The Eclipse Graphical Editing Framework Gef Pdf Reader

Editor's note: The following article, originally written by Randy Hudson in July 2003, was updated in March 2007 by Chris Aniszczyk. This article walks through the steps for using the Graphical Editing Framework (GEF). Rather than finishing each step in its entirety, we'll use a subset of your application's model and get that working first. Halo Mod Download 1.7 2. For example, we might initially ignore connections or focus on just a subset of the types of graphical elements in your application.

The Eclipse Graphical Editing Framework. An excellent eBook reader ought to be. Links of The Eclipse Graphical Editing Framework (GEF) (Eclipse Series) pdf. Learn the initial steps involved in creating an Eclipse-based application using the Graphical Editing Framework (GEF). Also, discover the options you have these days.

Next, learn what other technologies are available to add graphical editing to your applications. In the past, stand-alone GEF used to be the only option for graphical editing in Eclipse, but this has changed as Eclipse has evolved. Overview of GEF GEF assumes you have a model you would like to display and edit graphically.

To do this, 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. The controllers bridge the view and model (see Figure 1). Each controller, or EditPart as they are called here, is responsible 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. Pink Floyd Patch Kurzweil Pc88 here. EditParts are covered in detail later. Model-View-Controller 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. Step 1: Bring your own model GEF knows nothing about a model. Any model type should work, as long as it meets the properties described below. What's in a model? Everything is in the model.

The model is the only thing persisted and restored. Your application should store all important data in the model.

During the course of editing, undo, and redo, the model is the only thing that endures. Figures and EditParts will be garbage collected and recreated over time. When the user interacts with EditParts, the model is not manipulated directly by the EditParts. Instead, a Command is created that encapsulates the change. Commands can be used to validate the user's interaction, and to provide undo and redo support. Strictly speaking, Commands are also conceptually part of the model. They are not the model per se, but the means by which the model is edited.

Commands are used to perform all of the user's undoable changes. Ideally, commands should only know about the model. They should avoid referencing an EditPart or figure. Similarly, a command should avoid invoking the user interface (such as a pop-up dialog) whenever possible. A tale of two models A straightforward GEF application is an editor for drawing diagrams. (Here, diagram means just a picture, not class diagram.) A diagram can be modeled as some shapes. A shape might have properties for location, color, etc., and may be a group structure of multiple shapes.

There are no surprises here, and the previous requirement is easily maintained. A simple model.

Another common GEF application is a UML editor, such as a class diagram editor. One important piece of information in the diagram is the (x, y) location where a class appears. You might assume that the model must describe a class as having an x and y property. Most developers want to avoid polluting their models with attributes that don't make sense.

In such applications, the term business model can be used to refer to the base model in which the important semantic details are stored. While diagram-specific information is stored in the view model (which means a view of something in the business model; an object may be viewed multiple times in one diagram). Sometimes the split is even reflected in the workspace, where different resources might be used to persist the diagram and business model separately. There may even be several diagrams for the same business model (see Figure 3). A common term for view models is notational models. A model split into business and view models. If your use cases have you using the Eclipse Modeling Framework for your model, it is highly recommend that you use GMF instead of GEF directly.