How to get data from UITableView's cells?

TextFieldCell.swift

import UIKit
import XCPlayground

// SKIP FOR NOW :)

protocol SmartCell {

    associatedtype Model

    static var reuseId: String { get }

    func loadModel(m: Model)

}

extension SmartCell {

    static var reuseId: String { return "\(self.dynamicType)" }

}

class DataSource<Cell: UITableViewCell where Cell: SmartCell>: NSObject, UITableViewDataSource {

    var items: [Cell.Model]

    init(items: [Cell.Model]) {
        self.items = items
    }

    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return items.count
    }
    
    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier(Cell.reuseId) as! Cell
        cell.loadModel(items[indexPath.row])
        return cell
    }

}

/// Target-Action helper.
final class Action: NSObject {

    private let _action: () -> ()

    init(action: () -> ()) {
        _action = action
        super.init()
    }

    func action() {
        _action()
    }

}

// READ FROM HERE

class TextFieldCell: UITableViewCell, SmartCell, UITextFieldDelegate {

    class Model {

        let placeholder: String?
        var text: String?

        init(placeholder: String?, text: String? = nil) {
            self.placeholder = placeholder
            self.text = text
        }

    }

    var model: Model? {
        didSet {
            textField.placeholder = model?.placeholder
            textField.text = model?.text
        }
    }

    let textField = UITextField()

    required init?(coder: NSCoder) {
        super.init(coder: coder)
        commonInit()
    }

    override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        commonInit()
    }

    private func commonInit() {
        contentView.addSubview(textField)
        textField.delegate = self
    }

    override func layoutSubviews() {
        textField.frame = contentView.bounds.insetBy(dx: 15, dy: 8)
    }

    func loadModel(m: Model) {
        model = m
    }

    func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
        let text = (textField.text as NSString?)?.stringByReplacingCharactersInRange(range, withString: string)
        // Update the model.
        model?.text = text
        return true
    }
}

// Sample items.
let items = [
    TextFieldCell.Model(placeholder: "1"),
    TextFieldCell.Model(placeholder: "2"),
    TextFieldCell.Model(placeholder: "3", text: "xxx"),
    TextFieldCell.Model(placeholder: "4"),
    TextFieldCell.Model(placeholder: "5"),
    TextFieldCell.Model(placeholder: "6")
]
let dataSource = DataSource<TextFieldCell>(items: items)
let tableView = UITableView(frame: CGRect(x: 0, y: 0, width: 320, height: 100))
tableView.registerClass(TextFieldCell.self, forCellReuseIdentifier: TextFieldCell.reuseId)
tableView.dataSource = dataSource

// This way we'll dump user input to the console.
let dumpAction = Action {
    for m in items {
        print(m.text)
    }
}
let dumpButton = UIButton(type: .System)
dumpButton.frame = CGRect(x: 15, y: 108, width: 50, height: 20)
dumpButton.setTitle("Dump", forState: .Normal)
dumpButton.addTarget(dumpAction, action: #selector(dumpAction.action), forControlEvents: .TouchUpInside)

let view = UIView(frame: CGRect(x: 0, y: 0, width: 320, height: 136))
view.backgroundColor = .whiteColor()
view.addSubview(tableView)
view.addSubview(dumpButton)

XCPlaygroundPage.currentPage.liveView = view