RestKit/Code/CoreData/RKFetchRequestManagedObjectCache.m

//
//  RKFetchRequestMappingCache.m
//  RestKit
//
//  Created by Jeff Arena on 1/24/12.
//  Copyright (c) 2009-2012 RestKit. All rights reserved.
//

#import "RKFetchRequestManagedObjectCache.h"
#import "NSEntityDescription+RKAdditions.h"
#import "RKLog.h"
#import "RKPropertyInspector.h"
#import "RKPropertyInspector+CoreData.h"

// Set Logging Component
#undef RKLogComponent
#define RKLogComponent RKlcl_cRestKitCoreData

@implementation RKFetchRequestManagedObjectCache

- (NSArray *)findInstancesOfEntity:(NSEntityDescription *)entity
           withPrimaryKeyAttribute:(NSString *)primaryKeyAttribute
                             value:(id)primaryKeyValue
            inManagedObjectContext:(NSManagedObjectContext *)managedObjectContext
{
    NSAssert(entity, @"Cannot find existing managed object without a target class");
    NSAssert(primaryKeyAttribute, @"Cannot find existing managed object instance without mapping that defines a primaryKeyAttribute");
    NSAssert(managedObjectContext, @"Cannot find existing managed object with a nil context");

    id searchValue = primaryKeyValue;
    Class type = [[RKPropertyInspector sharedInspector] typeForProperty:primaryKeyAttribute ofEntity:entity];
    if (type && ([type isSubclassOfClass:[NSString class]] && NO == [primaryKeyValue isKindOfClass:[NSString class]])) {
        searchValue = [NSString stringWithFormat:@"%@", primaryKeyValue];
    } else if (type && ([type isSubclassOfClass:[NSNumber class]] && NO == [primaryKeyValue isKindOfClass:[NSNumber class]])) {
        if ([primaryKeyValue isKindOfClass:[NSString class]]) {
            searchValue = [NSNumber numberWithDouble:[(NSString *)primaryKeyValue doubleValue]];
        }
    }

    // Use cached predicate if primary key matches
    NSPredicate *predicate = nil;
    if ([entity.primaryKeyAttributeName isEqualToString:primaryKeyAttribute]) {
        predicate = [entity predicateForPrimaryKeyAttributeWithValue:searchValue];
    } else {
        // Parse a predicate
        predicate = [NSPredicate predicateWithFormat:@"%K = %@", primaryKeyAttribute, searchValue];
    }
    NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:[entity name]];
    fetchRequest.predicate = predicate;
    NSError *error = nil;
    NSArray *objects = [managedObjectContext executeFetchRequest:fetchRequest error:&error];
    if (! objects) {
        RKLogError(@"Failed to execute fetch request due to error: %@", error);
    }
    RKLogDebug(@"Found objects '%@' using fetchRequest '%@'", objects, fetchRequest);

    return objects;
}

- (NSManagedObject *)findInstanceOfEntity:(NSEntityDescription *)entity
                  withPrimaryKeyAttribute:(NSString *)primaryKeyAttribute
                                    value:(id)primaryKeyValue
                   inManagedObjectContext:(NSManagedObjectContext *)managedObjectContext
{
    NSArray *objects = [self findInstancesOfEntity:entity withPrimaryKeyAttribute:primaryKeyAttribute value:primaryKeyValue inManagedObjectContext:managedObjectContext];

    NSManagedObject *object = nil;
    if ([objects count] > 0) {
        object = [objects objectAtIndex:0];
    }
    return object;
}

@end