EMF Facet project has been created

EMF Facet is a new Eclipse/Modeling project which will provide solutions to extend existing metamodels without changing them. It has been provisioned recently in EMFT by Greg Dupé of Mia-Software, the co-leader of the project.

With EMF Facet, it will be more easy to dynamically extend and customize a tool based on EMF.

The idea is to allow defining new attributes, new relations and new types in a non-intrusive way (you can read this older post about EMF Facet).

This mechanism has already been developped in the MoDisco project (the Eclipse/Modeling project dedicated to Software Modernization). It is completed by a QueryManager component which allow executing queries on a EMF model independently from the query technology (bridges for OCL, Java and XPath are already available). As it is independent from Software Modernization purposes, the corresponding code is going to move to this new EMF Facet project.

After some refactoring, it will be enriched with other components (such as customizable widgets to display extended EMF models). First version is planned to be ready in June 2011 for Indigo, the next Eclipse release. Before this date, early versions will be available with intermediate Indigo milestones.

To know more about this project, don't miss the talk EMF Facet: a Non-Intrusive Metamodel Extension Tooling, Thursday, the 4th of November during Eclipse Summit Europe 2010, in Germany.

EMF Facet, a new project for model customization and extensibility

How to dynamically extend and combine existing Ecore definitions without having to modify them?

EMF Facet, a new project we have proposed to create under EMFT, will propose dynamic extension mechanisms for all EMF-based tools exposing a view on a model:

• Navigation tools (browser, navigator, etc);
• Graphical modeling tools;
• Code or documentation generation (M2T) tools;
• Model-to-model transformation (M2M) tools.

Our proposition provides a solution to introduce new viewpoints (or "facets") on existing models:

• Extending an existing metamodel (Ecore model) in a non-intrusive way by adding new types, attributes, operations and relations. New relations could be used to compose several models by linking their elements.
• Computing an extension by executing queries against an existing model; queries will be implemented by making use of existing query mechanisms (e.g. considering Java, ATL, EMFQuery, Xpath, etc)

The Query "subClassifiers" visible as a "virtual" relation on Class

Some of these mechanisms have already been developped in the MoDisco project. But, as they could be reused by tools not related to software modernization (the scope of the MoDisco project), we have decided to contribute the corresponding components to EMF Facet.

In a previous post, I have presented these components (Facet Manager and Query Manager).

In another post, I have also illustrated how Facets can be used to extend the Java metamodel to highlight JUnit concepts.