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NSManagedObject+KTManagedObject.h

//
//  NSManagedObject+KTManagedObject.h
//  Created by Kamil Tusznio on 12-07-10.
//

#import <CoreData/CoreData.h>

@interface NSManagedObject (KTManagedObject)

+ (NSArray *)fetchAll;
+ (id)newRecord;

@end

NSManagedObject+KTManagedObject.m

//
//  NSManagedObject+KTManagedObject.m
//  Created by Kamil Tusznio on 12-07-10.
//

#import "NSManagedObject+KTManagedObject.h"

@implementation NSManagedObject (KTManagedObject)

+ (NSArray *)fetchAll {
    NSError *error;
    NSString *entityName = NSStringFromClass([self class]);
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:entityName
                                              inManagedObjectContext:[NSManagedObjectContext sharedInstance]];
    [fetchRequest setEntity:entity];

    NSArray *records = [[NSManagedObjectContext sharedInstance] executeFetchRequest:fetchRequest
                                                                              error:&error];
    if (error) {
        NSLog(@"Error fetching %@: %@", entityName, [error description]);
    }

    return records;
}

+ (id)newRecord {
    NSString *entityName = NSStringFromClass([self class]);
    NSManagedObjectContext *context = [NSManagedObjectContext sharedInstance];
    NSEntityDescription *entityDescription = [NSEntityDescription entityForName:entityName
                                                         inManagedObjectContext:context];

    // Insert the entity into the context and save it.
    id record = [[[self class] alloc] initWithEntity:entityDescription
                      insertIntoManagedObjectContext:context];
    [context save];

    return record;
}

@end

NSManagedObjectContext+SharedInstance.h

//
//  NSManagedObjectContext+SharedInstance.h
//  Created by Kamil Tusznio on 12-07-05.
//

#import <CoreData/CoreData.h>

@interface NSManagedObjectContext (SharedInstance)

+ (NSManagedObjectContext *)sharedInstance;

- (BOOL)save;

@end

NSManagedObjectContext+SharedInstance.m

//
//  NSManagedObjectContext+SharedInstance.m
//  Created by Kamil Tusznio on 12-07-05.
//

#import "NSManagedObjectContext+SharedInstance.h"

#import <objc/runtime.h>

#import "AppDelegate.h"

@implementation NSManagedObjectContext (SharedInstance)

+ (NSManagedObjectContext *)sharedInstance {
    if (objc_getAssociatedObject(self, @"sharedInstance") == nil) {
        AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];

        objc_setAssociatedObject(self, @"sharedInstance", [appDelegate managedObjectContext], OBJC_ASSOCIATION_RETAIN);
    }

    return (NSManagedObjectContext *)objc_getAssociatedObject(self, @"sharedInstance");
}

- (BOOL)save {
    NSError *error;
    BOOL result = [self save:&error];

    if (error) {
        NSLog(@"Error saving context %@", [error description]);
    }

    return result;
}

@end

NSManagedObjectContextSharedInstance.h

//
//  NSManagedObjectContext+SharedInstance.h
//  Created by Kamil Tusznio on 12-07-05.
//

#import <CoreData/CoreData.h>

@interface NSManagedObjectContext (SharedInstance)

+ (NSManagedObjectContext *)sharedInstance;

- (BOOL)save;

@end

NSManagedObjectContextSharedInstance.m

//
//  NSManagedObjectContext+SharedInstance.m
//  Created by Kamil Tusznio on 12-07-05.
//

#import "NSManagedObjectContext+SharedInstance.h"

#import <objc/runtime.h>

#import "AppDelegate.h"

@implementation NSManagedObjectContext (SharedInstance)

+ (NSManagedObjectContext *)sharedInstance {
    if (objc_getAssociatedObject(self, @"sharedInstance") == nil) {
        AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];

        objc_setAssociatedObject(self, @"sharedInstance", [appDelegate managedObjectContext], OBJC_ASSOCIATION_RETAIN);
    }

    return (NSManagedObjectContext *)objc_getAssociatedObject(self, @"sharedInstance");
}

- (BOOL)save {
    NSError *error;
    BOOL result = [self save:&error];

    if (error) {
        NSLog(@"Error saving context %@", [error description]);
    }

    return result;
}

@end

NSManagedObjectKTManagedObject.h

//
//  NSManagedObject+KTManagedObject.h
//  Created by Kamil Tusznio on 12-07-10.
//

#import <CoreData/CoreData.h>

@interface NSManagedObject (KTManagedObject)

+ (NSArray *)fetchAll;
+ (id)newRecord;

@end

NSManagedObjectKTManagedObject.m

//
//  NSManagedObject+KTManagedObject.m
//  Created by Kamil Tusznio on 12-07-10.
//

#import "NSManagedObject+KTManagedObject.h"

@implementation NSManagedObject (KTManagedObject)

+ (NSArray *)fetchAll {
    NSError *error;
    NSString *entityName = NSStringFromClass([self class]);
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:entityName
                                              inManagedObjectContext:[NSManagedObjectContext sharedInstance]];
    [fetchRequest setEntity:entity];

    NSArray *records = [[NSManagedObjectContext sharedInstance] executeFetchRequest:fetchRequest
                                                                              error:&error];
    if (error) {
        NSLog(@"Error fetching %@: %@", entityName, [error description]);
    }

    return records;
}

+ (id)newRecord {
    NSString *entityName = NSStringFromClass([self class]);
    NSManagedObjectContext *context = [NSManagedObjectContext sharedInstance];
    NSEntityDescription *entityDescription = [NSEntityDescription entityForName:entityName
                                                         inManagedObjectContext:context];

    // Insert the entity into the context and save it.
    id record = [[[self class] alloc] initWithEntity:entityDescription
                      insertIntoManagedObjectContext:context];
    [context save];

    return record;
}

@end