Monitoring change of a field

Question

Hi,
I'm working on a Tic Tac Toe game. For the undo move feature I have a stack:
LinkedList<Tuple<Integer, Integer>> stack; //The integers are X and Y coordinatesNow, the undo algorithm doesn't work exactly as expected and I need to debug it. I would like to monitor every change to the stack field and on each change print out the contents of the stack and tuple variables. How can I achieve that? Do I have to implement some kind of observer pattern?
Thanks,
PR.

Answer 1

YoungWinston wrote:
Aardenon wrote:
Now, the undo algorithm doesn't work exactly as expected and I need to debug it. I would like to monitor every change to the stack field and on each change print out the contents of the stack and tuple variables. How can I achieve that? Do I have to implement some kind of observer pattern?What Kayaman said. One possibility might be to actually store the game state in a Stack after each move, viz:Stack<LinkedList<Tuple<Integer, Integer>>> gameState;that way, you can "undo" with a simple pop().That is what I am trying to do. I'm recording all moves in the stack and I want to reverse (pop) the moves on each undo, only it reverses the moves in a different order.
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I think I might add a class that wraps the LinkedList first though.What for?
I have another related question: Why can't I see all the methods of the LinkedList class in all situations. The stack field is declared private, I can access it's push, peek, poll, pop methods from the enclosing class, but when I try to access these methods from another class through a getStack() method, these methods are unavailable. Why is that, what would I have to do to get access to these methods. Perhaps this is why the undo doesn't work quite right, because I use push() in one place and add() in another.
PR.