aggregatorProvider = new AggregatorProvider(config.getAggregators());
artifactHandlers = Collections.unmodifiableList(config.getHandlers());
// init root node
Aggregator rootAggregator = rootNode.getDepth() == 0
? new RootAggregator()
: getAggregator(rootNode, null);
root = new AggregateImpl(this, rootNode.getPath(), rootAggregator);
// setup node types
initNodeTypes();