Eclipse's
GMF project has just reached version 2.0 in June, 2007. After more than 2 years of development and presentations at
ECOOP 2006 and
OOPSLA 2006, among others, the project has reached the necessary stability to start being used in the industry. Having developed a
modeling tool myself, I was really impressed with the level of details that is possible to achieve with GMF. Of course, I was also amazed with the fact that the work that took approximately 6 months of my M.Sc. can now be done in
15 minutes. When combined to a code generation framework, such as
JET, the possibilities are literally endless. With not so much training, most developers can start creating their own modelers and generating Java, C#, VB, Javascript, XML, and other kinds of source code.
This is, from my point of view, the major achievement of these two particular projects. Code generation and domain-specific modeling are no longer technologies restricted to extremely highly skilled (and expensive) employees, researchers or companies. Maintaining modelers and generators does not require months of planning and implementation, but can be done directly by the developers.
This is where the problem begins. The most obvious (at least for me) application for this technology is to improve software reuse using product families/domain engineering ideas. Therefore, what is the best way to combine software reuse technology (components, repositories, design patterns, product lines, domain engineering, certification, ...) with model-driven development technology (platform-independent models, platform-specific models, model-to-text transformations, model-to-model transformations, ...) ?
The best starting point for answering this question is the
modelware initiative. Several research groups and companies are gathered around different areas, having already delivered interesting reports, including a
MDD Maturity Model and a
MDD Process Framework. However, these not only fail to include specific reuse concern, but are also more suited for european companies, which already have MDD in their knowledge base.
Thinking about introducing these technologies from scratch, we from the RiSE group are developing a model-driven reuse approach, including the needed activities and guidelines. Initial focus is being placed on engineering-related activities, and mainly in the implementation phase, with code generation and platform-specific modeling. The following figure shows a preliminary draft, showing three basic cycles.
The basic cycle is domain engineering, which is being represented as the RiDE (Rise process for Domain Engineering) approach. Based on the results of the domain design phase, the modeler engineering cycle begins. This is where a domain-specific modeler is developed, based on the domain's architecture's elements, such as variability points and architectural patterns.
During domain implementation, components are developed and the transformation engineering cycle starts. This cycle is responsible for developing transformations to be used together with the domain-specific modeler. A design by-example approach is used.
The result of these cycles includes not only source code components, but also transformations that can be used to generate parts of the final product. For example, some specific components may be handcrafted, while controller components and basic infrastructure code can be generated. One practical example is the Web Domain. Specific components for building dynamic web pages, such as a dynamic list or a date picker component, may be handcrafted, while the navigation code, such as
Struts's descriptor file, can be generated from a web navigation modeler.
According to Modelware's MDD Maturity Model, the next step regarding the engineering perspective is to incorporate MDD up in the analysis and design phases, allowing the domain engineer to benefit from model-to-model transformations to generate parts of the design or to automatically apply design patterns, performing some kind of model refactoring.
However, the terrain is a little more obscure in these cases than in the implementation. The problem here, I think, is not even the lack of tools, because there are model-to-model transformation engines based on eclipse and EMF available, such as
ATL, which have already been tested and proven to be practical. For me, the problem is that the kind of work that is performed during analysis and design is much more conceptual, and therefore, more likely to be erroneously performed by non-human workers, such as a computer-based transformer.
Therefore, except for some basic helper refactoring-like transformations, I think that the use of MDD in these higher-level models will still have to wait some years before reaching the same levels of automation that we can now use in implementation.
