Class Instance Release Order?

Question

This is probably a pretty basic question, but just something that I wanted to make sure I had right in my head. When I release the class instance "newPlanet_001" what is the order of disposal, Am I right in assuming that if the retain count of the object is 1 prior to the release that the instances dealloc method is called first (to release the instance variable "planetName") before continuing to release the class instance as a whole?

(i.e.)

// CLASS
@interface PlanetClass : NSObject {
    NSString *planetName;
}
- (NSString *)planetName;
- (void)setPlanetName:(NSString *)newPlanetName;
@end

// MAIN
int main (int argc, const char *argv[]) {
    PlanetClass *newPlanet_001;
    newPlanet_001 = [[PlanetClass alloc] init];
    [newPlanet release];
}

// DEALLOC
- (void)dealloc {
    [planetName release];
    [super dealloc];
}
@end

cheers -gary-

Answer 1

-[NSObject release] calls -dealloc if the retain count is zero. This allows the object to cleanup any objects it owns before calling [super dealloc] to do the actual deallocation.

If implemented properly, an object will release any objects it owns before calling the super (this them to get deallocated if their retain count is also zero).

_{An object owns another if it calls alloc, copy or retain on it.}

Answer 2

Your assumption is correct. The planetName object is released BEFORE the newPlanet_001 instance.