How can I validate fields in a table in Vaadin with Scala - scala

Question

How can I validate a field in a vaadin table? For example the year field with a regex:
val persons: BeanContainer[Int, Person] =
new BeanContainer[Int, Person] classOf[Person])
persons.setBeanIdProperty("id")
persons.addBean(new Person("Thomas", "Mann", 1929, 123123))
persons.addBean(new Person("W. B.", "Yeats", 1923, 643454))
persons.addBean(new Person("Günter", "Grass", 1999, 743523))
// create table
val table: Table = new Table("Nobel Prize for Literature", persons)
table.setVisibleColumns(Array("id", "firstName", "lastName", "year"))
table.setColumnHeader("lastName", "last name")
table.setColumnHeader("firstName", "first name")
table.setColumnHeader("year", "year")
// create a validator
val yearValidator = new RegexpValidator("[1-2][0-9]{3}",
"year must be a number 1000-2999.");
// TODO check the year field!
table.addValidator(yearValidator)
I create a Regex Validator, but how can I set the validator to the right field?

Answer 1

You have to intercept the creation of the fields with a field factory and add the validators there:
table.setTableFieldFactory(new DefaultFieldFactory() {
#Override
public Field createField(Item item, Object propertyId, Component uiContext) {
Field field = super.createField(item, propertyId, uiContext);
if ("year".equals(propertyId)) {
field.addValidator(new RegexpValidator("[1-2][0-9]{3}",
"year must be a number 1000-2999.");
}
return field;
}
});
(Java, not Scala, but it should be straightforward to translate this to scala).