public Collection<? extends GenericTarget> defaultFederationTargets() {
        if (sources.getComponents().isEmpty()) {
            return List.of(this);
        } else {
            return sources.getComponents();
        }
    }
Base config producer for search chains that communicate with backends.

@author Tony Vaagenes
config-model/src/main/java/com/yahoo/vespa/model/container/search/searchchain/Provider.java