Seam project structure and Presentation Layer

[joshd]

I'm in the process of planning to moving a Seam 2.3 project from Tomcat (Seam with POJO) to  JBoss 7 to use full EJB capabilities. I chose to go for a maven-based EAR packaging, since all Seam examples do so, and I also like the idea of separated projects.

So lets say I have a project structure like:

- foo

- foo-ear

- foo-ejb

- foo-web

What I see in all of the provided Seam exmaples and maven project archtypes - none of these is using Java classes in the web-project (foo-web here). Is there a reason for that?

If  someone aims at a "seperated presentation layer" wouldn' it be a good idea to put Backing Beans (JSF/RichFaces/Primefaces whatever)  and UI-related Seam-action (POJO Seam components) into this project? And only have business logic EJBs, Entity and Daos etc. in the foo-ejb? Doing so would make it possible to change the presentation layer without touching anything else - just by completely replacing the whole foo-web project.

Example:

foo-web/src/main/webapp

<p:dataTable id="groupGrid" value="#{groups}" var="group">
            <p:column headerText="Groups">                       
        <h:outputText value="#{group.name}" />       
            </p:column>
 </p:dataTable>

GroupAction providing the #{groups} in

foo-web/src/main/java/ui

@Name("groupAction")
@Scope(ScopeType.CONVERSATION)
public class GroupAction implements Serializable {

   @In private GroupDao groupDao;
   @In private GroupService groupService;
   @Out(required=false, scope=ScopeType.PAGE)
   private List<Group> groups;

   @Factory(value="groups")
   public void getGroups() {
        groups = groupDao.findAll();
   }
}

The GroupDao is a SLSB in

foo-ejb/src/main/java/dal and

and GroupService a SLSB in

foo-ejb/src/main/java/services

@Stateless
@AutoCreate
@Name(GroupDao.NAME)
public class GroupDaoBean extends AbstractDao<Group> implements GroupDao {
  ...
}

@Stateless
@Name("groupService")
public class GroupServiceBean implements GroupService {

  @Logger 
  private Log log;
  @EJB
  private OtherDao otherDao;
  @EJB
  private UserDao userDao;

..

}

I have tested a bit with this structure, and it works. Is there any good reason not to have it like this? Will it have any downsides or even serios problems? I dont find examples for having Java code in the web-project.

With the idea of having presentation logic separated from the business logic in mind, I always wonder why someone would have a "weblogic"-package right next to the "datamodel"-package, both in ejb-project.

I would be very interested in some feeback. How are you structuring small-, mediumsized- or big projects.

Thanks in advance

josh