Maintain solutions found using a listener

[Corallus]

Hi,

For my study I have to create a puzzle in java, which is almost done, but I have come across 1 problem.

I have a button in the GUI, which says compute solutions which activates this code:

BacktrackSolver solver = new BacktrackSolver(puzzle);
maintainer = new Maintainer();
solver.setListener(maintainer);
solver.findAll();
nextSolutionButton.setEnabled(true);

The maintainer has to maintain all the solutions found so far. When a solution is found in the BackTrackSolver the puzzle (solved) is sent to the listener (Maintainer in this case) by the following code:

listener.solutionFound(nSolutionsFound, puzzle);

solutionsFound in the Maintainer looks like this:

public void solutionFound(int solutionNumber, Puzzle puzzle) {
    solutions.add(puzzle);
}

where solutions is an ArrayList with all solutions.

When I textually print the puzzle in the solutionsFound method, the puzzle is printed as being solved (so correct), but when I try to get a solution form the ArrayList in another method of the Maintainer, I get the puzzle, but unsolved. So for instance in the GUI I have a "next solution" button with:

puzzle = maintainer.nextSolution();

Which returns the solved puzzle, but the puzzle is not solved anymore, so somehow the puzzle was not saved well?

Anyone know why this is and maybe how I can solve this?

Thanks in advance

[Fubarable]

It suggests to me that perhaps you have more than one Maintainer object, but I'm not sure we can tell precisely what is wrong based on the information presented. You may need to tell us and show us more.

Oh, and welcome to Java-Forums.org!! :)

[Corallus]

Thanks for the quick response! I edited my post to be more precise

[JosAH]

If your backtracking solver modifies your puzzle you should save a copy of the puzzle in your Maintainer object. Now it seems you're just saving a reference to a puzzle.

kind regards,

Jos

[Corallus]

So I have to implement a clone method for all the classes of the model used by the puzzle?

[Fubarable]

I'm not sure that this will fully solve your problem. I still suspect that you have more than one Maintainer object, that one is filled with solutions and the other not, but again, I can't tell based on the code posted.

[Corallus]

Thanks for helping me out. I am probably going to solve the issue by serializing the puzzle.