ObjectiveSugar & ObjectiveRecord

Supercharged
Cocoa development
with ObjectiveSugar & ObjectiveRecord
Saturday, September 21, 13

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@mneorr
mneorr.com

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Rijeka (Fiume)

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PROGRAMMERS

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PROGRAMMERS
Cat people

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PROGRAMMERS
Cat people Dog people

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That’s why I have a hybrid

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Đuro

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OSS

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Kiwi

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Alcatraz

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The point

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shorter != better

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BUT
many times, shorter can be better

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• Focusing on DOING a task, rather than
HOW the task is being done
• Going too much into implementation
can distract you from understanding
the context

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- (void)fetchEmployees
{
NSManagedObjectContext *moc = [self managedObjectContext];
NSEntityDescription *entityDescription = [NSEntityDescription
entityForName:@"Employee" inManagedObjectContext:moc];
NSFetchRequest *request = [[NSFetchRequest alloc] init];
[request setEntity:entityDescription];
// Set example predicate and sort orderings...
NSNumber *minimumSalary = @150000.00;
NSPredicate *predicate = [NSPredicate predicateWithFormat:
@"(lastName LIKE[c] 'Worsley') AND (salary > %@)", minimumSalary];
[request setPredicate:predicate];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc]
initWithKey:@"firstName" ascending:YES];
[request setSortDescriptors:@[sortDescriptor]];
NSError *error = nil;
NSArray *array = [moc executeFetchRequest:request error:&error];
if (array == nil)
{
// Deal with error...
}
}

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{
NSManagedObjectContext *moc = [self managedObjectConte
NSEntityDescription *entityDescription = [NSEntityDesc
entityForNam
NSFetchRequest *request = [[NSFetchRequest alloc] init
NSPredicate *predicate = [NSPredicate predicateWithFor
@"(lastName LIKE[c] 'Worsley
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor
initWithKey:@"firs
NSArray *array = [moc executeFetchRequest:request erro
if (array == nil)
{
}
}

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{
entityForNam
initWithKey:@"firs
if (array == nil)
{
}
}
Referencing a context

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{
entityForNam
initWithKey:@"firs
if (array == nil)
{
}
}
NSEntityDescription?

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{
entityForNam
initWithKey:@"firs
if (array == nil)
{
}
}
A fetch request!

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{
entityForNam
initWithKey:@"firs
if (array == nil)
{
}
}
A fetch request!
A predicate

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{
entityForNam
initWithKey:@"firs
if (array == nil)
{
}
}
A fetch request!
A predicate
..and a sort descriptor

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{
entityForNam
initWithKey:@"firs
if (array == nil)
{
}
}
A fetch request!
A predicate
Error handling

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{
entityForNam
initWithKey:@"firs
if (array == nil)
{
}
}
A fetch request!
A predicate
Error handling
Fetching

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Defaults out of the
box
tweaking when you need it

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NSArray *employees = [Employee all];

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NSArray *employees = [Employee where:@{ @"lastName": @"Worsley" }];

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ObjectiveC
@[] @{} @#

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ObjectiveSugar

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5.times {
puts "hello!"
}

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5.times {
puts "hello!"
}
for (int i = 0; i < 5; i++ ) {
NSLog(@"Hello");
}

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[@5 times:^{
NSLog(@"Hello!");
}];

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[@5 times:^{
NSLog(@"Hello!");
}];
[@1 upto:5 do:^(int number) {
NSLog(@"The number is: %d", number);
}];

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[cars enumerateObjectsUsingBlock:^(id car, NSUInteger index, BOOL *stop) {
NSLog(@"Car: %@", car.name);
}];

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[cars enumerateObjectsUsingBlock:^(id car, NSUInteger index, BOOL *stop) {
}];
[cars each:^(id car) {
}];

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NSDictionary *dict = @{ @"one" : @1, @"two" : @2, @"three" : @3 };
[dict each:^(id key, id value) {
NSLog(@"Key: %@, Value: %@", key, value);
}];
// Key: one, Value: 1
// Key: two, Value: 2
// Key: three, Value: 3

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- (NSArray *)createPeopleFromDictionaries:(NSArray *)peopleInDicts {
}

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! NSMutableArray *people = [NSMutableArray new];
}

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! for (NSDictionary *personDict in peopleInDicts) {
! }
}

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! ! Person *person = [[Person alloc] initWithDictionary:personDict];
! ! [people addObject:person];
! }
}

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! ! Person *person = [[Person alloc] initWithDictionary:personDict];
! ! [people addObject:person];
! }
! return [NSArray arrayWithArray:people];
}

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}

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NSArray *people = [peopleInDicts map:^id(NSDictionary *personDict) {
}];
return people;
}

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! ! return [[Person alloc] initWithDictionary:personDict];
}];
return people;
}

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}];
return people;
}
@{}, @{}, @{},...

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}];
return people;
}
@{}, @{}, @{},...
, , ...

