private void start()

in accord-core/src/main/java/accord/local/durability/DurabilityQueue.java [243:310]
64 lines of code
25 McCabe index (conditional complexity)

    private void start(SyncPoint<Range> exclusiveSyncPoint, @Nullable DurabilityRequest request, int attempt, AgentExecutor executor)
    {
        logger.debug("{}: Awaiting durability for {}", exclusiveSyncPoint.syncId, exclusiveSyncPoint.route.toRanges());
        AsyncResult<DurabilityResult> coordinate = coordinateIncluding(node, exclusiveSyncPoint, request == null ? null : request.including, executor, attempt);
        registerInProgress(exclusiveSyncPoint, coordinate);
        if (request != null)
            request.reportAttempt(exclusiveSyncPoint.syncId, node.elapsed(MICROSECONDS), coordinate);

        coordinate.invoke((success, fail) -> {
            synchronized (this)
            {
                unregisterInProgress(exclusiveSyncPoint, coordinate);
                TxnId txnId = exclusiveSyncPoint.syncId;
                Ranges ranges = exclusiveSyncPoint.route.toRanges();
                String requestor = request != null ? " requested by " + request.requestedBy : "";
                if (fail != null)
                {
                    if (logger.isTraceEnabled()) logger.trace("{}: failed awaiting durability for {}{}.", txnId, ranges, requestor, fail);
                    if (fail instanceof SyncPointErased || fail instanceof TopologyManager.TopologyRetiredException)
                    {
                        // we can't succeed. if this was requested, and the request is still waiting, submit another coordination request
                        // TODO (required): add back-off and expand this to all unknown exception outcomes
                        if (request != null)
                            node.durability().shards().request(request, request.stillWaiting(exclusiveSyncPoint.route));
                        success();
                        return;
                    }
                }
                if (success == null || (success.achievedRemote.compareTo(request == null ? All : request.remote) < 0))
                {
                    if (success != null)
                        fail = success.failure;

                    if (fail instanceof Exhausted || success != null)
                    {
                        Collection<Node.Id> failedNodes = success != null ? success.excluding : ((Exhausted)fail).failedNodes();
                        Ranges failedRanges = success != null ? exclusiveSyncPoint.route().toRanges() : ((Exhausted)fail).failedRanges();
                        boolean log = failedNodes == null;
                        if (!log)
                        {
                            Set<Node.Id> unlogged = new HashSet<>(failedNodes);
                            for (Collection<Node.Id> logged : WARNINGS_LOGGED.tailMap(System.nanoTime() - MINUTES.toNanos(EXHAUSTED_LOG_INTERVAL_MINUTES)).values())
                                unlogged.removeAll(logged);
                            log = !unlogged.isEmpty();
                        }
                        if (log)
                        {
                            logger.info("{}: Incomplete durability for {}{}. {} were unsuccessful.", txnId, failedRanges, requestor, failedNodes == null ? "some nodes" : failedNodes);
                            WARNINGS_LOGGED.headMap(System.nanoTime() - MINUTES.toNanos(EXHAUSTED_LOG_INTERVAL_MINUTES)).clear();
                            WARNINGS_LOGGED.put(System.nanoTime(), failedNodes == null ? Collections.emptyList() : failedNodes);
                        }
                    }
                    else
                    {
                        if (fail instanceof Timeout) logger.info("{}: Timeout awaiting durability for {}{}", txnId, ranges, requestor, fail);
                        else if (fail != null) logger.info("{}: Failed awaiting durability for {}{}; will retry", txnId, ranges, requestor, fail);
                    }
                    retry(exclusiveSyncPoint, request, attempt + 1);
                }
                else
                {
                    if (request != null) logger.info("{}: Successfully achieved durability for {}{}.", txnId, ranges, requestor);
                    else logger.debug("{}: Successfully achieved durability for {}.", txnId, ranges);
                    success();
                }
            }
        });
    }