Web services design issues.... for a newbie

Question

I have to develop several web services (JDev 9.0.2.822 and 9iAS R2). Almost all examples that can be downloaded from OTN expose simple web services that user java datatype like strings, ints and the like. In my case, the web services I should develop transfer custom information which are modeled as value classes or entity EJB's in my app. We deal with complex objects which contain collections/arrays/lists of other objects, and although most of the bussiness logic of the app is exposed via stateless session beanss and clases, I can not select their nethods since there ar no custom serializers for them.
By reviewing the sample newsfeed web service I noticed that int their implementation they decided to "hard-code" the data by doing an XML-query to the db and constructing a custom XML document. this document is returned as a java string so the web-service is, at the end a very simple one, which uses no custom serializers. Of course there is code to create the XML doc, and there should be some XML parsing at the client in order to deserialize the XML into java in order to do something with it.
My question is, is this the "preferred" method to deal with custom complex datatypes. should I include code in my beans and value classes so they "serialize" itself to XML so my web services have to deal with simple java strings? I have no experience in developing serializers, and I can't see why they are used? I am not sure which path should I follow, for example, should I use an array serializer to serialize a collection/array of object or should I better develop a method which will create a custom XML document repesenting the array? Are there any trade-off?
I have to start development right away, so please give me some insinght.
Thanks,
Fedro.

Answer 1

Yes, Oracle9iAS is currently production on 9.0.2. The target for OC4J 9.0.3 was end of summer but I have not seen it arrive yet. It is supposed to work in conjunction with 9.0.2 - i.e. you can use the OC4J 9.0.3 with the rest of your Oracle9iAS implementation. I think you are reasonably safe assuming it will be here by year end. I sit on the JDev side of the house so don't have specifics on what their actual delivery dates are but would guess sometime during September. The developer preview of OC4J 9.0.3 is currently available here on OTN as per the headline in the Web services Center at: http://otn.oracle.com/tech/webservices.
There are two big advantages of OC4J 9.0.3:
1. Interoperability testing ... it has been put through the SOAPBuilder's interoperability tests and includes a test suite for you to try it out 9.0.2 is fine here but you have evidence in 9.0.3;
2. Feature/functionality - support for Web services based on JMS, document style Web service support, testing harness at the end-point, J2EE 1.3 certification, custom serialization support (not there in 9.0.2), cleaner PL/SQL based Web services and more - see:
http://otn.oracle.com/products/ias/daily/jul22.html
The development environment that goes along with it is JDeveloper 9.0.3. While OC4J 9.02/9.03 comes with what is called the Web services assembly tool for those who like scripting/command-driven approaches, JDev puts a traditional visual dev environment on top of the OC4J 9.0.3 environment (and also Apache SOAP 2.2/2.3.1, incidently) The developer preview of JDev 9.03 is due out within days here on OTN ... probably Tuesday based on what I understand. JDev 9.0.3 production is scheduled to arrive probably in late September mid-October.
Hope this gives some background to help with your decision.
Mike.