Thanks, Howard. Splitting my per-thread service into interface and
implementation did the trick.
My intent, by the way, is to have all threads share the singleton eager-load
service but for some of that service's behavior to be per-thread, provided
by the per-thread service. This is an odd arrangement, I admit. Here's the
problem I'm trying to solve:
I have a legacy app that uses JSPs and a home-brew ORM framework. I'm
trying to migrate it to use T5 and Hibernate. Until it's completely
converted, both the old and the new parts must coexist. For this to work,
the legacy ORM must use the same transactions as Hibernate. I'm doing this
by having the legacy ORM get its connections from Hibernate.
I'm configuring Hibernate using Tapestry IoC, so how does my legacy ORM get
access to it? The answer is my eager-load service, whose real name is
T5IocAccess. T5IocAccess has a static "instance" variable that its
constructor sets to point to itself; this allows the legacy part of the app
to obtain the T5IocAccess instance (via a static "get()" method).
T5IocAccess must be eager-load to ensure that this static variable gets
populated immediately.
The per-thread service is a Hibernate session manager, which the legacy ORM
obtains via T5IocAccess.
This works, but it raises a broader question. What is the best way for
legacy code to gain access to services managed by Tapestry IoC? I created
my T5IocAccess service, with its static instance variable, because I saw no
other way.
Howard Lewis Ship wrote:
>
> This looks like an issue ... I think EagerLoad is not compatible with
> non-singleton scopes.
>
> What does it mean to eager load a service that is, in fact, used in
> multiple threads?
>
> Ah, here's the issue; when you bind a class, not an interface, as a
> service, it automatically uses singleton scope. Only proxiable
> services can have non-singleton scope, and that means an interface and
> an implementation. Tapestry should detect this and throw an
> exception.
>
> On Thu, Jul 24, 2008 at 11:01 AM, Franz Amador <[EMAIL PROTECTED]> wrote:
>>
>> I have an EagerLoad service that uses a PerThread service. I expected
>> the
>> EagerLoad service to hold a reference to a proxy to the PerThread service
>> so
>> that the actual instance of the PerThread service that is used depends
>> upon
>> the thread calling the EagerLoad service. Instead, the EagerLoad service
>> is
>> getting a reference to an actual instance of the PerThread service, not
>> to a
>> proxy, so the same instance of the PerThread service is getting used by
>> all
>> threads that call the EagerLoad service. This surely can't be right.
>> Here's a very simplified example:
>>
>> public class AppModule {
>> public static void bind(ServiceBinder binder) {
>> binder.bind(EagerLoadService.class);
>> binder.bind(PerThreadService.class);
>> }
>> }
>>
>> @EagerLoad
>> public class EagerLoadService {
>> public EagerLoadService(PerThreadService perThreadService) {
>> // prints "class PerThreadService", not a proxy class!
>> System.out.println(perThreadService.getClass());
>> }
>> }
>>
>> @Scope(PERTHREAD_SCOPE)
>> public class PerThreadService {
>> }
>>
>> Is this a bug? Am I confused about how this should work? All help
>> appreciated.
>>
>> --
>> View this message in context:
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>> Sent from the Tapestry - User mailing list archive at Nabble.com.
>>
>>
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>
>
>
> --
> Howard M. Lewis Ship
>
> Creator Apache Tapestry and Apache HiveMind
>
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