How to release several classes which have the same delegate?

(or even just one开发者_如何学运维 class with one delegate)

Say I have a class called DataGetter, which downloads a file from the web. It has a delegate method, which gets triggered when the file has been downloaded:

- (void) dataGetterFinished:(DataGetter *)dataGetter;

So somehere in my code I can set up several files to be downloaded like so:

// in AViewController.m
DataGetter *blueFile = [[DataGetter alloc] init];
blueFile.delegate = self;
[blueFile getData:@"http://example.com/blue-file"];

DataGetter *redFile = [[DataGetter alloc] init];
redFile.delegate = self;
[redFile getData:@"http://example.com/red-file"];

Using clang static analyzer, each alloc line above gets a 'potential leak of an object allocated on line…' error. So how would I release the object. It has to hang around because it has a delegate. So is it OK to release it as the last line of the dataGetterFinished method, like so

- (void) dataGetterFinished:(DataGetter *)dataGetter
{
// code
[dateGetter release];
}

...or should I be using autorelease somehow?

Technically, that works fine, however I would suggest keeping track of the different DataGetters in an NSMutableArray.

For example:

DataGetter *blueFile = [[DataGetter alloc] init];
blueFile.delegate = self;
[blueFile getData:@"http://example.com/blue-file"];
[dataGetters addObject:blueFile]; // dataGetters is an NSMutableArray declared in the .h
[blueFile release];

// Same for red

Then in the delegate method, simple remove the getter from the array:

- (void) dataGetterFinished:(DataGetter *)dataGetter
{
// code
[dataGetters removeObject:dataGetter];
}

The array takes care of retaining the object, and you don't get the analysis warning.

Just be sure to release dataGetters in the dealloc method.