Is NSMutableArray recursive in releasing it's items?

If I have a 2 dimensional NSMutableArray eg,

board = [[NSMutableArray alloc] initWithCapacity:boardHeight];
for (int y = 0; y < boardHeight; y++) {
    NSMutableArray *row = [[NSMutableArray alloc] initWithCapacity:boardWidth];

    for (int x = 0; x < boardWidth; x++) {
        [row insertObject:@"A string"];             
    }

    [board insertObject:row atIndex:y];
    [row release];
}

and I do

[board release];

Does that recursively release the array? Or do I have to manually go into the array and release each row?

If it does, and the object inserted into each row were a custom object, is there anything special I have to think about when w开发者_如何学运维riting the dealloc method for the custom object?

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Everything will just work fine. The array will retain the objects when they are added and released when removed or the array is deallocated.

No extra work on that part.

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When board is ready to be deallocated, it will send the release message to each object in itself. Even if those objects are NSArrays, they will still be released; and if those arrays are now ready to be deallocated, they will send release to their members, etc.

Your class should implement dealloc normally -- release any ivars that you hold a strong reference to before calling [super dealloc].