code: protected function getMetaModel()
      {
          if (!$this->metaModel) {
              if ($this->metaModel === null) {
                  throw new \RuntimeException('No MetaModel instance set for ' . $this->strTable);
              }
          }
          return $this->metaModel;
      }
docs: Retrieve the MetaModel.
  
  @return IMetaModel
  
  @throws \RuntimeException When the MetaModel could not be retrieved.