Internet usage using vnstat

My internet bill gave the first surprise yesterday. I got amazed after seeing my usage for the last one month. Unfortunately i do not have any option to check my usage from my provider. I decided to look for a good montoring tool in my opensource world itself. I came across nearly 15 good tools for monitoring the bandwidth usage, all are good but lacks some of the modules/functions i require. My search got ended up after seeing the cool small application vnstat. All the information i require is available at a single command. Just amazed to see such a wonderful command. But one thing which clearly lacks is a wonderful gui which alerts me whenever i exceed my daily usage, hmmm quiet an annoying requirement, but yes i need that. Finally i decided to come up with an interface for this cute command line in which I can incorporate my requirement also. I will be starting the work tomorrow. As a java developer, i need to find a real base for creating java desktop apps for Linux. I was evaluating some of projects for the past couple of days. One project which strikes me is the java-gnome project. But for developing an interface for vnstat i do not really require api's from this particular project. I believe core java api's can provide me the stuff what i was looking for.