Servlets.SessionUpdate.java Source code

Introduction

Here is the source code for Servlets.SessionUpdate.java

Source

/*
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 * and open the template in the editor.
 */
package Servlets;

import com.google.gson.Gson;
import com.google.gson.JsonObject;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.HashSet;
import java.util.Set;
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 Indunil
 */
public class SessionUpdate extends HttpServlet {

    /**
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code>
     * methods.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        PrintWriter out = response.getWriter();
        HttpSession session = request.getSession();

        response.setContentType("text/html;charset=UTF-8");
        response.setHeader("Cache-control", "no-cache, no-store");
        response.setHeader("Pragma", "no-cache");
        response.setHeader("Expires", "-1");

        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "POST");
        response.setHeader("Access-Control-Allow-Headers", "Content-Type");
        response.setHeader("Access-Control-Max-Age", "86400");

        Gson gson = new Gson();
        JsonObject myObj = new JsonObject();

        try {
            //session update
            session.setMaxInactiveInterval(60);
            myObj.addProperty("SESSION", session.getId());

            //System.out.println("Session Update [" + session.getId() + "]");
            if (session.getServletContext().getAttribute("Live") != null) {
                Set<String> live = (Set<String>) session.getServletContext().getAttribute("Live");
                live.add(session.getId());
                session.getServletContext().setAttribute("Live", live);
            } else {
                Set<String> live = new HashSet<String>();
                live.add(session.getId());
                session.getServletContext().setAttribute("Live", live);
            }

            //System.out.println("Live: " + session.getServletContext().getAttribute("Live"));
            myObj.add("Devices", gson.toJsonTree(session.getServletContext().getAttribute("Live")));

        } catch (Exception e) {
            System.out.println("Exception: " + e.getMessage());
        } finally {
            out.print(myObj);
            out.close();
        }
    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /**
     * Handles the HTTP <code>GET</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Handles the HTTP <code>POST</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Returns a short description of the servlet.
     *
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>

}