Re: Alternative To Members As Callbacks?
??The problem (as warned in the FAQ) is that doing so would
require some way for the loader to know the "this" pointer for each
object. ??And to make matters worse, the type of object that "this"
refers to will vary.
Is this just a broken approach from the start?
No, it's not a broken approach, just needs a tweak. What you want is
known as the Observer pattern, full details are easily searched online.
Summarily, use a base class containing virtual functions defining the
possible callbacks, derive the observers from that base class, and
provide a "register(Observer*)" function in your Loader class (probably
appending the observer's address to a vector...).
Actually both ideas match : the Observer design pattern suggested by tony
is really close to your first idea. The Loader indeed knows about a list
of pointers to "this".
Now you were concerned about the type of object pointed by "this". And
the answer proposed by tony's design pattern is : "they are all
Observers". Said differently, they all need to derive from the Observer
class. This latter could be as simple as :
class Observer
{
public:
virtual void notify() = 0;
};
Now your loader will call "notify" on every observers.
--
qdii -- www.mathseconde.fr
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