Alexis Muller

On some properties of parameterized model application

Designing Information Systems (IS) is a complex task that involves numerous aspects, being functional or not. A way to achieve this is to consider models as generic pieces of design in order to build a complete IS. Model composition provides a way to combine models and model parameterization allows the reuse of models in multiple contexts. In this paper, we focus on the use of parameterized models in model driven engineering processes. We outline the needs to compose parameterized models and apply them to a system according to alternative and coherent ordering rules. Such building processes raise open issues: Is the result influenced by the order of applications? Can we compose independent parameterized models? Is it possible to define composition chains and find equivalent ones that express the same resulting model? These requirements are formalized through an apply operator. This operator guarantees properties which can help in the formulation of model driven system construction methodologies. Finally, we briefly describe a modelling tool that supports processes based on this operator.

A Framework for Supporting Views in Component Oriented Information Systems

The Component Oriented Design of Information Systems is spreading. After being used for gaining in reusability at the architectural level, components are nowadays applied at the business logic level. We focus here on the design of multiple functional views in such information systems, specially within the EJB framework. Traditionally, in the database context, this problem is solved by the notion of view-schemas applied to a database schema. We present a composition-oriented approach grounded on the splitting of entities according to views requirements. Two original design patterns are formulated and capture the main issues of the approach. The first one is concerned with the management of the split component and its conceptual identity. The second offers a solution for relationships among such components. Finally, we apply these patterns to the EJB framework. This framework improves evolution and traceability of views.

An OCL Formulation of UML2 Template Binding

After being considered only as documentation for a long time, models are gaining more and more importance in the software development lifecycle, as full software artefacts. The UML standard contributes a lot to this mutation, with the identification and the structuration of models space dimensions and constructs. Models can nowadays be explicitly manipulated through metamodeling techniques, dedicated tools or processes such as model transformation chains. This is Model Driven Engineering. Once it is clear that models are full software ingredients, we are faced with new problems (needs!) such as the possibility of their reusability and composability. As a consequence, specific constructs are introduced in order to facilitate this, such as the template notion initiated by UML1.3. Applications of this notion are growing more and more so that it was deeply revisited and strengthened in UML2. Though, its specification still lacks precision, particularly concerning the binding mechanism that allows to obtain models from templates. We propose a set of OCL constraints which strengthens the definition and helps in verifying the correctness of resulting models. These constraints apply to the UML2 metamodel and were implemented in an OCL verifier that we integrated in the Eclipse environment.

A Coding Framework for Functional Adaptation of Coarse-Grained Components in Extensible EJB Servers

Separation of functional concerns is a major step for managing the complexity of large scale component systems. It allows the identification of well defined functional or non-functional dimensions in order to facilitate their assembly, adaptation and finally their reuse. Current component-based middleware and application servers offer container services that much more facilitate the reuse of the functional core throughout technical concerns, such as persistence, components distribution, transactions, security management, and so on. But they rarely offer facilities for the separation of functional concerns within this core itself. This contribution is dedicated to this question, specifically within the field of ”coarse-grained view components”. In the Information System domain, these components are common and capture ”real-world semantics”, that is a structured set of entities related to a specific functional concern. Inspired by previous works on Subject-Oriented or View-Oriented Modeling, we retain model templates as good candidates for the definition of coarse-grained reusable view components. We propose a framework to provide such components onto the EJB technology. It takes advantages of extensible containers and exploits their Aspect-Oriented Programming facilities in order to inject specific view services compatible with standard J2EE/EJB ones.

Transformations de modèles : d'un modèle abstrait aux modèles EJB et CCM

Improvements in stylographic technical writing pens, particularly through a venting channel design which provides for a pressure balancing, or equalization, between an ultimate ink reservoir pressure and the total pressure at the writing tip; as writing depletes ink within the reservoir. Particularly, a venting channel, extending from the reservoir to ambient air, has the size of its cross-sectional shape vary as a function of the distance from its communication with the reservoir, with the variation calculated to offset gravitational forces attendant to a moving ink meniscus inside the vent channel. The balancing of total pressures also provides a constant ink flow through the writing tip when writing since the total pressure at the tip is maintained constant by the vent channel configuration. The present invention is characterized by the novel approach, of beginning with the insight that a varying static pressure, from a varying level of ink to a vent channel, must exactly offset by the capillary forces at the meniscus of that ink level in the vent channel, and then creating a total vent structure that can follow that relationship.