public function current()
        {
            $this->_sort();
            current($this->_index);
            $hash = key($this->_index);

            if (isset($this->_pages[$hash])) {
                return $this->_pages[$hash];
            } else {
                throw new Exception(
                        'Corruption detected in container; ' .
                        'invalid key found in internal iterator');
            }
        }