お手製Swift Bondでリアクティブプログラミング ref: http://qiita.com/katryo/items/4f2473b72a629bb4257a

Bond.swift

class Bond<T> {
    typealias Listener = T -> Void
    var listener: Listener

    init(_ listener: Listener) {
        self.listener = listener
    }

    func bind(dynamic: Dynamic<T>) {
        dynamic.bondBoxes.append(BondBox(self))
    }
}

BondBox.swift

class BondBox<T> {
    weak var bond: Bond<T>?
    init(_ b:Bond<T>) {
        bond = b
    }
}

Dynamic.swift

            bondBoxes = bondBoxes.filter(
                {
                    (bondBox: BondBox<T>) -> Bool in
                    bondBox.bond != nil
                }
            )

MyViewController.swift

class MenuViewController: UITableViewController {
    var story: Story?
    var starCountBond: Bond<Int>?

    override func viewDidLoad() {
        super.viewDidLoad()
        starCountBond = Bond<Int> { [unowned self] viewingCount in
            self.tableView!.reloadData()
        }
        starCountBond!.bind(story!.starCount)
    }

    (略)

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

    (略)

        cell!.detailTextLabel!.text = String(story!.starCount.value)

story.swift

class Story {
    let title: String
    let body: String
    var starCount: Dynamic<Int>


    init(title: String, body: String, starCount: Int = 0) {
        self.title = title
        self.body = body
        self.starCount = Dynamic(starCount)
    }