/**
 * All the methods in the Database interface shall call asynchronous tasks.
 */
public interface Database {
    public void saveSinglePlayer(PlayerAccount account);
    public void saveAllPlayers(Collection<PlayerAccount> accounts);
    public void saveSingleBank(BankAccount account);
    public void saveAllBanks(Collection<BankAccount> banks);
    public void loadAllPlayers(AccountStorage destination);
    public void loadAllBanks(AccountStorage destination);
    public void pruneOldAccounts(long maxAge);
    /**
     * This method blocks until all running tasks are complete.
     */
    public void waitForTasks();
}