try {
long lastBackupTimestamp = Long.parseLong(DBHelper.readFirstLineFromFile(fBackupTimestampFile));
long now = System.currentTimeMillis();
return (now - lastBackupTimestamp) >= fBackupFrequency.longValue();
} catch (NumberFormatException e) {
throw new PersistenceException(fBackupTimestampFile.getAbsolutePath() + " does not contain a number for the date as expected", e); //$NON-NLS-1$
}
}