import javax.servlet.*;
import javax.servlet.http.*;

public class Test4Cookies extends HttpServlet {

  private static final Cookie cookie = new Cookie( "hello" , "world" );
  private static final String paramName = "foo";
  private static final String successURI = "/success.htm";
  private static final String failureURI = "/failure.htm";

  public void doPost(HttpServletRequest req, HttpServletResponse res) {
    if ( req.getParameter( paramName ) == null ) {
       res.addCookie( cookie );
       res.sendRedirect(req.getRequestURI() +"?"+ paramName +"=bar" );
    }
    else {
       res.sendRedirect
         (( req.getCookies().length == 0 ) ? failureURI : successURI
    )
  }

  public void doGet(HttpServletRequest req, HttpServletResponse res) {
    doPost(req, res);
  }
}