Telemachus wrote:
> <snip> JDO,DAO,JDBC,EJB <snip>
> Question : Which ones are currently in serious use out there and have a good
> chance of actually being around in a few years ?
IMHO, a 'serious' Java shop would not simply select one of the mentioned
technologies over the others. Like any other tool in the toolbox, you either
chose the right one for the job or you end up using the 'universal vice grip and
hammer combination' because that's all you know.
(Of course, todays programmers really don't have the time to learn the tools of
the trade. Heck, they don't even have time to write more than straight-line
prototype code. Forget error handling .... )
These are not mutually exclusive technologies. However, there are reasons and
places to use each. The following URLs obtained through Google. Hopefully the
site and my interpretation helps:
- JDBC (from http://java.sun.com/products/jdbc) is the fundemental data access
API. It appears to be the basic "if all else fails" but somewhat cumbersome
technique. Almost like writing low level code. Any programmer who learns the
others and doesn't know JDBC should be sent home.
- JDO (from http://www.jdocentral.com/) us a J2SE (Java 2 Standard Edition)
extension. J2SE (as compared to J2EE , or Java 2 Enterprise Edition) seems
mainly oriented towards a single, standalone app or the client in a C/S
environment. Use this when you use J2SE environment, not J2EE environment!
- DAO (from http://java.sun.com/blueprints/patterns/DAO.html) is a specific
design pattern (or technique) in the J2EE environment. Design patterns seem to
be templates, code techniques and even code snippets, published to assist a Java
programmer in accomplishing a specific type of task quickly without reinventing
the wheel. I see this as an effective shortcut in a J2EE/non-EJB environment.
- EJB (from http://java.sun.com/products/ejb/) is the definition and
implementation of a componment technology and a framework. In order to avoid
reinventing basic code (like database connectivity, security, mail, and so on)
an EJB compliant environment provides all the basics, or allows them to be
'clipped in', and simply invoked through configuration. IMHO, it is a very
ambitious design pattern that is reasonably successful for 'assembly line'
programming. EJBs have their place ... I strongly encourage their use (when
appropriate) ... learn about appropriate from the book "Mastering EJB" available
through http://www.theserverside.com
Which to use? Depends on the problem you are trying to solve!
/Hans
(Programmers have more religious fervor than priests. But priests only want to
save your soul, programmers want to save your computer.)
Received on Tue Apr 01 2003 - 09:47:46 CST
