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

public class SingleThreadedServlet extends GenericServlet
 {

  public void service(ServletRequest request, ServletResponse response)
    throws ServletException, IOException {
    int counter = 0;
    
    // get saved value
    try {
      BufferedReader reader = new BufferedReader(
        new FileReader("counter.txt"));
      counter = Integer.parseInt( reader.readLine() );
      reader.close();
    }
    catch (Exception e) {
    }

    // increment counter
    counter++;

    // save new value
    try {
      BufferedWriter writer = new BufferedWriter(
        new FileWriter("counter.txt"));
      writer.write(Integer.toString(counter));

      writer.close();
    }
    catch (Exception e) {
    }

    try {
      PrintWriter out = response.getWriter();
      out.println("You are visitor number " + counter);
    }
    catch (Exception e) {
    }
  }
}