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:

We start with the root of the tree:

PdfOutline root = pdfDoc.getOutlines(false);

Then we add a branch:

PdfOutline movieBookmark = root.addOutline(title);
        movieBookmark.addAction(PdfAction.createGoTo(
                PdfExplicitDestination.createFitH(pdfDoc.getLastPage(),
                        pdfDoc.getLastPage().getPageSize().getTop())));

To this branch, we add a leaf:

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

And so on.

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

As it is shown above, iText 7 has an intuitive algorithm of adding outlines, no matter do you work with an existing document or create a new one. The depth of the bookmarks can be set to any desired value too. Here is a list of a few simple steps to solve your problem:

1. Create a list with bookmarks:

PdfOutline calendar = pdfDoc.getOutlines(false);

2. Set title:

calendar.setTitle("Calendar");

3. Add a new outline to the existing one:

PdfOutline date = calendar.addOutline("2011-10-12");

4. Repeat:

PdfOutline day = date.addOutline("Monday");
PdfOutline hour = day.addOutline("10 AM");
//and so on…

Take a note that the addOutline() method can take different input arguments:

• addOutline(PdfOutline outline)

• addOutline(String title)

• PdfOutline addOutline(String title, int position)

You can also add an action using addAction() (see CreateOutlineTree or BookmarkedTimeTable example).

Click How to create hierarchical bookmarks? | iText 5 PDF Development Guide if you want to see how to answer this question in iText 5.