Detecting if user has logged out

Question

Hello,
I am currently using a Java proram to run as a periodic background process on a linux machine that I telnet to. I need the app to detect when I have logged out and exit. Ant ideas on how I can do this??
Cheers in advance for any help,
Shane

Answer 1

This post interested me and I wrote some code to see if this could be done. You would have to modify it to fit your needs, but I think this could help you. It is only class that verifies if the user "root" is logged in, it worked here when I tried it:
import java.io.*;
public class CheckLogin  {
  public CheckLogin() {
    super();
  public static void main(String arg[]) {
    try {
      Runtime rt= Runtime.getRuntime();
      Process p= rt.exec("who -q | grep root");
      try {
        int i= p.waitFor();
        if(i == 0) {
          BufferedReader br= new BufferedReader(new InputStreamReader(p.getInputStream()));
          System.out.println("User: "+ br.readLine());
        } else {
          System.out.println("Process did not ran.");
      } catch (InterruptedException iex) {
        System.err.println("Error: "+ iex.getMessage());
    } catch(IOException ioex) {
      System.err.println("Error: "+ ioex.getMessage());
}