/* Email */
checkNotEmpty( "email", "email_required", _customer.getEmail( ) );
/* Credit card */
CreditCard cc = _customer.getCreditCard( );
checkNotEmpty( "ccEmail", "ccType_required", cc.getType( ) );
checkNotEmpty( "ccNumber", "ccNumber_required", cc.getNumber( ) );
checkNotEmpty( "ccExpiryDate", "ccExpiryDate_required", cc.getExpiryDate( ) );
super.doValidation( );
}