Extending the javadoc generation functionality for methods

Hi! I'm new to plugin development, and can't find much documentation about
how to start.

I want to create a plugin to extend the functionality provided by IntelliJ
when a user types "/** + ]]>" before a method. What I want it to be
able to do is to insert additional information and tags in the generated
javadoc. Does anyone have an idea (no pun intended) on where and how to
start?

André