Question

I need the User class to contain a map of strings and I saw MongoMapField in the api so I used it because it seemed appropriate. Here’s my code:

class User private () extends ProtoAuthUser[User] with ObjectIdPk[User] {
  def meta = User

  object oauth extends MongoMapField[String, String]("") {
    def setToken(provider: String, token: String) {this.value += (provider -> token) }
    def getToken(value: String) = { 
      if(!this.value.isEmpty) Full(this.value.get(value) match {
        case Some(value) => value
        case None => ""
      })
      else Empty
    }
  }
}

setToken in this case doesn’t work because MongoMapField is immutable (from my assumption) and the following code doesn’t work either:

def setToken(provider: String, token: String) { this.value = this.value + (provider -> token) }

Does anyone know what is the best way to create/update a map of strings in mongo that is also attached to the user?

Thanks =)

Answer 1

When dealing with immutable data structures, you need to think in terms of replacing the existing value with a new value instead of trying to modify the existing value.

So, to get your code to work, you would need to change it to:

class User private () extends ProtoAuthUser[User] with ObjectIdPk[User] {
  def meta = User

  object oauth extends MongoMapField[String, String](this) {
    def setToken(provider: String, token: String) {
      this.set(this.value + (provider -> token))
    }
    def getToken(value: String): Box[String] = { 
      Box(this.value.get(value))
    }
  }
}