/**
     * Function called when an audio device is plugged or unplugged.
     *
     * @param event The property change event which may concern the audio device.
     */
    public void propertyChange(PropertyChangeEvent event) {
      if (DeviceConfiguration.PROP_AUDIO_SYSTEM_DEVICES.equals(event.getPropertyName())) {
        NotificationService notificationService = getNotificationService();

        if (notificationService != null) {
          // Registers only once to the  popup message notification
          // handler.
          if (!isRegisteredToPopupMessageListener) {
            isRegisteredToPopupMessageListener = true;
            managePopupMessageListenerRegistration(true);
          }

          // Fires the popup notification.
          ResourceManagementService resources = NeomediaActivator.getResources();
          Map<String, Object> extras = new HashMap<String, Object>();

          extras.put(NotificationData.POPUP_MESSAGE_HANDLER_TAG_EXTRA, this);
          notificationService.fireNotification(
              DEVICE_CONFIGURATION_HAS_CHANGED,
              resources.getI18NString("impl.media.configform" + ".AUDIO_DEVICE_CONFIG_CHANGED"),
              resources.getI18NString(
                  "impl.media.configform" + ".AUDIO_DEVICE_CONFIG_MANAGMENT_CLICK"),
              null,
              extras);
        }
      }
    }
  /**
   * Returns default <tt>WebRtcDataStream</tt> if it's ready or <tt>null</tt> otherwise.
   *
   * @return <tt>WebRtcDataStream</tt> if it's ready or <tt>null</tt> otherwise.
   * @throws IOException
   */
  public WebRtcDataStream getDefaultDataStream() throws IOException {
    WebRtcDataStream def;

    synchronized (this) {
      if (sctpSocket == null) {
        def = null;
      } else {
        // Channel that runs on sid 0
        def = channels.get(0);
        if (def == null) {
          def = openChannel(0, 0, 0, 0, "default");
        }
        // Pawel Domas: Must be acknowledged before use
        /*
         * XXX Lyubomir Marinov: We're always sending ordered. According
         * to "WebRTC Data Channel Establishment Protocol", we can start
         * sending messages containing user data after the
         * DATA_CHANNEL_OPEN message has been sent without waiting for
         * the reception of the corresponding DATA_CHANNEL_ACK message.
         */
        //                if (!def.isAcknowledged())
        //                    def = null;
      }
    }
    return def;
  }
  /**
   * Closes given {@link #transportManagers} of this <tt>Conference</tt> and removes corresponding
   * channel bundle.
   */
  void closeTransportManager(TransportManager transportManager) {
    synchronized (transportManagers) {
      for (Iterator<IceUdpTransportManager> i = transportManagers.values().iterator();
          i.hasNext(); ) {
        if (i.next() == transportManager) {
          i.remove();
          // Presumably, we have a single association for
          // transportManager.
          break;
        }
      }

      // Close manager
      try {
        transportManager.close();
      } catch (Throwable t) {
        logger.warn(
            "Failed to close an IceUdpTransportManager of" + " conference " + getID() + "!", t);
        // The whole point of explicitly closing the
        // transportManagers of this Conference is to prevent memory
        // leaks. Hence, it does not make sense to possibly leave
        // TransportManagers open because a TransportManager has
        // failed to close.
        if (t instanceof InterruptedException) Thread.currentThread().interrupt();
        else if (t instanceof ThreadDeath) throw (ThreadDeath) t;
      }
    }
  }
  /**
   * Returns, the <tt>TransportManager</tt> instance for the channel-bundle with ID
   * <tt>channelBundleId</tt>. If no instance exists and <tt>create</tt> is <tt>true</tt>, one will
   * be created.
   *
   * @param channelBundleId the ID of the channel-bundle for which to return the
   *     <tt>TransportManager</tt>.
   * @param create whether to create a new instance, if one doesn't exist.
   * @return the <tt>TransportManager</tt> instance for the channel-bundle with ID
   *     <tt>channelBundleId</tt>.
   */
  IceUdpTransportManager getTransportManager(String channelBundleId, boolean create) {
    IceUdpTransportManager transportManager;

    synchronized (transportManagers) {
      transportManager = transportManagers.get(channelBundleId);
      if (transportManager == null && create && !isExpired()) {
        try {
          // FIXME: the initiator is hard-coded
          // We assume rtcp-mux when bundle is used, so we make only
          // one component.
          transportManager = new IceUdpTransportManager(this, true, 1);
        } catch (IOException ioe) {
          throw new UndeclaredThrowableException(ioe);
        }
        transportManagers.put(channelBundleId, transportManager);
      }
    }

