private void buildTree(PdfObject structTreeRootObj){
  root=doc.createElement("TaggedPDF-doc");
  doc.appendChild(root);
  traverseContentTree(structTreeRootObj);
}

private void buildTree ( PdfObject structTreeRootObj ) { root = doc . createElement ( "TaggedPDF-doc" ) ; doc . appendChild ( root ) ; traverseContentTree ( structTreeRootObj ) ; }
scan down pdf struct object , creating xml tree
