Displaying line numbers in the editor

I want to display line numbers on my editor as in the example given in the link http://doc.trolltech.com/qtjambi-4.4...odeeditor.html.

I have implemented a tabbed interface and want the line number to appear on each tab.
Please let me know the easiest way that the line number area could be painted and the line numbers displayed on the same, in the editor.

Just do it the way it's done in the example you posted.
No easier way than that afaik.