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}];
return people;
}

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return [peopleInDicts map:^id(NSDictionary *personDict) {
}];
}

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NSArray
- lastObject

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NSArray
- lastObject
- ﬁrstObject ?

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Strings

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[NSString stringWithFormat:@"Hello %@", @"world"];

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@(@"Hello", @"world")

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@(@"Hello", @"world")
NSStringWithFormat(@"Hello %@", @"world");

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NSString *sentence = @"This is a text-with-numbers 1234";

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[sentence containsString:@"this is a"];
// YES

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[sentence containsString:@"this is a"];
// YES
NSRange range = [self rangeOfString:string options:NSCaseInsensitiveSearch];
return range.location != NSNotFound;

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unless

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unless(1 + 1 == 3) {
NSLog(@"Math rocks!");
}

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unless(1 + 1 == 3) {
NSLog(@"Math rocks!");
}
unless(_restaurants) {
_restaurants = [self fetchRestaurants];
}

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NSDate

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“NSDate API rocks!”

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“NSDate API rocks!”
- nobody ever

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int secondsInMinute = 60;
int minutesInHour = 60;
int hoursInDay = 24;
int days = 98 * hoursInDay * minutesInHour * secondsInMinute;
NSDate *christmas = [NSDate dateWithTimeInterval:days sinceDate:[NSDate date]];
// 2013-12-25 00:00:00 +0000

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NSDate *christmas = @(98).days.fromNow;
// 2013-12-25 00:00:00 +0000
// 2013-12-25 00:00:00 +0000

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NSDate *future = @(24).days.fromNow;
// 2013-12-25 00:00:00 +0000
// 2013-12-25 00:00:00 +0000
NSDate *reminder = [@(1).month until:newYearsDay];

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CoreData

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CoreData
3 talks so far

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ObjectiveRecord

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// store
Person *person = [Person create];
person.firstName = @"Tom";
person.lastName = @"Cat";
[person save];
[person delete];
// fetch
NSArray *people = [Person all];

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AppDelegate

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AppDelegate
160 loc

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CoreData
• creating
• fetching
• modifying
• saving / deleting

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Creating

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- (void)insertNewObject:(id)sender
{
NSManagedObjectContext *context = [self.fetchedResultsController managedObjectContext];
NSEntityDescription *entity = [[self.fetchedResultsController fetchRequest] entity];
NSManagedObject *newManagedObject = [NSEntityDescription insertNewObjectForEntityForName:[entity name]
inManagedObjectContext:context];
// If appropriate, configure the new managed object.
// Normally you should use accessor methods, but using KVC here avoids the need to add a custom class to the
template.
[newManagedObject setValue:[NSDate date] forKey:@"timeStamp"];
// Save the context.
if (![context save:&error]) {
// Replace this implementation with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a
shipping application, although it may be useful during development.
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
}
}

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NSManagedObjectContext *context = [self.fetchedResultsController managedObjectContext];
Event *event = [Event create:@{ @"timeStamp": [NSDate date] } inContext:context];
[event save];

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Fetching

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• Create an instance of NSPredicate
• Create an instance of NSFetchRequest,
but you need to talk with
NSEntityDescription as well
• Fetch and check for errors

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[Person all];

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[Person all];
[Person where:@"name == 'John'"];

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[Person all];
[Person where:@{ @"name": @"John", @"isMember": @YES }];

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[Person all];
[Person where:@{ @"name": @"John", @"isMember": @YES }];
[Person where:@"name == 'John'" inContext:context];

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BYOMOC™

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Testing

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Domain Logic Persistence

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[[CoreDataManager sharedManager] useInMemoryStore]
TestHelper.m

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Mapping

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@interface Person : NSManagedObject
@property(strong, nonatomic) NSString *firstName;
@property(strong, nonatomic) NSString *lastName;
@property(strong, nonatomic) NSNumber *age;
@end

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{
"people": [
{
"first_name": "John",
"last_name": "Doe",
"age": 24
},
{
"first_name": "Mark",
"last_name": "Smith",
"age": null
}!
]
}
@interface Person : NSManagedObject
@property(strong, nonatomic) NSString *firstName;
@property(strong, nonatomic) NSString *lastName;
@property(strong, nonatomic) NSNumber *age;
@end

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CoreData 3 NSNull

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• - you need NO AppDelegate code to start, and you
can still save context on `-applicationWillTerminate:`
• - all the important ObjectiveRecord methods have
a counterpart with `NSManagedObjectContext`
parameter
• - ObjectiveRecord supports writing your own
NSPredicates as well
• - unlike MagicalRecord, does not create
NSManagedObjectContexts for you
• - unlike MagicalRecord, it doesn't use mr_preﬁxes.
(you can go beat me later about that)
• - it's lightweight

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Thanks

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ObjectiveSugar & ObjectiveRecord

ObjectiveSugar & ObjectiveRecord

Marin Usalj

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