public TopologyUpdateEvent deepCopy() {
    SortedMap<String, TopologyCluster> copiedClusters = new TreeMap<>();
    for (Map.Entry<String, TopologyCluster> topologyClusterEntry : getClusters().entrySet()) {
      copiedClusters.put(topologyClusterEntry.getKey(), topologyClusterEntry.getValue().deepCopyCluster());
    }
    TopologyUpdateEvent copiedEvent = new TopologyUpdateEvent(copiedClusters, getEventType());
    copiedEvent.setHash(getHash());
    return copiedEvent;
  }
Type of update, is used to differ full current topology (CREATE), adding new or update existing topology
elements (UPDATE) and removing existing topology elements (DELETE).
ambari-server/src/main/java/org/apache/ambari/server/events/TopologyUpdateEvent.java