The classes from package y.option constitute a framework to conveniently handle property management and manipulation. It offers support for internationalization and localization of dialogs (i18n/l10n for short), as well as (de)serialization of settings. The framework separates responsibilities applying a Model-Delegate pattern, which facilitates, for example, different styles of settings presentations and manipulation. Figure 10.1, “Dialog-based and table-based settings presentation” shows the alternative presentation styles.

Figure 10.1. Dialog-based and table-based settings presentation

Dialog-based and...	table-based settings presentation.

The separation also permits the use of multiple dialogs (in other words, multiple views) to present and modify settings that are managed by a common model. Synchronization of model and view(s) is covered by different policies, following "push" and "pull" semantics.

Model-Delegate Pattern

The classes from package y.option reflect a modification of the Model-View-Controller (MVC) paradigm, dubbed Model-Delegate pattern. Two of the three responsibilities from MVC, namely the view and controller part, are brought together in a so-called User Interface (UI) Delegate. Hence classes with the following roles can be distinguished:

• Model classes: hold data specific to the application
• View/Controller classes: present information to and interact with the user

In terms of MVC then, class OptionHandler together with classes OptionItem and OptionSection make up the model which holds the data. The view/controller part is in the implementations of interface Editor.

Figure 10.2, “Settings framework core classes” shows the essential classes of the settings framework.

Figure 10.2. Settings framework core classes