Spring + iBATIS or Hibernate

[pdemilly]

Hi,

I am new to all those technologies so excuse my ignorance. I am in the process of rewriting a legacy cobol application in Java. Since it is a fairly large financial application (at least for us) and in use, I need to be very careful about the choices I make.

I have a JDBC interface to the legacy cobol filesystem that works pretty well (there are some problems though) so I cannot completely rely on it, which is not a problem since we want to migrate slowly to an RDBMS (Postgresql is my first choice).

I am leaning toward writing our new version as a swing based Rich client platform. However we also need to have a web interface but mostly for viewing accounts information, at least at first.

My question is: Since I need to maintain 2 databases concurrently, what do you recommend me using as a data access layer. Hibernate or iBATIS or something else ?

Is remoting scalable? (we have instances with around 500 users connected per database)

I am studying the jpetstore and the petclinc example. Which one is the recommended approach to client-server deployment and why?

I am still trying to understand ioc (I am reading the J2ee design and development and have the 2nd book coming). I love the book but I am having difficulties making the jump from it to the springframework. The appeal of the book to me was to find an alternative to EJB which I find way to complex and overwhelming.

TIA

Pascal

[katentim]

I am leaning toward writing our new version as a swing based Rich client platform

Look at Spring's RCP project. This may be exactly what you want.

However we also need to have a web interface but mostly for viewing accounts information, at least at first.

If you use Spring, all business functionality between RCP and Web can easily be re-used.

Since I need to maintain 2 databases concurrently, what do you recommend me using as a data access layer

For the true DB (Postgres), you can use JDBC, iBatis, OJB or Hibernate. They all support JTA for distributed transactions (although I suspect both Postgres and your second DB are not XA compliant, so this isn't a factor). iBatis simplifies mapping from SQL to objects. Hibernate (and OJB I believe) does this and allows you to manage object relationship in you source with XDoclet, or in the hibernate mapping files.

I have a JDBC interface to the legacy cobol filesystem

How is this achieved? Is it transactional? Is it XA capable? I'd probably recommend just using Spring's JDBC template for this connection. If it's not a true database you might want to keep it basic JDBC. If Hibernate or iBatis tries to use an unsupported feature, debugging will be more difficult.

Is remoting scalable?

Remoting is. Scalability will depend more on your architecture.

jpetstore and the petclinc example. Which one is the recommended approach to client-server deployment and why?

JPetstore demonstrates remoting examples, while Petclinic demonstrates different data access techniques. I'd say you could take a bit from both.