Hey
Chip Wilson wrote:
> [Chip Wilson]
> If this is true, then there are several corollaries:
> * Your persistent store must be coupled to your particular EJB server,
> and must be blessed by your server vendor, even if you are using BMP. This
> is implied by the fact that JTA/JTS is not required by the EJB spec. So,
> when you choose an EJB server, you must choose a persistent store from the
> list of supported ones for that server. BMP does not allow you to use just
> any persistence mechanism.
Not really. The persistent store must support JTA, and the server must
provide a JTA implementation. The store does not have to be
server-specific in any way.
> * If your persistent store is not variable, then you must choose a
> server which supports it.
As above, not really true. Store supports JTA && Server supports JTA ->
Ok!
> * You cannot use BMP to integrate EJB with a legacy persistent store
> or application. The persistent store or application vendor must provide a
> version that is coupled with your particular EJB server. This would seem to
> contradict the statement in the spec that "In many cases, the underlying
> data source may be an existing application rather than a database."
The legacy store must probably be wrapped in some way in order for it to
hook into the JTA implementation. This is a rather low requirement I
think; how else would it be possible to do this kind of integration?
> * You cannot use BMP with an off-the-shelf O/R mapping framework,
> since these typically implement their own transaction mechanism, unaware of
> JTS/JTA/EJB.
The O/R tool would have to either support JTA, in which case it is
directly usable, or one must put a wrapper on top of it in order to hook
it into the JTA. Again, a rather straightforward requirement IMHO.
> I was under the impression that one motivation for BMP was to accommodate
> all of the existing, "legacy" applications out there, but this does not
> appear to be true. Comments?
Well, given the above I think it is very possible.
Have I missed something vital here? Other comments?
/Rickard
--
Rickard �berg
Computer Science student@LiTH
@home: +46 13 177937
Email: [EMAIL PROTECTED]
Homepage: http://www-und.ida.liu.se/~ricob684
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