code: public final URL getUrl(final Operation op) throws TransportException {
          try {
              return new URL(url.toExternalForm() + "?operation=" + op.getName());
          } catch (MalformedURLException e) {
              throw new TransportException(e);
          }
      }
docs: Returns the <tt>URL</tt> for the given operation.
  
  @param op
  the operation.
  @return the <tt>URL</tt> for the given operation.
  @throws TransportException
  if the generated <tt>URL</tt> is malformed.