Generic meta-modelling with concepts, templates and mixin layers

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-16145-2_2Proceedings of 13th International Conference, MODELS 2010, Oslo, Norway, October 3-8, 2010.Meta-modelling is a key technique in Model Driven Engineering, where it is used for language engineering and domain modelling. However, mainstream approaches like the OMG’s Meta-Object Facility provide little support for abstraction, modularity, reusability and extendibility of (meta-)models, behaviours and transformations. In order to alleviate this weakness, we bring three elements of generic programming into meta-modelling: concepts, templates and mixin layers. Concepts permit an additional typing for models, enabling the definition of behaviours and transformations independently of meta-models, making specifications reusable. Templates use concepts to express requirements on their generic parameters, and are applicable to models and meta-models. Finally, we define functional layers by means of meta-model mixins which can extend other meta-models. As a proof of concept we also report on MetaDepth, a multi-level meta-modelling framework that implements these ideas.Work sponsored by the Spanish Ministry of Science, project TIN2008-02081 and mobility grants JC2009-00015 and PR2009-0019, and by the R&D programme of the Community of Madrid, project S2009/TIC-165

From types to type requirements: Genericity for model-driven engineering

The final publication is available at Springer via http://dx.doi.org/10.1007/s10270-011-0221-0Model-driven engineering (MDE) is a software engineering paradigm that proposes an active use of models during the development process. This paradigm is inherently type-centric, in the sense that models and their manipulation are defined over the types of specific meta-models. This fact hinders the reuse of existing MDE artefacts with other meta-models in new contexts, even if all these meta-models share common characteristics. To increase the reuse opportunities of MDE artefacts, we propose a paradigm shift from type-centric to requirement-centric specifications by bringing genericity into models, meta-models and model management operations. For this purpose, we introduce so-called concepts gathering structural and behavioural requirements for models and meta-models. In this way, model management operations are defined over concepts, enabling the application of the operations to any meta-model satisfying the requirements imposed by the concept. Model templates rely on concepts to define suitable interfaces, hence enabling the definition of reusable model components. Finally, similar to mixin layers, templates can be defined at the meta-model level as well, to define languages in a modular way, as well as layers of functionality to be plugged-in into other meta-models. These ideas have been implemented in MetaDepth, a multi-level meta-modelling tool that integrates action languages from the Epsilon family for model management and code generation.This work has been sponsored by the Spanish Ministry of Science and Innovation with projects METEORIC (TIN2008-02081) and Go Lite (TIN2011-24139), and by the R&D program of the Community of Madrid with project “e-Madrid” (S2009/TIC-1650)

Interoperability and Composition of DSLs with Melange

Domain-Specific Languages (DSLs) are now developed for a wide variety of domains to address specific concerns in the development of complex systems. However, DSLs and their tooling still suffer from substantial development costs which hamper their successful adoption in the industry. For over a decade, researchers and practitioners have developed language workbenches with the promise to ease the development of DSLs. Despite many advances, there is still little support for advanced scenarios such as language evolution, composition , and interoperability. In this paper, we present a modular approach for assembling DSLs from other ones and seamlessly evolving them, while ensuring the reuse of associated tools through subsequent versions or across similar DSLs. We introduce the conceptual foundations of our approach, its implementation in the Melange language workbench, and summarize its benefits on various case studies

Rapid Prototyping of Domain-Specific Architecture Languages

International audienceSoftware architecture has become a sensitive discipline, which consists in concretizing the user requirements into a set of artifacts that can be used to model and reason about the software to be developed. However, the architect often relies on its own knowledge to map domain-specific requirements onto generic software abstractions. Most of the time, this leads to the definition of repetitive tasks and architecture fragments, which can be particularly error prone. We therefore believe that architects need a more flexible approach to cope with the definition of domain-specific architectures by leveraging general purpose architecture description languages. This paper introduces the FraSCAla framework as an architectural framework that can be used to rapidly prototype and experiment domain-specific ADLs in order to catalyze the definition and to improve the reliability of software architectures. We demonstrate the merits of this approach on two case studies that illustrate component-based architectures exhibiting various categories of architectural patterns

