public function load()
    {
        if (!isset($this->cache[$this->testSessionId])) {
            $encodedData = $this->getStorageService()->get($this->getUserKey(), $this->getStorageKey());
            \common_Logger::d(sprintf('QtiTimer: Loaded %d bytes from state storage', strlen($encodedData)));

            $this->cache[$this->testSessionId] = $this->getStorageFormat()->decode($encodedData);
        }

        return $this->cache[$this->testSessionId];
    }