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/ObjectMapping/RKObjectMappingResult.m

@@ -0,0 +1,70 @@
+//
+//  RKObjectMappingResult.m
+//  RestKit
+//
+//  Created by Blake Watters on 5/7/11.
+//  Copyright 2011 Two Toasters. All rights reserved.
+//
+
+#import "RKObjectMappingResult.h"
+#import "RKObjectMapperError.h"
+
+@implementation RKObjectMappingResult
+
+- (id)initWithDictionary:(id)dictionary {
+    self = [self init];
+    if (self) {
+        _keyPathToMappedObjects = [dictionary retain];
+    }
+    
+    return self;
+}
+
+- (void)dealloc {
+    [_keyPathToMappedObjects release];
+    [super dealloc];
+}
+
++ (RKObjectMappingResult*)mappingResultWithDictionary:(NSDictionary*)keyPathToMappedObjects {
+    return [[[self alloc] initWithDictionary:keyPathToMappedObjects] autorelease];
+}
+
+- (NSDictionary*)asDictionary {
+    return _keyPathToMappedObjects;
+}
+
+- (NSArray*)asCollection {
+    // Flatten results down into a single array
+    NSMutableArray* collection = [NSMutableArray array];
+    for (id object in [_keyPathToMappedObjects allValues]) {
+        // We don't want to strip the keys off of a mapped dictionary result
+        
+        if (NO == [object isKindOfClass:[NSDictionary class]] && [object respondsToSelector:@selector(allObjects)]) {
+            [collection addObjectsFromArray:[object allObjects]];
+        } else {
+            [collection addObject:object];
+        }
+    }
+    
+    return collection;
+}
+
+- (id)asObject {
+    // TODO: Warn that only last object was returned...
+    return [[self asCollection] objectAtIndex:0];
+}
+
+- (NSError*)asError {
+    NSArray* collection = [self asCollection];
+    // TODO: What is the correct behavior when there is an empty collection we expect to contain an error???
+    NSAssert([collection count] > 0, @"Expected mapping result to contain at least one object to construct an error");
+    NSString* description = [[collection valueForKeyPath:@"description"] componentsJoinedByString:@", "];
+    
+    NSDictionary* userInfo = [NSDictionary dictionaryWithObjectsAndKeys:description, NSLocalizedDescriptionKey,
+                              collection, RKObjectMapperErrorObjectsKey, nil];
+    
+    NSError* error = [NSError errorWithDomain:RKRestKitErrorDomain code:RKObjectMapperErrorFromMappingResult userInfo:userInfo];
+    return error;
+}
+
+@end