Is it possible to have BMP EJBs, which are not
persisted to a Database but to other persistance Layer ,
let say XML files , or RAM ?!
What stand beyond this , is that using EJB , you get
all the benefits of Remote interface, Security,
Transactions ,Threads and so on , and by using
BMP ,i would control where and how to persist my BMP
If by spec it is possible , is there any effor in this
direction, are there any AppServer which do allow this
kind of control and flexiblity.
BMP EJBs can store their data wherever you like. After all, you get to write your own persistence code.
Unfortunately, if you are using a non-transactional datasources, like memory, XML or the file system, your BMP EJB operations will not be transactional.
can AppServer , JBoss for particular , will allow deployment of such
bean , does it allow droping db,table definitions from all its deployment
Only CMP entity beans have database-related information in the deployment descriptors. BMP entities can do (almost) anything you want, and the server will take it just fine.
is there any Persistance Layer which substitue Database ,for example
files,RAM ... , which also manage Transactions and do it effectivly with
good perfomance ? is there any effor in this kind ?
This really sounds like your asking if there is a way to use CMP (Container Managed Persistance) with something other then a db as the storage mechanism. I do not know of any vendor off hand that supports this and if there is your pretty much locked in.
As for BMP beans all of the persistance is up to the developer to implement. For what your looking for something along the lines of castor could help you out with what it sounds like your trying to do, but it is still up to YOU, not the server, to deal with the persistance.