public static FlumeAppender createAppender()

in log4j-flume-ng/src/main/java/org/apache/logging/log4j/flume/appender/FlumeAppender.java [189:298]
102 lines of code
19 McCabe index (conditional complexity)

    public static FlumeAppender createAppender(@PluginElement("Agents") final Agent[] agents,
                                               @PluginElement("Properties") final Property[] properties,
                                               @PluginAttribute("hosts") final String hosts,
                                               @PluginAttribute("embedded") final String embedded,
                                               @PluginAttribute("type") final String type,
                                               @PluginAttribute("dataDir") final String dataDir,
                                               @PluginAliases("connectTimeout")
                                               @PluginAttribute("connectTimeoutMillis") final String connectionTimeoutMillis,
                                               @PluginAliases("requestTimeout")
                                               @PluginAttribute("requestTimeoutMillis") final String requestTimeoutMillis,
                                               @PluginAttribute("agentRetries") final String agentRetries,
                                               @PluginAliases("maxDelay") // deprecated
                                               @PluginAttribute("maxDelayMillis") final String maxDelayMillis,
                                               @PluginAttribute("name") final String name,
                                               @PluginAttribute("ignoreExceptions") final String ignore,
                                               @PluginAttribute("mdcExcludes") final String excludes,
                                               @PluginAttribute("mdcIncludes") final String includes,
                                               @PluginAttribute("mdcRequired") final String required,
                                               @PluginAttribute("mdcPrefix") final String mdcPrefix,
                                               @PluginAttribute("eventPrefix") final String eventPrefix,
                                               @PluginAttribute("compress") final String compressBody,
                                               @PluginAttribute("batchSize") final String batchSize,
                                               @PluginAttribute("lockTimeoutRetries") final String lockTimeoutRetries,
                                               @PluginElement("FlumeEventFactory") final FlumeEventFactory factory,
                                               @PluginElement("Layout") Layout<? extends Serializable> layout,
                                               @PluginElement("Filter") final Filter filter) {

        final boolean embed = embedded != null ? Boolean.parseBoolean(embedded) :
            (agents == null || agents.length == 0 || hosts == null || hosts.isEmpty()) && properties != null && properties.length > 0;
        final boolean ignoreExceptions = Booleans.parseBoolean(ignore, true);
        final boolean compress = Booleans.parseBoolean(compressBody, true);
        ManagerType managerType;
        if (type != null) {
            if (embed && embedded != null) {
                try {
                    managerType = ManagerType.getType(type);
                    LOGGER.warn("Embedded and type attributes are mutually exclusive. Using type " + type);
                } catch (final Exception ex) {
                    LOGGER.warn("Embedded and type attributes are mutually exclusive and type " + type +
                        " is invalid.");
                    managerType = ManagerType.EMBEDDED;
                }
            } else {
                try {
                    managerType = ManagerType.getType(type);
                } catch (final Exception ex) {
                    LOGGER.warn("Type " + type + " is invalid.");
                    managerType = ManagerType.EMBEDDED;
                }
            }
        }  else if (embed) {
           managerType = ManagerType.EMBEDDED;
        }  else {
           managerType = ManagerType.AVRO;
        }

        final int batchCount = Integers.parseInt(batchSize, 1);
        final int connectTimeoutMillis = Integers.parseInt(connectionTimeoutMillis, 0);
        final int reqTimeoutMillis = Integers.parseInt(requestTimeoutMillis, 0);
        final int retries = Integers.parseInt(agentRetries, 0);
        final int lockTimeoutRetryCount = Integers.parseInt(lockTimeoutRetries, DEFAULT_LOCK_TIMEOUT_RETRY_COUNT);
        final int delayMillis = Integers.parseInt(maxDelayMillis, DEFAULT_MAX_DELAY);

        if (layout == null) {
            final int enterpriseNumber = Rfc5424Layout.DEFAULT_ENTERPRISE_NUMBER;
            layout = new Rfc5424Layout.Rfc5424LayoutBuilder()
                    .setFacility(Facility.LOCAL0)
                    .setEin(String.valueOf(enterpriseNumber))
                    .setIncludeMDC(true)
                    .setMdcId(Rfc5424Layout.DEFAULT_MDCID)
                    .setMdcPrefix(mdcPrefix)
                    .setEventPrefix(eventPrefix)
                    .setIncludeNL(false)
                    .setExcludes(excludes)
                    .setIncludes(includes)
                    .setRequired(required)
                    .setUseTLSMessageFormat(false)
                    .build();
        }

        if (name == null) {
            LOGGER.error("No name provided for Appender");
            return null;
        }

        AbstractFlumeManager manager;

        switch (managerType) {
            case EMBEDDED:
                manager = FlumeEmbeddedManager.getManager(name, agents, properties, batchCount, dataDir);
                break;
            case AVRO:
                manager = FlumeAvroManager.getManager(name, getAgents(agents, hosts), batchCount, delayMillis, retries, connectTimeoutMillis, reqTimeoutMillis);
                break;
            case PERSISTENT:
                manager = FlumePersistentManager.getManager(name, getAgents(agents, hosts), properties, batchCount, retries,
                    connectTimeoutMillis, reqTimeoutMillis, delayMillis, lockTimeoutRetryCount, dataDir);
                break;
            default:
                LOGGER.debug("No manager type specified. Defaulting to AVRO");
                manager = FlumeAvroManager.getManager(name, getAgents(agents, hosts), batchCount, delayMillis, retries, connectTimeoutMillis, reqTimeoutMillis);
        }

        if (manager == null) {
            return null;
        }

        return new FlumeAppender(name, filter, layout,  ignoreExceptions, includes,
            excludes, required, mdcPrefix, eventPrefix, compress, factory, Property.EMPTY_ARRAY, manager);
    }