Model-Driven Design of Distributed Applications

A recent trend in the design of distributed applications is to systematically separate their platform-independent and platform-specific aspects, by describing them in separate models. The main benefits of this approach stem from the possibility to derive different platform-specific models (PSMs) from the same platform-independent model (PIM), and to partially automate the model transformation process and the realization of the distributed application on specific target (middleware) platforms. This may reduce initial development costs and improve software quality, but also forms the basis for facilitating evolution and migration of software solutions, hence contributing to the limitation of maintenance costs for distributed applications. A prominent development in this trend is the Model-Driven Architecture (MDA) approach. In the context of MDA, much effort has been invested in enabling technologies and techniques for model-driven design, which include metamodelling (MOF), language definition and extension mechanisms (e.g., UML and UML profiles), model transformation specification languages (MOF Query/View/Transformation), tool support and tool chain interoperability. In contrast, the methodological and architectural foundations of platform-independent design have received little attention. In particular, the state-of-the-art in model-driven design can be criticized on a number of points: – there is a lack of guidelines to select abstraction criteria and modelling concepts for platform-independent design; – there is little methodological support to distinguish between platformindependent and platform-specific concerns, which is detrimental to the beneficial exploitation of the separation between PIMs and PSMs; – the distinction between PIM-PSM is coarse and insufficient to cope with the diversity of application requirements and platform characteristics; – little attention is given to the role of platform characteristics throughout the development trajectory, possibly leading to models with unaccept-