How does the isolation work in iPOJO Composite?

Question

iPOJO provides a mechanism to create composites that contain instances of primitive type components. I am interested in understanding the mechanism in which iPOJO provides an isolation for the services provided by the composite sub-instances from being accessed from outside the composite.

For exmaple, assume I have the following composition (Using iPOJO API):

 PrimitiveComponentType prov = createAProvider(); // Create a primitive type
 PrimitiveComponentType cons = createAConsumer(); // Create another primitive type

       CompositeComponentType type = new CompositeComponentType()
           .setBundleContext(context)
           .setComponentTypeName("comp1")
           .addInstance(new Instance(prov.getFactory().getName())) // Create an instance in the composite
           .addInstance(new Instance(cons.getFactory().getName())); 

       ComponentInstance ci = type.createInstance();

Let's say that the component "prov" implements a service interface called HelloService. What does it mean that this service is isolated?

Does it mean that if I tried to access the service from an external bundle (not part of the composite) by having a service reference:

   ServiceReference ref = 
                  context.getServiceReference(HelloService.class.getName());

Is this reference really going to fail because its scope is outside the composite?

What if a component inside the composite contains a reference to a service published outside the composite? Is this reference also going to fail?

Note: I am not interested in the imported or exported services for the moment.

Answer 1

iPOJO composite relies on the iPOJO Service Context. In iPOJO the regular OSGi bundle context is composed by two parts: the bundle-centric part responsible for a class loading activities and the service-centric part responsible for all service interactions (publication, lookup, binding...).

When an instance runs inside a composite it as a 'local' service context, using a local service registry (the one from the composite). So services registered from inside the composite are not accessible from from outside as they are using two different service registries: the composite's one and the one from the OSGi framework.