org.apache.tapestry5
Interface FieldValidator<T>

Type Parameters:

T -

All Known Implementing Classes:

BeanFieldValidator, CompositeFieldValidator, FieldValidatorImpl

public interface FieldValidator<T>

Responsible for validation of a single field.

See Also:

Validator, FieldValidatorDefaultSource

Method Summary

boolean	isRequired() Returns true if any underlying Validator returns true from Validator.isRequired().
void	render(MarkupWriter writer) Invokes Validator.render(Field, Object, org.apache.tapestry5.ioc.MessageFormatter, MarkupWriter, org.apache.tapestry5.services.FormSupport).
void	validate(T value) Invoked after the client-submitted value has been translated to check that the value conforms to expectations (often, in terms of minimum or maximum value).

Method Detail

validate

void validate(T value)
              throws ValidationException

Invoked after the client-submitted value has been translated to check that the value conforms to expectations (often, in terms of minimum or maximum value). If and only if the value is approved by all Validators is the value applied by the field.

Parameters:

value - the translated value supplied by the user

Throws:

ValidationException - if the value violates the constraint

render

void render(MarkupWriter writer)

Invokes Validator.render(Field, Object, org.apache.tapestry5.ioc.MessageFormatter, MarkupWriter, org.apache.tapestry5.services.FormSupport). This is called at a point "inside" the tag, so that additional attributes may be added. In many cases, the underlying Validator may write client-side JavaScript to enforce the constraint as well.

Parameters:

writer - markup writer to direct output to.

See Also:

MarkupWriter.attributes(Object[])

isRequired

boolean isRequired()

Returns true if any underlying Validator returns true from Validator.isRequired().

Returns:

true if the field is required (a non-blank value is expected)