Components offered by JFace

Explain the components offered by JFace. i.e. image, font registries, dialogs, wizard, action mechanism, viewers and editors

ImageRegistry:
The mapping between symbolic image names and SWT image objects is maintained by the ImageRegistry class until the SWT image objects are needed. It owns all the images registered with it and automatically disposes them when the SWT Display that creates the images is disposed.

FontRegistry:
The FontRegistry maps between symbolic font names and SWT fonts. It owns all the fonts registered with it and automatically disposes them when the SWT Display that creates the fonts is disposed.

Dialog:
Dialogs are used to communicate the information from the user or to the user. The following are the different types of messages:

1. The MessageDialog displays information to the user
2. The InputDialog accepts the input from the user in the form of text
3. The ErrorDialog displays one or more errors to the user.

Wizard:
A wizard can be used to create new Java classes, projects, files and folders. Wizards provide step by step process to create these elements. A well defined wizard is targeted to simplify user tasks and increase productivity. Wizard is meant to take out the hassle of creating repetitive and tedious tasks.

Action Mechanism:
Actions are tasks for various users operations such as clicks on menus, toolbars, status lines etc. In order to support these actions the action mechanism is implemented. There are listeners and managers for each of these actions.

Viewers:
Viewers are used to display objects using different SWT widgets. Types of viewers are as follows:

1. The ListViewer uses the SWT List widget to display the object. A simple list of elements can be created by using ListViewer.
2. The CheckboxTableViewer uses the SWT widget to display the objects of checkboxes.
3. The CheckboxTreeViewer uses the SWT table control with checkboxes on each node.
4. The CheckboxTreeViewer uses the SWT Tree control with checkboxes on each node.
5. The TableTreeViewer uses the SWT Table Tree control.
6. TableViewer, uses the SWT TableViewer control.
7. TreeViewer, uses the SWT TreeViewer control.

Editors:
Using JFace Text framework, sophisticated editors such as XML editors and text editors can be developed. Any application needs editors to author the designated code. For example XML file needs tags to be written a flat text file. A program needs editor to author the code. By using different development template these editors can be plugged in and developed.