@Override
    public void add(SearchChain searchChain) {
        assert !(searchChain instanceof Source);

        super.add(searchChain);

        if (searchChain instanceof Provider) {
            sourceGroups.addSources((Provider)searchChain);
        }
    }
Root config producer of the whole search chains model (contains searchchains and searchers).

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