    return transportManager;
  }
  /**
   * Adds the channel-bundles of this <tt>Conference</tt> as
   * <tt>ColibriConferenceIQ.ChannelBundle</tt> instances in <tt>iq</tt>.
   *
   * @param iq the <tt>ColibriConferenceIQ</tt> in which to describe.
   */
  void describeChannelBundles(ColibriConferenceIQ iq) {
    synchronized (transportManagers) {
      for (Map.Entry<String, IceUdpTransportManager> entry : transportManagers.entrySet()) {
        ColibriConferenceIQ.ChannelBundle responseBundleIQ =
            new ColibriConferenceIQ.ChannelBundle(entry.getKey());

        entry.getValue().describe(responseBundleIQ);
        iq.addChannelBundle(responseBundleIQ);
      }
    }
  }
  /** Closes the {@link #transportManagers} of this <tt>Conference</tt>. */
  private void closeTransportManagers() {
    synchronized (transportManagers) {
      for (Iterator<IceUdpTransportManager> i = transportManagers.values().iterator();
          i.hasNext(); ) {
        IceUdpTransportManager transportManager = i.next();

        i.remove();
        closeTransportManager(transportManager);
      }
    }
  }
  /**
   * {@inheritDoc}
   *
   * <p>SCTP input data callback.
   */
  @Override
  public void onSctpPacket(
      byte[] data, int sid, int ssn, int tsn, long ppid, int context, int flags) {
    if (ppid == WEB_RTC_PPID_CTRL) {
      // Channel control PPID
      try {
        onCtrlPacket(data, sid);
      } catch (IOException e) {
        logger.error("IOException when processing ctrl packet", e);
      }
    } else if (ppid == WEB_RTC_PPID_STRING || ppid == WEB_RTC_PPID_BIN) {
      WebRtcDataStream channel;

      synchronized (this) {
        channel = channels.get(sid);
      }

      if (channel == null) {
        logger.error("No channel found for sid: " + sid);
        return;
      }
      if (ppid == WEB_RTC_PPID_STRING) {
        // WebRTC String
        String str;
        String charsetName = "UTF-8";

        try {
          str = new String(data, charsetName);
        } catch (UnsupportedEncodingException uee) {
          logger.error("Unsupported charset encoding/name " + charsetName, uee);
          str = null;
        }
        channel.onStringMsg(str);
      } else {
        // WebRTC Binary
        channel.onBinaryMsg(data);
      }
    } else {
      logger.warn("Got message on unsupported PPID: " + ppid);
    }
  }
  /**
   * Opens new WebRTC data channel using specified parameters.
   *
   * @param type channel type as defined in control protocol description. Use 0 for "reliable".
   * @param prio channel priority. The higher the number, the lower the priority.
   * @param reliab Reliability Parameter<br>
   *     This field is ignored if a reliable channel is used. If a partial reliable channel with
   *     limited number of retransmissions is used, this field specifies the number of
   *     retransmissions. If a partial reliable channel with limited lifetime is used, this field
   *     specifies the maximum lifetime in milliseconds. The following table summarizes this:<br>
   *     </br>
   *     <p>+------------------------------------------------+------------------+ | Channel Type |
   *     Reliability | | | Parameter |
   *     +------------------------------------------------+------------------+ |
   *     DATA_CHANNEL_RELIABLE | Ignored | | DATA_CHANNEL_RELIABLE_UNORDERED | Ignored | |
   *     DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT | Number of RTX | |
   *     DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT_UNORDERED | Number of RTX | |
   *     DATA_CHANNEL_PARTIAL_RELIABLE_TIMED | Lifetime in ms | |
   *     DATA_CHANNEL_PARTIAL_RELIABLE_TIMED_UNORDERED | Lifetime in ms |
   *     +------------------------------------------------+------------------+
   * @param sid SCTP stream id that will be used by new channel (it must not be already used).
   * @param label text label for the channel.
   * @return new instance of <tt>WebRtcDataStream</tt> that represents opened WebRTC data channel.
   * @throws IOException if IO error occurs.
   */
  public synchronized WebRtcDataStream openChannel(
      int type, int prio, long reliab, int sid, String label) throws IOException {
    if (channels.containsKey(sid)) {
      throw new IOException("Channel on sid: " + sid + " already exists");
    }

    // Label Length & Label
    byte[] labelBytes;
    int labelByteLength;

    if (label == null) {
      labelBytes = null;
      labelByteLength = 0;
    } else {
      labelBytes = label.getBytes("UTF-8");
      labelByteLength = labelBytes.length;
      if (labelByteLength > 0xFFFF) labelByteLength = 0xFFFF;
    }

