JooMDD provides a set of plugins for a model-driven development of Joomla! extension packages. The current version of JooMDD can be used within Eclipse, IntelliJ IDEA, and PHPStorm.
In addition, we JooMDD provides jext2eJSL to create eJSL-based models based on existing Joomla 3.x extension packages. We are currently working on the documentation of jext2eJSL. If you are interested in using the tool, see the current (german) documentation here.