How to use NSOperation and dispatch queue

问题

I am using NSoperation in Initiating request to server.Pullparser will be called and it will initiate a o/p & i/p stream.In connecitonDidRecievedata I am writing data coming from server to oStream.Imeediately I have to call custom method instead of letting the parser start parsing.How to handle this case.How to handle the ostream call to parser and handle my custom method first then in my custom method I have to call the parser.

- (void)run
{     
    [gObjAppDelegatePtr displayActivityIndicator];
    self.m_cObjDownloadOprPtr = [[[NSInvocationOperation alloc]initWithTarget:self selector:@selector(requestToServer) object:nil]autorelease];

    if((NSOperationQueue *)nil == m_cObjDownloadOprQueuePtr)
    {
         m_cObjDownloadOprQueuePtr = [[NSOperationQueue alloc]init];
         [m_cObjDownloadOprQueuePtr setMaxConcurrentOperationCount:1];
    }
    [m_cObjDownloadOprQueuePtr addOperation:self.m_cObjDownloadOprPtr];
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    //[self.m_cWebData setLength: 0];
    [self.m_cWebData appendData:data];    
    [self.m_cObjOriginalWebDataPtr appendData:data];
    [self attemptToWriteToStream];
}

- (void)attemptToWriteToStream 
{
    if([self.m_cWebData length] > 0) 
    {
        [self saveDownloadedData];
        NSUInteger written = [oStream write:(const uint8_t *)[m_cWebData bytes] maxLength:[m_cWebData length]];
        // NSLog(@"Rcvd Data=%d written = %d",[m_cWebData length],written);
        [m_cWebData replaceBytesInRange:NSMakeRange(0,written) withBytes:"" length:0];
        // NSLog(@"Rcvd Data after Reset =%d ",[m_cWebData length]);[self parseResponse];
    }
}

 self.m_cObjSAXHandler = [self createParser:(id)self];
 self.m_cCurrentDownloadInfo = pObjEntry;self.m_cObjConfig = (MobileCRMConfiguration*)super.m_cObjParent.m_cObjConfiguration;
 m_cIsSuccess = NO;

 self.m_cIsOrganizationMatches = NO;
 [self.m_cObjXmlParser ParseWithStream:iStream];

-(void)ParseWithStream:(NSInputStream *)pInputStream
{
    self.m_cObjXMLParser = [[NSXMLParser alloc] initWithStream:pInputStream];
    self.m_cObjXMLParser setDelegate:m_cObjSAXHandler];
    dispatch_block_t dispatch_block  = ^(void){
        [self.m_cObjXMLParser parse];
    };

    dispatch_queue_t dispatch_queue = dispatch_queue_create("parser.queue", NULL);
    dispatch_async(dispatch_queue, dispatch_block);
    dispatch_release(dispatch_queue);
}

回答1:

I have done this pullparser thing.I have to handle the parser delegates and stream data should be updated when it finished parsing and write the leftover data to stream.

来源：https://stackoverflow.com/questions/14643416/how-to-use-nsoperation-and-dispatch-queue

标签

objective-c

nsoperation

nsoperationqueue