private static void initNextLevel()

in apm-commons/apm-util/src/main/java/org/apache/skywalking/apm/util/ConfigInitializer.java [49:106]
49 lines of code
15 McCabe index (conditional complexity)

    private static void initNextLevel(Properties properties, Class<?> recentConfigType,
                                      ConfigDesc parentDesc) throws IllegalArgumentException, IllegalAccessException {
        for (Field field : recentConfigType.getFields()) {
            if (Modifier.isPublic(field.getModifiers()) && Modifier.isStatic(field.getModifiers())) {
                String configKey = (parentDesc + "." + field.getName()).toLowerCase();
                Class<?> type = field.getType();
                if (Map.class.isAssignableFrom(type)) {
                    /*
                     * Map config format is, config_key[map_key]=map_value, such as plugin.opgroup.resttemplate.rule[abc]=/url/path
                     * "config_key[]=" will generate an empty Map , user could use this mechanism to set an empty Map
                     */
                    ParameterizedType genericType = (ParameterizedType) field.getGenericType();
                    Type[] argumentTypes = genericType.getActualTypeArguments();
                    Type keyType = argumentTypes[0];
                    Type valueType = argumentTypes[1];
                    // A chance to set an empty map
                    if (properties.containsKey(configKey + "[]")) {
                        Map currentValue = (Map) field.get(null);
                        if (currentValue != null && !currentValue.isEmpty()) {
                            field.set(null, initEmptyMap(type));
                        }
                    } else {
                        // Set the map from config key and properties
                        Map map = readMapType(type, configKey, properties, keyType, valueType);
                        if (map.size() != 0) {
                            field.set(null, map);
                        }
                    }
                } else if (properties.containsKey(configKey)) {
                    //In order to guarantee the default value could be reset as empty , we parse the value even if it's blank
                    String propertyValue = properties.getProperty(configKey, "");
                    if (Collection.class.isAssignableFrom(type)) {
                        ParameterizedType genericType = (ParameterizedType) field.getGenericType();
                        Type argumentType = genericType.getActualTypeArguments()[0];
                        Collection collection = convertToCollection(argumentType, type, propertyValue);
                        field.set(null, collection);
                    } else {
                        // Convert the value into real type
                        final Length lengthDefine = field.getAnnotation(Length.class);
                        if (lengthDefine != null && propertyValue.length() > lengthDefine.value()) {
                            StringUtil.cut(propertyValue, lengthDefine.value());
                            System.err.printf("The config value will be truncated , because the length max than %d : %s -> %s%n", lengthDefine.value(), configKey, propertyValue);
                        }
                        Object convertedValue = convertToTypicalType(type, propertyValue);
                        if (convertedValue != null) {
                            field.set(null, convertedValue);
                        }
                    }
                }

            }
        }
        for (Class<?> innerConfiguration : recentConfigType.getClasses()) {
            parentDesc.append(innerConfiguration.getSimpleName());
            initNextLevel(properties, innerConfiguration, parentDesc);
            parentDesc.removeLastDesc();
        }
    }