In some situations,
we need our own special validation; for example, if we want to compare two fields, or if we want to validate some custom special component. In that case, we can add a custom validator and override the validate(Object) method. In this recipe, we will create a form for changing the password. We will add a custom validator that will match the new and confirmed password fields.
Carry out the following steps to create a form with a custom validation:
Create a Vaadin project with a main UI class called
Demo.public class Demo extends UI {…}We create a
ChangePasswordFormclass that is based on theFormLayoutclass.public class ChangePasswordForm extends FormLayout {…}At first, we prepare some class fields. We create two instances of the
PasswordFieldclass for the new and confirmation password fields. In these fields, the characters are visually hidden. They are replaced by dots. Then we create theokButtonobject that will be used...