code: @Override
  	protected void doExecute() {
  		Predicate<MailMessage> condition = createMessagePredicate();
  		MailMessage message = mailService.findMessage(accountReservationKey, condition);
  		validateMessage(message);
  	}
docs: Retrieves an e-mail matching the patterns specified in the constructor. If the message is
  successfully retrieved, it is passed to {@link #validateMessage(MailMessage)} for further
  validation.