code: public Tunnel getTunnel( String destinationHostname, int destinationPort ) {
          // might be better to cache, but dont anticipate massive numbers
          // of tunnel connections...
          for ( TunnelConnection tunnelConnection : tunnelConnections ) {
              Tunnel tunnel = tunnelConnection.getTunnel(
                      destinationHostname, destinationPort );
              if ( tunnel != null ) {
                  return tunnel;
              }
          }
          return null;
      }
docs: Returns the tunnel matching the supplied values, or <code>null</code> if
  there isn't one that matches.
  
  @param destinationHostname
  The tunnels destination hostname
  @param destinationPort
  The tunnels destination port
  
  @return The tunnel matching the supplied values
  
  @see com.pastdev.jsch.tunnel.TunnelConnection#getTunnel(String, int)