private KNNStatsRequest getRequest()

in src/main/java/org/opensearch/knn/plugin/rest/RestKNNStatsHandler.java [100:139]
33 lines of code
10 McCabe index (conditional complexity)

    private KNNStatsRequest getRequest(RestRequest request) {
        // parse the nodes the user wants to query
        String[] nodeIdsArr = null;
        String nodesIdsStr = request.param("nodeId");
        if (!Strings.isEmpty(nodesIdsStr)) {
            nodeIdsArr = nodesIdsStr.split(",");
        }

        KNNStatsRequest knnStatsRequest = new KNNStatsRequest(knnStats.getStats().keySet(), nodeIdsArr);
        knnStatsRequest.timeout(request.param("timeout"));

        // parse the stats the customer wants to see
        Set<String> statsSet = null;
        String statsStr = request.param("stat");
        if (!Strings.isEmpty(statsStr)) {
            statsSet = new HashSet<>(Arrays.asList(statsStr.split(",")));
        }

        if (statsSet == null) {
            knnStatsRequest.all();
        } else if (statsSet.size() == 1 && statsSet.contains("_all")) {
            knnStatsRequest.all();
        } else if (statsSet.contains(KNNStatsRequest.ALL_STATS_KEY)) {
            throw new IllegalArgumentException("Request " + request.path() + " contains _all and individual stats");
        } else {
            Set<String> invalidStats = new TreeSet<>();
            for (String stat : statsSet) {
                if (!knnStatsRequest.addStat(stat)) {
                    invalidStats.add(stat);
                }
            }

            if (!invalidStats.isEmpty()) {
                throw new IllegalArgumentException(unrecognized(request, invalidStats,
                        knnStatsRequest.getStatsToBeRetrieved(), "stat"));
            }

        }
        return knnStatsRequest;
    }