kylefang/RestKit
1
0
Fork 0
mirror of https://github.com/zhigang1992/RestKit.git synced 2026-04-23 04:20:21 +08:00
Code Issues Packages Projects Releases Wiki Activity

Add support for mapping a relationship directly from the parent object representation, rather than at a nested key path. closes #859

Browse Source 
* Update documentation in RKRelationshipMapping.h
This commit is contained in:
Blake Watters
2012-12-24 16:18:39 -05:00
parent bc719087ac
commit b3899ac191
6 changed files with 73 additions and 64 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
Code/ObjectMapping/RKMapperOperation.h
View File

@@ -50,9 +50,11 @@
Note that the keys of the dictionary are **key paths**. Deeply nested content can be mapped by specifying the full key path as the key of the mappings dictionary.
### The NSNull Key
### Mapping the Root Object Representation
A mapping set for the key `[NSNull null]` value has special significance to the mapper operation. When a mapping is encountered with the a null key, the entire `representation` is processed using the given mapping. This provides support for mapping content that does not have an outer nesting attribute.
Note that it is possible to map the same representation with multiple mappings, including a combination of a root key mapping and nested keypaths.
## Data Source

3
Code/ObjectMapping/RKMappingOperation.m
View File

@@ -532,7 +532,8 @@ NSArray *RKApplyNestingAttributeValueToMappings(NSString *attributeName, id valu
for (RKRelationshipMapping *relationshipMapping in [self relationshipMappings]) {
if ([self isCancelled]) return NO;
id value = [self.sourceObject valueForKeyPath:relationshipMapping.sourceKeyPath];
// The nil source keyPath indicates that we want to map directly from the parent representation
id value = (relationshipMapping.sourceKeyPath == nil) ? self.sourceObject : [self.sourceObject valueForKeyPath:relationshipMapping.sourceKeyPath];
// Track that we applied this mapping
[mappingsApplied addObject:relationshipMapping];

8
Code/ObjectMapping/RKRelationshipMapping.h
View File

@@ -26,6 +26,12 @@
The `RKRelationshipMapping` class is used to describe relationships of a class in an `RKObjectMapping` or an entity in an `RKEntityMapping` object.
`RKRelationshipMapping` extends `RKPropertyMapping` to describe features specific to relationships, including the `RKMapping` object describing how to map the destination object.
Relationship mappings are described in terms of a source key path, which identifies a key in the parent object representation under which the data for the relationship is nested, and a destination key path, which specifies the key path at which the mapped object is to be assigned on the parent entity. The key-paths of the property mappings of the `RKMapping` object in the relationship mapping are evaluated against the nested object representationship at the source key path.
## Mapping a Non-nested Relationship from the Parent Representation
It can often be desirable to map data for a relationship directly from the parent object representation, rather than under a nested key path. When a relationship mapping is constructed with a `nil` value for the source key path, then the `RKMapping` object is evaluated against the parent representation.
*/
@interface RKRelationshipMapping : RKPropertyMapping
@@ -38,7 +44,7 @@
The mapping may describe a to-one or a to-many relationship. The appropriate handling of the source representation is deferred until run-time and is determined by performing reflection on the data retrieved from the source object representation by sending a `valueForKeyPath:` message where the key path is the value given in `sourceKeyPath`. If an `NSArray`, `NSSet` or `NSOrderedSet` object is returned, the related object representation is processed as a to-many collection. Otherwise the representation is considered to be a to-one.
@param sourceKeyPath A key path from which to retrieve data in the source object representation that is to be mapped as a relationship.
@param sourceKeyPath A key path from which to retrieve data in the source object representation that is to be mapped as a relationship. If `nil`, then the mapping is performed directly against the parent object representation.
@param destinationKeyPath The key path on the destination object to set the object mapped results.
@param mapping A mapping object describing how to map the data retrieved from `sourceKeyPath` that is to be set on `destinationKeyPath`.
*/