* @param structureTreeElement its parent structure element
*/
void addLinkContentItem(PDFLink link, PDFStructElem structureTreeElement) {
int structParent = getNextParentTreeKey();
link.setStructParent(structParent);
PDFDictionary contentItem = new PDFDictionary();
contentItem.put("Type", OBJR);
contentItem.put("Pg", this.currentPage);
contentItem.put("Obj", link);
parentTree.getNums().put(structParent, structureTreeElement);
structureTreeElement.addKid(contentItem);
}