presto-main/src/main/java/io/prestosql/sql/rewrite/ShowQueriesRewrite.java/Visitor/Visitor
class Visitor:        public Visitor(Metadata metadata, SqlParser sqlParser, Session session, AccessControl accessControl)
        {
            this.metadata = requireNonNull(metadata, "metadata is null");
            this.sqlParser = requireNonNull(sqlParser, "sqlParser is null");
            this.session = requireNonNull(session, "session is null");
            this.accessControl = requireNonNull(accessControl, "accessControl is null");
        }