JSF doesn't support cross-field validation, is there a workaround?

Question

JSF 2.0 only allows you to validate the input on one field, like check to see if it\'s a certain length. It doesn\'t allow you to have a form that says, \"enter city and sta

Answer 1

The easiest custom approach I've seen and used as far is to create a field with a wherein you reference all involved components as . If you declare it before the to-be-validated components, then you can obtain the submitted values inside the validator by UIInput#getSubmittedValue().

E.g.

(please note the value="true" on the hidden input; the actual value actually doesn't matter, but keep in mind that the validator won't necessarily be fired when it's null or empty, depending on the JSF version and configuration)

with

@FacesValidator(value="fooValidator")
public class FooValidator implements Validator {

    @Override
    public void validate(FacesContext context, UIComponent component, Object value) throws ValidatorException {
        UIInput input1 = (UIInput) component.getAttributes().get("input1");
        UIInput input2 = (UIInput) component.getAttributes().get("input2");
        UIInput input3 = (UIInput) component.getAttributes().get("input3");
        // ...
        
        Object value1 = input1.getSubmittedValue();
        Object value2 = input2.getSubmittedValue();
        Object value3 = input3.getSubmittedValue();
        // ...
    }

}

If you declare the after the to-be-validated components, then the values of the involved components are already converted and validated and you should obtain them by UIInput#getValue() or maybe UIInput#getLocalValue() (in case the UIInput isn't isValid()) instead.

See also:

• Validator for multiple fields (JSF 1.2 targeted)

---

Alternatively, you can use 3rd party tags/components for that. RichFaces for example has a tag for this, Seam3 has a for this, and OmniFaces has several standard components for this which are all showcased here. OmniFaces uses a component based approach whereby the job is done in UIComponent#processValidators(). It also allows customizing it in such way so that the above can be achieved as below:

with

@ManagedBean
@RequestScoped
public class FooValidator implements MultiFieldValidator {

    @Override
    public boolean validateValues(FacesContext context, List components, List