/**
* Inserts more entries in the random numbers pool. Numbers are obtained from the QRBG service.
* The total amount of integers inserted can be calculated as ({@link #NUMBER_OF_BYTES}/4 * {@link
* #NUMBER_OF_REQUESTS}.
*
* @throws IOException If there is no Internet connectivity.
* @throws ServiceDeniedException If the QRBG account is not valid.
* @see <a href="http://random.irb.hr/">QRBG Service</a>
* @since 1.0
*/
private void insertMoreNumbersInPool() throws IOException, ServiceDeniedException {
QRBG source = new QRBG(SettingBusiness.getQRBGUsername(), SettingBusiness.getQRBGPassword());
for (int request = 0; request < NUMBER_OF_REQUESTS; request++) {
byte[] buffer = new byte[NUMBER_OF_BYTES];
source.getBytes(buffer, NUMBER_OF_BYTES);
Session session = HibernateUtil.getSession();
try {
session.beginTransaction();
for (int i = 0; i < (NUMBER_OF_BYTES - 4); i += 4) {
double randomNumber = QRBG.readInt(buffer, i);
if (randomNumber < 0) {
randomNumber *= -1;
}
randomNumber /= Integer.MAX_VALUE;
if (randomNumber != 0) {
session.save(new RandomNumber(randomNumber));
}
}
session.getTransaction().commit();
} catch (HibernateException ex) {
session.getTransaction().rollback();
Logger.getLogger(Database.class.getName()).log(Level.SEVERE, null, ex);
} finally {
HibernateUtil.closeSession(session);
}
}
}
/**
* Gets the given amount of random numbers from the random numbers pool. The effectiveness of this
* method depends on a proper configuration of a valid account on the QRBG service and an active
* Internet connection. Also, the QRBG service uses the port 1227. Make sure your firewall is
* configured properly.
*
* @param amount the amount of random numbers to get.
* @throws IOException If there is no Internet connectivity.
* @throws ServiceDeniedException If the QRBG account is not valid.
* @see <a href="http://random.irb.hr/">QRBG Service</a>
* @see RandomNumber
* @since 1.0
*/
public List<Double> getRandomNumbers(int amount) throws IOException, ServiceDeniedException {
List<RandomNumber> numbersList = getRandomNumbersFromPool(amount);
if (numbersList.size() < amount) {
insertMoreNumbersInPool();
numbersList = getRandomNumbersFromPool(amount);
}
List<Double> returnList = new ArrayList<Double>();
Session session = HibernateUtil.getSession();
try {
session.beginTransaction();
for (int i = 0; i < amount; i++) {
RandomNumber randomNumber = numbersList.get(i);
returnList.add(randomNumber.getValue());
session.delete(randomNumber);
}
session.getTransaction().commit();
} catch (HibernateException ex) {
session.getTransaction().rollback();
Logger.getLogger(Database.class.getName()).log(Level.SEVERE, null, ex);
} finally {
HibernateUtil.closeSession(session);
}
return returnList;
}
/**
* Gets a list of {@link RandomNumber} registries from the random numbers pool.
*
* @param amount the amount of random numbers to get from the pool.
* @return a list of random numbers from the pool. The resulting list has, at most, the number of
* elements given by <code>amount</code>.
* @see RandomNumber
* @since 1.0
*/
private List<RandomNumber> getRandomNumbersFromPool(int amount) {
Session session = HibernateUtil.getSession();
List<RandomNumber> numbersList = new ArrayList<RandomNumber>();
try {
numbersList =
(List<RandomNumber>)
session.createCriteria(RandomNumber.class).setMaxResults(amount).list();
} catch (HibernateException ex) {
Logger.getLogger(Database.class.getName()).log(Level.SEVERE, null, ex);
} finally {
HibernateUtil.closeSession(session);
}
return numbersList;
}