/**
   * Validate event creation.
   *
   * @param event the event
   * @throws ValidationException the validation exception
   */
  public static void validateEventCreation(final Event event) throws ValidationException {

    if (event == null) {
      return;
    }

    final ValidationException validationException = new ValidationException();

    if (StringUtils.isEmpty(StringUtils.trimToEmpty(event.getName()))) {
      validationException.addMessage("Event must have a name.");
    }

    if (event.getEventType() == null) {
      validationException.addMessage("EventType can not be empty.");
    }

    if (event.getStartTime() == null) {
      validationException.addMessage("Start date must be supplied.");
    }

    if (event.getEndTime() == null) {
      validationException.addMessage("End date must be supplied.");
    }

    if (event.getStartTime() != null
        && event.getEndTime() != null
        && (!event.getStartTime().isBefore(event.getEndTime()))) {
      validationException.addMessage("Start date must be before end date.");
    }

    if (event.getVoteCategories() == null || event.getVoteCategories().isEmpty()) {
      validationException.addMessage("At least one voting category must be supplied.");
    } else {

      for (final VoteCategory category : event.getVoteCategories()) {
        try {
          validateVoteCategory(category);
        } catch (final ValidationException e) {
          validationException.addAllMessages(e.getErrorMessages());
        }
      }
    }

    if (validationException.hasErrorMessages()) {
      throw validationException;
    }
  }
  /**
   * Validate event update.
   *
   * @param event the event
   * @throws ValidationException the validation exception
   */
  public static void validateEventUpdate(final Event event) throws ValidationException {
    final ValidationException validationException = new ValidationException();

    try {
      validateEventCreation(event);
    } catch (final ValidationException e) {
      validationException.addAllMessages(e.getErrorMessages());
    }

    if (event.getStartTime() != null && DateTime.now().isAfter(event.getStartTime())) {
      validationException.addMessage("Can not update event after start time");
    }

    if (validationException.hasErrorMessages()) {
      throw validationException;
    }
  }