Dirk Deridder

Module superimposition: a composition technique for rule-based model transformation languages

As the application of model transformation becomes increasingly commonplace, the focus is shifting from model transformation languages to the model transformations themselves. The properties of model transformations, such as scalability, maintainability and reusability, have become important. Composition of model transformations allows for the creation of smaller, maintainable and reusable transformation definitions that together perform a larger transformation. This paper focuses on composition for two rule-based model transformation languages: the ATLAS Transformation Language (ATL) and the QVT Relations language. We propose a composition technique called module superimposition that allows for extending and overriding rules in transformation modules. We provide executable semantics as well as a concise and scalable implementation of module superimposition based on ATL.

Supporting multiple perspectives in feature-based configuration

Feature diagrams have become commonplace in software product line engineering as a means to document variability early in the life cycle. Over the years, their application has also been extended to assist stakeholders in the configuration of software products. However, existing feature-based configuration techniques offer little support for tailoring configuration views to the profiles of the various stakeholders. In this paper, we propose a lightweight, yet formal and flexible, mechanism to leverage multidimensional separation of concerns in feature-based configuration. We propose a technique to specify concerns in feature diagrams and to generate automatically concern-specific configuration views. Three alternative visualisations are proposed. Our contributions are motivated and illustrated through excerpts from a real web-based meeting management application which was also used for a preliminary evaluation. We also report on the progress made in the development of a tool supporting multi-view feature-based configuration.

Towards Multi-view Feature-Based Configuration

[Context & motivation] Variability models, feature diagrams ahead, have become commonplace in software product line engineering as a means to document variability early in the lifecycle. Over the years though, their application span has been extended to aid stakeholders in the configuration of software products. [Question/problem] However, current feature-based configuration techniques hardly support the tailoring of configuration views to the profiles of heterogeneous stakeholders. [Principal ideas/results] In this paper, we introduce a lightweight mechanism to leverage multidimensional separation of concerns in feature-based configuration. [Contribution] We propose a technique to specify concerns in feature diagrams and to build automatically concern-specific configuration views, which come with three alternative visualisations.

Realizing Model Transformation Chain interoperability

A single Model Transformation Chain (MTC) takes a high-level input model rooted in the problem domain and through one or more transformation steps produces a low-level output model rooted in the solution domain. To build a single “almighty” MTC that is in charge of every design, implementation and specific platform concern is a complex task. Instead, we can use several smaller MTCs that are easier to develop and maintain, because each MTC is independently developed focusing on a specific concern. However, the MTCs must interoperate to produce complete applications; this inherently creates dependencies between them, because each MTC generates a part of the final low-level model. In this paper, we propose an external and explicit mechanism to track dependencies between the MTCs (i.e., the MTCs are oblivious to the mechanism), which is used to automatically derive correspondence relationships between the final models generated by each MTC. The contribution of our mechanism is the reduction of complexity of building interoperable MTCs because the derived correspondences are resolved after the transformations execution, in the solution domain where the semantics of every concept is well-defined. The resolution process consists of (1) checking the consistency between the models, (2) producing communication bridges or (3) guiding the composition of the models. This paper presents three case studies to illustrate the derivation and resolution of correspondence relationships through the MTCs.

MMC-BPM: A Domain-Specific Language for Business Processes Analysis

Business Process Management approaches incorporate an analysis phase as an essential activity to improve business processes. Although business processes are defined at a high-level of abstraction, the actual analysis concerns are specified at the workflow implementation level resulting in a technology-dependent solution, increasing the complexity to evolve them. In this paper we present a language for high-level monitoring, measurement data collection, and control of business processes and an approach to translate these specifications into executable implementations. The approach we present offers process analysts the opportunity to evolve analysis concerns independently of the process implementation.

Extensibility in Model-Based Business Process Engines

An organization’s ability to embrace change, greatly depends on systems that support their operation. Specifically, process engines might facilitate or hinder changes, depending on their flexibility, their extensibility and the changes required: current workflow engine characteristics create difficulties in organizations that need to incorporate some types of modifications. In this paper we present Cumbia, an extensible MDE platform to support the development of flexible and extensible process engines. In a Cumbia process, models represent participating concerns (control, resources, etc.), which are described with concern-specific languages. Cumbia models are executed in a coordinated way, using extensible engines specialized for each concern.

A practical approach to multi-modeling views composition

The use of several view models to specify a complex system is a common practice to provide the most appropriate abstractions to model its diverse concerns. When several view models are used to specify a system, it is necessary to compose them to generate the application. When the view models are expressed in different Domain Specific Modeling Languages a problem arises because a heterogeneous composition is required. A possible approach to avoid a heterogeneous composition is to transform the diverse models into low-level models using a common low-level modeling language as target. Therefore, when all the view models are transformed in low-level models specified with a common language, it is possible to apply a ho- mogeneous composition to obtain the final application. However, it is necessary to identify the elements to compose in the low-level. In this paper, we present an auto- matic mechanism to identify which elements will be composed. This mechanism is based on defining correspondence relationships between the high-level view mod- els and automatically deriving new correspondence between the generated low-level models.

DEUCE : A Declarative Framework for Extricating User Interface Concerns.

Evolving a software system not only affects the source code responsible for the core application, but also the user interface. Unfortunately user interface code is often scattered through and entangled with the application code. In large and complex user-interfaces, this tangling renders the implementation complex and hard to maintain. Currently, the application needs to perform both the necessary changes to the user-interface (e.g. disabling other buttons, propagating events, etc.) as well as invoke the required application logic. The Deuce framework (Declarative User Interface Concerns Extrication) intends to reduce the complexity of user-interface implementations by applying separation of concerns on three UI concerns : presentation logic, business and data logic, and connection logic. It does so by using a declarative meta-language (SOUL) on top of an object oriented language (Smalltalk) such that an adequate language is provided to describe the entire structure and behaviour of the user-interface, as well as to link it with the application.

MONITORING AND ANALYSIS CONCERNS IN WORKFLOW APPLICATIONS: FROM CONCEPTUAL SPECIFICATIONS TO CONCRETE IMPLEMENTATIONS

Workflow monitoring and analysis concerns aim at identifying potential improvements of workflow applications. This paper presents an approach to specify and implement monitoring and analysis concerns on workflow applications raising the level of abstraction for workflow analysts. First, the specification of monitoring and analysis concerns is declared in a technology-independent way with a domain-specific language named MonitA. MonitA makes extensive use of the data available in the workflow application and its constituents to enhance the monitoring and analysis specifications. Second, we defined and implemented a strategy to assist developers to enhance a given workflow technology to support the generation of the monitoring and analysis code and its composition with the workflow application. This instrumentation-based approach enables the monitoring and analysis of workflow applications during their operational execution. We illustrate the flexibility of our approach by targeting different workflow platforms and different workflow applications.

An Approach for Evolving Transformation Chains

A transformation chain (TC ) generates applications from high-level models that are defined in terms of problem domain concepts. The result is a low-level model that is rooted in the solution domain. The evolution of a TC is a complex and expensive endeavor since there are intricate dependencies between all its constituent parts. More specific, an evolution problem arises when we need to add an unanticipated concern (e.g., security) that does not fit the expressiveness of the high-level metamodel, because such an addition forces us to adapt existing assets (i.e., metamodels, models, and transformations). We present a solution that adds a new concern model to the TC, in an independent way.