code: protected void checkContextURL(ODataRequestContext requestContext, Option<String> contextURL)
              throws ODataRenderException {
  
          if (!contextURL.isDefined()) {
              throw new ODataRenderException(
                      String.format("Not possible to create context URL for request %s", requestContext));
          }
      }
docs: Check whether the given 'Context URL' is defined.
  
  @param requestContext The 'Request Context' used to build the given 'Context URL'.
  @param contextURL     The given 'Context URL'.
  @throws ODataRenderException if the 'Context URL' is not defined