public ClusterNode elect(List<ClusterNode> candidates) 
{
      InetSocketAddress sockAddress = this.preferredMaster;
      ClusterNode master = null;
      // If preferred master is defined and contained in cluster, return it
      if (sockAddress != null) 
      {
         InetAddress address = sockAddress.getAddress();
         int port = sockAddress.getPort();
         // First find by address
         master = this.find(candidates, address.getHostAddress(), port);
         if (master == null)
         {
            // Then try by hostname
            master = this.find(candidates, address.getHostName(), port);
         }
      }
      return (master != null) ? master : super.elect(candidates);
}

 public String getPreferredMaster() 
{
      InetSocketAddress address = this.preferredMaster;
      return (address != null) ? address.toString() : null;
}

 public  void setPreferredMaster(String value) 
{
      String node = (value != null) ? value.trim() : "";
      if (node.length()  > 0)
      {
         try
         {
            URI uri = new URI("cluster://" + node);
            String host = uri.getHost();
            if (host == null)
            {
               throw new IllegalArgumentException("Cannot extract host/address from " + node);
            }
            this.preferredMaster = new InetSocketAddress(InetAddress.getByName(host), uri.getPort());
         }
         catch (URISyntaxException e)
         {
            throw new IllegalArgumentException("Cannot extract URI from " + node, e);
         }
         catch (UnknownHostException e)
         {
            throw new IllegalArgumentException("Cannot resolve host from " + node, e);
         }
      }
      else
      {
         this.preferredMaster = null;
      }
}