code: @Override
      public String getDatacenter(final InetAddress endpoint)
      {
          final NodeData nodeData = nodeDataMap.get(endpoint);
          return nodeData != null ? nodeData.datacenter
                  : defaultNodeData.datacenter;
      }
docs: Returns the name of the data center for the endpoint, or {@code UNKNOWN} if not known.
  
  @return the name of the data center for the endpoint, or {@code UNKNOWN} if not known