protected final void loadChildren(DynamicNode node) throws DbException {
    if (node.hasLoaded() || node.isLeaf()) return;
    node.setHasLoaded();
    Object userObject = node.getUserObject();
    if (userObject == ROOT) return;
    SrVector children = new SrVector(10);
    boolean isSorted = true;
    DbObject dbParent = null;
    if (userObject == DB_RAM) {
      Db[] dbs = Db.getDbs();
      for (int i = 0; i < dbs.length; i++) {
        if (dbs[i] instanceof DbRAM) insertProjects(children, dbs[i]);
      }
    } else if (userObject instanceof Db) {
      insertProjects(children, (Db) userObject);
    } else {
      dbParent = (DbObject) userObject;
      dbParent.getDb().beginTrans(Db.READ_TRANS);
      insertComponents(children, dbParent);
      isSorted = childrenAreSorted(dbParent);
      dbParent.getDb().commitTrans();
    }

    if (isSorted) {
      children.sort(getComparator(dbParent));
    }

    ArrayList groupNodeList = new ArrayList();
    DynamicNode groupNode = null;
    Enumeration enumeration = children.elements();
    while (enumeration.hasMoreElements()) {
      DynamicNode childNode = (DynamicNode) enumeration.nextElement();
      GroupParams group = childNode.getGroupParams();
      if (group.name == null) {
        node.add(childNode);
      } else {
        if (groupNode == null) {
          groupNode = createGroupNode(group);
          node.add(groupNode);
          groupNodeList.add(groupNode);
        } else if (!groupNode.toString().equals(group.name)) {
          boolean groupFound = false;
          for (int i = 0; i < groupNodeList.size(); i++) {
            groupNode = (DynamicNode) groupNodeList.get(i);
            if (groupNode.toString().equals(group.name)) {
              groupFound = true;
              break;
            }
          }
          if (!groupFound) {
            groupNode = createGroupNode(group);
            node.add(groupNode);
            groupNodeList.add(groupNode);
          }
        }
        groupNode.add(childNode);
      }
    }
    groupNodeList.clear();
  }
  private DbJVPackage importJarFile(
      File jarFile,
      DbJVPackage topMostPackage,
      Controller controller,
      int startJobDone,
      int endJobDone)
      throws DbException {
    DbJVClass dbClass;
    String filename = jarFile.getName();

    try {
      ZipFile zip = new ZipFile(jarFile);
      int i = 0, nb = zip.size();
      int span = endJobDone - startJobDone;

      for (Enumeration<?> e = zip.entries(); e.hasMoreElements(); ) {
        int jobDone = startJobDone + (i * span) / nb;

        ZipEntry entry = (ZipEntry) e.nextElement();
        String entryName = entry.getName();
        int idx = entryName.lastIndexOf('.');
        String ext = (idx == -1) ? null : entryName.substring(idx + 1);
        if ("class".equals(ext)) {
          InputStream is = zip.getInputStream(entry);

          ClassParser parser = new ClassParser(is, filename);
          JavaClass claz = parser.parse();
          dbClass = importClass(claz, controller);

          if (dbClass != null) {
            DbJVPackage pack = (DbJVPackage) dbClass.getCompositeOfType(DbJVPackage.metaClass);
            topMostPackage = findTopMostPackage(topMostPackage, pack);
            addToImportedPackage(pack);
          } // end if
        } // end if

        // check job done
        controller.checkPoint(jobDone);
        i++;

        // stop to reverse engineer if user has cancelled
        boolean finished = controller.isFinalState();
        if (finished) {
          break;
        }
      } // end for

      zip.close();

    } catch (IOException ex) {
      controller.println(ex.toString());
      dbClass = null;
    }

    return topMostPackage;
  } // end importClassFile()
 protected final void updateInsertIndexInChildrenOfNode(DynamicNode parentNode)
     throws DbException {
   Enumeration childrenEnum = parentNode.children();
   while (childrenEnum.hasMoreElements()) {
     DynamicNode node = (DynamicNode) childrenEnum.nextElement();
     DbObject dbo = (DbObject) node.getRealObject();
     DbObject dbParent = dbo.getComposite();
     node.insertIndex = getSequence(dbParent, dbo);
   }
 }