Implementation of Object Mapping 2.0 design:

* Removed RestKit from inheritance hierarchy
  * Mappings are implemented as concrete classes
  * Mapper is much more flexible & powerful
  * Much more robust error handling
  * Serialization is reimplemented as an object mapping operation
  * Added ability to serialize to JSON natively
  * Reworked Core Data integration
  * Simplified the codebase substantially

Code/CoreData/RKManagedObjectFactory.m

@@ -0,0 +1,80 @@
+//
+//  RKManagedObjectFactory.m
+//  RestKit
+//
+//  Created by Blake Watters on 5/10/11.
+//  Copyright 2011 Two Toasters. All rights reserved.
+//
+
+#import "RKManagedObjectFactory.h"
+#import "RKManagedObjectMapping.h"
+
+@implementation RKManagedObjectFactory
+
+- (id)initWithObjectStore:(RKManagedObjectStore*)objectStore {
+    NSAssert(objectStore, @"Object store cannot be nil");
+    
+    self = [self init];
+    if (self) {
+        _objectStore = [objectStore retain];
+    }
+    
+    return self;
+}
+
++ (id)objectFactoryWithObjectStore:(RKManagedObjectStore*)objectStore {
+    return [[[self alloc] initWithObjectStore:objectStore] autorelease];
+}
+
+- (void)dealloc {
+    [_objectStore release];
+    [super dealloc];
+}
+
+- (id)objectWithMapping:(RKObjectMapping*)mapping andData:(id)mappableData {
+    NSAssert(mapping, @"Mapping cannot be nil");
+    NSAssert(mappableData, @"Mappable data cannot be nil");
+    NSAssert(_objectStore, @"Object store cannot be nil");
+    
+    id object = nil;
+    id primaryKeyValue = nil;
+    NSString* primaryKeyAttribute;
+    
+    if ([mapping isKindOfClass:[RKManagedObjectMapping class]]) {        
+        NSEntityDescription* entity = [(RKManagedObjectMapping*)mapping entity];
+        RKObjectAttributeMapping* primaryKeyAttributeMapping = nil;        
+        
+        primaryKeyAttribute = [(RKManagedObjectMapping*)mapping primaryKeyAttribute];
+        if (primaryKeyAttribute) {
+            // If a primary key has been set on the object mapping, find the attribute mapping
+            // so that we can extract any existing primary key from the mappable data
+            for (RKObjectAttributeMapping* attributeMapping in mapping.attributeMappings) {
+                if ([attributeMapping.destinationKeyPath isEqualToString:primaryKeyAttribute]) {
+                    primaryKeyAttributeMapping = attributeMapping;
+                    break;
+                }
+            }
+            
+            // Get the primary key value out of the mappable data (if any)
+            NSString* keyPathForPrimaryKeyElement = primaryKeyAttributeMapping.sourceKeyPath;
+            if (keyPathForPrimaryKeyElement) {
+                primaryKeyValue = [mappableData valueForKeyPath:keyPathForPrimaryKeyElement];
+            }
+        }
+        
+        // If we have found the primary key attribute & value, try to find an existing instance to update
+        if (primaryKeyAttribute && primaryKeyValue) {                
+            object = [_objectStore findOrCreateInstanceOfEntity:entity withPrimaryKeyAttribute:primaryKeyAttribute andValue:primaryKeyValue];
+            NSAssert2(object, @"Failed creation of managed object with entity '%@' and primary key value '%@'", entity.name, primaryKeyValue);
+        } else {
+            object = [[[NSManagedObject alloc] initWithEntity:entity
+                               insertIntoManagedObjectContext:_objectStore.managedObjectContext] autorelease];
+        }
+        
+        return object;
+    }
+    
+    return [[mapping.objectClass new] autorelease];
+}
+
+@end