/* (non-Javadoc)
  * @see org.eclipse.wst.jsdt.internal.ui.typehierarchy.TypeHierarchyContentProvider#getRootTypes(java.util.List)
  */
 protected final void getRootTypes(List res) {
   ITypeHierarchy hierarchy = getHierarchy();
   if (hierarchy != null) {
     IType input = hierarchy.getType();
     if (input == null) {
       IType[] classes = hierarchy.getRootClasses();
       for (int i = 0; i < classes.length; i++) {
         res.add(classes[i]);
       }
     } else {
       IType[] roots = hierarchy.getRootClasses();
       for (int i = 0; i < roots.length; i++) {
         if (isObject(roots[i])) {
           res.add(roots[i]);
           return;
         }
       }
       res.addAll(Arrays.asList(roots)); // something wrong with the hierarchy
     }
   }
 }