public function registerCache(FrontendInterface $cache, $persistent = false) { $identifier = $cache->getIdentifier(); if (isset($this->caches[$identifier])) { throw new DuplicateIdentifierException('A cache with identifier "' . $identifier . '" has already been registered.', 1203698223); } $this->caches[$identifier] = $cache; if ($persistent === true) { $this->persistentCaches[$identifier] = $cache; } }