eZ\Publish\Core\Search\Common\FieldValueMapper::map PHP Method

    public abstract function map(Field $field);

 /**
  * Map search field value to solr value using FieldValueMapper.
  *
  * @param mixed $value
  * @param \eZ\Publish\SPI\Search\FieldType $searchFieldType
  *
  * @return mixed
  */
 protected function mapSearchFieldValue($value, FieldType $searchFieldType = null)
 {
     if (null === $searchFieldType) {
         return $value;
     }
     $searchField = new SearchField('field', $value, $searchFieldType);
     $value = (array) $this->fieldValueMapper->map($searchField);
     return current($value);
 }