With parser:
<?php
$index = Zend_Search_Lucene::open('/data/my-index');
$userQuery = Zend_Search_Lucene_Search_QueryParser::parse($queryStr);
$hits = $index->find($query);
?>
With API:
<?php
$userQuery = Zend_Search_Lucene_Search_QueryParser::parse($queryStr);
$pathTerm = new Zend_Search_Lucene_Index_Term('/data/doc_dir/' . $filename, 'path');
$pathQuery = new Zend_Search_Lucene_Search_Query_Term($pathTerm);
$query = new Zend_Search_Lucene_Search_Query_Boolean();
$query->addSubquery($userQuery);
$query->addSubquery($pathQuery);
$hits = $index->find($query);
?>