code: protected List<Object> getParameters(GString gstring) {
          return new ArrayList<Object>(Arrays.asList(gstring.getValues()));
      }
docs: Hook to allow derived classes to override behavior associated with
  extracting params from a GString.
  
  @param gstring a GString containing the SQL query with embedded params
  @return extracts the parameters from the expression as a List
  @see #expand(Object)