protected function loadFromCache()
    {
        $this->log->debug("Load from cache file {$this->filePath}");
        $data = $this->getDataFromFile();
        if ($data === false) {
            $data = '';
        }

        // validate data through parser
        if (!$this->isDataValid($data)) {
            $this->addError($this->filePath, 'Data not valid according to parser');

            return false;
        }

        // verify if local cache is expired
        if ($this->isCacheExpired()) {
            $this->addError($this->filePath, 'Local cache is expired');

            return false;
        }

        return true;
    }