辅导COMP303 MVC辅导留学生Java语言

练习MVC的设计模式。

Purpose

This mini assignment practices the MVC architectural style by refactoring an existing application to improve its design.

Question

Consider the code given with this assignment, which creates a small instance of the 2048 game (adapted from https://github.com/bulenkov/2048). I have partly extracted a Controller from the original code. Continue the refactoring to implement the MVC style by fully extracting the model, the controller, and the view. Once the refactoring is done, draw a UML sequence diagram showing what happens when the user makes a move.

Requirements

• Your final system should have at least the following three classes in their own files: GamePanel, GameModel, and Controller. Hint: The Controller class already exists inside Game2048. You need to move it to its own file and make all necessary adjustments.
• The class Tile, currently nested inside Game2048, may or may not be moved to its own file. This will be part of the decisions to take for this assignment.
• The main method can be extracted into its own Launcher class, or kept inside one of the other classes.
• You may use or not the Observer pattern. Both solutions are fine (assuming your design is consistent).
• You only need to modify the code so that it explicitly uses the MVC architecture. You do not need to correct all design or performance problems of this code. However, your modifications should not introduce new design problems (in particular, be careful with encapsulation).
• Some information (variables) will be needed by both the model and the view. It’s ok to have some duplication, as long as it makes sense: the model should only have variables (and methods) relevant to it, and the same applies to the view. The fact that there is some overlap between the two is normal.
• Your refactoring should not change the behavior of the program. In particular, do not add new functionalities (e.g., the ability to continue the game after 2048).
• I’m insisting that this is primarily a refactoring exercise: you should rely on existing methods as much as possible. If you find that you need to rewrite the whole program from scratch, you’re doing it wrong. (It may be tempting, but that’s not the point!)

Once you have finished refactoring the program, draw a UML sequence diagram showing what happens when the user makes a move to the left. Use a drawing software to draw your diagram (no hand drawing). Assume that there are only two tiles on the board before the move, and that they do not merge as a result of the move. Start your diagram at the method keyPressed in the Controller. Your diagram should show how pressing the left arrow updates the model and the view. You do not need to show any method that is not visible in your files (e.g., the internal methods of an array or other data structure), nor the internals of repaint() or paint(Graphics g).

What to hand in?

Submit the sequence diagram as a PDF file, and all your Java files.

How it will be graded?

• +10 - The result shows a correct implementation of the MVC style
• +5 - The result is functionally identical to the original system
• +5 - The result does not introduce new design flaws
• +5 - The sequence diagram correctly represents the refactored system