// HowToS.java provides a simple servlet example

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;

public class HowToS extends HttpServlet {

  public void doGet( HttpServletRequest req, HttpServletResponse resp )
    throws IOException
  {
    String c = getInitParameter("count");

    int n = (c != null) ? Integer.parseInt(c) : 3;

    String myPath = req.getServletPath();

    resp.setContentType( "text/html" );
    
    PrintWriter toClient = resp.getWriter();

    toClient.println(
      "<title>HowToS servlet page</title>\n" +
      "<h1>Welcome to the HowToS servlet</h1>\n" +
      "<form method=post action="+myPath+">\n" +
      "  <input type=hidden name=N value="+n+"></input>\n" +
      "  <p><strong>Countdown at "+n+"</strong></p>\n" +
      "  <input type=submit value='Click here to continue'></input>\n" +
      "</form>\n" +
      "<address>Lars Appel, August 2000</address>"
    );

    toClient.close();
  }
  
  public void doPost( HttpServletRequest req, HttpServletResponse resp )
    throws IOException
  {
    String s = req.getParameter("N");

    int n = (s != null) ? Integer.parseInt(s) : /*form error*/ 0;

    String myPath = req.getServletPath();

    resp.setContentType( "text/html" );
    
    PrintWriter toClient = resp.getWriter();

    if (--n > 0) {
      toClient.println(
        "<title>HowToS servlet page</title>\n" +
        "<h1>Welcome back</h1>\n" +
        "<form method=post action="+myPath+">\n" +
        "  <input type=hidden name=N value="+n+"></input>\n" +
        "  <p><strong>Countdown at "+n+"</strong></p>\n" +
        "  <input type=submit value='Click here to continue'></input>\n" +
        "</form>\n" +
        "<address>Lars Appel, August 2000</address>"
      );
    } else {
      toClient.println(
        "<title>HowToS servlet page</title>\n" +
        "<h1>Thanks for your time</h1>\n" +
        "<p><strong>Countdown finished</strong>;\n" +
        "<a href="+myPath+">click here</a> to start over</p>\n" +
        "<address>Lars Appel, August 2000</address>"
      );
    }

    toClient.close();
  }
  
}