<?php
  
  /**
   * Adds caldav notification support to a backend.
   *
   * Note: This feature is experimental, and may change in between different
   * SabreDAV versions.
   *
   * Notifications are defined at:
   * http://svn.calendarserver.org/repository/calendarserver/CalendarServer/trunk/doc/Extensions/caldav-notifications.txt
   *
   * These notifications are basically a list of server-generated notifications 
   * displayed to the user. Users can dismiss notifications by deleting them.
   *
   * The primary usecase is to allow for calendar-sharing.
   *
   * @package Sabre
   * @subpackage CalDAV
   * @copyright Copyright (C) 2007-2013 Rooftop Solutions. All rights reserved.
   * @author Evert Pot (http://www.rooftopsolutions.nl/) 
   * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
   */
  interface Sabre_CalDAV_Backend_NotificationSupport extends Sabre_CalDAV_Backend_BackendInterface {
  
      /**
       * Returns a list of notifications for a given principal url.
       *
       * The returned array should only consist of implementations of
       * Sabre_CalDAV_Notifications_INotificationType. 
       * 
       * @param string $principalUri
       * @return array 
       */
      public function getNotificationsForPrincipal($principalUri);
  
      /**
       * This deletes a specific notifcation.
       *
       * This may be called by a client once it deems a notification handled. 
       * 
       * @param string $principalUri 
       * @param Sabre_CalDAV_Notifications_INotificationType $notification 
       * @return void
       */
      public function deleteNotification($principalUri, Sabre_CalDAV_Notifications_INotificationType $notification); 
  
  }