    // Protocol Length & Protocol
    String protocol = WEBRTC_DATA_CHANNEL_PROTOCOL;
    byte[] protocolBytes;
    int protocolByteLength;

    if (protocol == null) {
      protocolBytes = null;
      protocolByteLength = 0;
    } else {
      protocolBytes = protocol.getBytes("UTF-8");
      protocolByteLength = protocolBytes.length;
      if (protocolByteLength > 0xFFFF) protocolByteLength = 0xFFFF;
    }

    ByteBuffer packet = ByteBuffer.allocate(12 + labelByteLength + protocolByteLength);

    // Message open new channel on current sid
    // Message Type
    packet.put((byte) MSG_OPEN_CHANNEL);
    // Channel Type
    packet.put((byte) type);
    // Priority
    packet.putShort((short) prio);
    // Reliability Parameter
    packet.putInt((int) reliab);
    // Label Length
    packet.putShort((short) labelByteLength);
    // Protocol Length
    packet.putShort((short) protocolByteLength);
    // Label
    if (labelByteLength != 0) {
      packet.put(labelBytes, 0, labelByteLength);
    }
    // Protocol
    if (protocolByteLength != 0) {
      packet.put(protocolBytes, 0, protocolByteLength);
    }

    int sentCount = sctpSocket.send(packet.array(), true, sid, WEB_RTC_PPID_CTRL);

    if (sentCount != packet.capacity()) {
      throw new IOException("Failed to open new chanel on sid: " + sid);
    }

    WebRtcDataStream channel = new WebRtcDataStream(sctpSocket, sid, label, false);

    channels.put(sid, channel);

    return channel;
  }
  /**
   * Handles control packet.
   *
   * @param data raw packet data that arrived on control PPID.
   * @param sid SCTP stream id on which the data has arrived.
   */
  private synchronized void onCtrlPacket(byte[] data, int sid) throws IOException {
    ByteBuffer buffer = ByteBuffer.wrap(data);
    int messageType = /* 1 byte unsigned integer */ 0xFF & buffer.get();

    if (messageType == MSG_CHANNEL_ACK) {
      if (logger.isDebugEnabled()) {
        logger.debug(getEndpoint().getID() + " ACK received SID: " + sid);
      }
      // Open channel ACK
      WebRtcDataStream channel = channels.get(sid);
      if (channel != null) {
        // Ack check prevents from firing multiple notifications
        // if we get more than one ACKs (by mistake/bug).
        if (!channel.isAcknowledged()) {
          channel.ackReceived();
          notifyChannelOpened(channel);
        } else {
          logger.warn("Redundant ACK received for SID: " + sid);
        }
      } else {
        logger.error("No channel exists on sid: " + sid);
      }
    } else if (messageType == MSG_OPEN_CHANNEL) {
      int channelType = /* 1 byte unsigned integer */ 0xFF & buffer.get();
      int priority = /* 2 bytes unsigned integer */ 0xFFFF & buffer.getShort();
      long reliability = /* 4 bytes unsigned integer */ 0xFFFFFFFFL & buffer.getInt();
      int labelLength = /* 2 bytes unsigned integer */ 0xFFFF & buffer.getShort();
      int protocolLength = /* 2 bytes unsigned integer */ 0xFFFF & buffer.getShort();
      String label;
      String protocol;

      if (labelLength == 0) {
        label = "";
      } else {
        byte[] labelBytes = new byte[labelLength];

        buffer.get(labelBytes);
        label = new String(labelBytes, "UTF-8");
      }
      if (protocolLength == 0) {
        protocol = "";
      } else {
        byte[] protocolBytes = new byte[protocolLength];

        buffer.get(protocolBytes);
        protocol = new String(protocolBytes, "UTF-8");
      }

      if (logger.isDebugEnabled()) {
        logger.debug(
            "!!! "
                + getEndpoint().getID()
                + " data channel open request on SID: "
                + sid
                + " type: "
                + channelType
                + " prio: "
                + priority
                + " reliab: "
                + reliability
                + " label: "
                + label
                + " proto: "
                + protocol);
      }

      if (channels.containsKey(sid)) {
        logger.error("Channel on sid: " + sid + " already exists");
      }

      WebRtcDataStream newChannel = new WebRtcDataStream(sctpSocket, sid, label, true);
      channels.put(sid, newChannel);

      sendOpenChannelAck(sid);

      notifyChannelOpened(newChannel);
    } else {
      logger.error("Unexpected ctrl msg type: " + messageType);
    }
  }