public List<AlertDefinition> getAggregateDefinitions(long clusterId) {
    if (!m_aggregateMap.containsKey(clusterId)) {
      return Collections.emptyList();
    }

    Map<String, AlertDefinition> map = m_aggregateMap.get(clusterId);
    return new ArrayList<>(map.values());
  }
Gets a copy of all of the aggregate definitions for the specified cluster.

@param clusterId
         the cluster ID
@return the list of all aggregate definitions
ambari-server/src/main/java/org/apache/ambari/server/state/alert/AggregateDefinitionMapping.java