code: public List<CmsUUID> getPrincipals() {
  
          List<CmsUUID> principals = new ArrayList<CmsUUID>(m_permissions.keySet());
          Collections.sort(principals, CmsAccessControlEntry.COMPARATOR_PRINCIPALS);
          return principals;
      }
docs: Returns the principals with specific permissions stored in this access control list.<p>
  
  @return enumeration of principals (each group or user)