* required is put automatically if the ParsleyValidationBehavior is manually added to a component,
* there is no need to extract a not null behavior.
*/
@Override
public void modify(final FormComponent<?> component, final ComponentTag tag, final NotNull annotation) {
ValidatorBag bag = new ValidatorBag(getLabelString(component));
final ParsleyValidationBehavior validationBehavior =
new ParsleyValidationBehavior();
validationBehavior.error("required", getLocalizedMessage(component, annotation.message(), bag));
validationBehavior.require(true);
validationBehavior.onComponentTag(component, tag);