code: protected function getFormatter()
      {
          if ($this->formatter) {
              return $this->formatter;
          }
  
          if (!$this->formatterFactory) {
              throw new RuntimeException("Please call setFormatterFactory() first.");
          }
  
          return $this->formatter = $this->formatterFactory->create();
      }
docs: Returns the formatter.
  
  @return Formatter