/**
  * Adds the given <tt>FileTransferListener</tt> that would listen for file transfer requests and
  * created file transfers.
  *
  * @param listener the <tt>FileTransferListener</tt> to add
  */
 public void addFileTransferListener(FileTransferListener listener) {
   synchronized (fileTransferListeners) {
     if (!fileTransferListeners.contains(listener)) {
       this.fileTransferListeners.add(listener);
     }
   }
 }
  /**
   * Construct (with WhiteboardSession) and send a WhiteboardObject to a contact.
   *
   * @param wbSession the white-board session, to which the object would be send
   * @param ws WhiteboardShape to convert and send
   * @param c contact
   * @return WhiteboardObject sent
   */
  public WhiteboardObject sendWhiteboardObject(WhiteboardSession wbSession, WhiteboardShape ws)
      throws OperationFailedException {
    Vector supportedWBO = new Vector(Arrays.asList(wbSession.getSupportedWhiteboardObjects()));

    if (ws instanceof WhiteboardObjectPath) {
      if (!supportedWBO.contains(WhiteboardObjectPath.NAME)) return null;
      WhiteboardObjectPath obj =
          (WhiteboardObjectPath) wbSession.createWhiteboardObject(WhiteboardObjectPath.NAME);
      ws.setID(obj.getID());
      obj.setPoints(((WhiteboardObjectPath) ws).getPoints());
      obj.setColor(ws.getColor());
      obj.setThickness(ws.getThickness());
      wbSession.sendWhiteboardObject(obj);
      return obj;
    } else if (ws instanceof WhiteboardObjectPolyLine) {
      if (!supportedWBO.contains(WhiteboardObjectPolyLine.NAME)) return null;
      WhiteboardObjectPolyLine obj =
          (WhiteboardObjectPolyLine)
              wbSession.createWhiteboardObject(WhiteboardObjectPolyLine.NAME);
      ws.setID(obj.getID());
      obj.setPoints(((WhiteboardObjectPolyLine) ws).getPoints());
      obj.setColor(ws.getColor());
      obj.setThickness(ws.getThickness());
      wbSession.sendWhiteboardObject(obj);
      return obj;
    } else if (ws instanceof WhiteboardObjectPolygon) {
      if (!supportedWBO.contains(WhiteboardObjectPolygon.NAME)) return null;
      WhiteboardObjectPolygon obj =
          (WhiteboardObjectPolygon) wbSession.createWhiteboardObject(WhiteboardObjectPolygon.NAME);
      ws.setID(obj.getID());
      obj.setPoints(((WhiteboardObjectPolygon) ws).getPoints());
      obj.setBackgroundColor(((WhiteboardObjectPolygon) ws).getBackgroundColor());
      obj.setFill(((WhiteboardObjectPolygon) ws).isFill());
      obj.setColor(ws.getColor());
      obj.setThickness(ws.getThickness());
      wbSession.sendWhiteboardObject(obj);
      return obj;
    } else if (ws instanceof WhiteboardObjectLine) {
      if (!supportedWBO.contains(WhiteboardObjectLine.NAME)) return null;
      WhiteboardObjectLine obj =
          (WhiteboardObjectLine) wbSession.createWhiteboardObject(WhiteboardObjectLine.NAME);
      ws.setID(obj.getID());
      obj.setWhiteboardPointStart(((WhiteboardObjectLine) ws).getWhiteboardPointStart());
      obj.setWhiteboardPointEnd(((WhiteboardObjectLine) ws).getWhiteboardPointEnd());
      obj.setColor(ws.getColor());
      obj.setThickness(ws.getThickness());
      wbSession.sendWhiteboardObject(obj);
      return obj;
    } else if (ws instanceof WhiteboardObjectRect) {
      if (!supportedWBO.contains(WhiteboardObjectRect.NAME)) return null;
      WhiteboardObjectRect obj =
          (WhiteboardObjectRect) wbSession.createWhiteboardObject(WhiteboardObjectRect.NAME);
      ws.setID(obj.getID());
      obj.setFill(((WhiteboardObjectRect) ws).isFill());
      obj.setHeight(((WhiteboardObjectRect) ws).getHeight());
      obj.setWhiteboardPoint(((WhiteboardObjectRect) ws).getWhiteboardPoint());
      obj.setWidth((((WhiteboardObjectRect) ws)).getWidth());
      obj.setColor(ws.getColor());
      obj.setThickness(ws.getThickness());
      wbSession.sendWhiteboardObject(obj);
      return obj;
    } else if (ws instanceof WhiteboardObjectCircle) {
      if (!supportedWBO.contains(WhiteboardObjectCircle.NAME)) return null;
      WhiteboardObjectCircle obj =
          (WhiteboardObjectCircle) wbSession.createWhiteboardObject(WhiteboardObjectCircle.NAME);
      ws.setID(obj.getID());
      obj.setFill(((WhiteboardObjectCircle) ws).isFill());
      obj.setRadius(((WhiteboardObjectCircle) ws).getRadius());
      obj.setWhiteboardPoint(((WhiteboardObjectCircle) ws).getWhiteboardPoint());
      obj.setBackgroundColor((((WhiteboardObjectCircle) ws)).getBackgroundColor());
      obj.setColor(ws.getColor());
      obj.setThickness(ws.getThickness());
      wbSession.sendWhiteboardObject(obj);
      return obj;
    } else if (ws instanceof WhiteboardObjectText) {
      if (!supportedWBO.contains(WhiteboardObjectText.NAME)) return null;
      WhiteboardObjectText obj =
          (WhiteboardObjectText) wbSession.createWhiteboardObject(WhiteboardObjectText.NAME);
      ws.setID(obj.getID());
      obj.setFontName(((WhiteboardObjectText) ws).getFontName());
      obj.setFontSize(((WhiteboardObjectText) ws).getFontSize());
      obj.setText(((WhiteboardObjectText) ws).getText());
      obj.setWhiteboardPoint(((WhiteboardObjectText) ws).getWhiteboardPoint());
      obj.setColor(ws.getColor());
      obj.setThickness(ws.getThickness());
      wbSession.sendWhiteboardObject(obj);
      return obj;
    } else if (ws instanceof WhiteboardObjectImage) {
      if (!supportedWBO.contains(WhiteboardObjectImage.NAME)) return null;
      WhiteboardObjectImage obj =
          (WhiteboardObjectImage) wbSession.createWhiteboardObject(WhiteboardObjectImage.NAME);
      ws.setID(obj.getID());
      obj.setBackgroundImage(((WhiteboardObjectImage) ws).getBackgroundImage());
      obj.setHeight(((WhiteboardObjectImage) ws).getHeight());
      obj.setWhiteboardPoint(((WhiteboardObjectImage) ws).getWhiteboardPoint());
      obj.setWidth(((WhiteboardObjectImage) ws).getWidth());
      obj.setColor(ws.getColor());
      obj.setThickness(ws.getThickness());
      wbSession.sendWhiteboardObject(obj);

      return obj;
    }

    return null;
  }