public void setAggregateContext(IAggregateContext aggregateContext) {
   this.aggregateContext = aggregateContext;
   for (AggregatorListener listener : getAggregatorListeners()) {
     listener.setAggregateContext(aggregateContext);
   }
 }
 public void onAggregate(IAggregation aggregate) {
   this.aggregate = aggregate;
   for (AggregatorListener listener : getAggregatorListeners()) {
     listener.onAggregate(aggregate);
   }
 }