code: void setPageAction(PdfName actionType, PdfAction action, int page) throws PdfException {
          if (!actionType.equals(PAGE_OPEN) && !actionType.equals(PAGE_CLOSE))
              throw new PdfException("Invalid page additional action type: " + actionType.toString());
          PdfDictionary pg = reader.getPageN(page);
          PdfDictionary aa = (PdfDictionary)PdfReader.getPdfObject(pg.get(PdfName.AA), pg);
          if (aa == null) {
              aa = new PdfDictionary();
              pg.put(PdfName.AA, aa);
              markUsed(pg);
          }
          aa.put(actionType, action);
          markUsed(aa);
      }
docs: Sets the open and close page additional action.
  @param actionType the action type. It can be <CODE>PdfWriter.PAGE_OPEN</CODE>
  or <CODE>PdfWriter.PAGE_CLOSE</CODE>
  @param action the action to perform
  @param page the page where the action will be applied. The first page is 1
  @throws PdfException if the action type is invalid