Using Model Types to Support Contract-Aware Model Substitutability

International audienceModel typing brings the benefit associated with well-defined type systems to model-driven development (MDD) through the assignment of specific types to models. In particular, model type systems enable reuse of model manipulation operations (e.g., model transformations), where manipulations defined for models of a supertype can be used to manipulate models of subtypes. Existing model typing approaches are limited to structural typing defined in terms of object-oriented metamodels (e.g., MOF) in which the only structural (well-formedness) constraints are those that can be expressed directly in metamodeling notations (e.g., multiplicity and element containment constraints). In this paper we describe an extension to model typing that takes into consideration structural invariants, other than those that can be expressed directly in metamodeling notation, and specifications of behaviors associated with model types. The approach supports contract-aware substitutability, where contracts are defined in terms of invariants and pre-/postconditions expressed using OCL. Support for behavioral typing paves the way for behavioral substitutability. We also describe a technique to rigorously reason about model type substitutability as supported by contracts and apply the technique in use cases from the optimizing compiler community

Well-Formed and Scalable Invasive Software Composition

Software components provide essential means to structure and organize software effectively. However, frequently, required component abstractions are not available in a programming language or system, or are not adequately combinable with each other. Invasive software composition (ISC) is a general approach to software composition that unifies component-like abstractions such as templates, aspects and macros. ISC is based on fragment composition, and composes programs and other software artifacts at the level of syntax trees. Therefore, a unifying fragment component model is related to the context-free grammar of a language to identify extension and variation points in syntax trees as well as valid component types. By doing so, fragment components can be composed by transformations at respective extension and variation points so that always valid composition results regarding the underlying context-free grammar are yielded. However, given a language’s context-free grammar, the composition result may still be incorrect. Context-sensitive constraints such as type constraints may be violated so that the program cannot be compiled and/or interpreted correctly. While a compiler can detect such errors after composition, it is difficult to relate them back to the original transformation step in the composition system, especially in the case of complex compositions with several hundreds of such steps. To tackle this problem, this thesis proposes well-formed ISC—an extension to ISC that uses reference attribute grammars (RAGs) to specify fragment component models and fragment contracts to guard compositions with context-sensitive constraints. Additionally, well-formed ISC provides composition strategies as a means to configure composition algorithms and handle interferences between composition steps. Developing ISC systems for complex languages such as programming languages is a complex undertaking. Composition-system developers need to supply or develop adequate language and parser specifications that can be processed by an ISC composition engine. Moreover, the specifications may need to be extended with rules for the intended composition abstractions. Current approaches to ISC require complete grammars to be able to compose fragments in the respective languages. Hence, the specifications need to be developed exhaustively before any component model can be supplied. To tackle this problem, this thesis introduces scalable ISC—a variant of ISC that uses island component models as a means to define component models for partially specified languages while still the whole language is supported. Additionally, a scalable workflow for agile composition-system development is proposed which supports a development of ISC systems in small increments using modular extensions. All theoretical concepts introduced in this thesis are implemented in the Skeletons and Application Templates framework SkAT. It supports “classic”, well-formed and scalable ISC by leveraging RAGs as its main specification and implementation language. Moreover, several composition systems based on SkAT are discussed, e.g., a well-formed composition system for Java and a C preprocessor-like macro language. In turn, those composition systems are used as composers in several example applications such as a library of parallel algorithmic skeletons

Supporting Management lnteraction and Composition of Self-Managed Cells

Management in ubiquitous systems cannot rely on human intervention or centralised decision-making functions because systems are complex and devices are inherently mobile and cannot refer to centralised management applications for reconfiguration and adaptation directives. Management must be devolved, based on local decision-making and feedback control-loops embedded in autonomous components. Previous work has introduced a Self-Managed Cell (SMC) as an infrastructure for building ubiquitous applications. An SMC consists of a set of hardware and software components that implement a policy-driven feedback control-loop. This allows SMCs to adapt continually to changes in their environment or in their usage requirements. Typical applications include body-area networks for healthcare monitoring, and communities of unmanned autonomous vehicles (UAVs) for surveillance and reconnaissance operations. Ubiquitous applications are typically formed from multiple interacting autonomous components, which establish peer-to-peer collaborations, federate and compose into larger structures. Components must interact to distribute management tasks and to enforce communication strategies. This thesis presents an integrated framework which supports the design and the rapid establishment of policy-based SMC interactions by systematically composing simpler abstractions as building elements of a more complex collaboration. Policy-based interactions are realised – subject to an extensible set of security functions – through the exchanges of interfaces, policies and events, and our framework was designed to support the specification, instantiation and reuse of patterns of interaction that prescribe the manner in which these exchanges are achieved. We have defined a library of patterns that provide reusable abstractions for the structure, task-allocation and communication aspects of an interaction, which can be individually combined for building larger policy-based systems in a methodical manner. We have specified a formal model to ensure the rigorous verification of SMC interactions before policies are deployed in physical devices. A prototype has been implemented that demonstrates the practical feasibility of our framework in constrained resources