What is the best way modeling in Scala with Spring Data JPA - scala

Question

Scala does not get first class support as Kotlin in Spring.
I tried to create a Spring Boot API application with Scala.
Spring Boot 2.2.0.M5
Spring Data JPA
H2
Scala 2.13
I created a JPA Entity with case class like:
#Entity
case class Post(#BeanProperty title: String, #BeanProperty content: String) {
def this() {
this(null, null)
}
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#BeanProperty
var id: Long = _
#BeanProperty
val createdOn: LocalDateTime = LocalDateTime.now()
override def toString: String = s"Post[id:$id, title:$title, content:$content, createdOn:$createdOn]"
}
And create a Repository using trait, it works.
trait PostRepository extends JpaRepository[Post, Long]
I want to try bean validation.
class PostForm {
#NotNull
#NotEmpty
#BeanProperty var title: String = _
#BeanProperty var content: String = _
}
And in the controller, create a POST method like:
#PostMapping
def save(#RequestBody #Valid form: PostForm, errors: BindingResult) = errors.hasErrors match {
case true => {
badRequest().build()
}
case _ => {
val data = Post(title = form.title, content = form.content)
val saved = posts.save(data)
created(ServletUriComponentsBuilder.fromCurrentContextPath().path("/{id}").buildAndExpand(saved.id).toUri).build()
}
}
It works.
But the model classes are little tedious. I am trying to use a case class like the following:
case class PostForm(#NotNull #NotEmpty #BeanProperty title: String, #BeanProperty content: String)
The validation does not work.
When we are modeling for JPA etc, case class or generic class is better?
Why we can not apply the Bean Validation annotations as Kotlin data clase in the case class?
Update: Got this work like:
case class PostForm(#(NotNull#field) #(NotEmpty#field) #BeanProperty title: String, #BeanProperty content: String)
The source codes is hosted on my Github.

Answer 1

Case class fields are considered as vals by default, which means you can't set a new value to them. #BeanProperty, however, is to automatically generate field setters and getters.
You may try adding var keywords to the fields explicitly.
case class PostForm(
#NotNull #NotEmpty #BeanProperty var title: String,
#BeanProperty var content: String
)