Functional Overview of Visual Editor
The Eclipse Visual Editor (VE) can be used to open any .java file. It then parses the Java source code looking for visual beans. If it finds any then it opens several VE tools that can be used to view and/or manipulate the source code in several different ways. Wizards are also provided so that new visual classes are created which can then be customized.
Functionally, the Eclipse VE provides the following; a Graphical Viewer, a JavaBeans Tree, a Properties View, a Palette and a Java source editor. Table 1 summarizes the actions that can be undertaken using each of the functional elements and the information that each provides to the user.
|Functional Component||Actions available to user||View|
|Graphical Viewer||Preview the GUI. Select beans from the palette and drop them onto the canvas or another bean or resize them. Invoke pop-up menu actions such as copy, delete, adding events etc. Select a bean so that its properties are displayed in the Properties view and the source editor scrolls to the relevant source code.||Each bean is instantiated on a separate VM(Target/Proxy VM).
Code is then invoked on the bean and the image of the bean displayed on the canvas. For beans that contain other beans only the image of the containing bean is used as this will include the images of the other beans.
|JavaBeans Tree||Select beans from the palette and drop them onto the tree or onto another bean. Invoke pop-up menu actions. Select a bean so that its properties are displayed in the Properties view and the source editor scrolls to the relevant source code.||Provides a 'tree' view of the GUI showing container-contained relationships, and field names. Also shows events which are activated on a bean.|
|Properties View||Properties of a selected bean can be edited, usually using appropriate CellEditors.||Displays properties for a selected bean.|
|Source Editor||A fully functional Java Editor allowing editing of source code as well as editor actions such as formatting, refactoring, etc.||If a bean is selected, the editor scrolls to the code line where the bean in created.|
|Palette||Provides Selection, Marquee and bean creation tools.||Provides a convenient way for users to create beans.|
|Wizards||'New Visual Class' wizards allows users to select from pre-defined GUI templates.||Provides a convenient starting point for writing a GUI class.|
Some visual editing tools will only provide a visual model of code that that particular visual tool itself has generated. Subsequent direct editing of the source code can prevent the visual tool from parsing the code and building a model.
Eclipse VE, however, can be opened on any .java file. Hence it can either be used to edit GUIs from scratch, or from Java files that have been 'hardcoded' or built in a different visual tool. The source file can either be updated using the Graphical Viewer, JavaBeans Tree or Properties view or it can be edited directly by the Source Editor. Any editing action can be un-done or re-done by using the 'undo' and 'redo' actions.