public Parser readLockClause() {
        if (readLockClauseParser == null) {
           FutureParser future = scoped("readLockClause");
           readLockClauseParser = future;
           future.setParser(
               sequence(
                   optional(
                       choice(
                           token("KEPT"),
                           token("NO"),
                           token("IGNORE")
                       )
                   ),
                   token("LOCK")
               )
           );
        }

        return readLockClauseParser;
    }