/****
 *
 * Module CalendarDB defines the major database objects of the calendar system
 * as well as the objects that define the underlying calendar structure.  The
 * core object of the calendar system is the UserCalendar, which is modeled as
 * a collection of scheduled items.  The calendar structure of years, months,
 * weeks, and days is not directly modeled in the UserCalendar.  These
 * structures are computed views that are derived from the underlying scheduled
 * item collection.  The operations in the View module are the ones that
 * compute the these views.
 *
 */

import java.util.Collection;

/**
 * The CalendarDB is the top-level object for the Calendar Tool.  The
 * first component is the list of UserCalendars for all registered users.
 * The next three components are the registered UserDB, the user GroupDB,
 * and the LocationDB.  The Options component is the set of calendar
 * options common by default for all users, both registered and
 * non-registered.  The UserWorkSpace component is active calendars upon
 * which the current user is working.
 *
 * objects that are available for the user to view and edit.  There is a <a
 * href="../images/uml.gif">draft UML diagram</a> of the Calendar Tool object
 * hierarchy, of which CalendarDB is the topmost object.
 */
abstract class CalendarDB {
    Collection<UserCalendar> calendars;
    UserDB udb;
    GroupDB gdb;
    GlobalOptions options;
}

/**
 * A user calendar is named, with its own set of options.  It extends the
 * Calendar object, which contains the collection of scheduled items.
 */
abstract class UserCalendar extends Calendar {
    String userName;
    UserOptions options;
}