public void rename(String oldName, String newName) throws SystemException {
CounterRegister counterRegister = getCounterRegister(oldName);
synchronized (counterRegister) {
if (_counterRegisterMap.containsKey(newName)) {
throw new SystemException("Cannot rename " + oldName + " to " + newName);
}
Connection connection = null;
PreparedStatement preparedStatement = null;
try {
connection = getConnection();
preparedStatement = connection.prepareStatement(_SQL_UPDATE_NAME_BY_NAME);
preparedStatement.setString(1, newName);
preparedStatement.setString(2, oldName);
preparedStatement.executeUpdate();
} catch (ObjectNotFoundException onfe) {
} catch (Exception e) {
throw processException(e);
} finally {
DataAccess.cleanUp(connection, preparedStatement);
}
counterRegister.setName(newName);
_counterRegisterMap.put(newName, counterRegister);
_counterRegisterMap.remove(oldName);
}
}
private long _competeIncrement(CounterRegister counterRegister, int size) throws SystemException {
CounterHolder counterHolder = counterRegister.getCounterHolder();
// Try to use the fast path
long newValue = counterHolder.addAndGet(size);
if (newValue <= counterHolder.getRangeMax()) {
return newValue;
}
// Use the slow path
CompeteLatch completeLatch = counterRegister.getCompeteLatch();
if (!completeLatch.compete()) {
// Loser thread has to wait for the winner thread to finish its job
try {
completeLatch.await();
} catch (InterruptedException ie) {
throw processException(ie);
}
// Compete again
return _competeIncrement(counterRegister, size);
}
// Winner thread
try {
// Double check
counterHolder = counterRegister.getCounterHolder();
newValue = counterHolder.addAndGet(size);
if (newValue > counterHolder.getRangeMax()) {
CounterHolder newCounterHolder =
_obtainIncrement(counterRegister.getName(), counterRegister.getRangeSize(), 0);
newValue = newCounterHolder.addAndGet(size);
counterRegister.setCounterHolder(newCounterHolder);
}
} catch (Exception e) {
throw processException(e);
} finally {
// Winner thread opens the latch so that loser threads can continue
completeLatch.done();
}
return newValue;
}
