Custom providers and listing query types

These are different extension axes:

• A provider teaches JSF where a renderer lives and how to produce its AJAX replacement.
• A query type teaches the native JSF Listing how to fetch and identify items from another data source.

Prefer a query type when the native JSF Listing/card renderer is suitable. Create a provider only when the target renderer itself is unsupported.

Register a provider

The provider base class is loaded immediately before the registration action, so require the subclass inside that action: