NSManagedObject+FFFindAndOrCreate

NSManagedObject+FFFindAndOrCreate.h

//
//  NSManagedObject+FFFindAndOrCreate.h
//
//  Created by Florian Friedrich on 15.12.13.
//  Copyright (c) 2013 Florian Friedrich. All rights reserved.
//
//  Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"),
//  to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
//  and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
// 
//  The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
//  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>

// Defines
#ifndef kNSManagedObjectFFFindOrCreateCrashOnError
#if DEBUG
    #define kNSManagedObjectFFFindOrCreateCrashOnError YES
#else
    #define kNSManagedObjectFFFindOrCreateCrashOnError NO
#endif
#endif

#ifndef kNSManagedObjectFFFindOrCreateDefaultCombineAction
    #define kNSManagedObjectFFFindOrCreateDefaultCombineAction @"AND"
#endif

/**
 *  Some useful find and/or create extensions to NSManagedObject.
 *  @see NSManagedObject
 */
@interface NSManagedObject (FFFindAndOrCreate)

#pragma mark - Just create
/**
 *  Creates a managed object in a given managed object context with the class name as entity name.
 *  @param context The context in which to create the managed object.
 *  @return The new managed object instance or nil if an error occured.
 */
+ (instancetype)createObjectInManagedObjectContext:(NSManagedObjectContext *)context;
/**
 *  Creates a managed object with a given entity name in a given managed object context.
 *  @param entityName The entity name of the new managed object.
 *  @param context    The context in which to create the managed object.
 *  @return The new managed object instance or nil if an error occured.
 */
+ (instancetype)createObjectWithEntityName:(NSString *)entityName
                    inManagedObjectContext:(NSManagedObjectContext *)context;

#pragma mark - Just find
// Single values
/**
 *  Find objects by a key and an objectValue in a given context and the class name as entity.
 *  @param key         The key to which to match the objectvalue.
 *  @param objectValue The objectValue for the given key.
 *  @param context     The context in which to search.
 *  @return An array of found objects (may be empty) or nil if an error occurred.
 */
+ (NSArray *)findObjectsByKey:(NSString *)key
                  objectValue:(NSObject *)objectValue
       inManagedObjectContext:(NSManagedObjectContext *)context;
/**
 *  Find objects of a given entity by a key and an objectValue in a given context.
 *  @param entityName  The entity of which to search instances.
 *  @param key         The key to which to match the objectvalue.
 *  @param objectValue The objectValue for the given key.
 *  @param context     The context in which to search.
 *  @return An array of found objects (may be empty) or nil if an error occurred.
 */
+ (NSArray *)findObjectsWithEntityName:(NSString *)entityName
                                 byKey:(NSString *)key
                           objectValue:(NSObject *)objectValue
                inManagedObjectContext:(NSManagedObjectContext *)context;
/**
 *  Find objects of a given entity by a key and an objectValue in a given context.
 *  @param entityName  The entity of which to search instances.
 *  @param key         The key to which to match the objectvalue.
 *  @param objectValue The objectValue for the given key.
 *  @param context     The context in which to search.
 *  @param error       A pointer to a NSError in which to save any error.
 *  @return An array of found objects (may be empty) or nil if an error occurred.
 */
+ (NSArray *)findObjectsWithEntityName:(NSString *)entityName
                                 byKey:(NSString *)key
                           objectValue:(NSObject *)objectValue
                inManagedObjectContext:(NSManagedObjectContext *)context
                             withError:(NSError *__autoreleasing *)error;

// Multiple values
/**
 *  Find objects by a key/objectValue dictionary in a given context and the class name as entity name.
 *  @param keyObjectDictionary The dictionary containing keys and objects to match.
 *  @param context             The context in which to search.
 *  @return An array of found objects (may be empty) or nil if an error occurred.
 */
+ (NSArray *)findObjectsByKeyObjectValue:(NSDictionary *)keyObjectDictionary
                  inManagedObjectContext:(NSManagedObjectContext *)context;
/**
 *  Find objects of a given entity by a key/objectValue dictionary in a given context.
 *  @param entityName          The entity of which to search objects.
 *  @param keyObjectDictionary The dictionary containing keys and objects to match.
 *  @param context             The context in which to search.
 *  @return An array of found objects (may be empty) or nil if an error occurred.
 */
+ (NSArray *)findObjectsWithEntityName:(NSString *)entityName
                 byKeyObjectDictionary:(NSDictionary *)keyObjectDictionary
                inManagedObjectContext:(NSManagedObjectContext *)context;
/**
 *  Find objects of a given entity by a key/objectValue dictionary in a given context.
 *  @param entityName          The entity of which to search objects.
 *  @param keyObjectDictionary The dictionary containing keys and objects to match.
 *  @param context             The context in which to search.
 *  @param error               A pointer to a NSError in which to save any error.
 *  @return An array of found objects (may be empty) or nil if an error occurred.
 */
+ (NSArray *)findObjectsWithEntityName:(NSString *)entityName
                 byKeyObjectDictionary:(NSDictionary *)keyObjectDictionary
                inManagedObjectContext:(NSManagedObjectContext *)context
                             withError:(NSError *__autoreleasing *)error;

