/**
  * Return the list of users
  *
  * @return array
  */
 public function getChildren()
 {
     if ($this->disableListing) {
         throw new DAV\Exception\MethodNotAllowed('Listing members of this collection is disabled');
     }
     $children = array();
     foreach ($this->principalBackend->getPrincipalsByPrefix($this->principalPrefix) as $principalInfo) {
         $children[] = $this->getChildForPrincipal($principalInfo);
     }
     return $children;
 }