private function createLinksBetweenArtifacts(PFUser $user, Tracker_XML_Importer_ArtifactImportedMapping $artifacts_imported_mapping, Tracker_Artifact $root_artifact)
 {
     $comment_message = '';
     $send_notifications = false;
     $original_id = $artifacts_imported_mapping->getOriginal($root_artifact->getId());
     $children = $this->children_collector->getChildrenForParent($original_id);
     if (!$children) {
         return;
     }
     foreach ($children as $key => $original_child_id) {
         $children[$key] = $artifacts_imported_mapping->get($original_child_id);
     }
     $field_id = $root_artifact->getAnArtifactLinkField($user)->getId();
     $fields_data = array($field_id => array(Tracker_FormElement_Field_ArtifactLink::NEW_VALUES_KEY => implode(',', $children)));
     $root_artifact->createNewChangeset($fields_data, $comment_message, $user, $send_notifications, Tracker_Artifact_Changeset_Comment::TEXT_COMMENT);
     foreach ($children as $child_id) {
         $artifact = $this->artifact_factory->getArtifactById($child_id);
         $this->createLinksBetweenArtifacts($user, $artifacts_imported_mapping, $artifact);
     }
 }
 public function userCanSearchOnArtifact(User $user, Tracker_Artifact $artifact)
 {
     return $artifact->getTracker()->getTitleField() !== null && $artifact->getTracker()->getTitleField()->userCanRead($user) && $artifact->getAnArtifactLinkField($user) !== null;
 }