The NSOperationQueue Workﬂow Subclasses of NSOperation are created Typically they override -(void) main An NSOperationQueue is created and NSOperations are added to it The queue is set in action and the operations are executed Queues may be suspended so operations must be aware of this
Operation Queues In ActionSimple Asynchronous Operations Note: As OperationA and OperationB are running on the same queue, operations won’t necessarily ﬁnish in the order they’re added.
Operation Queues In ActionListening For Individual Operation Completion
Operation Queues In ActionWaiting Until An Operation Queue Is Complete Before Continuing
Cancelling An Entire Queue NSOperationQueues offer a cancelAllOperations method All the NSOperations will be notiﬁed of this They can choose to perform certain actions based upon their isCancelled property Individual operations can be cancelled using cancel
Loads More To ExploreBlocks instead of delegates Dispatch Resources Concurrent Operations SemaphoresDelayed dispatches Check The Apple Documentation