public static Map<Ring, Map<Host, Map<Domain, RuntimeStatisticsAggregator>>> computeRuntimeStatistics(Coordinator coordinator, RingGroup ringGroup) throws IOException { Map<Ring, Map<Host, Map<Domain, RuntimeStatisticsAggregator>>> result = new HashMap<Ring, Map<Host, Map<Domain, RuntimeStatisticsAggregator>>>(); for (Ring ring : ringGroup.getRings()) { result.put(ring, Rings.computeRuntimeStatistics(coordinator, ring)); } return result; }