Currently, ServiceDiscovery plugin relies on injecting tigase.xmpp.impl.ServiceDiscovery.AccountServiceProvider (only PEP from tigase-pubsub supports it) and if it present it forward query to the PEP plugin/pubsub for processing.

It would be better to make the logic extensible and allow creating multiple provider implementations and call them to add particular features to service discovery and combine the result in one request. It would simplify the processing logic and give us more flexibility.