Readonly properties in Swift

gistfile1.txt

public class User: Object {

    private var _username: String!
    public var username: String! {
        return _username
    }
    
    public var password: String!
    public var fullName: String!
    public var email: String?
    
    private var profileImageUrlString: String!
    public var profileImageUrl: NSURL {
        return NSURL(string: self.profileImageUrlString)
    }
    ...
  }