/**
  * Get search value for product attribute.
  *
  * @param CatalogProductAttribute $attribute
  * @return string
  */
 protected function getSearchValue(CatalogProductAttribute $attribute)
 {
     $searchValue = '';
     switch ($attribute->getFrontendInput()) {
         case 'Multiple Select':
         case 'Dropdown':
             foreach ($attribute->getOptions() as $option) {
                 if ($option['is_default'] == 'Yes') {
                     $searchValue = $option['admin'];
                 }
             }
             break;
         case 'Text Field':
             $searchValue = $attribute->getDefaultValueText();
             break;
         case 'Text Area':
             $searchValue = $attribute->getDefaultValueTextarea();
             break;
         case 'Date':
             $searchValue = $attribute->getDefaultValueDate();
             break;
         case 'Yes/No':
             $searchValue = $attribute->getDefaultValueYesno();
             break;
     }
     return $searchValue;
 }