_delay = delay;
_period = period;
// health stats pipeline
_healthStatsAggregationPipeline = new Pipeline();
_healthStatsAggregationPipeline.addStage(new ReadHealthDataStage());
StatsAggregationStage statAggregationStage = new StatsAggregationStage();
_healthStatsAggregationPipeline.addStage(statAggregationStage);
_alertItemCollection = statAggregationStage.getClusterAlertMBeanCollection();
registerStageLatencyMonitor(_healthStatsAggregationPipeline);