public function getWords($fileId = null, $tokenizer = null)
    {
        if(!$tokenizer) { 
            $tokenizer = new GeneralTokenizer();
        }
        $fileIds = [];
        if(empty($fileId)) { 
            $fileIds = $this->getFileIds();
        } else {
            $fileIds = [$fileId];
        }
        
        $words = [];
        foreach($fileIds as $filename )
        {
            $content = file_get_contents($this->getPackage()->getInstallationPath().$filename);
            $words = array_merge($words, $tokenizer->tokenize($content));
            unset($content);
        }
        return $words;
    }