KeylessUserDefaults.swift

protocol DefaultConvertible {
  var serialized: [String : AnyObject] { get }
  init?(dictionary: [String : AnyObject])
}

class Defaults {
  let userDefaults = NSUserDefaults.standardUserDefaults()

  func save<T: DefaultConvertible>(toSave: T)
  {
    userDefaults.setValue(toSave.serialized, forKey: "\(T.self)")
  }
  
  func fetch<T: DefaultConvertible>(type: T.Type) -> T?
  {
    let key = "\(T.self)"
    guard let dictionary = userDefaults.objectForKey(key) as? [String : AnyObject]
      else { return nil }
    
    return T(dictionary: dictionary)
  }
}