@Override
  public TreeElement addInternal(TreeElement first, ASTNode last, ASTNode anchor, Boolean before){
    if (first == last && first.getElementType() == JavaElementType.TYPE){
      if (getLastChildNode() != null && getLastChildNode().getElementType() == TokenType.ERROR_ELEMENT){
        super.deleteChildInternal(getLastChildNode());
      }
    }

    final CharTable treeCharTab = SharedImplUtil.findCharTableByTree(this);

    if (getFirstChildNode()== null || getFirstChildNode().getElementType() != JavaTokenType.LT){
      TreeElement lt = Factory.createSingleLeafElement(JavaTokenType.LT, "<", 0, 1, treeCharTab, getManager());
      super.addInternal(lt, lt, getFirstChildNode(), Boolean.TRUE);
    }
    if (getLastChildNode() == null || getLastChildNode().getElementType() != JavaTokenType.GT){
      TreeElement gt = Factory.createSingleLeafElement(JavaTokenType.GT, ">", 0, 1, treeCharTab, getManager());
      super.addInternal(gt, gt, getLastChildNode(), Boolean.FALSE);
    }

    if (anchor == null){
      if (before == null || before.booleanValue()){
        anchor = findChildByRole(ChildRole.GT_IN_TYPE_LIST);
        before = Boolean.TRUE;
      }
      else{
        anchor = findChildByRole(ChildRole.LT_IN_TYPE_LIST);
        before = Boolean.FALSE;
      }
    }

    final TreeElement firstAdded = super.addInternal(first, last, anchor, before);

    if (first == last && first.getElementType() == JavaElementType.TYPE) {
      JavaSourceUtil.addSeparatingComma(this, first, TYPE_SET);
    }

    return firstAdded;
  }
@Override
  public TreeElement addInternal(TreeElement first, ASTNode last, ASTNode anchor, Boolean before)