+- (NJMapping *)objectAtIndexedSubscript:(NSUInteger)idx {
+ return idx < _mappings.count ? _mappings[idx] : nil;
+}
+
+- (NSUInteger)countByEnumeratingWithState:(NSFastEnumerationState *)state
+ objects:(__unsafe_unretained id [])buffer
+ count:(NSUInteger)len {
+ return [_mappings countByEnumeratingWithState:state
+ objects:buffer
+ count:len];
+}
+
+