public String getParticipantsAsXML() {
    List<Participant> pList = sortFullParticipantListByName();

    StringBuilder xml = new StringBuilder("<participants>");
    for (Participant p : pList) xml.append(p.toXML());
    xml.append("</participants>");
    return xml.toString();
  }
 private String participantSetToXML(Set<Participant> pSet, String header) {
   StringBuilder xml = new StringBuilder(header);
   for (Participant p : pSet) xml.append(p.toXML());
   xml.append("</participants>");
   return xml.toString();
 }