protected void buildIndexMap(RootDoc root)  {
        PackageDoc[] packages = root.specifiedPackages();
        ClassDoc[] classes = root.classes();
        if (!classesOnly) {
            if (packages.length == 0) {
                Set<PackageDoc> set = new HashSet<PackageDoc>();
                PackageDoc pd;
                for (int i = 0; i < classes.length; i++) {
                    pd = classes[i].containingPackage();
                    if (pd != null && pd.name().length() > 0) {
                        set.add(pd);
                    }
                }
                adjustIndexMap(set.toArray(packages));
            } else {
                adjustIndexMap(packages);
            }
        }
        adjustIndexMap(classes);
        if (!classesOnly) {
            for (int i = 0; i < classes.length; i++) {
                if (shouldAddToIndexMap(classes[i])) {
                    putMembersInIndexMap(classes[i]);
                }
            }
        }
        sortIndexMap();
    }