Someone

package edu.ncsu.ftp;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.PrintStream;import java.net.BindException;import java.net.ServerSocket;import java.net.Socket;import java.net.SocketException;import java.util.HashMap;public class Ident        extends Thread {    private volatile static boolean running = false;    private volatile static boolean enabled = false;    private static String userid;    private static int expectedConns;    private static ServerSocket ss;    private static HashMap requestMap = null;    private static Ident ident = null;    private Ident(String id) throws Exception {        if (running)            throw new Exception("Already running");        setUserID(id);        expectedConns = 0;    }    private synchronized void doNotify() {        notifyAll();    }    private synchronized void doWait() {        try {            wait();        } catch (InterruptedException e) {        }    }    public static Ident getInstance() {        return Ident.getInstance(Ident.getUserId());    }    public static Ident getInstance(String user_id) {        if (requestMap == null)            requestMap = new HashMap();        if (ident == null)            try {                running = false; // should never matter                ident = new Ident(user_id);            } catch (Exception e) {                e.printStackTrace(); // Should never get here..            }        return ident;    }    public static Ident startServer(String userid) throws Exception {        //Ident.userid = userid;        Ident.setUserID(userid);        return Ident.startServer();    }    public static Ident startServer() throws Exception {        if (userid == null)            throw new Exception("IDENT service could not start (cannot start when user_id is empty)");        if (ident == null)            ident = Ident.getInstance();        if (running == true)            throw new Exception("IDENT service is already runnning");        if (enabled == false)            throw new Exception("IDENT service could not start (disabled)");        ident.start();        Thread.yield();        return ident;    }    public static void setUserID(String userid) {        Ident.userid = userid;        Ident.enable();    }    public static String getUserId() {        return userid;    }    public static void expectRequest() {        if (!enabled)            return;        expectedConns++;        Ident.getInstance().doNotify();    }    /**     * @param ipAddress     * @param customId     */    public static void expectRequest(String ipAddress, String customId) {        if (!enabled)            return;        requestMap.put(ipAddress, customId);        Ident.expectRequest();    }    public static void doneRequest() {        if (expectedConns > 0)            expectedConns--;        if (ss != null && expectedConns <= 0)            try {                ss.close();            } catch (IOException e) {            }    }    public static void enable() {        enabled = true;    }    public static boolean isEnabled() {        return enabled;    }    public static void disable() {        enabled = false;        expectedConns = 0;        Ident.doneRequest();        if (requestMap == null)            return;        requestMap.clear();        requestMap = null;        if (!ss.isClosed())            try {                ss.close();            } catch (Exception e) {                e.printStackTrace();            }    }    public static boolean isRunning() {        return running;    }    public static void stopServer() {        Ident.disable();        Ident.getInstance().doNotify();        try {            ident.join();        } catch (InterruptedException e) {            System.err.println(e.toString());            e.printStackTrace();        } finally {            ident = null;        }    }    public void run() {        // 1 at a time, please        if (running == true)            return;        running = true;        while (running) {            try {                while (expectedConns <= 0) {                    /*                     * try { Thread.sleep(500); } catch (InterruptedException e) { }                     */                    Ident.getInstance().doWait();                    continue;                }                try {                    ss = new ServerSocket(113);                } catch (BindException e) {                    System.err                            .println("IDENT service unable to listen on port 113 (port already in use)");                    expectedConns = 0;                    continue;                } catch (Exception e) {                    e.printStackTrace();                    expectedConns = 0;                    System.out                            .println("IDENT service unable to listen on port 113 (unknown error)");                    continue;                }                // ss.setSoTimeout(30 * 1000);                while (expectedConns > 0) {                    IdentConn ic = new IdentConn(ss.accept());                    ic.start();                    Thread.yield();                }                ss.close();            } catch (IOException e) {                // e.printStackTrace();            }            ss = null;        }        running = false;    }    class IdentConn            extends Thread {        private Socket sock;        public IdentConn(Socket s) throws SocketException {            sock = s;            sock.setSoTimeout(30 * 1000);        }        public void run() {            try {                System.out.println("IDENT: Received IDENT request from "                        + sock.getInetAddress().getHostAddress());                BufferedReader in = new BufferedReader(new InputStreamReader(sock                        .getInputStream()));                PrintStream out = new PrintStream(sock.getOutputStream());                Object o = requestMap.get(sock.getInetAddress().getHostAddress());                String tmp_id = o == null ? userid : o.toString();                String line = in.readLine();                if (line != null) {                    out.print(line + " : USERID : UNIX : " + tmp_id + "\r\n");                    System.out.println(line + " : USERID : UNIX : " + tmp_id);                }                in.close();                out.close();                sock.close();            } catch (SocketException e) {                // boomshakalaka don't care            } catch (IOException e) {                e.printStackTrace();            }        }    }}