com.scoredev.scores.HighScore.java Source code

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Here is the source code for com.scoredev.scores.HighScore.java

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/*
 * Copyright (c) 1995, 2008, Oracle and/or its affiliates. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle or the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.scoredev.scores;

import java.io.*;
import java.security.*;
import java.util.Hashtable;

public class HighScore {
    private String gameName;
    private File highScoreFile;

    public HighScore(String gameName) {
        this.gameName = gameName;

        AccessController.doPrivileged(new PrivilegedAction() {
            public Object run() {
                String path = System.getProperty("user.home") + File.separator + ".highscore";

                highScoreFile = new File(path);
                return null;
            }
        });
    }

    public void setHighScore(final int score) throws IOException {
        //check permission first
        SecurityManager sm = System.getSecurityManager();
        if (sm != null) {
            sm.checkPermission(new HighScorePermission(gameName));
        }

        // need a doPrivileged block to manipulate the file
        try {
            AccessController.doPrivileged(new PrivilegedExceptionAction() {
                public Object run() throws IOException {
                    Hashtable scores = null;
                    // try to open the existing file. Should have a locking
                    // protocol (could use File.createNewFile).
                    try {
                        FileInputStream fis = new FileInputStream(highScoreFile);
                        ObjectInputStream ois = new ObjectInputStream(fis);
                        scores = (Hashtable) ois.readObject();
                    } catch (Exception e) {
                        // ignore, try and create new file
                    }

                    // if scores is null, create a new hashtable
                    if (scores == null)
                        scores = new Hashtable(13);

                    // update the score and save out the new high score
                    scores.put(gameName, new Integer(score));
                    FileOutputStream fos = new FileOutputStream(highScoreFile);
                    ObjectOutputStream oos = new ObjectOutputStream(fos);
                    oos.writeObject(scores);
                    oos.close();
                    return null;
                }
            });
        } catch (PrivilegedActionException pae) {
            throw (IOException) pae.getException();
        }
    }

    /**
     * get the high score. return -1 if it hasn't been set.
     *
     */
    public int getHighScore() throws IOException, ClassNotFoundException {
        //check permission first
        SecurityManager sm = System.getSecurityManager();
        if (sm != null) {
            sm.checkPermission(new HighScorePermission(gameName));
        }

        Integer score = null;

        // need a doPrivileged block to manipulate the file
        try {
            score = (Integer) AccessController.doPrivileged(new PrivilegedExceptionAction() {
                public Object run() throws IOException, ClassNotFoundException {
                    Hashtable scores = null;
                    // try to open the existing file. Should have a locking
                    // protocol (could use File.createNewFile).
                    FileInputStream fis = new FileInputStream(highScoreFile);
                    ObjectInputStream ois = new ObjectInputStream(fis);
                    scores = (Hashtable) ois.readObject();

                    // get the high score out
                    return scores.get(gameName);
                }
            });
        } catch (PrivilegedActionException pae) {
            Exception e = pae.getException();
            if (e instanceof IOException)
                throw (IOException) e;
            else
                throw (ClassNotFoundException) e;
        }
        if (score == null)
            return -1;
        else
            return score.intValue();
    }

    public static void main(String args[]) throws Exception {
        HighScore hs = new HighScore(args[1]);
        if (args[0].equals("set")) {
            hs.setHighScore(Integer.parseInt(args[2]));
        } else {
            System.out.println("score = " + hs.getHighScore());
        }
    }
}