Jason Hise wrote:
Alright... I believe that my multiton dependency lifetime is functional based on a few simple tests. However, I could easily be wrong, so I would appreciate the efforts of everyone who tries to break my code. My next task will be to try a multiton longevity lifetime policy, and then perhaps I'll try to find a way to make GetInst accept multiple keys. The code at http://boost-sandbox.sourceforge.net/vault/ under Singleton is up to date.
I just realized that I should probably at least provide a small sample program so that people can see how the multiton is intended to be used. In the following example, a unique country can exist for each unique name, a unique state can exist for each unique name, and states depend upon the country "USA". #include <string> #include <Multiton.h> using namespace boost::singleton; class Country : public Multiton < std::string, Country > { protected: Country ( ) { } ~ Country ( ) { } }; // uncomment to enable lazy creation class State : public Multiton < std::string, State/*, MultitonDependencyLifetime < std::string, State, true >*/ > { private: // guarantee that the USA is created immediately // before the creation of the first state Country::LifetimePolicy::Dependency require_usa; protected: State ( ) : require_usa ( "USA" ) { } ~ State ( ) { } }; void f ( ) { // this creates the ohio instance only if lazy creation is false State::LifetimePolicy::Dependency require_oh ( "Ohio" ); { // this creates the ohio instance if it has not been created yet State::Pointer ohio = State::GetInst ( "Ohio" ); // this creates the florida instance State::Pointer florida = State::GetInst ( "Florida" ); } int i = 5; // florida has been destroyed // but dependency on ohio is still in scope, so ohio lives on } // ohio is destroyed, after which point the USA is destroyed // if it is desired for these things to live to the end of the program, // just add static dependencies, ex: // Country::LifetimePolicy::Dependency require_usa ( "USA" ); int main ( ) { f ( ); return 0; }