/**
     * Appends the XML <tt>String</tt> representation of this <tt>Content</tt> to a specific
     * <tt>StringBuilder</tt>.
     *
     * @param xml the <tt>StringBuilder</tt> to which the XML <tt>String</tt> representation of this
     *     <tt>Content</tt> is to be appended
     */
    public void toXML(StringBuilder xml) {
      xml.append('<').append(ELEMENT_NAME);
      xml.append(' ').append(NAME_ATTR_NAME).append("='").append(getName()).append('\'');

      List<Channel> channels = getChannels();
      List<SctpConnection> connections = getSctpConnections();

      if (channels.size() == 0 && connections.size() == 0) {
        xml.append(" />");
      } else {
        xml.append('>');
        for (Channel channel : channels) channel.toXML(xml);
        for (SctpConnection conn : connections) conn.toXML(xml);
        xml.append("</").append(ELEMENT_NAME).append('>');
      }
    }
 /**
  * Gets a <tt>Channel</tt> which is included into this <tt>Content</tt> and which has a specific
  * ID.
  *
  * @param channelID the ID of the <tt>Channel</tt> included into this <tt>Content</tt> to be
  *     returned
  * @return the <tt>Channel</tt> which is included into this <tt>Content</tt> and which has the
  *     specified <tt>channelID</tt> if such a <tt>Channel</tt> exists; otherwise, <tt>null</tt>
  */
 public Channel getChannel(String channelID) {
   for (Channel channel : getChannels()) if (channelID.equals(channel.getID())) return channel;
   return null;
 }