Invient Charts

Hi..
I want to use Invient chart as a portlet..i dont want it as a servlet..

i took the source code from github..in that src its having AppServlet and all...but i want use invient chart as vaadin portlet..
Suggest some idea to use it as portlet instead of servlet...

import java.io.BufferedWriter;
import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;

import com.vaadin.Application;
import com.vaadin.terminal.gwt.server.ApplicationServlet;
import com.vaadin.ui.Window;

public class InvientChartsDemoAppServlet extends ApplicationServlet {

@Override
protected void writeAjaxPageHtmlVaadinScripts(Window window,
String themeName, Application application, BufferedWriter page,
String appUrl, String themeUri, String appId,
HttpServletRequest request) throws ServletException, IOException {
page.write("<script type=\"text/javascript\">\n");
page.write("//<![CDATA[\n");
page.write("document.write(\"<script language='javascript' src='./jquery/jquery-1.4.4.min.js'><\\/script>\");\n");
page.write("document.write(\"<script language='javascript' src='./js/highcharts.js'><\\/script>\");\n");
page.write("document.write(\"<script language='javascript' src='./js/modules/exporting.js'><\\/script>\");\n");
page.write("//]]>\n</script>\n");
super.writeAjaxPageHtmlVaadinScripts(window, themeName, application,
page, appUrl, themeUri, appId, request);
}

}
i dono how to change this to my portlet Application...suggest me...