Raible Designs

Posted by Jason Boutwell on June 11, 2003 at 02:47 PM MDT #

Well, that much I did realize :) (I like Hibernate a lot too), so I guess the only question left is - since you are instantiating the UserManagerImpl in the Business Delegates (e.g. UserManager) in Struts-Resume, why can't you just make a UserManagerImpl(Session s) constructor, rather than desecrating the interface API, and tying it to the interface API signature. I think that's a helluva lot cleaner :). And inside the Impl class, have a private instance Session var to which you will assign the Session and use it for the entire transaction. Or have a JDBC "Connection" constructor, and just pass in a connection if you're a JDBC junkie and you can afford to handcode JDBC for your project... Makes more sense, no? :) So your UserManager interface becomes:

public interface UserManager {
public UserForm getUser(String username) throws Exception;
public ArrayList getUsers(UserForm userForm) throws Exception;
public UserForm saveUser(UserForm userForm) throws Exception;
public void removeUser(UserForm userForm) throws Exception;
}

And then for each type of UserManagerImpl, you'd have a constructor like:

public class UserManagerImpl implements UserManager {
...
private Session session;

UserManagerImpl(Session session) {
    this.session = session;
}
...
rest of API implemented
}

And then for a JDBC based UserManagerImpl, you'd have

import java.sql.Connection;

public class UserManagerImpl implements UserManager {
...
private Connection conn;

UserManagerImpl(Connection conn) {
    this.conn = conn;
}
...
rest of API implemented
}

Now everyone's happy because they can use either a Hibernate implementation or handcoded JDBC implementation (or EJB, if you're really perverted ;), and the interface API signatures are clean, that is, not tied to any particular persistence layer.

:)
Martin

Posted by Martin Naskovski on June 11, 2003 at 04:03 PM MDT #

Posted by Pratik Patel on June 12, 2003 at 04:26 PM MDT #

Posted by billy vandory on June 18, 2010 at 03:13 PM MDT #