private static Node readNode()

in java-client/src/main/java/co/elastic/clients/transport/rest5_client/low_level/sniffer/ElasticsearchNodesSniffer.java [138:271]
112 lines of code
36 McCabe index (conditional complexity)

    private static Node readNode(String nodeId, JsonParser parser, Scheme scheme) throws IOException {
        HttpHost publishedHost = null;
        /*
         * We sniff the bound hosts so we can look up the node based on any
         * address on which it is listening. This is useful in Elasticsearch's
         * test framework where we sometimes publish ipv6 addresses but the
         * tests contact the node on ipv4.
         */
        Set<HttpHost> boundHosts = new HashSet<>();
        String name = null;
        String version = null;
        /*
         * Multi-valued attributes come with key = `real_key.index` and we
         * unflip them after reading them because we can't rely on the order
         * that they arive.
         */
        final Map<String, String> protoAttributes = new HashMap<String, String>();

        boolean sawRoles = false;
        final Set<String> roles = new TreeSet<>();

        String fieldName = null;
        while (parser.nextToken() != JsonToken.END_OBJECT) {
            if (parser.getCurrentToken() == JsonToken.FIELD_NAME) {
                fieldName = parser.getCurrentName();
            } else if (parser.getCurrentToken() == JsonToken.START_OBJECT) {
                if ("http".equals(fieldName)) {
                    while (parser.nextToken() != JsonToken.END_OBJECT) {
                        if (parser.getCurrentToken() == JsonToken.VALUE_STRING && "publish_address".equals(parser.getCurrentName())) {
                            String address = parser.getValueAsString();
                            String host;
                            URI publishAddressAsURI;

                            // ES7 cname/ip:port format
                            if (address.contains("/")) {
                                String[] cnameAndURI = address.split("/", 2);
                                publishAddressAsURI = URI.create(scheme + "://" + cnameAndURI[1]);
                                host = cnameAndURI[0];
                            } else {
                                publishAddressAsURI = URI.create(scheme + "://" + address);
                                host = publishAddressAsURI.getHost();
                            }
                            publishedHost = new HttpHost(publishAddressAsURI.getScheme(), host, publishAddressAsURI.getPort());
                        } else if (parser.currentToken() == JsonToken.START_ARRAY && "bound_address".equals(parser.getCurrentName())) {
                            while (parser.nextToken() != JsonToken.END_ARRAY) {
                                URI boundAddressAsURI = URI.create(scheme + "://" + parser.getValueAsString());
                                boundHosts.add(
                                    new HttpHost(boundAddressAsURI.getScheme(), boundAddressAsURI.getHost(), boundAddressAsURI.getPort())
                                );
                            }
                        } else if (parser.getCurrentToken() == JsonToken.START_OBJECT) {
                            parser.skipChildren();
                        }
                    }
                } else if ("attributes".equals(fieldName)) {
                    while (parser.nextToken() != JsonToken.END_OBJECT) {
                        if (parser.getCurrentToken() == JsonToken.VALUE_STRING) {
                            String oldValue = protoAttributes.put(parser.getCurrentName(), parser.getValueAsString());
                            if (oldValue != null) {
                                throw new IOException("repeated attribute key [" + parser.getCurrentName() + "]");
                            }
                        } else {
                            parser.skipChildren();
                        }
                    }
                } else {
                    parser.skipChildren();
                }
            } else if (parser.currentToken() == JsonToken.START_ARRAY) {
                if ("roles".equals(fieldName)) {
                    sawRoles = true;
                    while (parser.nextToken() != JsonToken.END_ARRAY) {
                        roles.add(parser.getText());
                    }
                } else {
                    parser.skipChildren();
                }
            } else if (parser.currentToken().isScalarValue()) {
                if ("version".equals(fieldName)) {
                    version = parser.getText();
                } else if ("name".equals(fieldName)) {
                    name = parser.getText();
                }
            }
        }
        // http section is not present if http is not enabled on the node, ignore such nodes
        if (publishedHost == null) {
            logger.debug("skipping node [" + nodeId + "] with http disabled");
            return null;
        }

        Map<String, List<String>> realAttributes = new HashMap<>(protoAttributes.size());
        List<String> keys = new ArrayList<>(protoAttributes.keySet());
        for (String key : keys) {
            if (key.endsWith(".0")) {
                String realKey = key.substring(0, key.length() - 2);
                List<String> values = new ArrayList<>();
                int i = 0;
                while (true) {
                    String value = protoAttributes.remove(realKey + "." + i);
                    if (value == null) {
                        break;
                    }
                    values.add(value);
                    i++;
                }
                realAttributes.put(realKey, unmodifiableList(values));
            }
        }
        for (Map.Entry<String, String> entry : protoAttributes.entrySet()) {
            realAttributes.put(entry.getKey(), singletonList(entry.getValue()));
        }

        if (version.startsWith("2.")) {
            /*
             * 2.x doesn't send roles, instead we try to read them from
             * attributes.
             */
            boolean clientAttribute = v2RoleAttributeValue(realAttributes, "client", false);
            Boolean masterAttribute = v2RoleAttributeValue(realAttributes, "master", null);
            Boolean dataAttribute = v2RoleAttributeValue(realAttributes, "data", null);
            if ((masterAttribute == null && false == clientAttribute) || masterAttribute) {
                roles.add("master");
            }
            if ((dataAttribute == null && false == clientAttribute) || dataAttribute) {
                roles.add("data");
            }
        } else {
            assert sawRoles : "didn't see roles for [" + nodeId + "]";
        }
        assert boundHosts.contains(publishedHost) : "[" + nodeId + "] doesn't make sense! publishedHost should be in boundHosts";
        logger.trace("adding node [" + nodeId + "]");
        return new Node(publishedHost, boundHosts, name, version, new Roles(roles), unmodifiableMap(realAttributes));
    }