Beginning Objective-C pdf - EBook Free Download

324CHAPTER 9: Writing an ApplicationNSOperationQueue. The input stream is scheduled on the main run loop and the class is set asits delegate; the output stream is handled separately on a per-operation basis. Then the streamsare opened to complete initialization. The code can be seen in Listing 9-63.Listing 9-63. Initializing the Remote Address Book- (id) initWithResolvedService: (NSNetService *) resolvedServicedelegate: (id) delegate{self = [super init];if ( self == nil )return ( nil );if ( [resolvedService getInputStream: &_inputStreamoutputStream: &_outputStream] == NO )return ( nil );_delegate = delegate;_inputSize = NSNotFound;_inputMessageData = [NSMutableData new];_networkQ = [NSOperationQueue new];[_networkQ setMaxConcurrentOperationCount: 1];[_inputStream setDelegate: self];[_inputStream scheduleInRunLoop: [NSRunLoop mainRunLoop] forMode: NSRunLoopCommonModes];// NOT scheduling the output stream here: it's going to be scheduled only upon// need while a single operation is sending data and needs to wait for output// buffer space to become available.[_inputStream open];[_outputStream open];_replyHandlersByUUID = [NSMutableDictionary new];}return ( self );When the address book is deallocated, the connections get torn down. When using ARC, the-dealloc method can usually be left out and everything will work, but we’ve chosen to use onehere for illustrative purposes in Listing 9-64.Listing 9-64. Remote Address Book Deallocation- (void) dealloc{NSLog(@"Remote address book deallocating: %@", self);[_networkQ cancelAllOperations];if ( [_inputStream streamStatus] != NSStreamStatusClosed )www.it-ebooks.info