code: @Nullable
    public static String getURLString (@Nullable final String sPath,
                                       @Nullable final List <? extends URLParameter> aQueryParams,
                                       @Nullable final String sAnchor,
                                       @Nullable final IEncoder <String, String> aQueryParameterEncoder)
    {
      return getURLString (sPath, getQueryParametersAsString (aQueryParams, aQueryParameterEncoder), sAnchor);
    }
docs: Get the final representation of the URL using the specified elements.
  
  @param sPath
  The main path. May be <code>null</code>.
  @param aQueryParams
  The list of query parameters to be appended. May be
  <code>null</code> .
  @param sAnchor
  An optional anchor to be added. May be <code>null</code>.
  @param aQueryParameterEncoder
  The parameters encoding to be used. May be <code>null</code>.
  @return May be <code>null</code> if path, anchor and parameters are
  <code>null</code>.