var6

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Date;
import java.util.function.Predicate;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 *
 * @author slapo_000
 */
public class var6 extends HttpServlet {

    Date d;
    ArrayList<HttpSession> s = new ArrayList<HttpSession>();

    Predicate<HttpSession> isOld = new Predicate<HttpSession>() {
        @Override
        public boolean test(HttpSession t) {
            try
            {
            return ((d.getTime()-t.getLastAccessedTime())) > 6000;
            }
            catch(IllegalStateException e)
            {
               return true;
            }
        }
    };
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        int i;
        //refresh date
        d = new Date();
        //delete old session
        s.removeIf(isOld);
        //if the current session exists in list
        //delete the cur session
        if((i = s.indexOf(request.getSession())) > -1)
           s.remove(i);
        s.add(request.getSession());
        try (PrintWriter out = response.getWriter()) {
            out.println("<!DOCTYPE html>");
            out.println("<html>");
            out.println("<head>");
            out.println("<title>Servlet var6</title>");
            out.println("</head>");
            out.println("<body>");
            out.println("<b>Count Sessions:" + Integer.toString(s.size()) + "</b>");
            out.println("</body>");
            out.println("</html>");
        }
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }


    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>

}