question: private Iterable < ? extends DocumentScore > evaluateQuery ( QuerySpec query ) { Iterable < ? extends DocumentScore > hits = null ; try { String sQuery = query . getQueryString ( ) ; if ( ! sQuery . isEmpty ( ) ) { boolean highlight = ( query . getSnippetVariableName ( ) != null || query . getPropertyVariableName ( ) != null ) ; hits = query ( query . getSubject ( ) , query . getQueryString ( ) , query . getPropertyURI ( ) , highlight ) ; } else { hits = null ; } } catch ( Exception e ) { logger . error ( "There was a problem evaluating query '" + query . getQueryString ( ) + "' for property '" + query . getPropertyURI ( ) + "!" , e ) ; } return hits ; }
target:  Evaluates one Lucene Query. It distinguishes between two cases, the one where no subject is given and the one were it is given.