre marcos de trabajo ejecutables, en automatizar el proceso desarrollo de software de software y en proporcionar técnicas que eviten errores durante ese proceso. El estándar MOF describe un marco de trabajo genérico que permite definir la sintaxis abstracta de lenguajes de modelado. Este estándar persigue la definición de los conceptos básicos que son utilizados en procesos de desarrollo de software dirigidos por modelos: que es un modelo, que es un metamodelo, qué es reflexión en un marco de trabajo basado en MOF, etc. Sin embargo, la mayoría de estos conceptos carecen de una semántica formal en la versión actual del estándar MOF. Además, OCL se utiliza como un lenguage de definición de restricciones que permite añadir semántica a un metamodelo MOF. Desafortunadamente, la relación entre un metamodelo y sus restricciones OCL también carece de una semántica formal. Este hecho es debido, en parte, a que los metamodelos solo pueden ser definidos como dato en un marco de trabajo basado en MOF. El estándar MOF también proporciona las llamadas facilidades de reflexión de MOF (MOF ReflectiBoronat Moll, A. (2007). A formal framework for model management [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/1964Palanci

Software Architecture Evolution

This chapter provides an overview, comparison and detailed treatment of the various state-of-the-art approaches to evolving software architectures. Furthermore, we discuss one particular framework for software architecture evolution in more detail

PTL: A Model Transformation Language based on Logic Programming

In this paper we present a model transformation language based on logic programming. The language, called PTL (Prolog based Transformation Language), can be considered as a hybrid language in which ATL (Atlas Transformation Language)-style rules are combined with logic rules for defining transformations. ATL-style rules are used to define mappings from source models to target models while logic rules are used as helpers. The implementation of PTL is based on the encoding of the ATL-style rules by Prolog rules. Thus, PTL makes use of Prolog as a transformation engine. We have provided a declarative semantics to PTL and proved the semantics equivalent to the encoded program. We have studied an encoding of OCL (Object Constraint Language) with Prolog goals in order to map ATL to PTL. Thus a subset of PTL can be considered equivalent to a subset of ATL. The proposed language can be also used for model validation, that is, for checking constraints on models and transformations. We have equipped our language with debugging and tracing capabilities which help developers to detect programming errors in PTL rules. Additionally, we have developed an Eclipse plugin for editing PTL programs, as well as for debugging, tracing and validation. Finally, we have evaluated the language with several transformation examples as well as tested the performance with large models