DAO question

Question

I am working on a slightly different variation of DAO pattern as shown by Sun:
* I have 2 Singleton classes "MSSqlServerConnectionManager" and "OracleConnectionManager". ( For brevity I will consider only 1):
public class MSSqlServerConnectionManager {
public static String s_driverName = "com.microsoft.jdbc.sqlserver.SQLServerDriver";
public static String s_databaseUrl;
public static String s_userId;
public static String s_password;
public static Connection getConnection(  ) {
}* I have a DAO Factory "DAOFactory":
public abstract class DAOFactory {
public static final int MSSQLSERVER = 1;
public static final int ORACLE = 2;
public static DAOFactory getDAOFactory( int whichFactory ) {
switch (whichFactory) {
case MSSQLSERVER:
return new MSSqlServerDAOFactory();
case ORACLE:
return new OracleDAOFactory();
default:
return null;
// specifies the DAOs
}* I have 2 concrete DAO Factories for each DAO type which to get Connection call their respective ConnectionManagers:
public class MSSqlServerDAOFactory implements DAOFactory {
public static Connection getConnection() { returns MSSqlServerConnectionManager.getConnection(); }
public class OracleDAOFactory implements DAOFactory { ...
public static Connection getConnection() { returns OracleConnectionManager.getConnection(); }
}* Then I have the DAOs (as interfaces) and their implementation for each DAO type. In each DAO method the first statement is to call the getConnection() method. For example:
public interface CustomerDAO {
public int insertCustomer(...);
public class MSSqlServerCustomerDAO implements CustomerDAO {
public int insertCustomer(...) {
Connection conn = MSSqlServerDAOFactory.getConnection();
}First of all is this desgin ok?
Second the database url, user id and password are not hard-coded as users have choices in these areas. Right now after login they are available in the HttpSession. My question is at what time I needs to put them in the ConnectionManager?
Thirdly I want my connection mangers to also be able provide connection through jndi look up. In my development environment i want to use DriverManager; In QA environment i want to use jndi. How is it possible?
Thanks
thanks

Answer 1

ok I am confused. This is the final code I was thinking:
public interface ConnectionManager {
  public void configure( Properties properties );
  public Connection getConnection();
  public void closeConnection( Connection );
public class DriverManagerConnectionManager implements ConnectionManager {
  private String _driverName = "com.microsoft.jdbc.sqlserver.SQLServerDriver";
  private String _databaseUrl;
  private String _userId;
  private String _password;
  public void configure( Properties properties ) {
    _databaseUrl = properties.getProperty("DATABASEURL");
    _userId= properties.getProperty("USERID");
    _password= properties.getProperty("PASSWORD");
public class JNDIConnectionManager implements ConnectionManager {
  private String _jndiName;
  public void configure( Properties properties ) {
    _jndiName = properties.getProperty("JNDINAME");
public class ConnectionManagerFactory {
  public static final int DRIVERMANAGER = 1;
  public static final int JNDI = 2;
  public static ConnectionManager getConnectionManager( Properties properties ) {
  ConnectionManager connectionManager;
  int connectionClass = new Int(properties.getProperty("CONNECTIONCLASS")).intValue();
  switch ( connectionClass ) {
    case DRIVERMANAGER:
      connectionManager = new DriverManagerConnectionManager ();
    case JNDI:
      connectionManager = new JNDIConnectionManager ();
    default:
      return null;
  connectionManager.configure( properties );
  return connectionManager;
public abstract class DAOFactory {
  public static final int MSSQLSERVER = 1;
  public static final int ORACLE = 2;
  public static DAOFactory getDAOFactory( int whichFactory , ConnectionManager connectionManager ) {
    switch (whichFactory) {
      case MSSQLSERVER:
        return new MSSqlServerDAOFactory( connectionManager );
      case ORACLE:
        return new OracleDAOFactory( connectionManager );
      default:
        return null;
  // specifies the DAOs
public class MSSqlServerDAOFactory implements DAOFactory {
  private ConnectionManager _connectionManager;
  private MSSqlServerDAOFactory() {}
  public MSSqlServerDAOFactory( ConnectionManager connectionManager ) {
     _connectionManager = connectionManager;
  public static Connection getConnection() { returns _connectionManager.getConnection(); }
public class OracleDAOFactory implements DAOFactory {
  private ConnectionManager _connectionManager;
  private OracleDAOFactory() {}
  public OracleDAOFactory( ConnectionManager connectionManager ) {
     _connectionManager = connectionManager;
  public static Connection getConnection() { returns _connectionManager.getConnection(); }
public interface CustomerDAO {
  public int insertCustomer(...);
public class MSSqlServerCustomerDAO implements CustomerDAO {
  public int insertCustomer(...) {
    Connection conn = MSSqlServerDAOFactory.getConnection();
}the ConnectionManagerFactory is a class which hands out ConnectionManager interface. Each type (JNDI and DriverManager) implements the ConnectionManager interface with its own class. Then I passes that ConnectionManager interface to the DAO Factory.
Define an interface for the ConnectionFactory that
each type will implement (JNDI and DriverManager).First of all I am assuming that ConnectionFactory you mentioned is actually ConnectionManagerFactory. Please correct me if I am wrong.
If I understand correctly, what you are suggesting is to make ConnectionManagerFactory an interface. which will be implemented by each type. That means each type will be implementing 2 interfaces: ConnectionManagerFactory and ConnectionManager? Is it true? If yes then what is the reason?
I think I am understanding you wrong. Please explain.
Thanks