private List<ResolveResult> getTargets(Set<String> sources, Properties properties) {
        return sources.isEmpty() ?
                defaultSearchChains(properties):
                resolveSources(sources, properties);
    }
TODO This is probably a dirty hack for bug 4711376. There are probably better ways.
But I will leave that to trd-processing@

@param group the merging hitgroup to be updated if necessary
@param orderer the per provider hit orderer
@return he hitorderer chosen
container-search/src/main/java/com/yahoo/search/federation/FederationSearcher.java