Doctor en Ciencias, Mención Computación / It is inevitable that some concerns crosscut a sizable application, resulting in code scattering and tangling. This issue is particularly severe for security-related concerns: it is difficult to be confident about the security of an application when the implementation of its security related concerns is scattered all over the code and tangled with other concerns, making global reasoning about security precarious. In this thesis work, we consider the case of access control, a cornerstone of every security architecture, which turns out to be a crosscutting concern with a non-modular implementation based on runtime stack inspection in mainstream languages such as Java and C#. We make use of aspect orientation for the modular definition of access control. More precisely, we design and implement access control, including the advanced features associated to it, in a modular way. We demonstrate that this modular implementation is secure, even in the presence of untrusted aspects. A modular implementation alleviates maintenance and evolution issues produced by the crosscutting nature of access control, and, more importantly, paves the way to global reasoning about access control.

La programmation orientée aspect (AOP) vise à améliorer la modularité et la réutilisation des couches logiciels en proposant un mécanisme d’abstraction pour faire face aux préoccupations transversales. Cependant, dans la plupart des langages d’aspects généralistes, les aspects ont un pouvoir presque illimité, rentrant éventuellement en conflit avec ces objectifs. Dans ce travail, nous présentons Effective Aspects : une nouvelle approche pour incorporer le modèle pointcut/advice de l’AOP dans un langage de programmation fonctionnel statiquement typé comme Haskell. Notre travail comprend deux contributions principales. Premièrement, nous définissons un plongement monadique du modèle pointcut/advice complet de l’AOP. La correction du typage est garantie par l’exploitation du système de type sous-jacent, en particulier les types fantômes et une nouvelle classe de type pour faire de l’anti-unification de types. Dans ce modèle, les aspects sont de première classe, peuvent être déployés de façon dynamique, et le langage de pointcuts est extensible, combinant donc la flexibilité des langages d’aspect typés dynamiquement avec les garanties d’un système de type statique. Les monades nous permettent de raisonner directement sur les effets du calcul à la fois dans les aspects et les programmes de base en utilisant des techniques monadiques traditionnelle. Avec ce système, nous étendons la notion de “open modules” avec des effets, et aussi avec les interfaces de pointcut protégés à l’extérieur d’un advice. Ces restrictions sont appliquées statiquement par le système de type. Aussi, nous adaptons les techniques de EffectiveAdvice afin de raisonner sur des propriétés du flot de contrôle. En outre, nous montrons comment contrôler l’interférence des effets en utilisant l’approche fondée sur la paramétricité de EffectiveAdvice. Nous montrons que cette approche n’est pas satisfaisante en présence de multiples aspects et proposons une approche différente en utilisant des vues monadiques, une nouvelle technique pour le traitement de la pile monadique, développée par Schrijvers et Oliveira. Ensuite, nous exploitons les propriétés de notre modèle pour permettre la construction modulaire de nouvelles sémantiques pour la portée d’aspects et le tissage. Notre deuxième contribution s’appuie sur un modèle puissant pour raisonner sur la composition de mixins avec effets et leur interférence, fondée sur un raisonnement équationnelle, paramétrique, et les lois algébriques sur les effets monadiques. Notre contribution est de montrer comment raisonner sur l’interférence en présence de quantification sans restriction pour les pointcuts. Nous montrons que le raisonnement global peut être compositionnelle, ce qui est essentiel pour le passage à l’échelle de l’approche face aux évolutions de grands systèmes. / Aspect-oriented programming (AOP) aims to enhance modularity and reusability in software systems by offering an abstraction mechanism to deal with crosscutting concerns. But, in most general-purpose aspect languages aspects have almost unrestricted power, eventually conflicting with these goals. This work presents Effective Aspects: a novel approach to embed the pointcut/advice model of AOP in a statically-typed functional programming language like Haskell; along two main contributions. First, we define a monadic embedding of the full pointcut/advicemodel of AOP. Type soundness is guaranteed by exploiting the underlying type system, in particular phantom types and a new anti-unification type class. In this model aspects are first-class, can be deployed dynamically, and the pointcut language is extensible, therefore combining the flexibility of dynamically-typed aspect languages with the guarantees of a static type system. Monads enable us to directly reason about computational effects both in aspects and base programs using traditional monadic techniques. Using this we extend the notion of Open Modules with effects, and also with protected pointcut interfaces to external advising. These restrictions are enforced statically using the type system. Also, we adapt the techniques of EffectiveAdvice to reason about and enforce control flow properties as well as to control effect interference. We show that the parametricity-based approach to effect interference falls short in the presence of multiple aspects and propose a different approach using monad views, a novel technique for handling the monad stack, developed by Schrijvers and Oliveira. Then, we exploit the properties of our model to enable the modular construction of new semantics for aspect scoping and weaving. Our second contribution builds upon a powerful model to reason about mixin-based composition of effectful components and their interference, based on equational reasoning, parametricity, and algebraic laws about monadic effects. Our contribution is to show how to reason about interference in the presence of unrestricted quantification through pointcuts. We show that global reasoning can be compositional, which is key for the scalability of the approach in the face of large and evolving systems. We prove a general equivalence theorem that is based on a few conditions that can be established, reused, and adapted separately as the system evolves. The theorem is defined for an abstract monadic AOP model; we illustrate its use with a simple version of the model just described. This work brings type-based reasoning about effects for the first time in the pointcut/advice model, in a framework that is expressive, extensible and well-suited for development of robust aspect-oriented systems as well as a research tool for new aspect semantics.

