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After some hours understanding differences between CDI Beans and EJBs lifecycle when used as independent modules (JBoss Modules), i found:
Singleton CDI Beans are instantiated one time per module, not really singleton among all modules.
To avoid this i had to create Registry as a Singleton Enterprise Session Bean.
This cames with new problems, CDI injection doesn't works among modules, so i had to package a CDI producer (i don't care if it's singleton or not, its only a producer) which can be instantiated by any module. Main responsibility of this producer is to lookup Registry EJB, this to avoid hardcoding jndi path each time i need access the Registry.
I changed my trivial example to support JSF plugins also, this is an example of what i am using currently.
Module facelets:
Registry interface:
public interface FaceletsModuleRegistry {
void registerModule(String module);
List<String> getRegisteredModules();
}
Registry implementation:
@Local(FaceletsModuleRegistry.class)
@Singleton(name="FaceletsModuleRegistry")
@TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED)
@Vetoed
public class FaceletsModuleRegistryImpl implements FaceletsModuleRegistry {
private Set<String> registeredModuleNames = new TreeSet<>();
@Override
public void registerModule(String module) {
registeredModuleNames.add(module);
}
@Override
public List<String> getRegisteredModules() {
return Collections.unmodifiableList(new ArrayList<>(registeredModuleNames));
}
}
Registry producer:
@ApplicationScoped
public class FaceletsModuleRegistryBuilder {
@EJB(lookup="java:global/facelets/FaceletsModuleRegistry!co.hatit.enterprise.facelets.services.FaceletsModuleRegistry")
protected FaceletsModuleRegistry faceletsModuleRegistry;
@Produces
public FaceletsModuleRegistry getFaceletsModuleRegistry(){
return faceletsModuleRegistry;
}
}
Any other module that i want to plugin implements this code (please see @Inject can be used on any module requiring access the Registry singleton instance):
@ApplicationScoped
public class InmueblesActivator {
@Inject
private FaceletsModuleRegistry faceletsModuleRegistry;
public void init(@Observes @Initialized(ApplicationScoped.class) Object init){
String moduleName = Module.getCallerModule().getIdentifier().getName();
String name = StringUtils.substringBetween(moduleName, "deployment.", ".jar");
faceletsModuleRegistry.registerModule(name);
}
}
Then i can reference Registry from any module as a really singleton instance (solved my problem having multiple instances of same class when used CDI singleton beans among several modules).
Now, i can plugin JEE modules, not just java code, but facelets resources also:
public class FaceletsResourceHandler extends ResourceHandlerWrapper {
Logger logger = LoggerFactory.getLogger(FaceletsResourceHandler.class);
@Inject
FaceletsModuleRegistry faceletsModuleRegistry;
private ResourceHandler wrapped;
public FaceletsResourceHandler(ResourceHandler wrapped) {
this.wrapped = wrapped;
}
@Override
public ViewResource createViewResource(FacesContext context, final String name) {
ViewResource resource = super.createViewResource(context, name);
if (resource == null) {
resource = new ViewResource() {
@Override
public URL getURL() {
try {
//iterates over plugins to find the required resource.
for(String module : faceletsModuleRegistry.getRegisteredModules()){
URL resource = Module.getCallerModule().getModuleLoader()
.loadModule(ModuleIdentifier.create("deployment." + module + ".jar"))
.getExportedResource("META-INF/resources" + name);
if (resource != null) return resource;
}
} catch (ModuleLoadException e) {
throw new FacesException(e);
}
return null;
}
};
}
return resource;
}
@Override
public ResourceHandler getWrapped() {
return wrapped;
}
}
