eZ\Publish\Core\Persistence\Legacy\Content\StorageHandler::getFieldData PHP Method

    public function getFieldData(VersionInfo $versionInfo, Field $field)
    {
        $storage = $this->storageRegistry->getStorage($field->type);
        if ($storage->hasFieldData()) {
            $storage->getFieldData($versionInfo, $field, $this->context);
        }
    }

 /**
  * Performs external loads for the fields in $content
  *
  * @param Content $content
  *
  * @return void
  */
 public function loadExternalFieldData(Content $content)
 {
     foreach ($content->fields as $field) {
         $this->storageHandler->getFieldData($content->versionInfo, $field);
     }
 }