Understanding handler interceptors in Spring Portlet MVC

In this post I've shown a figure from Chapter 7 of Portlets in Action which shows the role of handler interceptors in portlet request processing.

Handler interceptors are invoked before and after the execution of the handler. The preRenderHandle method is invoked before the handler execution, and the postRenderHandle method is invoked after the handler  execution. The afterRenderCompletion method is invoked after the postRenderHandle method of all the interceptors is executed.