A programação orientada a aspectos é uma abordagem que utiliza conceitos da separação de interesses para modularizar o software de maneira mais adequada. Com o surgimento dessa abordagem vieram também novos desafios, dentre eles o teste de programas orientados a aspectos. Duas estratégias de ordenação de classes e aspectos para apoiar o teste de integração orientado a aspectos são propostas nesta tese. As estratégias de ordenação tem o objetivo de diminuir o custo da atividade de teste por meio da diminuição do número de stubs implementados durante o teste de integração. As estratégias utilizam um modelo de dependências aspectuais e um modelo que descreve dependências entre classes e aspectos denominado AORD (Aspect and Oriented Relation Diagram) também propostos neste trabalho. Tanto o modelo de dependências aspectuais como o AORD foram elaborados a partir da sintaxe e semântica da linguagem AspectJ. Para apoiar as estratégias de ordenação, idealmente aplicadas durante a fase de projeto, um processo de mapeamento de modelos de projeto que usam as notações UML e MATA para o AORD é proposto neste trabalho. O processo de mapeamento é composto de regras que mostram como mapear dependências advindas da programação orientada a objetos e também da programação orientada a aspectos. Como uma forma de validação das estratégias de ordenação, do modelo de dependências aspectuais e do AORD, um estudo exploratório de caracterização com três sistemas implementados em AspectJ foi conduzido. Durante o estudo foram coletadas amostras de casos de implementação de stubs e drivers de teste. Os casos de implementação foram analisados e classificados. A partir dessa análise e classificação, um catálogo de stubs e drivers de teste é apresentado / Aspect-oriented programming is an approach that uses principles of separation of concerns to improve the sofware modularization. Testing of aspect-oriented programs is a new challenge related to this approach. Two aspects and classes test order strategies to support integration testing of aspect-oriented programs are proposed in this thesis. The objective of these strategies is to reduce the cost of testing activities through the minimization of the number of implemented stubs during integration test. An aspectual dependency model and a diagram which describes dependencies among classes and aspects called AORD (Aspect and Object Relation Diagram) used by the ordering strategies are also proposed. The aspectual dependency model and the AORD were defined considering the syntax constructions and the semantics of AspectJ. As the proposed estrategies should be applied in design phase of software development, a process to map a desing model using UML and MATA notations into a AORD is proposed in order to support the ordering strategies. The mapping process is composed by rules that show how to map both aspect and object-oriented dependencies. A characterization exploratory study using three systems implemented with AspectJ was conducted to validate the ordering strategies, the aspectual dependency model and the AORD. Interesting samples of stubs implementations were collected during the study conduction. The stubs were analyzed and classified. Based on these analysis and classification a catalog of stubs and drivers is presented

Hardware engineers frequently create formal specification documents as part of the verification process. Doing so is a time-consuming and error-prone process, as the primary documents for communications and standards use a mixture of prose, diagrams and tables. We would like this process to be partially automated, in which the engineer's role would be to refine a machine-generated skeleton of a specification's formal model. We have created a preliminary intermediate language which allows specifications to be captured using formal semantics, and allows an engineer to easily find, understand, and modify critical portions of the specification. We have converted most of ARM's AMBA AHB specification to our language; our representation is able to follow the structure of the original document.

