+<?php
+
+namespace Drupal\libraries\ExternalLibrary\Type;
+
+use Drupal\libraries\ExternalLibrary\LibraryInterface;
+
+/**
+ * An interface for library types that want to react to library instantiation.
+ */
+interface LibraryLoadingListenerInterface {
+
+ /**
+ * Reacts to the instantiation of a library.
+ *
+ * @param \Drupal\libraries\ExternalLibrary\LibraryInterface $library
+ * The library that is being instantiated.
+ */
+ public function onLibraryLoad(LibraryInterface $library);
+
+}