How to determine if a user has scrolled to the end of an NSTableView

Question

I have an NSTableView, and I would like to know when the user has scrolled to the bottom, so I can perform an action. Not quite sure how to go about this?

UPDATE: Here is how I am calculating the bottom of the table:

-(void)tableViewDidScroll:(CPNotification) notification
{
    var scrollView = [notification object];
    var currentPosition = CGRectGetMaxY([scrollView visibleRect]);
    var tableViewHeight = [messagesTableView bounds].size.height - 100;

    //console.log("TableView Height: " + tableViewHeight);
    //console.log("Current Position: " + currentPosition);

    if (currentPosition > tableViewHeight - 100)
    {
       console.log("we're at the bottom!");
    }
}