RKRelationshipConnectionOperation Class Reference
| Inherits from | NSOperation |
| Declared in | RKRelationshipConnectionOperation.h |
Overview
The RKRelationshipConnectionOperation class is a subclass of NSOperation that manages the connection of NSManagedObject relationships as described by an RKConnectionDescription object. When executed, the operation will find related objects by searching the associated managed object cache for objects matching the connection description and setting them as the value for the relationship being connected.
For example, given a managed object for the Employee entity with a one-to-one relationship to a Company named company (with an inverse relationship one-to-many relationship named employees) and a connection specifying that the relationship can be connected by finding the Company managed object whose companyID attribute matches the companyID of the Employee, the operation would find the Company that employs the Employee by primary key and set the Core Data relationship to reflect the relationship appropriately.
Tasks
Initializing a Relationship Connection Operation
-
– initWithManagedObject:connection:managedObjectCache:Initializes the receiver with a given managed object, connection mapping, and managed object cache.
Accessing Details About the Operation
-
managedObjectThe managed object the receiver will attempt to connect a relationship for.
property -
connectionThe connection mapping describing the relationship connection the receiver will attempt to connect.
property -
managedObjectCacheThe managed object cache the receiver will use to fetch a related object satisfying the connection mapping.
property -
connectedValueThe object or collection of objects that was connected by the operation.
property
Setting the Connection Block
-
– setConnectionBlock:Sets a block to be executed on the operation attempted to establish the connection.
Properties
connectedValue
The object or collection of objects that was connected by the operation.
@property (nonatomic, strong, readonly) id connectedValueDiscussion
The connected object will either be nil, indicating that the relationship could not be connected, a single NSManagedObject object (if the relationship is one-to-one), or an array of NSManagedObject objects (if the relationship is one-to-many).
Declared In
RKRelationshipConnectionOperation.hconnection
The connection mapping describing the relationship connection the receiver will attempt to connect.
@property (nonatomic, strong, readonly) RKConnectionDescription *connectionDeclared In
RKRelationshipConnectionOperation.hmanagedObject
The managed object the receiver will attempt to connect a relationship for.
@property (nonatomic, strong, readonly) NSManagedObject *managedObjectDeclared In
RKRelationshipConnectionOperation.hmanagedObjectCache
The managed object cache the receiver will use to fetch a related object satisfying the connection mapping.
@property (nonatomic, strong, readonly) id<> managedObjectCacheDeclared In
RKRelationshipConnectionOperation.hInstance Methods
initWithManagedObject:connection:managedObjectCache:
Initializes the receiver with a given managed object, connection mapping, and managed object cache.
- (id)initWithManagedObject:(NSManagedObject *)managedObject connection:(RKConnectionDescription *)connection managedObjectCache:(id<RKManagedObjectCaching>)managedObjectCacheParameters
- managedObject
The object to attempt to connect a relationship to.
- managedObjectCache
The managed object cache from which to attempt to fetch a matching object to satisfy the connection.
- connectionMapping
A mapping describing the relationship and attributes necessary to perform the connection.
Return Value
The receiver, initialized with the given managed object, connection mapping, and managed object cache.
Declared In
RKRelationshipConnectionOperation.hsetConnectionBlock:
Sets a block to be executed on the operation attempted to establish the connection.
- (void)setConnectionBlock:(void ( ^ ) ( RKRelationshipConnectionOperation *operation , id connectedValue ))blockParameters
- block
A block object to be executed when the connection is evaluated. The block accepts two arguments: the operation itself and the value, if any, that was set for the relationship targetted by the connection description.
Discussion
Unlike the block set with setCompletionBlock:, this block is executed during the body of the operation within the queue of the managed object context in which the connection was established. This means that it is safe to executed both the connectedValue and managedObject directly within the body of the block.
Declared In
RKRelationshipConnectionOperation.h