How to create hierarchical bookmarks?

ArrayList tree = new ArrayList();
tree.add(getDTO(1,"Root",0));
tree.add(getDTO(239,"Node-1",1));
tree.add(getDTO(242,"Node-2",239));
tree.add(getDTO(243,"Node-3",239));
tree.add(getDTO(244,"Node-4",242));
tree.add(getDTO(245,"Node-5",243));

Root
-----Node-1
------------Node-2
------------------Node-4
------------Node-3
------------------Node-5

In PDF terminology, bookmarks are referred to as outlines. Please take a look at the CreateOutlineTree example to find out how to create an outline tree as shown in this PDF:

Outline tree shown in the bookmarks panel

We start with the root of the tree:

PdfOutline root = writer.getRootOutline();

Then we add a branch:

PdfOutline movieBookmark = new PdfOutline(root,
    new PdfDestination(
        PdfDestination.FITH, writer.getVerticalPosition(true)),
        title, true);

To this branch, we add a leaf:

PdfOutline link = new PdfOutline(movieBookmark,
    new PdfAction(String.format(RESOURCE, movie.getImdb())),
    "link to IMDB");

And so on.

The key is to use PdfOutline and to pass the parent outline as a parameter when constructing a child outline.

There's also an example called BookmarkedTimeTable where we create the outline tree in a completely different way:

ArrayList> outlines =
    new ArrayList>();
HashMap map = new HashMap();
outlines.add(map);

In this case, map is the root object to which we can add branches and leaves. To create a hierarchy, you just need to add kids like this:

First level:

HashMap calendar = new HashMap();
calendar.put("Title", "Calendar");

Second level:

HashMap day = new HashMap();
day.put("Title", "Monday");
ArrayList> days =
    new ArrayList>();
days.add(day);
calendar.put("Kids", days);

Once we're finished, we add the outline tree to the PdfStamper like this:

stamper.setOutlines(outlines);

Note that PdfStamper is the class we need when we manipulate an existing PDF (as opposed to PdfWriter which is to be used when we create a PDF from scratch).

Third level:

HashMap hour = new HashMap();
hour.put("Title", "10 AM");
ArrayList> hours = new ArrayList>();
hours.add(hour);
day.put("Kids", hours);

And so on...