Re: Usable flyweight template class
On Thu, 22 Nov 2007 14:21:29 +0000, Tom Widmer [VC++ MVP] wrote:
Daniel Lidstr?m wrote:
* How can I create a policy so that entries in the internal factory can be
erased when no flyweight refers to them any longer. It is ok to use
weak_ptr and shared_ptr for this implementation, I just don't have a good
idea of how.
The factory type you use just needs to have a variable of type:
std::unordered_multimap<std::size_t, std::tr1::weak_ptr<const fly> > mMap;
pointer == shared_ptr<const fly>
Additionally, you could at certain times erase entries that have an
empty weak_ptr, or have a specific call to let you do it.
* Any other ideas for improvements?
You could write a policy based factory to go with it, offering policies
for thread safety (e.g. insert is synchronised), etc.
Thanks for the constructive criticism Tom! I will try your very good
suggestions. About exception safety in the operator-> chaining, I will have
to do some experiments.
--
Daniel
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