module development - object instance in module

Hello,

Firstly I'm not an experienced software developer, but I found the Netbeans platform documentation good enough to start this project of my own: 
    I'm trying to create a plugin to help me with editing VHDL files.
I managed to create custom context menu entries but I would like to parse the project's available .vhd files and store the information in a object - let us call it module_obj ( instance of custom created class Module_class  that models specific vhdl structures).   

This instance should be persistent all the time (i.e from the time module is loaded into NetBeans , until user closes the IDE).

Could anyone please point me to where should I instantiate this module_obj , so I can access it from my action listeners ?
 
Thank you!