Generic Collection View and Table View data sources in Swift

CollectionViewCellConfigurable.swift

import UIKit

protocol CollectionViewCellConfigurable {
    typealias ItemType
    typealias CellType: UICollectionViewCell
    
    static func reuseIdentifierForIndexPath(indexPath: NSIndexPath) -> String
    static func configureCellAtIndexPath(indexPath: NSIndexPath, item: ItemType, cell: CellType)
}

CollectionViewDataSource.swift

import UIKit

class CollectionViewDataSource<T: IndexPathIndexable, C: CollectionViewCellConfigurable where T.ItemType == C.ItemType>: NSObject, UICollectionViewDataSource {
    let data: T
    
    init(data: T) {
        self.data = data
    }
    
    func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
        return data.numberOfSections()
    }
    
    func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return data.numberOfItemsInSection(section)
    }
    
    func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        let reuseIdentifier = C.reuseIdentifierForIndexPath(indexPath)
        guard let cell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, forIndexPath: indexPath) as? C.CellType else {
            fatalError("Cells with reuse identifier \(reuseIdentifier) not of type \(C.CellType.self)")
        }
        let item = data.objectAtIndexPath(indexPath)
        C.configureCellAtIndexPath(indexPath, item: item, cell: cell)
        return cell
    }
}

IndexPathIndexable.swift

import Foundation

protocol IndexPathIndexable {
    // associatedType keyword is comming in Swift 2.2
    typealias ItemType
    
    func objectAtIndexPath(indexPath: NSIndexPath) -> ItemType
    func numberOfSections() -> Int
    func numberOfItemsInSection(section: Int) -> Int
}

extension Array: IndexPathIndexable {
    
    func objectAtIndexPath(indexPath: NSIndexPath) -> Element {
        return self[indexPath.item]
    }
    
    func numberOfSections() -> Int {
        return 1
    }
    
    func numberOfItemsInSection(section: Int) -> Int {
        return count
    }
}

TableViewCellConfigurable.swift

import UIKit

protocol TableViewCellConfigurable {
    typealias ItemType
    typealias CellType: UITableViewCell
    
    static func reuseIdentifierForIndexPath(indexPath: NSIndexPath) -> String
    static func configureCellAtIndexPath(indexPath: NSIndexPath, item: ItemType, cell: CellType)
}

TableViewDataSource.swift

import UIKit

class TableViewDataSource<T: IndexPathIndexable, C: TableViewCellConfigurable where T.ItemType == C.ItemType>: NSObject, UITableViewDataSource {
    let data: T
    
    init(data: T) {
        self.data = data
    }
    
    func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return data.numberOfSections()
    }
    
    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return data.numberOfItemsInSection(section)
    }
    
    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let reuseIdentifier = C.reuseIdentifierForIndexPath(indexPath)
        guard let cell = tableView.dequeueReusableCellWithIdentifier(reuseIdentifier) as? C.CellType else {
            fatalError("Cells with reuse identifier \(reuseIdentifier) not of type \(C.CellType.self)")
        }
        let item = data.objectAtIndexPath(indexPath)
        C.configureCellAtIndexPath(indexPath, item: item, cell: cell)
        return cell
    }
}

You use it like this:

Your custom data model object:

struct CustomCellData {
    let title: String
    let detail: String
}

In your view controller:

import UIKit

class ViewController: UIViewController {

    var dataSource: DataSource<Array<CustomCellData>, CustomTableViewCell>?
    @IBOutlet weak var tableView: UITableView!

    let data = [
        CustomCellData(title: "Hi", detail: "CocoaHeads"),
        CustomCellData(title: "Utah", detail: "Devs Rule!")
    ]

    override func viewDidLoad() {
        super.viewDidLoad()

        dataSource = DataSource(data: data)
        tableView.dataSource = dataSource
    }
}

In your custom cell:

import UIKit

class CustomTableViewCell: UITableViewCell, TableViewCellConfigurable {
    @IBOutlet weak var titleLabel: UILabel!
    @IBOutlet weak var detailLabel: UILabel!

    static func reuseIdentifierForIndexPath(indexPath: NSIndexPath) -> String {
        return "Custom"
    }

    static func configureCellAtIndexPath(indexPath: NSIndexPath, item: CustomCellData, cell: CustomTableViewCell) {
        cell.titleLabel.text = item.title
        cell.detailLabel.text = item.detail
    }
}