001    package users.events;
002    
003    /**
004     * An abstract adapter class for receiving user data events. The methods in this class are
005     * empty. This class exists as convenience for creating listener objects.
006     *
007     * <p>Extend this class to create a UserDataEvent listener and override the methods for the
008     * events of interest. (If you implement the UserDataListener interface, you have to define
009     * all of the methods in it. This abstract class defines empty method bodies for them all, so you
010     * can concentrate on defining methods only for events you care about.)</p>
011     *
012     * <p>Create a listener object using the extended class and then register it with a
013     * {@link users.UserManager} using the UserManager's {@link users.UserManager#addUserDataListener} method.
014     * When a user is added or removed, the relevant method in the listener object is invoked, and the
015     * {@link UserDataEvent} is passed to it.</p>
016     *
017     * @see UserDataEvent
018     * @see UserDataListener
019     * @see users.UserManager
020     *
021     * @author Steffen Zschaler
022     * @version 2.0 06/05/1999
023     * @since v2.0
024     */
025    public abstract class UserDataAdapter implements UserDataListener {
026    
027        /**
028         * Called whenever a user was added to the source. The new user will be contained
029         * in the event object.
030         *
031         * @param e the event object describing the event.
032         *
033         * @override Sometimes
034         */
035        public void userAdded(UserDataEvent e) {}
036    
037        /**
038         * Called whenever a user was deleted from the source. The deleted user will be
039         * contained in the event object.
040         *
041         * @param e the event object describing the event.
042         *
043         * @override Sometimes
044         */
045        public void userDeleted(UserDataEvent e) {}
046    }