Appendix D. The Graphical Editing Framework (GEF)

GEF development is, without question, the most complex topic thus far—it would take an entire book to examine the GEF toolset in full. So, this appendix will only describe the structure and function of a simple (but complete) graphical editor.

Building a graphical editor involves much more than Draw2D Figures: It requires a sound knowledge of plug-ins, Model-View-Controller (MVC) architecture, JavaBean components, JFace Viewers, JFace Actions, JFace properties, and many of the classes that make up the Eclipse Workbench. Although this appendix won’t attempt to explain any of these concepts in depth, we’ll clarify how they work together in the GEF. Learning to build a graphical editor isn’t easy, but with sufficient experience, you can create powerful applications with reusable, interchangeable code.

GEF development is complicated but not impossible. How do you eat a two-ton elephant? One bite at a time.

D.1. A GEF overview

D.2. Creating the FlowchartProject

D.3. Creating the editor’s PaletteViewer

D.4. The Model aspect: Model classes

D.5. Changing Model properties with Commands

D.6. The Controller aspect: EditPart classes

D.7. Creating Commands with EditPolicy objects

D.8. Adding Actions to the editor

D.9. Editing with GEF: two examples

D.10. Introducing the EditorPart

D.11. Other GEF aspects