How can I create a "changing" and "dynamic" dock icon?

Hey guys,



So I'd like to create a Mac OS X dock icon that basically allows for a "dynamic change" when the status of the application updates.


Is there anyway I can customize the dock icon in order to change if and when:


- The application is closed/open

OR

- The application has a new notification/all notifications have been checked?


My primary goal is to get the icon to change images (for example, closed book, open book, etc.) when the application has new notifications that haven't been checked.


Is there a way to do this? I'm thinking there must be a way since the trashbin icon is dynamic. But there is a folder located somewhere in Finder that allows a user to do this as opposed to the standard copy/paste under "get info" in an application.



Can someone help me accomplish this?

Thanks