Swift2 でトーチをオンにする

ViewController.swift

let devices = AVCaptureDevice.devices()
for capDevice in devices {
    if capDevice.position == AVCaptureDevicePosition.Back {
        avDevice = capDevice as? AVCaptureDevice
    }
}

// トーチオン
if avDevice.hasTorch
    do {
        try avDevice.lockForConfiguration()
        avDevice.torchMode = AVCaptureTorchMode.On
        avDevice.unlockForConfiguration()
    } catch let error as NSError {
        print(error)
    }
}