Allow modules to modify which object is being loaded.

includes/metadata.inc

@@ -20,6 +20,8 @@ function islandora_retrieve_metadata_markup(AbstractObject $object, $print = FAL
   $viewer = variable_get('islandora_metadata_display', 'dublin_core');
   $markup = '';
   if (isset($viewers[$viewer]['metadata callback'])) {
+    $hooks = islandora_build_hook_list(ISLANDORA_METADATA_OBJECT_ALTER, $object->models);
+    drupal_alter($hooks, $object);
     $markup = call_user_func($viewers[$viewer]['metadata callback'], $object, $print);
     // The callback doesn't have any markup provided for this particular object,
     // default back to the dublin_core display.
@@ -44,6 +46,8 @@ function islandora_retrieve_description_markup(AbstractObject $object) {
   $viewer = variable_get('islandora_metadata_display', 'dublin_core');
   $markup = '';
   if (isset($viewers[$viewer]['description callback'])) {
+    $hooks = islandora_build_hook_list(ISLANDORA_METADATA_OBJECT_DESCRIPTION_ALTER, $object->models);
+    drupal_alter($hooks, $object);
     $markup = call_user_func($viewers[$viewer]['description callback'], $object);
     // The callback doesn't have any markup provided for this particular object,
     // default back to the dublin_core display.

islandora.api.php

@@ -794,3 +794,25 @@ function hook_islandora_metadata_display_info() {
     ),
   );
 }
+
+/**
+ * Allows modifications to the object whose metadata is being rendered.
+ *
+ * @param AbstractObject $object
+ *   An AbstractObject representing an object within Fedora.
+ */
+function hook_islandora_metadata_object_alter(AbstractObject &$object) {
+  $this_other_object = islandora_object_load('awild:indirectionappears');
+  $object = $this_other_object;
+}
+
+/**
+ * Allows modifications to the object whose metadata is being rendered.
+ *
+ * @param AbstractObject $object
+ *   An AbstractObject representing an object within Fedora.
+ */
+function hook_islandora_metadata_object_description_alter(AbstractObject &$object) {
+  $this_other_object = islandora_object_load('awild:indirectionappears');
+  $object = $this_other_object;
+}

islandora.module

@@ -49,6 +49,8 @@ define('ISLANDORA_POST_INGEST_HOOK', 'islandora_ingest_post_ingest');
 define('ISLANDORA_PRE_PURGE_OBJECT_HOOK', 'islandora_pre_purge_object');
 define('ISLANDORA_POST_PURGE_OBJECT_HOOK', 'islandora_post_purge_object');
 define('ISLANDORA_UPDATE_RELATED_OBJECTS_PROPERTIES_HOOK', 'islandora_update_related_objects_properties');
+define('ISLANDORA_METADATA_OBJECT_ALTER', 'islandora_metadata_object');
+define('ISLANDORA_METADATA_OBJECT_DESCRIPTION_ALTER', 'islandora_metadata_object_description');
 
 // @todo Add Documentation.
 define('ISLANDORA_OBJECT_INGESTED_HOOK', 'islandora_object_ingested');