Creating Singleton with Workshop

Question

I am trying to create a Singleton with Workshop and am having some difficulties. When I try to add the <singleton-service> element to the weblogic-application.xml deployment descriptor, I get a schema error because the element is not defined in the supplied schema location of http://www.bea.com/ns/weblogic/90/weblogic-application.xsd. If I change the location to http://www.bea.com/ns/weblogic/920/weblogic-application.xsd (note the change from "90" to "920"), then the <singleton-service> element is defined, but this schema has two subelements defined as <singleton-class> and <singleton-uri>. According to the documentation (and oddly enough the comments in the schema itself), these elements should be <class-name> and <name> respectively.
There is a weblogic-application.xsd file located in a eclipse plugins folder under workshop that is the same as the old version without the <singleton-service> element. I am assuming that some eclipse builder uses this schema and may be causing the problem. I tried updating this file, but that just causes eclipse to crash on startup.
Anyone have any ideas on how to get an EAR project with a singleton to build successfully in Workshop?

Answer 1

Hi Vimala,
I tried your example and got the deployment problem as well. I don't think the way you have your schema defined is correct. By putting xmlns:xls="http://www.bea.com/ns/weblogic/90", you are associating all tags that begin with "wls:" with that namespace. By specifying the schemas location for http://www.bea.com/ns/weblogic/920, you are telling it where it can find the "920" schema, but it is never stated where you find the "90" schema. This effectively turns off schema checking for the "90" namespace. By not putting "wls:" in front of singleton-service, you are putting it at the default namespace which is not defined. This all seems to make Eclipse happy because it cannot fully validate the document.
I did find a jar file in the weblogic install that contains the schemas that weblogic uses internally. The jar file is at \beahome\weblogic92\server\lib\schema\weblogic-container-binding.jar. The schema for weblogic-application.xml is in this jar and is different from either the "90" or "920" schemas that is online. I believe this is why there is an error when you try to deploy your app. It must validate against this schema.
I have found as long as I match this schema, I can just leave the schemaLocation out of my weblogic-application.xml file and get it to build and deploy. I do get problems reported by eclipse that I need to define library references because it is needed by dependent projects. I believe this is because internally eclipse has its own copy of the schema which predates the <singleton-service> element. The builder is trying to validate the document against this schema and is failing because of the <singleton-service> element, so it cannot find the <library-ref> elements that are in the document. I did not get the same problem with your example application and I haven't figured out why yet. Funny thing, I can make a change to some other file in the project and save and all the reported problems disappear.
I believe using this work-around, I am able to get a good EAR file to build and deploy. It just seems that after I deploy and define my singleton using the admin console that nothing happens. I get no indications that the singleton is working or not in the logs. This did cause me to try a little experiment in that I configured a singleton service using the admin console to a singleton that did not exist. It acts identically to the one that did exist. No warnings or errors at all. I would hope that if I configured a singleton that I would get an error if weblogic could not start it.
Thanks for your efforts. Let me know if you find out anything else,
Jeff