NSOperation pass back data

Question

I have been searching but can only find the delegate pattern idea to pass back data from a NSOperation. I have a NSOperation that downloads data upon completion of that NSOperation I would like it to pass back to the class that put it in a NSoperationQueue the data it downloaded. There could be upmost of 100 of these NSOPerations in my queue, all retrieving unique data. Any ideas would be greatly appreciated.

Answer 1

Another idea would be to use blocks. You can initialize your NSOperation object with a block

typedef void(^CompletionBlock)(NSData *data);

- (id) initWithCompletionBlock: (CompletionBlock) block;

and call it after the operation is finished and data has been downloaded.

dispatch_async(dispatch_get_main_queue(), ^{
    if(block){
        block(fetchedData);
    }
});