Reactor is a service locator implementation intended to replace traditional dependency injection techniques.
To achieve the above goal it binds factories to interface classes and when an interface is requested it either returns the already produced "service" or creates it if necessary. This basically means that each service behaves like a singleton, and their life-cycle is managed by reactor.
Among other things, reactor supports validating of dependencies, resetting all services, and overrides of service factories. These help to write easily testable code, run all tests in a clean state and prevent crashes due to missing dependencies only detected on their first usage.
- Original repository: https://gitlab.iwstudio.hu/u-foka/reactor
- Mirrored to: https://github.com/u-foka/reactor
First you need to define the interface of the service:
class i_example
{
public:
virtual ~i_example() {}
virtual int add(int a, int b) = 0;
};Then define the implementation:
class example_impl : public i_example
{
public:
virtual void add(int a, int b) override
{
return a+b;
}
}And finally register the a factory that instantiates the implementation when a service is requested for your interface:
static const reactor::factory_registrator<i_example, example_impl> registrator(reactor::prio_normal);First you have to declare a contract to the interface you want to use, preferably it's a global variable in the compilation unit where the interface will be used:
static const reactor::contract<i_example> example_contract;Then wherever you need to use i_example you can acquire a reference to backing service using:
auto res = r.get(example_contract).add(1, 1);Let's assume you want to test code that uses i_example and want to replace it's implementation with a mock:
const reactor::factory_wrapper_registrator<i_example, true> mock_registrator
(reactor::prio_test, [&](const std::string &) {
return example_mock;
});