Can I make a WAR depend on a JNDI entry in JBoss 5.1?

Question

As part of an upgrade from JBoss 4.0.4 to 5.1, I am trying to get a WAR to deploy after an EAR is successfully deployed. JBoss 5.x does not support PrefixDeploymentSorter like 4.x did, which means that I have to use <depends> in the WAR's jboss-web.xml.

It seems I cannot depend on the EAR itself, so I pick the last deployed EJB instead. This EJB provides a JNDI entry that the WAR needs.

Here's the EJB as it deploys when the WAR is absent from the deploy directory:

2010-03-25 10:47:30,348 INFO  [org.jboss.ejb3.session.SessionSpecContainer] (main) Starting jboss.j2ee:ear=my-ear.ear,jar=mypackage-ejb.jar,name=MyFacadeBean,service=EJB3
2010-03-25 10:47:30,350 INFO  [org.jboss.ejb3.EJBContainer] (main) STARTED EJB: my.package.MyFacadeBean ejbName: MyFacadeBean
2010-03-25 10:47:30,371 INFO  [org.jboss.ejb3.proxy.impl.jndiregistrar.JndiSessionRegistrarBase] (main) Binding the following Entries in Global JNDI:

        my/MyFacade/local - EJB3.x Default Local Business Interface
        my-ear/MyFacadeBean/local-my.package.MyFacade - EJB3.x Local Business Interface

And here's the depends snippet from jboss-web.xml:

<depends>jboss.j2ee:ear=my-ear.ear,jar=mypackage-ejb.jar,name=MyFacadeBean,service=EJB3</depends>

My problem is: The WAR starts to deploy immediately after "STARTED EJB:", i.e. before MyFacadeBean is bound to JNDI, which causes bean deployments to fail:

2010-03-25 10:47:39,068 ERROR [my.facade.FacadeFactory] (main) MyFacade not bound
2010-03-25 10:47:39,069 ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[my.host.no].[/]] (main) StandardWrapper.Throwable
java.lang.ExceptionInInitializerError
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:164)
        at my.freemarker.servlet.FreemarkerController.setupPojoServiceFactory(FreemarkerController.java:621)
[...]
Caused by: java.lang.RuntimeException: javax.naming.NameNotFoundException: MyFacade not bound
        at my.facade.FacadeFactory.getFacade(FacadeFactory.java:61)

After the WAR has finished its deployment, MyFacade happily (mockingly?) continues its deployment and binds the JNDI entries.

If I hot-deploy the WAR after the EAR has deployed, everything works as intended.

I even thought of depending on a dummy EJB in the EAR, and using <module-order>strict</module-order> in jboss-app.xml to force it to load as the last module. But alas, JBoss 5.x does not support that either. Doh!

Is there a way to depend on the JNDI entry itself? Are there other ways of solving this?

Answer 1

Here's how you can achieve this on JBoss 5.1.x.

First, add a file called aliases.txt into the META-INF directory of your EAR. This file should just contain a single line with an arbitrary name / identifier for your EAR. For example, if you have my-ear.ear, your META-INF/aliases.txt file could contain 'my-ear'. It just needs to be something that won't clash with any other aliases declared by other apps deployed on the same server.

Next, add a jboss-dependency.xml file to the META-INF directory of your WAR, containing the following (subsituting 'my-ear' for the alias you created above):

<dependency xmlns="urn:jboss:dependency:1.0">
  <item whenRequired="Real" dependentState="Create">my-ear</item>
</dependency>

This will ensure the EAR is deployed before the WAR.

Also, if you try to deploy the WAR without the EAR being present, JBoss will log a clear deployment error message telling you about the missing dependency.