O Guia Definitivo do Yii 1.1

Second, at the beginning of a controller class file, insert the following lines:
Yii::import('application.vendors.*');
require_once('Zend/Search/Lucene.php');
The above code includes the class file Lucene.php. Because we are using a relative path,
we need to change the PHP include path so that the file can be located correctly. This is
done by calling Yii::importbefore require_once.
Once the above set up is ready, we can use the Lucene class in a controller action, like the
following:
$lucene=new Zend_Search_Lucene($pathOfIndex);
$hits=$lucene->find(strtolower($keyword));