code: protected Collection<String> getUserRoles(PortletRequest request) {
          ArrayList<String> portletUserRolesList = new ArrayList<String>();
  
          for (String role : portletMappableRoles) {
              if (request.isUserInRole(role)) {
                  portletUserRolesList.add(role);
              }
          }
  
          return portletUserRolesList;
      }
docs: Obtains the list of user roles based on the current user's Portlet roles. The
  {@link javax.portlet.PortletRequest#isUserInRole(String)} method is called for each of the values
  in the {@code portletMappableRoles} set to determine if that role should be assigned to the user.
  
  @param request the request which should be used to extract the user's roles.
  @return The subset of {@code portletMappableRoles} which applies to the current user making the request.