/**
  * Tests if an entry exists in the cache.
  *
  * @param string $id The cache id of the entry to check for.
  *
  * @return bool TRUE if a cache entry exists for the given cache id, FALSE otherwise.
  */
 protected function doContains($id)
 {
     $e = $this->getStopwatchEvent(__FUNCTION__);
     $result = parent::doContains($id);
     if ($e) {
         $e->stop();
     }
     return $result;
 }