Andrej Koelewijn

Just posted on OTN: Developing JSF Apps with Oracle JDeveloper 10g.

Oracle just released it’s BPEL Process Manager. Mark Rittman has more background information.

OTN has an article on new connection caching features in 10g jdbc: Keep Your Connections.

Eclipse version 3.0 has been released. Downloads are here , all the changes are documented in on the new and noteworthy page.

I’m currently working on a prototype for a mobile java application. It’s going to run on a laptop, so i can just use swing and j2se, nothing exciting there. The biggest challenge is to use ADF for a mostly offline jclient application. The current idea is to use xml for ofline data storage. When a network connection becomes available we’ll use a web service to send the xml document to a server.

Some weeks ago I saw Oracle’s Steven Davelaar demo ADF in combination with xml. He was using castor to create java bindings for his xml document. He showed that it’s pretty straightforward to use these castor generated classes with ADF. Now castor is OK, but i’d rather go with something standard, like JAXB. So i first tried using that. But it looks like ADF doesn’t like JAXB generated java.

The difference between JAXB and castor is that JAXB uses interfaces. It generates Interfaces for all your elements and types in an xml schema. Castor doesn’t use interfaces. So my guess is, ADF doesn’t like interfaces. You can only create data controls for javabeans (i.e., classes), not for interfaces.

Bad luck. So now we are also using castor. I also briefly looked at apache’s xmlbeans, but i think they have the same problem.

On the server side we’re using the readXml method provided by ADF’s business components to read the xml document into tables. Works really nice, sofar. I couldn’t find a lot of documentation on the readXml method, but Steve Muench has some usefull entries in his blog: Writing XML Using View Objects and Code Sample Illustrating Various BC4J Programming Techniques.

I ran into the following error in jdeveloper today: JBO-35000: Cant resolve spel expression for attribute {0} in {1}. If this happens, check your ui model. In my case, i had an iterator binding referencing a non-existent method data control binding. Removing the iterator binding fixed the problem.

Looks like the Jdeveloper team is making good progess in making UIX JSF compliant. The project is called ADF faces.

Brian Duff is writing about Oracle SCM and the Future. He basically says that support for Oracle SCM is not very important for Oracle. They’ll support it, but don’t expect them to put a lot of effort into improving it. Currectly CVS support gets the most attention.

Oracle SCM uses the oracle Designer Repository to store files and version information. OracleDesigner, it’s Repository (and thus Oracle SCM) are no longer developer further. Oracle still supports them. but don’t expect a lot of improvements.

Instead Oracle is improving support for pvcs and subversion. I’ve used pvcs in the past, and i hope i don’t have to use it anymore in the future. CVS is much nicer. Subversion is a bit nicer than CVS, so i’m glad Oracle will also support it. But the real improvement in version control systems is brought by tools like arch and bitkeeper. Hopefully Oracle will also start to support these tools.

I noticed something weird with the ADF data control palette today. I’ve generated some files using jaxb. One of the files is an interface (PurchaseOrder) extending another interface (PurchaseOrderType). The interface PurchaseOrder doesn’t declare any methods itself, all methods are declared by PurchaseOrderType. I’ve created a service object with a method to return a purchase type. In the generated data control xml file for this service a BeanClass atrribute specifies which class is returned. If this class is PurchaseOrder, no methods and attributes are displayed in the Data Control palette. You can manually change the BeanClass attribute to PurchaseOrderType. When you refresh the data control palette you’ll see all of it’s attributes.

Windows XP Bedevils Wi-Fi Users (Wired) describes how Windows XP users are having problems with their wireless conections. For no apparent reason their connections seem to drop. I’ve experienced the same problem. Half a year ago, when there were just 2 access points in my neightborhood, I had no problems. Today however, there are 6 access points, and i think this confuses windows xp. My connection stays up for about 1 minute, then it drops, and 10 seconds later windows xp reports that it has found some usable access points, and i have to select which one i want to use.

I’ve found a workaround though. I run netstumbler all the time. Netstumbler disables the windows xp wireless zero configuration. No more dropped connections!

Devx just published an article called Politically Charged EJB Decision Hands a Victory to JBoss. It states that the EJB expert group has decided to use Hibernate as the persistence mechanism in EJB 3.0. That’s not how i understood it. EJB 3.0 will provide a POJO object relational mapping much like Hibernate, but i don’t think it will be exactly like Hibernate.

The article further states that Hibernate users are more likely to choose Mysql as their database, so the writer doesn’t understand why companies like Oracle and IBM agreed to go with Hibernate in EJB 3.0. I think this statement is also incorrect. The last time i used hibernate was in combination with Oracle. In my experience most companies have already standardized on a database, and are building new application using existing data in existing databases.