public static void addListener(TRTrackerServerFactoryListener l) {
    try {
      class_mon.enter();

      listeners.add(l);

      Iterator it = servers.iterator();

      while (it.hasNext()) {

        l.serverCreated((TRTrackerServer) it.next());
      }
    } finally {

      class_mon.exit();
    }
  }
  protected Object[] handleAnnounceAndScrape(
      String client_ip_address, PRUDPPacketRequest request, int request_type) throws Exception {
    if (!checkConnectionId(client_ip_address, request.getConnectionId())) {

      return (null);
    }

    List hashbytes = new ArrayList();
    HashWrapper peer_id = null;
    int port = 0;
    String event = null;

    long uploaded = 0;
    long downloaded = 0;
    long left = 0;
    int num_want = -1;

    String key = null;

    if (request_type == TRTrackerServerRequest.RT_ANNOUNCE) {

      if (PRUDPPacketTracker.VERSION == 1) {
        PRUDPPacketRequestAnnounce announce = (PRUDPPacketRequestAnnounce) request;

        hashbytes.add(announce.getHash());

        peer_id = new HashWrapper(announce.getPeerId());

        port = announce.getPort();

        int i_event = announce.getEvent();

        switch (i_event) {
          case PRUDPPacketRequestAnnounce.EV_STARTED:
            {
              event = "started";
              break;
            }
          case PRUDPPacketRequestAnnounce.EV_STOPPED:
            {
              event = "stopped";
              break;
            }
          case PRUDPPacketRequestAnnounce.EV_COMPLETED:
            {
              event = "completed";
              break;
            }
        }

        uploaded = announce.getUploaded();

        downloaded = announce.getDownloaded();

        left = announce.getLeft();

        num_want = announce.getNumWant();

        int i_ip = announce.getIPAddress();

        if (i_ip != 0) {

          client_ip_address = PRHelpers.intToAddress(i_ip);
        }
      } else {

        PRUDPPacketRequestAnnounce2 announce = (PRUDPPacketRequestAnnounce2) request;

        hashbytes.add(announce.getHash());

        peer_id = new HashWrapper(announce.getPeerId());

        port = announce.getPort();

        int i_event = announce.getEvent();

        switch (i_event) {
          case PRUDPPacketRequestAnnounce.EV_STARTED:
            {
              event = "started";
              break;
            }
          case PRUDPPacketRequestAnnounce.EV_STOPPED:
            {
              event = "stopped";
              break;
            }
          case PRUDPPacketRequestAnnounce.EV_COMPLETED:
            {
              event = "completed";
              break;
            }
        }

        uploaded = announce.getUploaded();

        downloaded = announce.getDownloaded();

        left = announce.getLeft();

        num_want = announce.getNumWant();

        int i_ip = announce.getIPAddress();

        if (i_ip != 0) {

          client_ip_address = PRHelpers.intToAddress(i_ip);
        }

        key = "" + announce.getKey();
      }
    } else {

      PRUDPPacketRequestScrape scrape = (PRUDPPacketRequestScrape) request;

      hashbytes.addAll(scrape.getHashes());
    }

    Map[] root_out = new Map[1];
    TRTrackerServerPeerImpl[] peer_out = new TRTrackerServerPeerImpl[1];

    TRTrackerServerTorrentImpl torrent =
        processTrackerRequest(
            server,
            "",
            root_out,
            peer_out,
            request_type,
            (byte[][]) hashbytes.toArray(new byte[0][0]),
            null,
            null,
            peer_id,
            false,
            TRTrackerServerTorrentImpl.COMPACT_MODE_NONE,
            key, // currently no "no_peer_id" / "compact" in the packet and anyway they aren't
                 // returned / key
            event,
            false,
            port,
            0,
            0,
            client_ip_address,
            client_ip_address,
            downloaded,
            uploaded,
            left,
            num_want,
            TRTrackerServerPeer.CRYPTO_NONE,
            (byte) 1,
            0,
            null);

    Map root = root_out[0];

    if (request_type == TRTrackerServerRequest.RT_ANNOUNCE) {

      if (PRUDPPacketTracker.VERSION == 1) {
        PRUDPPacketReplyAnnounce reply = new PRUDPPacketReplyAnnounce(request.getTransactionId());

        reply.setInterval(((Long) root.get("interval")).intValue());

        List peers = (List) root.get("peers");

        int[] addresses = new int[peers.size()];
        short[] ports = new short[addresses.length];

        for (int i = 0; i < addresses.length; i++) {

          Map peer = (Map) peers.get(i);

          addresses[i] = PRHelpers.addressToInt(new String((byte[]) peer.get("ip")));

          ports[i] = (short) ((Long) peer.get("port")).shortValue();
        }

        reply.setPeers(addresses, ports);

        return (new Object[] {reply, torrent});

      } else {

        PRUDPPacketReplyAnnounce2 reply = new PRUDPPacketReplyAnnounce2(request.getTransactionId());

        reply.setInterval(((Long) root.get("interval")).intValue());

        boolean local_scrape = client_ip_address.equals("127.0.0.1");

