I'm still digesting this, but isn't there another approach to this?
Here's what I'm thinking (please let me know if I'm on the right track):
1. Create a StateObjectPersistenceManager similar to the SessionScopeManager
that uses attributes on the request rather than the session.
2. Add the following contribution to the StateObjectPersistenceManagers
configuration point:
<manager scope="request" object="service:RequestScopeManager"/>
3. Contribute entries to the ApplicationObjects configuration point for
request scoped objects. A sample:
<state-object name="objectPerRequest" scope="request">
<create-instance class="SomeClass" .../>
</state-object>
4. Add the following in page(s) to gain access to a shared, per-request
instance
@InjectState("objectPerRequest")
public abstract SomeClass getObjectPerRequest();
-Lance
-----Original Message-----
From: Howard Lewis Ship [mailto:[EMAIL PROTECTED]
Sent: Monday, October 17, 2005 3:27 PM
To: Tapestry users
Subject: Re: Dependency injection within an ASO
The general approach is to define you own StateObjectFactory and
inject your dependencies there. It can pass them to the ASO when it
creates it.
http://jakarta.apache.org/tapestry/tapestry/apidocs/org/apache/tapestry/engi
ne/state/StateObjectFactory.html
http://jakarta.apache.org/tapestry/tapestry/hivedocs/config/tapestry.state.F
actoryObjects.html
http://jakarta.apache.org/tapestry/tapestry/hivedocs/config/tapestry.state.A
pplicationObjects.html
In theory, you could also create an annotations-driven
StateObjectFactory implementation.
On 10/17/05, Lance Arlaus <[EMAIL PROTECTED]> wrote:
> I'm currently designing a dependency injection solution for use within
> application state objects that I'd also like to use elsewhere in my
> application.
>
> The idea is simple - I have a set of services that I need to use
throughout
> the app for which I don't want to be passing references around.
> A good example is the Vlib sample that ships with Tap4. Taking a look at
> the Visit object, it requires an IRequestCycle object to be passed in to
get
> the current user - I'd like to do away with this.
>
> // Copied from Vlib - Visit.java
> // Don't want to be passing this around!
> public Person getUser(IRequestCycle cycle)
> {
> ...
> VirtualLibraryEngine vengine = (VirtualLibraryEngine)
cycle.getEngine();
> _user = vengine.readPerson(_userId);
> ...
> }
>
> What I'd like to do is simply annotate my Visit object and, with the right
> HiveMind configuration, have it retrieve a request specific reference to
> necessary application services.
> Something like the following (additional notes inline):
>
> public class Visit implements Serializable {
>
> /*
> * This should retrieve an object created or retrieved
> * from a pool and bound to the current request (thread).
> * AppServices will have injected objects of its own
> * (references to EJBs, etc.)
> */
> @InjectObject("service:myapp.services")
> public abstract AppServices getAppServices()
> {
> }
> }
>
>
> Any idea on how to get this to work properly and efficiently (including
the
> nested HiveMind annotations within AppServices)?
>
> -Lance
>
>
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>
>
>
--
Howard M. Lewis Ship
Independent J2EE / Open-Source Java Consultant
Creator, Jakarta Tapestry
Creator, Jakarta HiveMind
Professional Tapestry training, mentoring, support
and project work. http://howardlewisship.com
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