Question

Let’s say I have a HashMap:

val userMap = new HashMap[String, String]
userMap += "username" -> "user"
userMap += "password" -> "pass"

and an Object:

username:String = ""
password:String = ""

What would be the best way to put the values from the HashMap into the object, without using the Java Reflection API (with or without Annotations)?

It might be similar to that question: Scala – Lift – map a custom boxed object for bind?

Answer 1

Since you don’t want reflection, you can’t match up the names automatically. But doing it manually isn’t hard.

Given

class User(val username: String = "", val password: String = "") {}

I would just

for {
  name <- userMap.get("username")
  pwd <- userMap.get("password")
} yield new User(name,pwd)

which will give you an Option[User] with Some user if it is in that map, and None if not.