Horde_Kolab_Storage_Cache_Data::backendMap PHP Method

    public function backendMap($backend_ids)
    {
        $map = array();
        foreach ($backend_ids as $item) {
            $map[$item] = $this->_data[self::B2O][$item];
        }
        return $map;
    }

 /**
  * Synchronize the query data with the information from the backend.
  *
  * @param array $params Additional parameters.
  *
  * @return NULL
  */
 public function synchronize($params = array())
 {
     $current = $this->getStamp();
     if (!$this->_data_cache->isInitialized()) {
         $this->_completeSynchronization($current);
         return;
     }
     $previous = unserialize($this->_data_cache->getStamp());
     if ($previous === false || $previous->isReset($current)) {
         $this->_completeSynchronization($current);
         return;
     }
     if (!isset($params['changes'])) {
         $changes = $previous->getChanges($current);
         $params['changes'][Horde_Kolab_Storage_Folder_Stamp::ADDED] = $this->fetch($changes[Horde_Kolab_Storage_Folder_Stamp::ADDED]);
         $params['changes'][Horde_Kolab_Storage_Folder_Stamp::DELETED] = $this->_data_cache->backendMap($changes[Horde_Kolab_Storage_Folder_Stamp::DELETED]);
     }
     if ($params['changes'] !== false) {
         $params['last_sync'] = $this->_data_cache->getLastSync();
         $this->_data_cache->store($params['changes'][Horde_Kolab_Storage_Folder_Stamp::ADDED], $current, $this->getVersion(), $params['changes'][Horde_Kolab_Storage_Folder_Stamp::DELETED]);
         $params['current_sync'] = $this->_data_cache->getLastSync();
         parent::synchronize($params);
         $this->_data_cache->save();
     }
     $this->_init = true;
 }