RE: DAO design pattern -- JAVA400-L

Niall,

How much joy have you had with hibernate. I have had a lot of problems
getting it to do some stuff, especially stored procedures.

For stored procedures I had to drop back to native SQL. I soon as I had to
do that I lost the benefits of using hibernate in the first place.

Apparently you can access stored procedures in the latest version, tried it,
didn't work.

The other thing that I found was that hibernates lazy loading is either a)
very complex to setup, or b) just plain does not work, and I spent
considerable time trying to get it to work.

With these and other problems I gave up and switched to Ibatis. It was
sooooo much easier, as you have control of the sql.

The thing that put the nail in the hibernate coffin for me, is that when I
had problems I posted questions on the hibernate forum. My questions were
ignored?

cheers
Colin.W

http://as400blog.blogspot.com
 
Extension   5800
Direct dial   0870 429 5800


-----Original Message-----
From: Niall.Smart@xxxxxxxxxxxxxxx [mailto:Niall.Smart@xxxxxxxxxxxxxxx] 
Sent: 04 January 2005 11:23
To: Java Programming on and around the iSeries / AS400
Cc: 'Java Programming on and around the iSeries / AS400';
java400-l-bounces@xxxxxxxxxxxx
Subject: RE: DAO design pattern


We use Hibernate here, it is extremely useful indeed.

Anyone want to elaborate on the pros and cons of JDBC versus AS400File?




Colin Williams <colin.williams@xxxxxxxxxxxx> 
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04/01/2005 11:23
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RE: DAO design pattern






Lim, Niall,

And if you want to take this stuff even further,

Use a framework such as Ibatis or Hibernate for your Object/Database
mapping.

Hard work initially, especially hibernate, but as your application gets
complex, you do see the benefits

cheers
Colin.W

http://as400blog.blogspot.com
 
Extension   5800
Direct dial   0870 429 5800


-----Original Message-----
From: Niall.Smart@xxxxxxxxxxxxxxx [mailto:Niall.Smart@xxxxxxxxxxxxxxx] 
Sent: 04 January 2005 10:59
To: Java Programming on and around the iSeries / AS400
Cc: java400-l-bounces+niall.smart=friendsfirst.ie@xxxxxxxxxxxx; Java
Programming on and around the iSeries / AS400
Subject: Re: DAO design pattern


Lim

Create an interface which defines the data related operations 
independantly of any particular representation/access method (i.e., 
file/JDBC, etc)

public interface SomeObjectDAO {

        public void create(SomeObject object)
                throws DAOException;

        public void delete(Integer objectID)
                throws DAOException;

        public SomeObject findByID(Integer objectID)
                throws DAOException;

        public List findByKeyword(String keyword)
                throws DAOException;
}

Then write an implementation of this interface using the JT/400 API:

public class JT400SomeObjectDAO {

        public SomeObject findByID(Integer objectID) {
 
                AS400File file = ....

                SomeObject someObject = new someObject();

                someObject.setFoo(file.readInteger());
 
                return someObject;
        }

        // ...
}

And finally write a factory to create instances of SomeObjectDAO:

public class SomeObjectDAOFactory {

        private static instance = new SomeObjectDAOFactory();

        public static SomeObjectDAOFactory getInstance() {
                return instance;
        }

        public SomeObjectDAO newInstance() {
                return new JT400SomeObjectDAO();
        }

}

You don't gave to use checked exceptions.   A framework like spring can 
obviate the need for trivial factory objects.




"Lim Hock-Chai" <Lim.Hock-Chai@xxxxxxxxxxxxxxx> 
Sent by: java400-l-bounces+niall.smart=friendsfirst.ie@xxxxxxxxxxxx
03/01/2005 18:40
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Java Programming on and around the iSeries / AS400 
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DAO design pattern






Anybody has a good example on how should I design my web application for 
any file access related transaction?
 
I'm using struts to create this web apps.  I just wonder when I'm in the 
Action Form and I need to do some edit/insert/update on a record in a 
file, what is the correct way to design this.  I've read some article 
about DAO design pattern.  If this is a good approach, can anybody provide 

some example.  (Note: I'm using Tomcat4.1 and plan to use DBCP for 
connection pooling.) 
 
thanks.
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