/**
  * delete folderstate (aka: forget that we have sent the folder to the client)
  *
  * @param string $_class the class from the xml
  * @param string $_contentId the Tine 2.0 id of the folder
  */
 protected function _deleteFolderState($_class, $_folderId)
 {
     $folderStateFilter = new ActiveSync_Model_FolderStateFilter(array(array('field' => 'device_id', 'operator' => 'equals', 'value' => $this->_device->getId()), array('field' => 'class', 'operator' => 'equals', 'value' => $_class), array('field' => 'folderid', 'operator' => 'equals', 'value' => $_folderId)));
     $state = $this->_folderStateBackend->search($folderStateFilter, NULL, true);
     if (count($state) > 0) {
         $this->_folderStateBackend->delete($state[0]);
     } else {
         Tinebase_Core::getLogger()->warn(__METHOD__ . '::' . __LINE__ . " no folderstate found for " . print_r($folderStateFilter->toArray(), true));
     }
 }