Question

If I create an NSObject class with a method that returns an NSMutableArray do I need to release the array inside the class or does the Class never retain?

Not sure on how to explain so here is some code:

@implementation PointsClass

- (NSMutableArray *)pointsForLevel 
{
NSMutableArray *_points = [NSMutableArray new];

   [_points addObject:[NSValue valueWithCGPoint:CGPointMake(521, 279)]];
   [_points addObject:[NSValue valueWithCGPoint:CGPointMake(321, 491)]];
   [_points addObject:[NSValue valueWithCGPoint:CGPointMake(419, 477)]];

return _points;
}

@end

If i call this method from a ViewController like this:

PointsClass *pointsClass = [PointsClass new];
NSMutableArray *points = [pointsClass pointsForLevel];
[pointsClass release];

Do I only need to release the pointers Array?
Has the _points array been retained at all?

Answer 1

new will give you an object with a retain count of 1. So, yes, you do need to balance this with a release somewhere.

The convention here is to return [_points autorelease] and then let the caller decide if he needs to retain the array for some period of time.