code: private void requiredParameter(String value, String name, String description)
      throws WebApplicationException
    {
      if (value == null)
      {
        throw new WebApplicationException(
          Response.status(Response.Status.BAD_REQUEST).type(
          MediaType.TEXT_PLAIN).entity(
          "missing required parameter '" + name + "' (" + description + ")").
          build());
      }
    }
docs: Throw an exception if the parameter is missing.
  
  @param value Value which is checked for null.
  @param name The short name of parameter.
  @param description A one line description of the meaing of the parameter.