try {
            // Thread safety
            requestModel.enterCriticalSection(Lock.READ);
            final QueryExecution queryExecution = QueryExecutionFactory.create(QueryFactory.create(queryString),
                    requestModel);

            queryExecution.getContext().set(Symbol.create("TransportSection"), transportSection);

            try {
                final ResultSet resultSet = queryExecution.execSelect();

                while(resultSet.hasNext()) {
                    listRankedOfferedServices.add(resultSet.next());
                }
            } finally {
                queryExecution.close();
            }
        } finally {
            requestModel.leaveCriticalSection();
        }