public synchronized List getShardList()

in src/main/java/com/amazonaws/services/dynamodbv2/streamsadapter/DynamoDBStreamsProxy.java [211:260]
42 lines of code
11 McCabe index (conditional complexity)

    public synchronized List<Shard> getShardList() {

        if (shardGraph == null) {
            shardGraph = new ShardGraph();
        }

        // ShardGraph may not be empty if this call is being made after DescribeStream throttling.
        // In that case, the graph will have a lot of closed leaf nodes since their descendants were not
        // discovered earlier due to throttling. We do not handle that explicitly and allow the next round of
        // inconsistency fix attempts to resolve it.
        if (buildShardGraphSnapshot() == ShardGraphProcessingResult.STREAM_DISABLED) {
            LOG.info("Stream was disabled during getShardList operation.");
            return null;
        }

        if (shardGraph.size() < MAX_SHARD_COUNT_TO_TRIGGER_RETRIES) {
            int retryAttempt = 0;
            while (shardGraph.closedLeafNodeCount() > 0 && retryAttempt < maxRetriesToResolveInconsistencies) {
                final long backOffTime = getInconsistencyBackoffTimeInMillis(retryAttempt);
                String infoMsg = String.format("Inconsistency resolution retry attempt: %d. Backing off for %d millis.",
                    retryAttempt, backOffTime);
                LOG.info(infoMsg);
                sleeper.sleep(backOffTime);
                ShardGraphProcessingResult shardGraphProcessingResult = resolveInconsistenciesInShardGraph();
                if (shardGraphProcessingResult.equals(ShardGraphProcessingResult.STREAM_DISABLED)) {
                    LOG.info("Stream was disabled during getShardList operation.");
                    return null;
                } else if (shardGraphProcessingResult.equals(ShardGraphProcessingResult.RESOLVED_INCONSISTENCIES_AND_ABORTED)) {
                    infoMsg = String.format("An intermediate page in DescribeStream response resolved inconsistencies. "
                        + "Total retry attempts taken to resolve inconsistencies: %d", retryAttempt + 1);
                    LOG.info(infoMsg);
                    break;
                }
                retryAttempt++;
            }
            if (retryAttempt == maxRetriesToResolveInconsistencies && shardGraph.closedLeafNodeCount() > 0) {
                LOG.warn("Inconsistencies in the shard graph were not resolved after exhausting all retries.");
            }
        } else {
            if (shardGraph.closedLeafNodeCount() > 0) {
                String msg = String.format("Returning shard list with %s closed leaf node shards.",
                    shardGraph.closedLeafNodeCount());
                LOG.debug(msg);
            }
        }

        this.listOfShardsSinceLastGet.set(shardGraph.getShards());
        this.shardGraph = new ShardGraph();
        return listOfShardsSinceLastGet.get();
    }