Graphics Programs Reference
In-Depth Information
call
BNRItemStore
's
allocWithZone:
again, which would then call
sharedStore
, which would... well, you get the picture.
Figure 9.8 Not sending allocWithZone: to NSObject causes loop
This is why we had
sharedStore
call
NSObject
's implementation of
al-
locWithZone:
.
sharedStore = [[super allocWithZone:nil] init];
By sending
allocWithZone:
to
super
, we skip over our trap and get an instance of
BNRItemStore
when we need it (
Figure 9.9
).
Figure 9.9 BNRItemStore and NSObject allocation methods
We can only skip over our
alloc
trap within the implementation of
BNRItemStore
because the
super
keyword is only relevant to the class in which the method is imple-
mented.
