/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package test;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *
 * @author oleksiys
 */
public class RecursiveServlet extends HttpServlet {

    private static final String COUNTER_PROPERTY = "counter";

    /**
     * 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 {
        String counterS = request.getParameter(COUNTER_PROPERTY);
        Integer counter = -1;
        try {
            counter = Integer.parseInt(counterS);
        } catch(NumberFormatException e) {
        }
        
        String responseString = counter.toString();
        if (counter > -1) {
            if (counter > 0) {
                String counterToSend = Integer.toString(counter - 1);
                URL url = new URL("http://localhost:8080/TestServlet/RecursiveServlet?" +
                        COUNTER_PROPERTY + "=" + counterToSend);
                HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
                try {
                    String reply = reader.readLine();
                    if (reply.equals(counterToSend)) {
                        responseString = counter.toString();
                    } else {
                        responseString = "Unexpected response. Expected: " + counterToSend + " Received: (" + reply + ")";
                    }
                } finally {
                    reader.close();
                    connection.getInputStream().close();
                }
            }
        } else {
            responseString = "No " + COUNTER_PROPERTY + " header!";
        }

        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        try {
            out.println(responseString);
        } finally {
            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>
}