public static void ajaxFormEdit(Long documentId) {
   Serializer serializer = Serializer.getInstance();
   renderJSON(serializer.getDocumentLastVersion(documentId));
 }
 /*
  * List all documents
  */
 public static void ajaxAllDocuments() {
   Serializer serializer = Serializer.getInstance();
   renderJSON(serializer.getAllDocuments());
 }
 /*
  * List only requested documents
  */
 public static void ajaxRequestDocuments(Long[] documentIds) {
   Serializer serializer = Serializer.getInstance();
   renderJSON(serializer.getDocuments(documentIds));
 }
 public static void ajaxBuildTree() {
   DocumentRootJSON root = new DocumentRootJSON("Documents");
   Serializer serializer = Serializer.getInstance();
   serializer.buildNode(0L, root);
   renderJSON(root);
 }