/**
  * Class constructor
  *
  * @param $spec
  * @param array $options
  */
 public function __construct($spec, $options = null)
 {
     if (!isset($options['class'])) {
         $options['class'] = '';
     }
     $classes = explode(' ', $options['class']);
     $classes[] = 'btn btn-default';
     if (isset($options['buttonType']) && in_array($options['buttonType'], $this->buttons)) {
         $classes[] = 'btn-' . $options['buttonType'];
         unset($options['buttonType']);
     }
     if (isset($options['disabled'])) {
         $classes[] = 'disabled';
     }
     $classes = array_unique($classes);
     $options['class'] = trim(implode(' ', $classes));
     parent::__construct($spec, $options);
 }