cT2Qrj7d

1import javax.swing.*;
2import java.sql.*;
3import java.util.Vector;
4
5public class HighscoreDB {
6
7    private static final String SCORE_TABLE = "scores";
8
9
10    private Connection conn;
11
12
13    /** Default constructor **/
14    public HighscoreDB() {
15
16        // connect to the database
17        createConnection();
18        // initialize the score table
19        initializeScoreTable();
20    }
21
22    /************************** Overridden Methods **************************/
23
24    /****************************** Accessors *******************************/
25
26    /****************************** Mutators ********************************/
27
28    /**************************** Other Methods *****************************/
29
30    /**
31     * Add a score to the database.
32     * @param name the person who got the score
33     * @param score the score value
34     * @param difficulty the game difficulty level. Must be one of <code>Game.EASY</code>, <code>Game.MEDIUM</code>,
35     *        or <code>Game.HARD</code>.
36     * @return <code>true</code> if the score was successfully added, <code>false</code> otherwise.
37     */
38    public boolean addScore(String name, int score, int difficulty) {
39
40        try {
41
42            // prepare an sql statement to insert the score
43            PreparedStatement prep = conn.prepareStatement(String.format("INSERT INTO %s VALUES (?, ?, ?);", SCORE_TABLE));
44
45            // bind the correct values
46            prep.setString(1, name);
47            prep.setInt(2, score);
48            prep.setInt(3, difficulty);
49            prep.addBatch();
50
51            // execute the statement
52            conn.setAutoCommit(false);
53            prep.executeBatch();
54            conn.setAutoCommit(true);
55
56            return true;
57
58        } catch (SQLException e) {
59
60            // failed to add score
61            return false;
62        }
63    }
64
65    /**
66     * Gets a list of scores obtained on the specified difficulty.
67     * @param difficulty the game difficulty level. Must be one of <code>Game.EASY</code>, <code>Game.MEDIUM</code>,
68     *        or <code>Game.HARD</code>.
69     * @return a <code>Vector</code> of <code>Vector</code>s of <code>Object</code>s
70     */
71    public Vector<Vector<Object>> getScores(int difficulty) {
72
73        try {
74
75            // create and execute a statement to find a list of scores matching the given difficulty, sorted in
76            // descending order by score.
77            Statement stat = conn.createStatement();
78            ResultSet rs = stat.executeQuery(String.format("SELECT * FROM %s WHERE difficulty = %d ORDER BY score DESC",
79                    SCORE_TABLE, difficulty));
80
81            // create the vector to store the scores
82            Vector<Vector<Object>> scores = new Vector<Vector<Object>>();
83
84            // loop through all the results and add them to the scores vector
85            while (rs.next()) {
86                Vector<Object> row = new Vector<Object>();
87                row.add(rs.getString("name"));
88                row.add(rs.getInt("score"));
89                scores.add(row);
90            }
91
92            // return the vector
93            return scores;
94
95        } catch (SQLException e) {
96
97            // error getting the scores, return null
98            return null;
99        }
100    }
101
102    /**
103     * Create a connection to the scores db.
104     */
105    private void createConnection() {
106
107        try {
108
109            // attempt to load the sqlite manager class
110            Class.forName("org.sqlite.JDBC");
111            // create the connection
112            conn = DriverManager.getConnection("jdbc:sqlite:scores.db");
113
114        } catch (ClassNotFoundException e) {
115
116            // couldn't find the driver for sqlite
117            JOptionPane.showMessageDialog(null, "Failed to find sqlite driver. Cannot display highscores", "Error", JOptionPane.ERROR_MESSAGE);
118
119        } catch (SQLException e) {
120
121            // couldn't connect to database
122            JOptionPane.showMessageDialog(null, "Failed to connect to score database. Cannot display highscores", "Error", JOptionPane.ERROR_MESSAGE);
123        }
124    }
125
126    /**
127     * Create the scores table if it doesn't exist.
128     */
129    private void initializeScoreTable() {
130
131        try {
132            Statement stat = conn.createStatement();
133            stat.executeUpdate("CREATE TABLE IF NOT EXISTS " + SCORE_TABLE + " (name TEXT, score INTEGER, difficulty INTEGER);");
134
135        } catch (SQLException e) {
136
137            JOptionPane.showMessageDialog(null, "Could not create score table.", "Error", JOptionPane.ERROR_MESSAGE);
138        }
139    }
140}