Due

Objectives

• to use Java's List classes to implement efficient solutions

Introduction

Imagine a project aimed at understanding what makes Tipover puzzles hard. Such a project may have use for a Tipover server that collects information related to how much difficulty humans have when solving puzzles. For this project, you will create a class that can maintain that information.

Assignment

Create a class called TipoverDatabase that keeps track of players and puzzles, with the puzzles grouped by some initial estimate of their difficulty (the data gathered will help determine if those initial estimates were correct). For each player, the database will store the player's password, the list of puzzles the player has solved, the time taken to solve them, and puzzles attempted but not solved. For each puzzle, the database will record the number of players who have attempted the puzzle, the number of players who have solved the puzzle, and the average time taken by all the players who have solved the puzzle. TipoverDatabase must have the following methods and constructors.

• TipoverDatabase(), a constructor to initialize an empty database;
• addPuzzle(String filename, int difficulty), which adds the puzzle of the given difficulty in the file with the given name to the database;
• boolean addPlayer(String name, String pass), which registers a new player with the given username and password and returns true or false according to whether the username was available or not;
• boolean verifyPassword(String name, String pass), which determines if there is a player registered with the given name and, if so, whether the given password is correct for that player;
• void changePassword(String name, String pass), which changes the password for the given existing player to the given value;
• List< String > getPuzzles(String name, int difficulty), which returns a list of filenames containing the puzzles of the specified difficulty that have not yet been attempted by the given player;
• void puzzleSolved(String username, String puzzleFile, int time), which updates the database to reflect that the player with the given username solved the given puzzle in the given amount of time (in seconds);
• void puzzleAbandoned(String username, String puzzleFile), which updates the database to reflect that the player with the given name has given up on the given puzzle;
• List< String > getPlayerStatistics(String username), which returns a list with one item for each puzzle giving the status (not attempted, abandoned, or solved [and in what time]) of that puzzle for the given player; and
• List< Number > getPuzzleStatistics(String filename), which returns a 3-item list containing the number of players who have attempted the puzzle in the file with the given name, the number of players who have solved it, and their average time (as a Double) in that order.

You may add methods to the required classes, and you can create more classes as you see fit. For example, if you decide you need a list of players and the data for them, you may decide to create a Player object. Similarly, you may wish to create a Puzzle object if you decide you need a list of puzzles and the required information about those puzzles.

Grading

• Execution: 80% for correct execution of the required methods.
• Comments and Style: 10% for comments including a comment describing each class and each method within each class. Comments for methods should give an overall description of what the method does and should explain the use of each argument as well as what value is returned, if any. Use of Javadoc comments is encouraged but not required. Variable names should be chosen wisely.
• Efficiency: 10% for efficient solutions and an explanation of why you chose the data structures you did (or an explanation of why it didn't matter which data structures you chose).

Advice

• You should think carefully about the other classes you will have to create. What fields will they have to have in order to keep the data that will be requested by the TipoverDatabase methods? What methods will they have to update that data?
• Test those extra classes you created before working on TipoverDatabase.
• Create TipoverDatabase last. You should write and test the methods a few at a time. addPlayer, would be a good place to start, followed by verifyPassword and setPassword, and after them addPuzzle and getPuzzles. Finally, write the puzzleSolved, puzzleAbandoned, getPlayerStatistics, and getPuzzleStatistics methods.

Submissions