Generic UITableView/UICollectionView data source for Core Data

ADVKeyedSubscripting.h

//
//  Copyright © 2013 Yuri Kotov
//
#import <Foundation/Foundation.h>

@protocol ADVKeyedSubscripting <NSObject>
- (id) objectForKeyedSubscript:(id)key;
@end

ADVManagedDataSource.h

//
//  Copyright © 2013 Yuri Kotov
//

#import <Foundation/Foundation.h>
#import "ADVKeyedSubscripting.h"

typedef void(^ADVCellConfigurationBlock)(id cell, id object);

@interface ADVManagedDataSource : NSObject <ADVKeyedSubscripting, UITableViewDataSource, UICollectionViewDataSource>

@property (readonly, nonatomic) NSFetchedResultsController *dataController;

- (instancetype) initWithDataController:(NSFetchedResultsController *)controller
                 reusableCellIdentifier:(NSString *)identifier
                 cellConfigurationBlock:(ADVCellConfigurationBlock)block;

@end

ADVManagedDataSource.m

//
//  Copyright © 2013 Yuri Kotov
//

#import <CoreData/CoreData.h>
#import "ADVManagedDataSource.h"

@interface ADVManagedDataSource ()
@property (readonly, nonatomic) NSString *cellIdentifier;
@property (readonly, nonatomic) ADVCellConfigurationBlock configurationBlock;
@end

@implementation ADVManagedDataSource

#pragma mark - ADVManagedDataSource
- (instancetype) initWithDataController:(NSFetchedResultsController *)controller
                 reusableCellIdentifier:(NSString *)identifier
                 cellConfigurationBlock:(ADVCellConfigurationBlock)block
{
    if ((self = [super init]))
    {
        _configurationBlock = block;
        _cellIdentifier = identifier;
        _dataController = controller;
    }
    return self;
}

- (NSInteger) numberOfSections
{
    return [self.dataController.sections count];
}

- (NSInteger) numberOfItemsInSection:(NSInteger)section
{
    return [self.dataController.sections[section] numberOfObjects];
}

#pragma mark - ADVKeyedSubscripting
- (id) objectForKeyedSubscript:(NSIndexPath *)indexPath
{
        NSParameterAssert([indexPath isKindOfClass:[NSIndexPath class]]);
	return [self.dataController objectAtIndexPath:indexPath];
}

#pragma mark - UITableViewDataSource
- (NSInteger) numberOfSectionsInTableView:(UITableView *)tableView
{
    return [self numberOfSections];
}

- (NSString *) tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
{
    return [self.dataController.sections[section] name];
}

- (NSInteger) tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [self numberOfItemsInSection:section];
}

- (UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:self.cellIdentifier forIndexPath:indexPath];
    self.configurationBlock(cell, self[indexPath]);
    return cell;
}

#pragma mark - UICollectionViewDataSource
- (NSInteger) numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
    return self.numberOfSections;
}

- (NSInteger) collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return [self numberOfItemsInSection:section];
}

- (UICollectionViewCell *) collectionView:(UICollectionView *)collectionView
                   cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:self.cellIdentifier forIndexPath:indexPath];
    self.configurationBlock(cell, self[indexPath]);
    return cell;
}

@end