Question

I have the following spring pseudo-code wired scala class.

@Service
class Something {

@Value("${some.property}")
val someString : String

// do something with someString in the body
}

However this won’t work because the someString is part of the constructor body, and spring can’t wire in the values until after the constructor has executed.

How can I wire in @Value’s so that it works, and isn’t horrible (my current solution with a custom constructor containing all the values I need just doesn’t feel “scala” and looks horrible.

Edit: To clarify, my current solution is this:

@Service
class Something { 
  @Autowired 
  def this(@Value("${some.prop}") prop : String) { 
    this() 
    // do other construction stuff here
  }
}

I just think it looks ugly and feel there is a better way. I also don’t like having to create these secondary constructors when I’d rather enforce it on the primary constructor.

Edit 2: To further clarify, I was hoping there was a way to do something like this:

@Service
class Something(@Value("${some.property}") string : String) {
// use the value in your constructor here
}

Because this looks far more elegant. I just can’t get it to work 🙂

Answer 1

Ok, after all the back and forth, I think I understand better what you want, so here’s my take on it:

import scala.annotation.BeanProperty
import scala.annotation.target.beanSetter
class Something @Autowired() (@(Value @beanSetter)("{some.property}") @BeanProperty var prop: String)

This is essentially Paolo Falabella’s solution, except that I try to avoid having Spring acces private fields. To this end I let scala autogenerate a public java-like setter using @BeanProperty and apply @Value on it.
You can also improve the syntax somewhat by using a type alias:

type Value = org.springframework.beans.factory.annotation.Value @beanSetter @beanGetter
class Something @Autowired() ( @BeanProperty@Value("{some.property}") var prop: String)