I like the idea of having one service one interface. David, when you say "All
these would be injectable via @Resource" they could also be injected with
@Inject (Principal and UserTransaction already are).
On Thu, Sep 29, 2011 at 00:33, David Blevins <david.blevins_at_gmail.com>wrote:
>
> On Sep 28, 2011, at 12:55 AM, Antonio Goncalves wrote:
>
> > What asynch servlets also have is a timeout (asyncSupported = true,
> asyncTimeout = 3000). It could also be interesting to have a timeout
> attribute on @Asynchronous, what do you think ?
>
> See @javax.ejb.AccessTimeout. It's basically a wrapped version of the
> TimeUnit/long pair used in the java.util.concurrent APIs. Works for
> handling all multi-threaded access including @Asynchronous invocations.
>
> The part that I wonder about is what we might do with the relationship
> between the Future and javax.ejb.SessionContext. The cancel logic is tied
> together.
>
> Still preparing for JavaOne and don't have time for a concrete proposal,
> but off the top of my head it seems like we might want to start breaking up
> SessionContext into sub interfaces that are service specific to the related
> services. We've historically used the SessionContext (or EJBContext) as the
> way for beans to "talk to the container". We can still follow that pattern
> (and even keep compatibility) we probably just need to start slicing out
> methods into more specific interfaces.
>
> Specifically, perhaps a javax.ejb.AsynchronousContext interface to contain
> the 'boolean wasCancelCalled();' method and be the container compliment to
> the javax.ejb.Asynchronous support and container controlled Future object
> that might be the result of an @Asynchronous call. This could be injected
> into any object leveraging @Asynchronous support.
> We then make javax.ejb.
>
> package javax.ejb;
> public interface AsynchronousContext {
> boolean wasCancelCalled();
> }
>
> We then make SessionContext implement that interface:
>
> public interface SessionContext extends EJBContext, AsynchronousContext
> {
> EJBLocalObject getEJBLocalObject() throws IllegalStateException;
>
> EJBObject getEJBObject() throws IllegalStateException;
>
> MessageContext getMessageContext() throws IllegalStateException;
>
> <T> T getBusinessObject(Class<T> businessInterface);
>
> Class getInvokedBusinessInterface();
> }
>
> We could follow this pattern as we split up other parts. I can easily
> imagine the following:
>
> public interface SessionContext extends javax.ejb.EJBContext,
> AsynchronousContext {
>
> EJBLocalObject getEJBLocalObject() throws IllegalStateException;
> EJBObject getEJBObject() throws IllegalStateException;
>
> /**
> * These two methods could be interesting to any object using
> proxies
> * They allow the bean to call itself and get container services
> (interceptors, security, transaction)
> * Both are candidates for splitting
> */
> <T> T getBusinessObject(Class<T> businessInterface);
> Class getInvokedBusinessInterface();
>
> /**
> * Already a context object that can just be injected
> * No need to split out this method
> */
> MessageContext getMessageContext() throws IllegalStateException;
> }
>
> public interface AsynchronousContext {
> boolean wasCancelCalled();
> }
>
> public interface EJBContext extends SecurityContext, TransactionContext,
> NamingContext, InterceptorContext {
>
> EJBHome getEJBHome();
> EJBLocalHome getEJBLocalHome();
>
> /**
> * @deprecated
> */
> Properties getEnvironment();
> Identity getCallerIdentity();
> boolean isCallerInRole(Identity role);
>
> /**
> * Already a "context" object that can just be injected
> * No need to split out this method
> */
> TimerService getTimerService() throws IllegalStateException;
> }
>
> public interface SecurityContext {
> Principal getCallerPrincipal();
> boolean isCallerInRole(String roleName);
> }
>
> public interface TransactionContext {
> UserTransaction getUserTransaction() throws IllegalStateException;
> void setRollbackOnly() throws IllegalStateException;
> boolean getRollbackOnly() throws IllegalStateException;
> }
>
> public interface NamingContext {
> Object lookup(String name);
> }
>
> public interface InterceptorContext {
> Map<String, Object> getContextData();
> }
>
> All these would be injectable via @Resource and have standard names
> directly under "java:comp/", such as java:comp/AsynchronousContext
>
>
> -David
>
>
--
Antonio Goncalves
Software architect and Java Champion
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