#pragma mark - Find or Create
// Singleton objects
/**
 *  Finds or creates an object in a given managed object context and the class name as entity.
 *  @param context The context in which to search/create the object
 *  @return The singleton object or nil if an error occurred.
 */
+ (instancetype)findOrCreateObjectInManagedObjectContext:(NSManagedObjectContext *)context;
/**
 *  Finds or creates an object with a given entity in a given managed object context.
 *  @param entityName The entity of the object.
 *  @param context    The context in which to search/create the object.
 *  @return The singleton object or nil if an error occurred.
 */
+ (instancetype)findOrCreateObjectWithEntityName:(NSString *)entityName
                          inManagedObjectContext:(NSManagedObjectContext *)context;
/**
 *  Finds or creates an object with a given entity in a given managed object context.
 *  @param entityName The entity of the object.
 *  @param context    The context in which to search/create the object.
 *  @param error      A pointer to a NSError in which to save any error.
 *  @return The singleton object or nil if an error occurred.
 */
+ (instancetype)findOrCreateObjectWithEntityName:(NSString *)entityName
                          inManagedObjectContext:(NSManagedObjectContext *)context
                                       withError:(NSError *__autoreleasing *)error;


// Single values
/**
 *  Finds or creates an object with a given objectvalue for a given key in a given managed object context and the class as entity name.
 *  @param key         The key of the objectvalue to match.
 *  @param objectValue The objectvalue of the key.
 *  @param context     The context in which to search/create the object.
 *  @return The found/created object or nil if an error occurred.
 */
+ (instancetype)findOrCreateObjectByKey:(NSString *)key
                            objectValue:(NSObject *)objectValue
                 inManagedObjectContext:(NSManagedObjectContext *)context;
/**
 *  Finds or creates an object with a given objectvalue for a given key and a given entity in a given managed object context.
 *  @param entityName  The entity of the object.
 *  @param key         The key of the objectvalue to match.
 *  @param objectValue The objectvalue of the key.
 *  @param context     The context in which to search/create the object.
 *  @return The found/created object or nil if an error occurred.
 */
+ (instancetype)findOrCreateObjectWithEntityName:(NSString *)entityName
                                           byKey:(NSString *)key
                                     objectValue:(NSObject *)objectValue
                          inManagedObjectContext:(NSManagedObjectContext *)context;
/**
 *  Finds or creates an object with a given objectvalue for a given key and a given entity in a given managed object context.
 *  @param entityName  The entity of the object.
 *  @param key         The key of the objectvalue to match.
 *  @param objectValue The objectvalue of the key.
 *  @param context     The context in which to search/create the object.
 *  @param error       A pointer to a NSError in which to save any error.
 *  @return The found/created object or nil if an error occurred.
 */
+ (instancetype)findOrCreateObjectWithEntityName:(NSString *)entityName
                                           byKey:(NSString *)key
                                     objectValue:(NSObject *)objectValue
                          inManagedObjectContext:(NSManagedObjectContext *)context
                                       withError:(NSError *__autoreleasing *)error;

// Multiple values
/**
 *  Finds or creates an object with given keys/objectvalues in a given managed object context with the class as entity.
 *  @param keyObjectDictionary The keys/objectvalues of the object to search/create.
 *  @param context             The context in which to search/create the object.
 *  @return The found/created object or nil if an error occurred.
 */
+ (instancetype)findOrCreateObjectByKeyObjectDictionary:(NSDictionary *)keyObjectDictionary
                                 inManagedObjectContext:(NSManagedObjectContext *)context;
/**
 *  Finds or creates an object with a given entity and given keys/objectvalues in a given managed object context.
 *
 *  @param entityName          The entity of the object.
 *  @param keyObjectDictionary The keys/objectvalues of the object to search/create.
 *  @param context             The context in which to search/create the object.
 *  @return The found/created object or nil if an error occurred.
 */
+ (instancetype)findOrCreateObjectWithEntityName:(NSString *)entityName
                           byKeyObjectDictionary:(NSDictionary *)keyObjectDictionary
                          inManagedObjectContext:(NSManagedObjectContext *)context;
/**
 *  Finds or creates an object with a given entity and given keys/objectvalues in a given managed object context.
 *
 *  @param entityName          The entity of the object.
 *  @param keyObjectDictionary The keys/objectvalues of the object to search/create.
 *  @param context             The context in which to search/create the object.
 *  @param error               A pointer to a NSError in which to save any error.
 *  @return The found/created object or nil if an error occurred.
 */
+ (instancetype)findOrCreateObjectWithEntityName:(NSString *)entityName
                           byKeyObjectDictionary:(NSDictionary *)keyObjectDictionary
                          inManagedObjectContext:(NSManagedObjectContext *)context
                                       withError:(NSError *__autoreleasing *)error;