Uma Linha de Produtos de Software (LPS) consiste de um conjunto de sistemas de software que compartilham características comuns e satisfazem às necessidades específicas de um segmento particular. Para tornar o processo de instanciação de produtos mais rápido e menos suscetível a erros, o projeto de uma LPS pode adotar a utilização de geradores de aplicação, que podem gerar os artefatos da LPS utilizando uma especificação das variabilidades de um certo produto. Adicionalmente, notase que determinadas características transversais de uma linha de produtos têm potencial de reúso em diferentes domínios, podendo ser implementadas usando a programação orientada a aspectos (POA). Neste trabalho é proposto um processo para o desenvolvimento de LPS e geração automatizada de produtos levando em consideração os interesses transversais existentes em cada domínio de aplicação. Os interesses transversais são as características comuns espalhadas pelas divisões ou módulos do programa de diferentes domínios. O processo aqui proposto tem a finalidade de aumentar o reúso de características de linhas de produtos por meio da POA, permitindo que as LPSs sejam projetadas de forma mais coesa e, consequentemente, facilitando sua manutenção e evolução. Visando diminuir o esforço necessário para a instanciação dos produtos provenientes dessas linhas de produtos, neste trabalho também é apresentada uma extensão do gerador Captor, denominada Captor-AO. Esse gerador fornece suporte ao processo proposto, permitindo a criação de produtos formados por características de diferentes domínios. Por fim, é apresentado um estudo de caso em que é realizada a configuração de um domínio transversal para o interesse de persistência, a definição de um domínio-base compatível com esse domínio transversal e a geração de produtos formados pelas características de ambos os domínios utilizando o gerador estendido Captor-AO / A Software Product Line (SPL) consists of a set of software systems that share common features and fulfill the specific requirements of a particular domain. In order to make the products instantiation process faster and less prone to errors, the project of a SPL can adopt the utilization of application generators, which can can automatically generate the SPL artifacts based on the specification of the variabilities of a particular product. Additionally, it can be noticed that certain crosscutting features of a product line have potencial to be reused in different domains, so they can be implemented using aspect oriented programming (AOP). In this work, a process is proposed for the development of SPLs and automatic generation of products, considering the crosscutting concerns present in each application domain. The crosscutting concerns are related to the common features that are scattered around program divisions or modules of different domains. The process proposed here has the goal of enhancing the reuse of SPL features using AOP, allowing the design of SPL in a more cohesive way and, thus, easing its maintenance and evolution. Aiming at decreasing the effort needed to instantiate products from these SPL, this work also presents an extension to the Captor application generator, named Captor-AO. This generator supports the proposed process, allowing the creation of products composed by features of different domains. Finally, a case study is presented in which Captor-AO is configured with two domains: a crosscutting domain for the persistence concern and a base domain compatible with this crosscutting domain, such that the generation of products can be done by composing features of both domains

