public function close()
    {
        if ($this->_docCount == 0) {
            return null;
        }

        $this->_dumpFNM();
        $this->_generateCFS();

        /**
 * Zend_Search_Lucene_Index_SegmentInfo 
*/
        include_once 'Zend/Search/Lucene/Index/SegmentInfo.php';

        return new Zend_Search_Lucene_Index_SegmentInfo(
            $this->_directory,
            $this->_name,
            $this->_docCount,
            -1,
            null,
            true,
            true
        );
    }