setParentProperty

public void setParent(){

    for (int x = 0; x < datas.size(); x++){
        Person person = datas.get(x);
        general.add(person);
        children.add(0);
        person.setChildrenVisible(false);
        Friend[] friends = person.getFriends();
        for (int y = 0; y < friends.length; y++){
            Friend f = friends[y];
            f.setParentID(String.valueOf(x));
        }
    }
}