I'm writing a Grails application and I need to retrieve a persistent value for the collection of my domain class objects. Let's consider we have got the following domain object:
class UserGroup {
SortedSet<User> users
static hasMany = [ users: User ]
// ...
def beforeUpdate() {
println "BEFORE UPDATE: " + this.getPersistentValue('users');
}
}
class User implements Comparable<User> {
String name
}
And the controller which has the following action:
class UserGroupController {
def addUser() {
UserGroup group = UserGroup.get(params.long('gid'))
User user = User.get(params.long('uid'))
group.addToUsers(user)
group.save(failOnError:true, flush:true)
}
}
The problem is that when beforeUpdate() is called, the users collection already contains the recently added user. So, seems that addTo() method doesn't trigger the beforeUpdate() event.
The same problem occurs when we're talking about isDirty() method. As the changes are applied before the beforeUpdate() is called, the collection is not recognized as dirty field.
Does anyone know how to change this? I'm writing a feature which tracks the history of changes for lots of different object, so I need to have access to the previous value in order to understand whether its value was changed or not.
