private static Function<? super HttpService, ? extends HttpService> decorator(
            Method method, Class<?> clazz, DependencyInjector dependencyInjector) {
        final List<DecoratorAndOrder> decorators = DecoratorAnnotationUtil.collectDecorators(clazz, method);
        Function<? super HttpService, ? extends HttpService> decorator = Function.identity();
        for (int i = decorators.size() - 1; i >= 0; i--) {
            final DecoratorAndOrder d = decorators.get(i);
            decorator = decorator.andThen(d.decorator(dependencyInjector));
        }
        return decorator;
    }
Returns a decorator chain which is specified by {@link Decorator} annotations and user-defined
decorator annotations.
core/src/main/java/com/linecorp/armeria/internal/server/annotation/AnnotatedServiceFactory.java