public function getMetadataExtensionClassByMappedField($mappedFieldName)
    {
        $prefix = '';

        if (null != $data = $this->getDataForField($mappedFieldName, $this->columnDataName)) {

            switch (true) {

                case isset($data['fieldMappingExtensionClass']):
                    return $prefix.$data['fieldMappingExtensionClass'];

                case isset($this->propertyMetadataExtensionClass):
                    return $prefix.$this->propertyMetadataExtensionClass;
            }
        }

        return null;
    }