        Map scrape_details = torrent.exportScrapeToMap("", client_ip_address, !local_scrape);

        int seeders = ((Long) scrape_details.get("complete")).intValue();
        int leechers = ((Long) scrape_details.get("incomplete")).intValue();

        reply.setLeechersSeeders(leechers, seeders);

        List peers = (List) root.get("peers");

        int[] addresses = new int[peers.size()];
        short[] ports = new short[addresses.length];

        for (int i = 0; i < addresses.length; i++) {

          Map peer = (Map) peers.get(i);

          addresses[i] = PRHelpers.addressToInt(new String((byte[]) peer.get("ip")));

          ports[i] = (short) ((Long) peer.get("port")).shortValue();
        }

        reply.setPeers(addresses, ports);

        return (new Object[] {reply, torrent});
      }

    } else {

      if (PRUDPPacketTracker.VERSION == 1) {

        PRUDPPacketReplyScrape reply = new PRUDPPacketReplyScrape(request.getTransactionId());

        /*
        Long	interval = (Long)root.get("interval");

        if ( interval != null ){

        	reply.setInterval(interval.intValue());
        }
        */

        Map files = (Map) root.get("files");

        byte[][] hashes = new byte[files.size()][];
        int[] s_complete = new int[hashes.length];
        int[] s_downloaded = new int[hashes.length];
        int[] s_incomplete = new int[hashes.length];

        Iterator it = files.keySet().iterator();

        int pos = 0;

        while (it.hasNext()) {

          String hash_str = (String) it.next();

          hashes[pos] = hash_str.getBytes(Constants.BYTE_ENCODING);

          Map details = (Map) files.get(hash_str);

          s_complete[pos] = ((Long) details.get("complete")).intValue();
          s_incomplete[pos] = ((Long) details.get("incomplete")).intValue();
          s_downloaded[pos] = ((Long) details.get("downloaded")).intValue();

          pos++;
        }

        reply.setDetails(hashes, s_complete, s_downloaded, s_incomplete);

        return (new Object[] {reply, torrent});

      } else {

        PRUDPPacketReplyScrape2 reply = new PRUDPPacketReplyScrape2(request.getTransactionId());

        /*
        Long	interval = (Long)root.get("interval");

        if ( interval != null ){

        	reply.setInterval(interval.intValue());
        }
        */

        Map files = (Map) root.get("files");

        int[] s_complete = new int[files.size()];
        int[] s_downloaded = new int[s_complete.length];
        int[] s_incomplete = new int[s_complete.length];

        Iterator it = files.keySet().iterator();

        int pos = 0;

        while (it.hasNext()) {

          String hash_str = (String) it.next();

          Map details = (Map) files.get(hash_str);

          s_complete[pos] = ((Long) details.get("complete")).intValue();
          s_incomplete[pos] = ((Long) details.get("incomplete")).intValue();
          s_downloaded[pos] = ((Long) details.get("downloaded")).intValue();

          pos++;
        }

        reply.setDetails(s_complete, s_downloaded, s_incomplete);

        return (new Object[] {reply, torrent});
      }
    }
  }
  protected long allocateConnectionId(String client_address) {
    try {
      random_mon.enter();

      long id = random.nextLong();

      Long new_key = new Long(id);

      connectionData new_data = new connectionData(client_address, id);

      // check for timeouts

      if (new_data.getTime() - last_timeout_check > 500) {

        last_timeout_check = new_data.getTime();

        Iterator<Long> it = connection_id_map.keySet().iterator();

        while (it.hasNext()) {

          Long key = it.next();

          connectionData data = connection_id_map.get(key);

          if (new_data.getTime() - data.getTime() > CONNECTION_ID_LIFETIME) {

            // System.out.println( "TRTrackerServerProcessorUDP: connection id timeout" );

            it.remove();

            List<connectionData> cds = connection_ip_map.get(client_address);

            if (cds != null) {

              Iterator<connectionData> it2 = cds.iterator();

              while (it2.hasNext()) {

                if (it2.next().getID() == key) {

                  it2.remove();

                  break;
                }
              }

              if (cds.size() == 0) {

                connection_ip_map.remove(client_address);
              }
            }

          } else {
            // insertion order into map is time based - LinkedHashMap returns keys in same order

            break;
          }
        }
      }

      List<connectionData> cds = connection_ip_map.get(client_address);

      if (cds == null) {

        cds = new ArrayList<connectionData>();

        connection_ip_map.put(client_address, cds);
      }

      cds.add(new_data);

      if (cds.size() > 512) {

        connectionData dead = cds.remove(0);

        connection_id_map.remove(dead.getID());
      }

      connection_id_map.put(new_key, new_data);

      // System.out.println( "TRTrackerServerProcessorUDP: allocated:" + id + ", connection id map
      // size = " + connection_id_map.size());

      return (id);

    } finally {

      random_mon.exit();
    }
  }