How drive ejb beans from such as COMPANY with..

Question

I am very new to EJBs but would like to give a try and dooooooooooooo it of course. Now, I understnad how to write jave(ejb interfaces and classes) but makes me small is how define ejb beans from my bosses speach. He says we need to ....... so for example COMPANY(company name, contact, references + more) could be our business objects. HAH!
So pmy roblem is what should be an ejb bean and what should be ejb bean fields.
Thanks a lot in advance.
gapter

Answer 1

Its really not that difficult really. First - if you decide that your business object is going to be a Bean - Determine if it should be an EJB or just a regular Java Object bean in which case you'll probaly just use a Java Bean. The two are very similar with the exception that JB's are not Distributed but can do most of the grunge work that an EJB is suppose to do.
Next, determine what business methods or transactions are most likely to be done to your Business Object. This should determines the interface. So far that's all routine.
If you are decide that an EJB is what your problem demands (after much research into your problem) - then ask if your business object will be persistent (exist for a long time and will need storage (say on a persistent storage media like in a database) Or whether it will just require session scope (or just to be present the duration of a transaction/session - like say a shopping cart). The former requires a Entity Bean, the latter a Session Bean.
You then create your implementation code in a NameOfClassEJB class. A Container Management class NameOfClassHOME, and of course your Business Method Interface called NameOfClass.
The BMI (business method Interface class) is trivial. Your EJB class however will contain all the implementation required to get work done depending on the choice of Implementation - that is, whether you wish to handle all transactions (Bean Managed) or if you would rather delegate to the Container to handle Storage Issues (Container Managed). With Container Management - You get a lot for free - like concurrency control, database connectivity is trivial, distributed transaction management is trivial, field updates in your database is totally out of your hands. etc ...
For a beginner - its better if you take time to study the ejb lifecycle, the J2EE Business Architecture, then the solution that they proposed for application development. This is not trivial and has a steep learning curve.
Have fun.
Next determine if you want to handle all of the transactions between the properties (or fields) in the bean or you'd like the Application Server's Container to do this for you. (Most EJB's at least the simple ones are better off being handled by the Container).
going to be an employee: say with name, address, tel, email: Y