it will really ease third party applications integration.
I really don't see any value in the TCM and on the
transaction contexts. It adds an unnecessary burden
on applications that need to work with the geronimo
transaction layer.
So here is my happy +1 :)
--
Cheers,
Guillaume Nodet
On 8/1/06, Dain Sundstrom <[EMAIL PROTECTED]> wrote:
<history length="too long">
About a week ago there was a discussion on the OpenEJB mailing list
regarding the TransactionContextManager. In OpenEJB 3 we removed the
use of the TCM from Geronimo and replaced it with just a
javax.transaction.TransactionManager. This brought all of the
openejb containers into alignment. The other big motivation was to
ease the integration of OpenEJB and third part libraries,
specifically Spring. The problem with the TCM is that if you use it
you can't use the TM directly since the TCM needs to know about all
TM calls. Additionally, to use the TCM you must demarcate all
changes in "component context" by starting an unspecified transaction
context. This is all quite invasive and made OpenEJB hard to use in
Spring or plain old Tomcat.
That was all fine and good for OpenEJB 3, but as it turns out there
is a desire to keep the OpenEJB 2 and 3 code aligned as much as
possible, so a discussion started around how to backport the changes
to 2. We determined there were two options:
1) wrap the TCM with a class that implements TM but delegates to the
TCM - this would be tricky to get working and there is always the
problem of demarcating the unspecified transaction context
2) remove the TCM from Geronimo entirely - this could be a lot of work
After a quick look at the first option, I decided to try option two.
It turned out to be a lot easier than I thought since, the biggest
user of TCM was OpenEJB and I had already pulled it out of OpenEJB.
I also think I have become the master of using the IntelliJ refactor
tools and was able to remove the code without too much hand tweaking.
</history>
I have checked the fruits of this effort into https://svn.apache.org/
repos/asf/geronimo/branches/dain/notcm and there is a matching
OpenEJB branch that is checked out with maven m:co. I have not
updated the m2 build yet, as it was finalized during this work.
For those of you that are following the Jencks project, which wraps
the Geronimo transaction and connector modules with Spring bean
factories, I have created a branch there also, which contains a
massive simplification due to the refactors in the removal of the
Geronimo TCM. Here are some fun examples from that project:
http://fisheye.codehaus.org/browse/jencks/branches/notcm/src/test/
resources/org/jencks/samples/outbound/jencks-tranql.xml?r=112
http://fisheye.codehaus.org/browse/jencks/branches/notcm/src/test/
resources/org/jencks/spring-request-reply-jta.xml?r=112
So what does everyone think about removing the TCM in general? After
that I think we may want to discuss the specifics of my branch. I
may have gotten too refactory happy :) Details on the specific
changes I made follow:
TransactionContextManager
-------------------------
Removed TransactionContextManager and replaced all uses with a plain
old TransactionManager
Removed all code from web containers, app client and timer that was
simply demarcating an unspecified transaction context, which is no
longer needed
TransactionManager
------------------
Merged XATerminator portion of TCM into GeronimoTransactionManager
which is a subclass of TransactionManagerImpl
Improved tx thread association code so we can throw an error if
someone attempts to resume a tx associated with another thread
Added TransactionManagerMonitor which is used by the connection
tracker to know when a transaction context has changed
UserTransaction
---------------
TransactionManagerImpl now implements UserTransaction to ease
integration with third party libraries such as Spring
Removed OnlineUserTransaction since it was only really used by
OpenEJB and it has it's own UserTransaction implementation
Web containers now use GeronimoUserTransaction which is an always on
wrapper around a transaction manager
Third party support
-------------------
Moved use of ServerInfo from HOWLLog to HOWLLogGBean so it can be
more easily use by third party libraries
Moved connector related transaction data to connector module
Replace use of Geronimo's thread pool with a concurrent executor
-dain
