code: @Nullable
    public static String getURLString (@Nullable final String sPath,
                                       @Nullable final List <? extends URLParameter> aQueryParams,
                                       @Nullable final String sAnchor,
                                       @Nullable final Charset aParameterCharset)
    {
      final IEncoder <String, String> aQueryParameterEncoder = aParameterCharset == null ? null
                                                                                         : new URLParameterEncoder (aParameterCharset);
      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 parameters to be appended. May be <code>null</code>.
  @param sAnchor
  An optional anchor to be added. May be <code>null</code>.
  @param aParameterCharset
  If not <code>null</code> the parameters are encoded using this
  charset.
  @return May be <code>null</code> if all parameters are <code>null</code>.