public static void register()

in hugegraph-common/src/main/java/org/apache/hugegraph/config/OptionSpace.java [45:94]
45 lines of code
9 McCabe index (conditional complexity)

    public static void register(String module, String holder) {
        ClassLoader classLoader = OptionSpace.class.getClassLoader();
        Class<?> clazz;
        try {
            clazz = classLoader.loadClass(holder);
        } catch (ClassNotFoundException e) {
            throw new ConfigException(
                      "Failed to load class of option holder '%s'", e, holder);
        }

        // Check subclass
        if (!OptionHolder.class.isAssignableFrom(clazz)) {
            throw new ConfigException(
                      "Class '%s' is not a subclass of OptionHolder", holder);
        }

        OptionHolder instance = null;
        Exception exception = null;
        try {
            Method method = clazz.getMethod(INSTANCE_METHOD);
            if (!Modifier.isStatic(method.getModifiers())) {
                throw new NoSuchMethodException(INSTANCE_METHOD);
            }
            instance = (OptionHolder) method.invoke(null);
            if (instance == null) {
                exception = new ConfigException(
                                "Returned null from %s() method",
                                INSTANCE_METHOD);
            }
        } catch (NoSuchMethodException e) {
            LOG.warn("Class {} does not has static method {}.",
                     holder, INSTANCE_METHOD);
            exception = e;
        } catch (InvocationTargetException e) {
            LOG.warn("Can't call static method {} from class {}.",
                     INSTANCE_METHOD, holder);
            exception = e;
        } catch (IllegalAccessException e) {
            LOG.warn("Illegal access while calling method {} from class {}.",
                     INSTANCE_METHOD, holder);
            exception = e;
        }

        if (exception != null) {
            throw new ConfigException("Failed to instantiate option holder: %s",
                                      exception, holder);
        }

        register(module, instance);
    }