Flow: EmailValidator doesn't pass on an empty string

[mvysny]

Vaadin 14.1.19. I have the following code:

binder.forField(new TextField()).withValidator(new EmailValidator()).bind("field");

However, the validator marks an empty TextField as invalid, effectively disabling the possibility to have an optional email.

Certainly I can hook a converter before the validator which converts empty string to null and vice versa (it's required anyway because of TextField rejecting nulls), but I wonder whether EmailValidator should pass blank strings?

[caalador]

I would guess this is the same for if you use RegexpValidator?

[mvysny]

I think so. However the RegexpValidator is much more versatile and might be (mis)used to match non-blank strings, so I'm not sure whether RegexpValidator should pass for blank strings. Maybe an optional constructor parameter?

[caalador]

Feels like that. Else the email regex should be able to accept an empty value.

[rolandoisidoro]

Any workaround for this?

[Artur-]

new EmailValidator() {
protected boolean isValid(String value) {
if ("".equals(value)) return true;
return super.isValid(value);
}
}

[pleku]

Would be easy to contribute an OptionalEmailValidator or such which also accepts "". But we've had CompositeValidator earlier on https://vaadin.com/api/framework/7.7.17/com/vaadin/data/validator/CompositeValidator.html, I guess it should be just easy to chain the existing validators.

[denis-anisimov]

I suggest to overload EmailValidator CTOR with a boolean value which says whether an empty value should be accepted or not.
That will keep binary compatibility and won't require introducing a new class.