/**
  * Returns the directory structure to be created at first start.
  *
  * @return array The directory structure to be created if necessary
  */
 public function getDirectories()
 {
     // initialize the array with the directories
     $directories = array();
     // iterate over the directory keys and read the configuration values
     foreach (DirectoryKeys::getServerDirectoryKeys() as $directoryKey) {
         $directories[$directoryKey] = $this->getSystemConfiguration()->getParam($directoryKey);
     }
     // return the array with the directories
     return $directories;
 }