@end

NSManagedObject+FFFindAndOrCreate.m

//
//  NSManagedObject+FFFindAndOrCreate.m
//
//  Created by Florian Friedrich on 15.12.13.
//  Copyright (c) 2013 Florian Friedrich. All rights reserved.
//
//  Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"),
//  to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
//  and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
// 
//  The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
//  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

#import "NSManagedObject+FFFindAndOrCreate.h"


@implementation NSManagedObject (FFFindAndOrCreate)

#pragma mark - Just create
+ (instancetype)createObjectInManagedObjectContext:(NSManagedObjectContext *)context
{
    return [self createObjectWithEntityName:NSStringFromClass(self)
                     inManagedObjectContext:context];
}

+ (instancetype)createObjectWithEntityName:(NSString *)entityName
                    inManagedObjectContext:(NSManagedObjectContext *)context
{
    return [NSEntityDescription insertNewObjectForEntityForName:entityName inManagedObjectContext:context];
}

#pragma mark - Just find
#pragma mark Single values
+ (NSArray *)findObjectsByKey:(NSString *)key
                  objectValue:(NSObject *)objectValue
       inManagedObjectContext:(NSManagedObjectContext *)context
{
    return [self findObjectsByKeyObjectValue:@{key: objectValue} inManagedObjectContext:context];
}

+ (NSArray *)findObjectsWithEntityName:(NSString *)entityName
                                 byKey:(NSString *)key
                           objectValue:(NSObject *)objectValue
                inManagedObjectContext:(NSManagedObjectContext *)context
{
    return [self findObjectsWithEntityName:entityName
                     byKeyObjectDictionary:@{key: objectValue}
                    inManagedObjectContext:context];
}

+ (NSArray *)findObjectsWithEntityName:(NSString *)entityName
                                 byKey:(NSString *)key
                           objectValue:(NSObject *)objectValue
                inManagedObjectContext:(NSManagedObjectContext *)context
                             withError:(NSError *__autoreleasing *)error
{
    return [self findObjectsWithEntityName:entityName
                     byKeyObjectDictionary:@{key: objectValue}
                    inManagedObjectContext:context
                                 withError:error];
}

#pragma mark Multiple values
+ (NSArray *)findObjectsByKeyObjectValue:(NSDictionary *)keyObjectDictionary inManagedObjectContext:(NSManagedObjectContext *)context
{
    return [self findObjectsWithEntityName:NSStringFromClass(self)
                     byKeyObjectDictionary:keyObjectDictionary
                    inManagedObjectContext:context];
}

+ (NSArray *)findObjectsWithEntityName:(NSString *)entityName
                 byKeyObjectDictionary:(NSDictionary *)keyObjectDictionary
                inManagedObjectContext:(NSManagedObjectContext *)context
{
    return [self findObjectsWithEntityName:entityName
                     byKeyObjectDictionary:keyObjectDictionary
                    inManagedObjectContext:context
                                 withError:nil];
}

+ (NSArray *)findObjectsWithEntityName:(NSString *)entityName
                 byKeyObjectDictionary:(NSDictionary *)keyObjectDictionary
                inManagedObjectContext:(NSManagedObjectContext *)context
                             withError:(NSError *__autoreleasing *)error
{
    NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:entityName];
    
    if (keyObjectDictionary) {
        NSMutableString *formatString = [[NSMutableString alloc] init];
        NSMutableArray *argumentArray = [[NSMutableArray alloc] init];
        
        [keyObjectDictionary enumerateKeysAndObjectsUsingBlock:^(NSString *key, id obj, BOOL *stop) {
            if (formatString.length > 0) {
                [formatString appendFormat:@" %@ ", kNSManagedObjectFFFindOrCreateDefaultCombineAction];
            }
            [formatString appendString:[NSString stringWithFormat:@"%@ == %@", key, @"%@"]];
            [argumentArray addObject:obj];
        }];
        
        fetchRequest.predicate = [NSPredicate predicateWithFormat:formatString.copy
                                                    argumentArray:argumentArray.copy];
    }
    
