@Override
  @SuppressWarnings("null")
  protected void validateAndSaveInputParameters(
      @Nonnull final WebPageExecutionContext aWPEC,
      @Nullable final IUser aSelectedObject,
      @Nonnull final FormErrors aFormErrors,
      final boolean bEdit) {
    final HCNodeList aNodeList = aWPEC.getNodeList();
    final Locale aDisplayLocale = aWPEC.getDisplayLocale();
    final boolean bIsAdministrator = aSelectedObject != null && aSelectedObject.isAdministrator();
    final AccessManager aAccessMgr = AccessManager.getInstance();
    String sLoginName = aWPEC.getAttr(FIELD_LOGINNAME);
    final String sFirstName = aWPEC.getAttr(FIELD_FIRSTNAME);
    final String sLastName = aWPEC.getAttr(FIELD_LASTNAME);
    final String sEmailAddress = aWPEC.getAttr(FIELD_EMAILADDRESS);
    final String sPassword = aWPEC.getAttr(FIELD_PASSWORD);
    final String sPasswordConf = aWPEC.getAttr(FIELD_PASSWORD_CONFIRM);
    final boolean bEnabled =
        bIsAdministrator ? true : aWPEC.getCheckBoxAttr(FIELD_ENABLED, DEFAULT_ENABLED);
    final Collection<String> aUserGroupIDs =
        bIsAdministrator
            ? aAccessMgr.getAllUserGroupIDsWithAssignedUser(aSelectedObject.getID())
            : aWPEC.getAttrs(FIELD_USERGROUPS);

    if (useEmailAddressAsLoginName()) {
      sLoginName = sEmailAddress;
    } else {
      if (StringHelper.hasNoText(sLoginName))
        aFormErrors.addFieldError(
            FIELD_LOGINNAME, EText.ERROR_LOGINNAME_REQUIRED.getDisplayText(aDisplayLocale));
    }

    if (StringHelper.hasNoText(sLastName)) {
      if (isLastNameMandatory())
        aFormErrors.addFieldError(
            FIELD_LASTNAME, EText.ERROR_LASTNAME_REQUIRED.getDisplayText(aDisplayLocale));
    }

    if (StringHelper.hasNoText(sEmailAddress)) {
      if (isEmailMandatory())
        aFormErrors.addFieldError(
            FIELD_EMAILADDRESS, EText.ERROR_EMAIL_REQUIRED.getDisplayText(aDisplayLocale));
    } else if (!EmailAddressUtils.isValid(sEmailAddress))
      aFormErrors.addFieldError(
          FIELD_EMAILADDRESS, EText.ERROR_EMAIL_INVALID.getDisplayText(aDisplayLocale));
    else {
      final IUser aSameLoginUser = aAccessMgr.getUserOfLoginName(sEmailAddress);
      if (aSameLoginUser != null)
        if (!bEdit || !aSameLoginUser.equals(aSelectedObject))
          aFormErrors.addFieldError(
              FIELD_EMAILADDRESS, EText.ERROR_EMAIL_IN_USE.getDisplayText(aDisplayLocale));
    }

    if (!bEdit) {
      final List<String> aPasswordErrors =
          GlobalPasswordSettings.getPasswordConstraintList()
              .getInvalidPasswordDescriptions(sPassword, aDisplayLocale);
      for (final String sPasswordError : aPasswordErrors)
        aFormErrors.addFieldError(FIELD_PASSWORD, sPasswordError);
      if (!EqualsUtils.equals(sPassword, sPasswordConf))
        aFormErrors.addFieldError(
            FIELD_PASSWORD_CONFIRM,
            EText.ERROR_PASSWORDS_DONT_MATCH.getDisplayText(aDisplayLocale));
    }

    if (ContainerHelper.isEmpty(aUserGroupIDs))
      aFormErrors.addFieldError(
          FIELD_USERGROUPS, EText.ERROR_NO_USERGROUP.getDisplayText(aDisplayLocale));
    else if (!aAccessMgr.containsAllUserGroupsWithID(aUserGroupIDs))
      aFormErrors.addFieldError(
          FIELD_USERGROUPS, EText.ERROR_INVALID_USERGROUPS.getDisplayText(aDisplayLocale));

    // Call custom method
    final Map<String, String> aCustomAttrMap =
        validateCustomParameters(aWPEC, aSelectedObject, aFormErrors, bEdit);

    if (aFormErrors.isEmpty()) {
      // All fields are valid -> save
      if (bEdit) {
        final String sUserID = aSelectedObject.getID();

        final Map<String, Object> aAttrMap = aSelectedObject.getAllAttributes();
        if (aCustomAttrMap != null) aAttrMap.putAll(aCustomAttrMap);

        // We're editing an existing object
        aAccessMgr.setUserData(
            sUserID,
            sLoginName,
            sEmailAddress,
            sFirstName,
            sLastName,
            m_aDefaultUserLocale,
            aAttrMap,
            !bEnabled);
        aNodeList.addChild(
            getStyler().createSuccessBox(EText.SUCCESS_EDIT.getDisplayText(aDisplayLocale)));

        // assign to the matching user groups
        final Collection<String> aPrevUserGroupIDs =
            aAccessMgr.getAllUserGroupIDsWithAssignedUser(sUserID);
        // Create all missing assignments
        final Set<String> aUserGroupsToBeAssigned =
            ContainerHelper.getDifference(aUserGroupIDs, aPrevUserGroupIDs);
        for (final String sUserGroupID : aUserGroupsToBeAssigned)
          aAccessMgr.assignUserToUserGroup(sUserGroupID, sUserID);

        // Delete all old assignments
        final Set<String> aUserGroupsToBeUnassigned =
            ContainerHelper.getDifference(aPrevUserGroupIDs, aUserGroupIDs);
        for (final String sUserGroupID : aUserGroupsToBeUnassigned)
          aAccessMgr.unassignUserFromUserGroup(sUserGroupID, sUserID);

      } else {
        // We're creating a new object
        final IUser aNewUser =
            aAccessMgr.createNewUser(
                sLoginName,
                sEmailAddress,
                sPassword,
                sFirstName,
                sLastName,
                m_aDefaultUserLocale,
                aCustomAttrMap,
                !bEnabled);
        if (aNewUser != null) {
          aNodeList.addChild(
              getStyler().createSuccessBox(EText.SUCCESS_CREATE.getDisplayText(aDisplayLocale)));

          // assign to the matching internal user groups
          for (final String sUserGroupID : aUserGroupIDs)
            aAccessMgr.assignUserToUserGroup(sUserGroupID, aNewUser.getID());
        } else
          aNodeList.addChild(
              getStyler().createErrorBox(EText.FAILURE_CREATE.getDisplayText(aDisplayLocale)));
      }
    }
  }