Form what I understand, you're proposing to add a new specification to provide a facade and a common SPI for all the container. Is that it?
Antoine
> Le 22 déc. 2014 à 21:28, Antonio Goncalves <antonio.goncalves_at_gmail.com> a écrit :
>
> Hi all,
>
> We've talked about this topic in EE 7... and I'm bringing it back to EE 8.
>
> At the moment, the Java EE spec defines several containers (EE.2.4 - Containers) : Web Container, EJB Container, Application Client Container and Applet Container. Each having its own set of services (EE.2.7 - Java EE Standard Services) such as JTA, Validation, CDI... The spec also defines SPIs (EE.2.12.2 - Java EE Service Provider Interfaces) as "the contract between the Java EE platform and service providers that may be plugged into a Java EE product". But these SPIs are not really mandatory (only a few specs have SPIs).
>
> Why not go further and say "There is a single Java EE container, and each service can then be plugged in through a SPI" ?
>
> Let me take an example. If we want to persist a Book Entity in Java SE we go :
>
> EntityManagerFactory emf = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);
> EntityManager em = emf.createEntityManager();
> EntityTransaction tx em.getTransaction();
>
> tx.begin();
> Book book = service.createBook(new Book("H2G2"));
> tx.commit();
>
> em.close();
> emf.close();
>
>
> That's fine because the JPA service does persistence. But if the Book Entity has a Listener with a CDI @Inject, this doesn't work anymore : you need an extra injection services that comes from another spec (CDI in this case). The idea behind the EJBContainer API was to aggregate several services (i.e. the services given to an EJB component). So, to have JPA and CDI working in Java SE we would go :
>
> Map<String, Object> properties = new HashMap<>();
> properties.put(EJBContainer.MODULES, new File("target/classes"));
> EJBContainer ec = EJBContainer.createEJBContainer(properties);
> Context ctx = ec.getContext();
>
> BookEJB bookEJB = (BookEJB) ctx.lookup("java:global/classes/BookEJB");
>
> ec.close();
>
>
> But if the EJB spec is not updated, then the EJBContainer will not include the new services (such has the new Security spec, and so on).
>
> So what if the Java EE spec would define a single container API ? Something like this would trigger a full Java EE container with *all* the services :
>
> Container eec = Container.createContainer();
>
> EntityManagerFactory emf = eec.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);
> EntityManager em = emf.createEntityManager();
> EntityTransaction tx em.getTransaction();
>
> tx.begin();
> Book book = service.createBook(new Book("H2G2"));
> tx.commit();
>
> em.close();
> emf.close();
>
> eec.close();
>
>
> Or if we just need the JPA + BeanValidation + CDI providers, we would go :
>
> List<Container.PROVIDER> properties = new ArrayList<>();
> properties.put(PROVIDER.JPA);
> properties.put(PROVIDER.BEAN_VALIDATION);
> properties.put(PROVIDER.CDI);
> Container eec = Container.createContainer(properties);
> //...
> eec.close();
>
>
> To have a Web Profile we could go :
>
> List<Container.PROVIDER> properties = new ArrayList<>();
> properties.put(PROVIDER.WEB_PROFILE);
> Container ec = Container.createContainer(properties);
> //...
> ec.close();
>
>
> And the Container API would become a facade to create any Java EE provider :
>
> EntityManagerFactory emf = Container.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);
> CacheManager cache = Container.createCacheManager();
> WebManager web = Container.createWebManager();
> BeanManager bm = Container.createBeanManager();
>
>
> This would bring real modularity (even before Java EE 9) and, finally, would ease Java SE execution and testing.
>
> Any thoughts ?
>
> --
> Antonio Goncalves
> Software architect, Java Champion and Pluralsight author
>
> Web site <http://www.antoniogoncalves.org/> | Twitter <http://twitter.com/agoncal> | LinkedIn <http://www.linkedin.com/in/agoncal> | Pluralsight <http://pluralsight.com/training/Authors/Details/antonio-goncalves> | Paris JUG <http://www.parisjug.org/> | Devoxx France <http://www.devoxx.fr/>