Woohoo! I was hoping for this.. sorry, still a little green when it comes to
Tuscany. Thanks for the info!
-g.
On Mar 9, 2010, at 9:27 PM, Simon Nash wrote:
> George Baxter wrote:
>> Hi all,
>> We're hoping to use Tuscany for our stateless services. These services, by
>> and large, can be (and should be) totally stateless and thus, in the
>> interest of lower GC issues, singletons. Great, we @Scope them as
>> Composites.
>> However, if we want to have an asynchronous 'conversation' with these...
>> well.. we haven't figured out how to do it. Issues:
>> 1. The callback functionality is injected into the destination component
>> object rather than maintained by a proxy. If this object is a singleton-ish
>> entity.. well, not thread safe.
> >
> If the destination component is a singleton (composite scoped), it shouldn't
> use injection for the callback proxy. Instead, it should obtain the current
> RequestContext object and get the callback proxy from that. Here's an example
> of the code that you need when using this approach:
>
> @Context
> ComponentContext context;
>
> public void someMethod() {
> MyCallback myCallback = context.getRequestContext().getCallback();
> ....
> myCallback.receiveResult(theResult);
> }
>
>> 2. When the callback is actually made, the originating caller (that might
>> be scoped as 'Conversation') can't be located and a new instance is created.
>> This may be because the singleton's callback is being corrupted
>> (overwritten).. thus just another variant of issue 1.
> I'm not sure about this. Please can you try making the change suggested above
> and see if that improves things.
>> So is it possible to scope a component as a 'Composite' and yet enable
>> 'Stateless' or 'Conversation' scoped components interact with them in any
>> asynchronous way?
> Yes, it should be possible if you use the approach described above.
>
> Simon
>
>> Thanks,
>> George
>
