/**
   * Calls the given treeNode.
   *
   * @param treeNode the <tt>TreeNode</tt> to call
   */
  private void call(TreeNode treeNode, JButton button, boolean isVideo, boolean isDesktopSharing) {
    if (!(treeNode instanceof ContactNode)) return;

    UIContact contactDescriptor = ((ContactNode) treeNode).getContactDescriptor();

    Point location = new Point(button.getX(), button.getY() + button.getHeight());

    SwingUtilities.convertPointToScreen(location, treeContactList);

    location.y = location.y + treeContactList.getPathBounds(treeContactList.getSelectionPath()).y;
    location.x += 8;
    location.y -= 8;

    CallManager.call(contactDescriptor, isVideo, isDesktopSharing, treeContactList, location);
  }
  /**
   * Shows the appropriate user interface that would allow the user to add the given
   * <tt>SourceUIContact</tt> to their contact list.
   *
   * @param contact the contact to add
   */
  private void addContact(SourceUIContact contact) {
    SourceContact sourceContact = (SourceContact) contact.getDescriptor();

    List<ContactDetail> details =
        sourceContact.getContactDetails(OperationSetPersistentPresence.class);
    int detailsCount = details.size();

    if (detailsCount > 1) {
      JMenuItem addContactMenu =
          TreeContactList.createAddContactMenu((SourceContact) contact.getDescriptor());

      JPopupMenu popupMenu = ((JMenu) addContactMenu).getPopupMenu();

      // Add a title label.
      JLabel infoLabel = new JLabel();
      infoLabel.setText(
          "<html><b>"
              + GuiActivator.getResources().getI18NString("service.gui.ADD_CONTACT")
              + "</b></html>");

      popupMenu.insert(infoLabel, 0);
      popupMenu.insert(new Separator(), 1);

      popupMenu.setFocusable(true);
      popupMenu.setInvoker(treeContactList);

      Point location =
          new Point(
              addContactButton.getX(), addContactButton.getY() + addContactButton.getHeight());

      SwingUtilities.convertPointToScreen(location, treeContactList);

      location.y = location.y + treeContactList.getPathBounds(treeContactList.getSelectionPath()).y;

      popupMenu.setLocation(location.x + 8, location.y - 8);
      popupMenu.setVisible(true);
    } else if (details.size() == 1) {
      TreeContactList.showAddContactDialog(details.get(0), sourceContact.getDisplayName());
    }
  }