interface DataReferenceInterface

interface DataReferenceInterface {
    
    /**
     * Gets the referenced data.
     *
     * @return \Drupal\Core\TypedData\TypedDataInterface|null
     *   The referenced typed data object, or NULL if the reference is unset.
     */
    public function getTarget();
    
    /**
     * Gets the identifier of the referenced data.
     *
     * @return int|string|null
     *   The identifier of the referenced data, or NULL if the reference is unset.
     */
    public function getTargetIdentifier();

}