diff --git a/plugins/calendar/drivers/resources_driver.php b/plugins/calendar/drivers/resources_driver.php
index c51e9226..4c141cdf 100644
--- a/plugins/calendar/drivers/resources_driver.php
+++ b/plugins/calendar/drivers/resources_driver.php
@@ -1,114 +1,112 @@
 <?php
 
 /**
  * Resources directory interface definition
  *
  * @author Thomas Bruederli <bruederli@kolabsys.com>
  *
  * Copyright (C) 2014, Kolab Systems AG <contact@kolabsys.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as
  * published by the Free Software Foundation, either version 3 of the
  * License, or (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  * GNU Affero General Public License for more details.
  *
  * You should have received a copy of the GNU Affero General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
-
 /**
  * Interface definition for a resources directory driver classe
  */
 abstract class resources_driver
 {
-  protected$cal;
+  protected $cal;
 
   /**
    * Default constructor
    */
   function __construct($cal)
   {
       $this->cal = $cal;
   }
 
   /**
    * Fetch resource objects to be displayed for booking
    *
    * @param  string  Search query (optional)
    * @return array  List of resource records available for booking
    */
   abstract public function load_resources($query = null);
 
   /**
    * Return properties of a single resource
    *
    * @param string  Unique resource identifier
    * @return array  Resource object as hash array
    */
   abstract public function get_resource($id);
 
   /**
    * Return properties of a resource owner
    *
    * @param string  Owner identifier
    * @return array  Resource object as hash array
    */
   public function get_resource_owner($id)
   {
       return null;
   }
 
   /**
    * Get event data to display a resource's calendar
    *
    * The default implementation extracts the resource's email address
    * and fetches free-busy data using the calendar backend driver.
    *
    * @param  integer Event's new start (unix timestamp)
    * @param  integer Event's new end (unix timestamp)
    * @return array A list of event objects (see calendar_driver specification)
    */
   public function get_resource_calendar($id, $start, $end)
   {
       $events = array();
       $rec = $this->get_resource($id);
       if ($rec && !empty($rec['email']) && $this->cal->driver) {
           $fbtypemap = array(
               calendar::FREEBUSY_BUSY => 'busy',
               calendar::FREEBUSY_TENTATIVE => 'tentative',
               calendar::FREEBUSY_OOF => 'outofoffice',
           );
 
           // if the backend has free-busy information
           $fblist = $this->cal->driver->get_freebusy_list($rec['email'], $start, $end);
           if (is_array($fblist)) {
               foreach ($fblist as $slot) {
                   list($from, $to, $type) = $slot;
                   if ($type == calendar::FREEBUSY_FREE || $type == calendar::FREEBUSY_UNKNOWN) {
                       continue;
                   }
                   if ($from < $end && $to > $start) {
                       $event = array(
                           'id'     => sha1($id . $from . $to),
                           'title'  => $rec['name'],
                           'start'  => new DateTime('@' . $from),
                           'end'    => new DateTime('@' . $to),
                           'status' => $fbtypemap[$type],
                           'calendar' => '_resource',
                       );
                       $events[] = $event;
                   }
               }
           }
       }
 
       return $events;
   }
-
 }