public void setAggregator(String aggregator) {
   try {
     this.aggregator = Aggregators.valueOf(aggregator);
   } catch (IllegalArgumentException iae) {
     throw new IllegalArgumentException(
         "Unable to load aggregator of "
             + aggregator
             + ".  Valid aggregators are "
             + Joiner.on(',').join(Aggregators.values()));
   }
 }
 @Override
 public int hashCode() {
   int result = riskLevelRules != null ? riskLevelRules.hashCode() : 0;
   result = 31 * result + (aggregator != null ? aggregator.hashCode() : 0);
   result = 31 * result + (aggregationConfig != null ? aggregationConfig.hashCode() : 0);
   return result;
 }