code: public void userIdentifierInvalid(final String userId) {
  		this.addStatusMessage(
  				ProtocolConstants.StatusCodes.Create.Follow.USER_NOT_EXISTING,
  				"there is no user with the identifier \"" + userId
  						+ "\". Please provide a valid user identifier.");
  	}
docs: add status message: user identifier invalid
  
  @param userId
  user identifier passed