Hello Rob, how are you? I have a question if I may :-)
Here is the deal: for the past month or so, we (me, Thierry,
Juergen) have been chatting about introducing some kind of a
standalone JCA engine (implementing JCA system contracts e.g.
transactions, connection pooling, security, etc.) so one would be
able to deploy any JCA resource adapter in a "managed" mode without
requiring a full-blown J2EE server. Without re-inventing the wheel,
we've looked around but there was nothing really there (as far as
standalone JCA implementation goes). So, we've looked at the latest
Geronimo (M3 I think) code and noticed that they have a JCA module
implemented as a part of their J2EE stack. Then Thierry
experimented with it and made it work without the rest of the
Geronimo server! Take a look at the attached code and readme file.
Now, here is the question - how would it be possible to reuse/
modify/package Geronimo JCA module on its own, without the rest of
the Geronimo server? What the leagal implications might be? Do you
know any Geronimo folks, so you could forward it to them and
collaborate with them? Another thing we were thinking about is to
create a standalone project (code name Cancun) which would serve as
a thing wrapper around such (pluggable?) JCA implementations.
Did I miss anything?
Thanks,
Dmitriy.
-------- Original Message --------
Subject: Re: JCA CCI documentation
Date: Wed, 11 May 2005 11:38:30 +0200 (CEST)
From: Thierry Templier <[EMAIL PROTECTED]>
To: Dmitriy Kopylenko <[EMAIL PROTECTED]>
CC: Juergen Hoeller <[EMAIL PROTECTED]>, Thierry TEMPLIER
<[EMAIL PROTECTED]>
Hi Dmitriy,
Finally, I manage to make the application run ;-) I
clean the code and make everything to done with ant
tasks...
In attachment, I have put a detailed readme file to
explain how to use the application and which changes I
made on both Geronimo transaction/connector modules
and XAPool. I don't include the libraries in the zip
file but you can see my classpath in the .classpath
file...
Cheers,
Thierry
Thanks Thierry. Great job!
Take a look at my blog:
http://templth.blogspot.com/
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---
=========================================
== Spring Geronimo application ==
=========================================
@author Thierry Templier
1. MOTIVATION
The aim of this application is to make an application
to show the feasibility of use global transactions in
a non managed mode with different resources and and
more particularly JCA resource adapters.
The JCA resource will be configured with the JCA Spring
support.
The transaction manager will be the internal transaction
manager of Geronimo and the JCA connection manager
implementation will be provided too by Geronimo.
These components will be configured in Spring using the
facilities of this IoC framework (FactoryBean...).
The transaction demarcation will be done with the Spring
JTA transaction support.
2. CODE MODIFICATIONS
This application contains four parts:
- Spring integration of the Geronimo transaction and JCA
connection managers.
- The Geronimo transaction and JCA connection managers.
- XAPool to to make take part simple datasources in global
transactions.
- The application.
To make the application work, we need to make some modifications
in the second and third parts...
-- Geronimo --
When we try to use the Geronimo transaction manager, we have had
a NullPointerException in the newTransaction method of the
ConnectionTrackingCoordinator class. As a matter of fact, the
oldInstanceContext instance is null whereas we do the following
thing in the TransactionContextManagerFactoryBean class:
this.transactionContextManager.newUnspecifiedTransactionContext();
So we modify the newTransaction method as following:
public void newTransaction() throws ResourceException {
InstanceContext oldInstanceContext = (InstanceContext)
currentInstanceContexts.get();
if( oldInstanceContext!=null ) {
notifyConnections(oldInstanceContext);
}
}
Important note: When you configure the transaction strategy with the
XATransactionFactoryBean, you must imperatively set the
useTransactionCaching
property to true. Otherwise, the transaction manager will try to
enlist
two times the same XAResource...
-- XAPool --
As Geronimo transaction manager works only with NamedXAResource
which extends the XAResource, we need to wrap every XAResource
that XAPool tries to enlist in the current transaction...
So we need to modify the prepareStatement of the
StandardXAConnectionHandle
class:
try {
tx.enlistResource(new WrapperNamedXAResource
(xacon.getXAResource(),"XAPool"));
// enlist the xaResource in the transaction
} catch (RollbackException n) {
log.debug(
"StandardXAConnectionHandle:prepareStatemnet enlistResource
exception : "
+ n.toString());
}
and the preInvoke method of the StandardXACallableStatement class:
try {
con.tx.enlistResource(new WrapperNamedXAResource
(con.xacon.getXAResource(),"XAPool"));
// enlist the xaResource in the transaction
if (cs != null) {
cs.close();
cs = null;
}
} catch (RollbackException n) {
throw new SQLException(
"StandardXAStatement:preInvoke enlistResource exception: "
+ n.toString());
}
Without these modifications, you will have some ClassCastException,
when your application tries to enlist jdbc resources...
3. BUILD AND DEPLOYMENT
To build the application, just make:
"build build".
This task compiles it, copies necessary files and packages
all in a jar.
As the application runs in a non-managed mode, there is
no need of an application server so no deployment is
mandatory!
4. START AND CONFIGURE THE JORAM SERVER
Joram is the jms server of ObjectWeb (see the following url:
http://joram.objectweb.org/).
To start the Joram server, just make:
"build startJoram".
To configure the Joram server (creation of all needed resources),
just make:
"build configureJoram".
5. START THE HYPERSONIC DATABASES
As we want to test global transactions on several resources, we
will use to database servers. To start them, just make:
"build startHsqldb1" for the first
"build startHsqldb2" for the second
To execute sql requests on these, you can use the Hypersonic
console. To start it, just make:
"build adminHsqldb".
6. RUN THE APPLICATION
The application has three main features:
- initialize the different resource (databases).
- run the application in a global transaction. it can be
finished by a commit (everything is ok) or a rollback
(a RuntimeException occurs).
- check if very happened as envisaged (in the cas of a
commit or a rollback).
If you want to run the application and validate the
global transaction, just make:
"build launchCommit"
If you want to run the application and force a RuntimeException
to be thrown at the end (to make a rollback), just make:
"build launchRollback"
Note: These two ant tasks depend on the init task that
initialize the resources...
After running the application, we can check if every resource
are in the expected state (row inserted in database and jms
messages sent).
When you launch the application, it try to make the following
tasks:
- insert a row in the database1
- send a message to the jms queue Queue
- insert a row in the database2
- send a message to the jms queue Queue
So, if the commit occurs, you will have the following with
"build check":
Buildfile: build.xml
build:
check:
[java] Table 1: 1
[java] Table 2: 1
[java] Requests to receive messages...
[java] Waiting for message...
[java] First message : msg1 = Hello World!
[java] Waiting for message...
[java] Second message : msg2 = Hello World!
BUILD SUCCESSFUL
and, if the rollback occurs:
Buildfile: build.xml
build:
check:
[java] Table 1: 0
[java] Table 2: 0
[java] Requests to receive messages...
[java] Waiting for message...
and the process will block on waiting of jms messages...
Note: the numbers after "Table 1:" and "Table 2:" are respectively
the number of rows for the database tables, country1 and country2.
