//-------------------
// TransactionManager
//-------------------
public class TransactionManager {
	
	private static Connection _connection;

	public static Result initialize() {
		
		Result result = new Result();
		
		try {
			final String driver = "org.sqlite.JDBC";
			Class.forName(driver);
			result.setStatus(true);
		}
		catch(ClassNotFoundException e) {
			result.setMessage("Could not load database driver");
			return result;
		}
		
		return result;
	}
	
	//
	//
	//
	
	private TransactionManager() {
		return;
	}
	
	public static Connection getConnection() {
		return _connection;
	}

	public static Result begin() {
		
		Result result = new Result();

		String dbName = "db" + File.separator + "bookclub.sqlite";
		String connectionURL = "jdbc:sqlite:" + dbName;
		
		try {
			assert (_connection == null);
			
			_connection = DriverManager.getConnection(connectionURL);
			_connection.setAutoCommit(false);
			
			result.setStatus(true);
		}
		catch (SQLException e) {
			result.setMessage(e.getMessage());
		}
		
		return result;
	}
	
	public static Result end(boolean commit) {
		
		assert (_connection != null);		
		Result result = new Result();
		
		try {
			if (commit) {
				_connection.commit();
			}
			else {
				_connection.rollback();
			}
			
			result.setStatus(true);
		}
		catch (SQLException e) {
			result.setMessage(e.getMessage());
		}
		finally {
			DbUtils.safeClose(_connection);
		}
		
		_connection = null;
		return result;
	}
	
}