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COMP 202: Principles of Object-Oriented Programming II

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Home — Fall 2008

Homework #4: Hangman Refactored

Deadline: See Owlspace for due date.

Please note our README Guidelines and our submission instructions.

In Homework #1 and #2, you developed a Hangman game using the Model-View-Controller (MVC) design pattern. One of the benefits of the MVC pattern was that model and view were loosely coupled, and that the model or the view could be changed easily without impacting the other part very much.

We never actually proved this. In his paper OOP and the Janus Principle (cached locally), Joel C. Adams describes what he calls the Janus principle:

Design and write object-oriented applications so that they support multiple, reuseable, user interfaces with minimal redundant coding.

Adams argues that requiring multiple views (or models) forces developers to abandon the tight coupling that might still be there even if MVC is used. This is the reason the Temperature Calculator had multiple views.

In this assignment, you will apply what you have learned from the Programming for Change lecture and the Temperature Calculator assignment to the old Hangman game. In particular, you will write a second view that uses the console for text input and output, and change the MVC architecture of the original Hangman game so that the controller and the model do not have to be changed for either view.

Most likely, you will find that your original implementation and even our solution to the Hangman homeworks were not as good as we all thought. We used the MVC pattern, but model and view were still rather tightly coupled. But really, that is to be expected: Object-oriented development and refactoring requires several incremental passes, and a perfectly decoupled system is still inachievable. Even experienced developers don't write perfect solutions. Don't let that stop you from writing a first implementation, and then come back to improve it.

Click here to run a demo of the Hangman Refactored project!

We have also provided you with stub code to give you a fair start, independent of your previous homeworks.

Here are the specifications for the refactored assignment, as well as some hints:

There are two views, the GUI view you have developed for homeworks #1 and #2, and a new text-based view.
There is a GUI "launcher frame"that allows you to select the view, and to add new ones using reflection (provided).
On the outside, the GUI view remains unmodified.

The text view should repeat the following steps:

Display the word, with dashes for letters not guessed.
Display the body parts that have been drawn.
Read a line of text input.
1. If it's the string "reset", reset the game.
2. If it's the string "quit", quit the game.
3. If it's just a single letter, guess that letter.
4. Otherwise, jump to step 2. and repeat.

Example:

Starting a new game!
Word: ------ -------- -----------
Type in a letter to guess, or 'reset' to reset the game, or 'quit' to quit.
o
Word: O----- O------- --o--------
Body parts: 
Type in a letter to guess, or 'reset' to reset the game, or 'quit' to quit.
x
Word: O----- O------- --o--------
Body parts: head
Type in a letter to guess, or 'reset' to reset the game, or 'quit' to quit.
b
Word: Ob---- O------- --o--------
Body parts: head
Type in a letter to guess, or 'reset' to reset the game, or 'quit' to quit.
j
Word: Obj--- O------- --o--------
Body parts: head
Type in a letter to guess, or 'reset' to reset the game, or 'quit' to quit.
y
Word: Obj--- O------- --o--------
Body parts: head torso
Type in a letter to guess, or 'reset' to reset the game, or 'quit' to quit.
xx
Body parts: head torso
Type in a letter to guess, or 'reset' to reset the game, or 'quit' to quit.

If the player won, display "You won!" and do not accept further guesses; however, keep repeating the loop to allow entry of "reset" or "quit".

Example:

Word: Object Oriented Progr-mming
Body parts: head torso
Type in a letter to guess, or 'reset' to reset the game, or 'quit' to quit.
a
You won!
Word: Object Oriented Programming
Body parts: head torso
Type in a letter to guess, or 'reset' to reset the game, or 'quit' to quit.
a
Word: Object Oriented Programming
Body parts: head torso
Type in a letter to guess, or 'reset' to reset the game, or 'quit' to quit.
z
Word: Object Oriented Programming
Body parts: head torso
Type in a letter to guess, or 'reset' to reset the game, or 'quit' to quit.

If the player lost, display "You lost! The answer is:" followed by the word, and do not accept further guesses; however, keep repeating the loop to allow entry of "reset" or "quit".

Example:

Word: ----- -----
You lost! The answer is: Tinky Winky
Body parts: head torso right arm left arm right leg left leg right foot left foot noose
Type in a letter to guess, or 'reset' to reset the game, or 'quit' to quit.
x
Word: ----- -----
You lost! The answer is: Tinky Winky
Body parts: head torso right arm left arm right leg left leg right foot left foot noose
Type in a letter to guess, or 'reset' to reset the game, or 'quit' to quit.

Consider what is different between the two views, and where it was handled in the old assignment:
- Input
- Output
Input was handled inside the view. In fact, you did not really have to deal with it very much in the old view.
Output was done in the view for the words, but the actual drawing of the body parts happened in the model.bodyPart package. Does that seem right?
In the Temperature Calculator, the conversion functions differed. What did we use to abstract out the differences in calculating the other temperatures?
It is almost always impossible to completely separate model and view. In the old Hangman, the view's Graphics object was passed to the model to draw the body parts. In this refactoring, something similar may happen, and that's acceptable.

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