The objective of building the editor is graphically creates or edits the service in a work flow diagram.  In Eclipse we applied to use the Graphical Editing Framework (GEF) to implement the representation of the workflow. GEF provides viewers (of the type EditPartViewer) that can be used anywhere in the Eclipse workbench. Like JFace viewers, GEF viewers are adapters on an SWT Control. But the similarity stops there. GEF viewers are based on a model-view-controller (MVC) architecture. Each controller, or EditPart as they are called here, is responsible both for mapping the model to its view, and for making changes to the model. The EditPart also observes the model, and updates the view to reflect changes in the model's state. EditParts are the objects with which the user interacts. EditParts are covered in more detail later.

GEF provides two viewer types: graphical and tree-based. Each hosts a different type of view. The graphical viewer uses figures that paint on an SWT Canvas. Figures are defined in the Draw2D plug-in, which is included as part of GEF. The TreeViewer uses an SWT Tree and TreeItems for its view.