A factory for prototype scope services.
The factory can provide multiple, unique service objects.
When registering a service, a PrototypeServiceFactory object can be used instead of a service object, so that the bundle developer can create a unique service object for each caller that is using the service. When a caller uses a ServiceObjects to request a service instance, the framework calls the GetService method to return a service object specifically for the requesting caller. The caller can release the returned service object and the framework will call the UngetService method with the service object. When a bundle uses the BundleContext::GetService(const ServiceReferenceBase&) method to obtain a service object, the framework acts as if the service has bundle scope. That is, the framework will call the GetService method to obtain a bundle-scoped instance which will be cached and have a use count. See ServiceFactory.
A bundle can use both ServiceObjects and BundleContext::GetService(const ServiceReferenceBase&) to obtain a service object for a service. ServiceObjects::GetService() will always return an instance provided by a call to GetService(const Bundle&, const ServiceRegistrationBase&) and BundleContext::GetService(const ServiceReferenceBase&) will always return the bundle-scoped instance. PrototypeServiceFactory objects are only used by the framework and are not made available to other bundles. The framework may concurrently call a PrototypeServiceFactory.
Inherits from cppmicroservices::ServiceFactory
GetService(const Bundle &bundle, const ServiceRegistrationBase ®istration) = 0¶
Returns a service object for a caller.
The framework invokes this method for each caller requesting a service object using ServiceObjects::GetService(). The factory can then return a specific service object for the caller. The framework checks that the returned service object is valid. If the returned service object is empty or does not contain entries for all the interfaces named when the service was registered, a warning is issued and nullptr is returned to the caller. If this method throws an exception, a warning is issued and nullptr is returned to the caller.
UngetService(const Bundle &bundle, const ServiceRegistrationBase ®istration, const InterfaceMapConstPtr &service) = 0¶
Releases a service object created for a caller.
The framework invokes this method when a service has been released by a bundles such as by calling ServiceObjects::UngetService(). The service object may then be destroyed. If this method throws an exception, a warning is issued.
bundle: The bundle releasing the service.
registration: The ServiceRegistrationBase object for the service being released.
service: The service object returned by a previous call to the GetService method.