[jboss-user] [JBoss Seam] - HOWTO: web services in Seam 1.3 (CVS)

[avbentem]

Though Seam 1.3 is currently only available from CVS, it shows a nice way to use web services with JBoss. This is based on standard Java annotations and JBossWS 1.2.1 GA, as packaged with JBoss AS 4.2.0 GA. Seam 1.3 adds (or, work in progress: hopefully will add) support for conversations working across multiple web service requests. Nice!

Though I have not used the Seam specific things, here's a start for a mini-HOWTO, of course calling for comments. And welcoming Seam specific enhancements!

If you need conversations you'll first need a Seam 3.1 snapshot from CVS  or get a nightly. This only runs on JBoss 4.2.0 CR1 or later (no need for any JEMS installer, just unpack the download). Again: I don't know the development status; when not using Seam conversations then the code below can also be run in JBoss without Seam at all -- but that's not what this forum is about...

The new SeamBay example shows how to define the web services. Here, AuctionService  uses @WebService and @WebMethod annotations (and implements AuctionServiceRemote to comply with the @Stateless annotation). No further configuration in, for example, web.xml, but an additional configuration file META-INF/standard-jaxws-endpoint-config.xml for JBossWS. The name of this file could be changed using a JBoss proprietary annotation, @EndpointConfig.

After deployment, one would see the web services listed at http://localhost:8080/jbossws/. For JBoss 4.2.0 CR1 this gives URLs such as /seam-bay-seam-bay/AuctionService; in 4.2.0 CR2 and GA one gets the newer jbossws-1.2.1.GA, which creates URLs like /AuctionServiceService/AuctionService. Heiko Braun explained this in another forum post. 

Heiko also explained why this new mechanism might cause "Multiple context root not supported" errors, and that one can change the context path using another JBoss proprietary annotation, @WebContext from jbossws-core.jar. This error may also be caused by some left-overs after refactoring. I changed the name of my service using Eclipse, which left the old compiled classes in various exploded EAR folders. As those were then still loaded by JBoss this resulted in multiple services within the same application, and thus resulting in the "not supported" error.

Even when not running into errors it might be a good idea to somehow get a defined context path for the web service, as you do not want to have the clients know about a new URL when you upgrade the JBoss application server... Or maybe one should forget about the automatic deployment and simply go back to adding the web services to web.xml for better control. Any thoughts on this?

So, the following (which is not Seam specific) works just fine in AS 4.2.0 GA, if you include some  META-INF/standard-jaxws-endpoint-config.xml in your project:

package my.package;
  | import javax.jws.WebMethod;
  | import javax.jws.WebService;
  | 
  | // The Service Endpoint Interface
  | @WebService
  | public interface DeepThoughtSEI {
  | 
  |   @WebMethod
  |   public String getAnswer();
  | 
  | }

and

package my.package;
  | import javax.ejb.Stateless;
  | import javax.jws.WebMethod;
  | import javax.jws.WebService;
  | import org.jboss.ws.annotation.WebContext;
  | 
  | @Stateless
  | @WebContext(contextRoot = "/guide/to/the/galaxy")
  | @WebService(endpointInterface = "my.package.DeepThoughtSEI")
  | public class DeepThought implements DeepThoughtSEI {
  | 
  |   public String getAnswer() {
  |     return "42";
  |   }
  |      
  |   public String getUltimateQuestionToLifeTheUniverseAndEverything() {
  |     return "sorry, not exposed in endpointInterface";
  |   }
  | 
  | }

This serves the WSDL at http://universe.tld/guide/to/the/galaxy/DeepThought?wsdl 

Note that when not specifying a value for endpointInterface then ALL methods in the DeepThought implementation would be exposed, unless at least one method is explicitly annotated in that class -- even though the interface explicitly only declares a single method to be exposed. In other words: the @WebMethod annotations in the interface are only honored when endpointInterface is used. But this is all not Seam specific.

More documentation at the JBoss JAX-WS User Guide.
CVS at :pserver:anonymous at anoncvs.forge.jboss.com:/cvsroot/jboss/jboss-seam

Enjoy,
Arjan.

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