updateIndexState example

$topic = $section_plugin->renderTopicForSearch($item->topic_id, $language);
          if ($topic) {
            // Index the title plus body text.             $text = '<h1>' . $topic['title'] . '</h1>' . "\n" . $topic['text'];
            $words += $this->searchIndex->index($this->getType(), $item->sid, $langcode, $text, FALSE);
          }
        }
      }
    }
    finally {
      $this->searchIndex->updateWordWeights($words);
      $this->updateIndexState();
    }
  }

  /** * {@inheritdoc} */
  public function indexClear() {
    $this->searchIndex->clear($this->getType());
  }

  /** * Rebuilds the database table containing topics to be indexed. */