I'm doing my first experiments with Grails and am looking for a way to have fields represented by a combobox (such as one-to-one domain associations and numbers with a narrow range constraint) to be optional, i.e. there should be an empty entry in the combobox.
How can this be achieved? I've tried both adding a nullable:true constraint and listing the fields in the optionals static property, but neither produces the desired result.
These are my domain classes:
class Customer {
String name
}
class Book {
static optionals = ['year','loanedTo','loanedSince']
static constraints = {
title(blank:false)
author(blank:false)
year(range:1900..new Date().getAt(Calendar.YEAR), nullable:true)
loanedTo(nullable:true)
loanedSince(min:new Date())
}
String title;
String author;
Integer year;
Customer loanedTo;
Date loanedSince;
}