    NSError *__autoreleasing *errorPtr = error;
    if (errorPtr == NULL) {
        __autoreleasing NSError *localError = nil;
        errorPtr = &localError;
    }
    NSArray *fetchedObjects = [context executeFetchRequest:fetchRequest error:errorPtr];
    if (fetchedObjects == nil && *errorPtr != nil) {
        NSLog(@"Error while executing findOrCreate fetch request: %@", *errorPtr);
#if kNSManagedObjectFFFindOrCreateCrashOnError
        abort();
#endif
    }
    
    return fetchedObjects;
}

#pragma mark - Find or Create
#pragma mark Singleton objects
+ (instancetype)findOrCreateObjectInManagedObjectContext:(NSManagedObjectContext *)context
{
    return [self findOrCreateObjectByKeyObjectDictionary:nil inManagedObjectContext:context];
}

+ (instancetype)findOrCreateObjectWithEntityName:(NSString *)entityName
                          inManagedObjectContext:(NSManagedObjectContext *)context
{
    return [self findOrCreateObjectWithEntityName:entityName
                            byKeyObjectDictionary:nil
                           inManagedObjectContext:context];
}

+ (instancetype)findOrCreateObjectWithEntityName:(NSString *)entityName
                          inManagedObjectContext:(NSManagedObjectContext *)context
                                       withError:(NSError *__autoreleasing *)error
{
    return [self findOrCreateObjectWithEntityName:entityName
                            byKeyObjectDictionary:nil
                           inManagedObjectContext:context
                                        withError:error];
}

#pragma mark Single key/value methods
+ (instancetype)findOrCreateObjectByKey:(NSString *)key
                            objectValue:(NSObject *)objectValue
                 inManagedObjectContext:(NSManagedObjectContext *)context
{
    return [self findOrCreateObjectByKeyObjectDictionary:@{key: objectValue}
                                  inManagedObjectContext:context];
}

+ (instancetype)findOrCreateObjectWithEntityName:(NSString *)entityName
                                           byKey:(NSString *)key
                                     objectValue:(NSObject *)objectValue
                          inManagedObjectContext:(NSManagedObjectContext *)context
{
    return [self findOrCreateObjectWithEntityName:entityName
                            byKeyObjectDictionary:@{key: objectValue}
                           inManagedObjectContext:context];
}

+ (instancetype)findOrCreateObjectWithEntityName:(NSString *)entityName
                                           byKey:(NSString *)key
                                     objectValue:(NSObject *)objectValue
                          inManagedObjectContext:(NSManagedObjectContext *)context
                                       withError:(NSError *__autoreleasing *)error
{
    return [self findOrCreateObjectWithEntityName:entityName
                            byKeyObjectDictionary:@{key: objectValue}
                           inManagedObjectContext:context
                                        withError:error];
}

#pragma mark Key/value dict methods
+ (instancetype)findOrCreateObjectByKeyObjectDictionary:(NSDictionary *)keyObjectDictionary
                                 inManagedObjectContext:(NSManagedObjectContext *)context
{
    return [self findOrCreateObjectWithEntityName:NSStringFromClass(self)
                            byKeyObjectDictionary:keyObjectDictionary
                           inManagedObjectContext:context];
}

+ (instancetype)findOrCreateObjectWithEntityName:(NSString *)entityName
                           byKeyObjectDictionary:(NSDictionary *)keyObjectDictionary
                          inManagedObjectContext:(NSManagedObjectContext *)context
{
    return [self findOrCreateObjectWithEntityName:entityName
                            byKeyObjectDictionary:keyObjectDictionary
                           inManagedObjectContext:context
                                        withError:nil];
}

+ (instancetype)findOrCreateObjectWithEntityName:(NSString *)entityName
                           byKeyObjectDictionary:(NSDictionary *)keyObjectDictionary
                          inManagedObjectContext:(NSManagedObjectContext *)context
                                       withError:(NSError *__autoreleasing *)error
{
    NSArray *fetchedObjects = [self findObjectsWithEntityName:entityName
                                        byKeyObjectDictionary:keyObjectDictionary
                                       inManagedObjectContext:context withError:error];
    
    NSManagedObject *managedObject;
    if (fetchedObjects && fetchedObjects.count > 0) {
        managedObject = [fetchedObjects firstObject];
    } else {
        managedObject = [self createObjectWithEntityName:entityName inManagedObjectContext:context];
        if (keyObjectDictionary) {
            [keyObjectDictionary enumerateKeysAndObjectsUsingBlock:^(NSString *key, id obj, BOOL *stop) {
                if ([obj isKindOfClass:[NSManagedObjectID class]]) {
                    [managedObject setValue:[context objectWithID:obj] forKey:key];
                } else {
                    [managedObject setValue:obj forKey:key];
                }
            }];
        }
    }
    
    return managedObject;
}

@end