GUI Java Puzzle -- 2

I have an AI project which involves designing a futoshiki puzzle. The details are as follows - To complete the implementation of the text-based user interface to include the (as yet unimplemented) clear (i.e. reset the Futoshiki puzzle), undo (a single user entry), save (the state of the puzzle to a file) and load (the state of the puzzle from file) methods. You will need to make changes to all four user interface classes (Futoshiki UI, UserEntry, Assign and RelEntry) to achieve this. To design and implement a graphical user interface (GUI) for the Futoshiki model code that allows the user to assign cells, add relations between cells, undo user entries (both assignments and the addition of relations), clear the puzzle, save to, and load from file. At all times, the user should be protected from making illegal moves, and so e.g. provided with feedback on the possible number choices for a cell. The appearance of the interface is up to you, but an example is given in Figures 1 and 2. You should keep the user informed through the use of e.g. a status box, and may also consider the use of dialogue boxes where appropriate (such as file location selection). Develop a test plan and test the functionality of your classes. Write a report including design, testing and reflection. The report should not exceed 3000 words. I will provide you with four model classes - Futoshiki, Cell, Relation and Constraint; four user interface classes - Futoshiki UserEntry, Assign and RelEntry; plus a problem-specific exception class, Futoshiki Exception (all java files).