[Building Sakai] Servlet based presentation layer

[Sila Kayo]

Hi all,
I am new to Sakai, and I am trying to build a simple Sakai tool, and one requirement is to use a Servlet for the presentation layer (not JSP, JSF). I would like to also take advantage of Bean dependency injection to inject Kernel beans like UserDirectoryService etc...
My question is: should my servlet inherit from a special predefined Sakai servlet, if yes, which one.

Thanks in advance,
Sila Kayo