JDO with container (J2EE) managed DataSource

Question

Hello,
I would like to use application server managed DataSource with JDO and
would love to find a piece of documentation/link that would take me
through it.
In absence of such a document, any advice/idea will be appreciated.
Based on the bits and pieces that I have already discovered, I assume that:
when binding the PersistanceManagerFactory to JNDI, I should use
DataSource ds = (DataSource)ic.lookup("jdbc/myDataSourceName");
pmf.setConnectionFactory(ds);
... to set the datasource (instead of ConnectionFactory). Is that it?
I found some older topics (July?) that mentioned that this is NOT
officially supported. Quote:
<i>A couple of warnings, though:
* The use of external datasources is untested.
* If using the datasource within an appserver, the Connections from it
should not be automatically committed/rolled back with the completion of
the
global transaction. Kodo performs its own transaction management on the
Connections it uses. In future releases we'll be able to handle
Connections
that are controlled by the appserver.</i>
Is it still the case now or is this the official way to integrate
application server (Websphere 5.0) with JDO now? Assuming that Kodo was
configured to integrate with TransactionManager of the application server,
is there a reason not to let the application server control the
transactions? Are we going to run into problems if we do it?
Thank you,
Petr

Answer 1

Hi Ben,
Thank you for your advice, that is an experience that it is good to know
about.
In terms of forcing (configuring) Kodo to use the existing data source
from application server, how did you do it?
Based on the structure bellow, I would assume that you used the Java
Connector option. Other then the experience you mentioned, are you happy
camper?
Thank you,
Petr
Ben Eng wrote:
Here is my experience using Kodo with BEA WebLogic Server. Your mileage may
vary with IBM WebSphere.
When using a JDBC driver in the application server\'s classpath (which would
be the case with a managed DataSource), the JDBC driver does not have access
to your J2EE application\'s classes for deserializing them from BLOBs.
Therefore, the Kodo serialized BLOB mapping would not work in this
configuration. You will need to rely solely on more sophisticated O/R
mappings.
Kodo integrates well with the application servers managed Transactions, when
packaged as a JCA resource adapter. With BEA WLS, I found that I had to
repackage things as follows:
myApp.ear
|
+-application.xml
+-jakarta-commons-logging-1.0.2.jar
+-jdbc2_0-stdext.jar
+-jdo1_0.jar
+-kodo-jdo-runtime.jar
+-serp.jar
+-mysql-connector-java-3.0.3-beta-bin.jar  (or whatever your JDBC
driver is)
|
+-kodo.rar
| +-META-INF
| +-MANIFEST.MF
| +-ra.xml
| +-weblogic-ra.xml
+-myEJB.jar
+-META-INF
| +-MANIFEST.MF
+-myEJB.class
Both the kodo.rar and myEJB.jar MANIFEST.MF looks like this:
Manifest-Version: 1.0
Class-Path: serp.jar jdo1_0.jar kodo-jdo-runtime.jar
jakarta-commons-logging-1.0.2.jar jdbc2_0-stdext.jar
mysql-connector-java-3.0.3-beta-bin.jar
When the JDBC driver is packaged with the application EAR like this,
deserialization of BLOB also works fine. If you do have the JDBC driver in
the application server\'s classpath, it will be loaded from there first and
deserialization of BLOBs will break. Unfortunately, this is limitation is
terribly limiting, because CMP EntityBeans and JMS destinations that require
persistent storage will need to use managed DataSources. Probably the best
compromise is to have the JDBC driver in the application server\'s classpath,
not in the application EAR, and live without BLOB mappings (not a big loss
in real world applications).
Ben
\"Petr Bulanek\" <[email protected]> wrote in message
news:[email protected]...
Hello,
I would like to use application server managed DataSource with JDO and
would love to find a piece of documentation/link that would take me
through it.
In absence of such a document, any advice/idea will be appreciated.
Based on the bits and pieces that I have already discovered, I assumethat:
when binding the PersistanceManagerFactory to JNDI, I should use
DataSource ds = (DataSource)ic.lookup(\"jdbc/myDataSourceName\");
pmf.setConnectionFactory(ds);
.. to set the datasource (instead of ConnectionFactory). Is that it?
I found some older topics (July?) that mentioned that this is NOT
officially supported. Quote:
<i>A couple of warnings, though:
* The use of external datasources is untested.
* If using the datasource within an appserver, the Connections from it
should not be automatically committed/rolled back with the completion of
the
global transaction. Kodo performs its own transaction management on the
Connections it uses. In future releases we\'ll be able to handle
Connections
that are controlled by the appserver.</i>
Is it still the case now or is this the official way to integrate
application server (Websphere 5.0) with JDO now? Assuming that Kodo was
configured to integrate with TransactionManager of the application server,
is there a reason not to let the application server control the
transactions? Are we going to run into problems if we do it?
Thank you,
Petr