Swift 2.0, Protocol, Delegate and Timer Example using GC

swift-timer-example.swift

//Swift 2.0
import UIKit
protocol SomethingDelegate {
    func didUpdateSomething(SomethingHelper:SomethingHelper)
}

class SomethingHelper {
    private var timer : dispatch_source_t! = nil
    private var currentIntervalInSec = 0;
    var delegate: SomethingDelegate?
    required init(intervalInSec:Double){
        self.timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0))
        dispatch_source_set_timer(self.timer, dispatch_time(DISPATCH_TIME_NOW, 0), UInt64(intervalInSec*Double(NSEC_PER_SEC)), 0)
        dispatch_source_set_event_handler(self.timer, {
            self.delegate?.didUpdateSomething(self)
        });
    }
    deinit {
        stop()
    }

    func start(){
        dispatch_resume(self.timer)
    }
    
    func stop(){
        dispatch_suspend(self.timer)
    }
}
// For example.
class DetailViewController: UIViewController, SomethingDelegate {
    private var helper = SomethingHelper(intervalInSec: Double(2.0))
    override func viewDidLoad() {
        super.viewDidLoad()
        
        self.helper.delegate = self;
        self.helper.start()
    }

    func didUpdateSomething(SomethingHelper:SomethingHelper){
        print(NSDate.timeIntervalSinceReferenceDate())
    }
}