code: private static String getPreDefOuFqn(CmsObject cms, HttpServletRequest request, boolean logout) {
  
          if (logout && (request.getAttribute(PARAM_PREDEF_OUFQN) == null)) {
              String oufqn = cms.getRequestContext().getOuFqn();
              if (!oufqn.startsWith(CmsOrganizationalUnit.SEPARATOR)) {
                  oufqn = CmsOrganizationalUnit.SEPARATOR + oufqn;
              }
              request.setAttribute(CmsLoginHelper.PARAM_PREDEF_OUFQN, oufqn);
          }
          return (String)request.getAttribute(PARAM_PREDEF_OUFQN);
      }
docs: Returns the pre defined ou fqn.<p>
  
  @param cms the cms context
  @param request the request
  @param logout in case of a logout
  
  @return the ou fqn