PHPMD\PHPMD::setFileExtensions PHP Method

    public function setFileExtensions(array $fileExtensions)
    {
        $this->fileExtensions = $fileExtensions;
    }

 public function run($files)
 {
     $resultFile = tempnam(sys_get_temp_dir(), 'phpmd');
     $renderer = new JSONRenderer();
     $renderer->setWriter(new StreamWriter($resultFile));
     $ruleSetFactory = new RuleSetFactory();
     $phpmd = new PHPMD();
     if (isset($this->config['config']['file_extensions'])) {
         $phpmd->setFileExtensions(explode(',', $this->config['config']['file_extensions']));
     }
     $rulesets = Runner::RULESETS;
     if (isset($this->config['config']['rulesets'])) {
         $rulesets = $this->prefixCodeDirectory($this->config['config']['rulesets']);
     }
     $phpmd->processFiles(implode(",", $files), $rulesets, array($renderer), $ruleSetFactory);
     return $resultFile;
 }