public void addComment(Comment comment){
  assertNotNull(comment);
  if (comments == null) {
    comments=new TreeSet<Comment>(new AstNode.PositionComparator());
  }
  comments.add(comment);
  comment.setParent(this);
}

public void addComment ( Comment comment ) { assertNotNull ( comment ) ; if ( comments == null ) { comments = new TreeSet < Comment > ( new AstNode . PositionComparator ( ) ) ; } comments . add ( comment ) ; comment . setParent ( this ) ; }
add a comment to the comment set .
