Simple UIPickerView subclass

SimplePickerView.swift

class SimplePickerView : UIPickerView {
   
    class SimplePickerViewModel : NSObject, UIPickerViewDelegate, UIPickerViewDataSource {
        var titles: [String]
        var selectionHandler: ((pickerView: UIPickerView, row: Int, title: String) -> ())?
        
        init(titles: [String], selectionHandler: ((pickerView: UIPickerView, row: Int, title: String) -> ())? = nil) {
            self.titles = titles
            self.selectionHandler = selectionHandler
        }
        
        func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
            return 1
        }
        
        func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
            return titles.count
        }
        
        func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {
            return titles[row]
        }
        
        func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
            selectionHandler?(pickerView: pickerView, row: row, title: titles[row])
        }
    }

    let model: SimplePickerViewModel
    
    init(titles: [String], selectionHandler: ((pickerView: UIPickerView, row: Int, title: String) -> ())? = nil) {
        self.model = SimplePickerViewModel(titles: titles, selectionHandler: selectionHandler)
        println("titles: \(titles)")
        super.init(frame: CGRectZero)
        
        self.delegate = model
        self.dataSource = model
    }
    
    required init(coder aDecoder: NSCoder) {
        self.model = SimplePickerViewModel(titles: [], selectionHandler: nil)
        super.init(coder: aDecoder)
    }
}