In dynamic pointcut-advice join point models of Aspect-Oriented Programming (AOP), join points are typically selected and advised independently of each other. That is, the relationships between join points are not considered in join point selection and advice. But these inter-relationships are key to the designation and advice of arbitrary pieces of code when modularizing concerns such as exception handling and synchronization. Without a mechanism for associating join points, one must instead refactor (if possible) into one method the two or more related join points that are to be advised together. In practice, join points are often not independent. Instead, they form part of a higher-level operation that implements the intent of the developer (e.g. managing a resource). This relationship should be made more explicit. We extend the dynamic pointcut-advice join point model to make possible the designation, reication, and advice of interrelated join points. The Transactional Pointcut (transcut), which is a realization of this extended model, is a special join point designator that selects sets of interrelated join points. Each match of a transcut is a set of join points that are related through control ow, dataow, or both. This allows transcuts to dene new types of join points (pieces of computation) by capturing the key points of a computation and to provide effective access for their manipulation (i.e. advice). Essentially, transcuts almost eliminate the need for refactoring to expose join points, which is shown by others to have a signicant negative effect on software quality. The transcut construct was implemented as an extension to the AspectJ language and integrated into the AspectBench compiler. We used transcuts to modularize the concern of exception handling in two real-world software systems. The results show that transcuts are effective in designating target join points without unnecessary refactorings, even when the target code is written obliviously to the potential aspectization.

Program behavior that relies on contextual information, such as physical location or network accessibility, is common in today's applications, yet its representation is not sufficiently supported by programming languages. With context-oriented programming (COP), such context-dependent behavioral variations can be explicitly modularized and dynamically activated. In general, COP could be used to manage any context-specific behavior. However, its contemporary realizations limit the control of dynamic adaptation. This, in turn, limits the interaction of COP's adaptation mechanisms with widely used architectures, such as event-based, mobile, and distributed programming. The JCop programming language extends Java with language constructs for context-oriented programming and additionally provides a domain-specific aspect language for declarative control over runtime adaptations. As a result, these redesigned implementations are more concise and better modularized than their counterparts using plain COP. JCop's main features have been described in our previous publications. However, a complete language specification has not been presented so far. This report presents the entire JCop language including the syntax and semantics of its new language constructs. / Das Verhalten von modernen Software-Anwendungen benötigt häufig Informationen über den Kontext ihrer Ausführung, z.B. die geografische Position, die Tageszeit oder die aktuelle Netzwerkbandbreite. Dennoch bieten heutige Programmiersprachen nur wenig Unterstützung für die Repräsentation kontextspezifischen Verhaltens. Kontextorientiertes Programmieren ist ein Ansatz, der die explizite Modularisierung und Laufzeitaktivierung von kontextspezifischem Verhalten auf der Ebene von Programmiersprachkonstrukten ermöglicht. Die bisherigen Umsetzungen von kontextorientiertem Programmieren schränken jedoch die Kontrolle der Laufzeitaktivierungen solches kontextspezifischen Verhaltens ein. Daraus folgt eine Einschränkung der Anwendungsbereiche für kontextorientiertes Programmieren, unter anderem für solche Domänen, in denen Programme sehr häufig kontextabhängiges Verhalten bereitstellen, z.B. ereignisbasierte, mobile und dienstorientierte Systeme. Die Programmiersprache JCop erweitert Java um Sprachkonstrukte für kontextorientieres Programmieren und bietet zusätzlich eine domänenspezifische Aspektsprach an, mit deren Hilfe Laufzeitadaptionen deklarativ spezifiziert werden können. Die Kernkonzepte von JCop wurden bereits in mehrern Publikationen vorgestellt, dieser Bericht enthält nun eine umfassende Sprachspezifikation von JCop.

Crosscutting concerns are the issues in software that cannot be modularized within a software module. In this thesis work, a detailed evaluation of the use of Aspect Oriented Programming for the implementation of crosscutting concerns in embedded real-time systems is presented. The pilot Audio Switch project implementations are first evaluated in terms of software quality attributes. Then a detailed analysis of the two implementations, according to embedded real-time performance metrics has been carried out. Evaluation results show the benefits of Aspect Oriented Programming in embedded real-time systems.

Aspects are units of aspect oriented programming developed for influencing the software behavior. In order to use an aspect confidently in any software, first it should be verified. For verification of an aspect, the mock classes for the original software should be prepared. These mock classes are a model of the aspect environment which the aspect is woven. In this study, considering that there are not enough tools for supporting the aspect oriented programming developers, we have developed a tool for enabling aspect verification and unit testing. The tool enables verification by generating the general environment of the aspect. By this tool the users are ensured to focus on the verification of aspects isolated from woven software.

No description available.