Andrew Rubinger [
http://community.jboss.org/people/ALRubinger] replied to the discussion
"Deferring instance creation/injection to CDI"
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Marius Bogoevici wrote:
Restarting the discussion. In summary, what Weld/CDI needs is:
1) EJB defers instance creation to an external component
- Weld deployer sets the instantiator components that will:
a) invoke the applicable CDI constructor of the EJB class
b) apply decorators on the EJB
c) *not* apply interceptors on the EJB - for now, this remains a
responsibility of the EJB container
I believe I've now released something which
accounts for this.
http://github.com/jbossejb3/jboss-ejb3-bean-instantiator
http://github.com/jbossejb3/jboss-ejb3-bean-instantiator
The above has been released as 1.0.0-alpha-1 and integrated into ejb3-core (ie. we now use
the abstraction for EJB bean instance creation). This has not yet been integrated into AS
yet (as that relies upon a release of core, which is a formal release chain).
The general idea is that you create an implementation of the SPI, and create an MC bean
called NAME_BEAN_INSTANCE_INSTANTIATOR from
http://github.com/jbossejb3/jboss-ejb3-bean-instantiator/blob/master/spi/...
http://github.com/jbossejb3/jboss-ejb3-bean-instantiator/blob/master/spi/...
Once you do this, the deployer impl will pick it up and wire things along such that the
EJBContainer uses it. So make one artifact which implements jboss-ejb3-instantiator-spi,
and inside it put the impl class and a META-INF/weld-bean-instantiator-jboss-beans.xml
which may look like:
<?xml version="1.0" encoding="UTF-8"?>
<!--
Declares a EJB3 Bean Instantiator
-->
<deployment xmlns="urn:jboss:bean-deployer:2.0">
<bean name="org.jboss.ejb3.bean.BeanInstantiator"
class="org.jboss.ejb3.instantiator.impl.Ejb31SpecBeanInstantiator" />
</deployment>
Check out the layout of the jboss-ejb3-instantiator-impl module for our current legacy
impl. Basically you'll be writing the same thing. :)
Also note that we currently don't support any construction parameters. ejb3-core
doesn't have any available to pass along. So even though the contract accepts
construction params, I'm passing in Object[]{}. If that needs to be addressed...let
me know and we'll figure something.
Marius Bogoevici wrote:
2) EJB container provides a hook for preprocessing interceptors after instantiation. The
main reason is that EJB interceptors may be CDI-injected
(note: could we reuse the same mechanism as for EJB instantiation, since it boils down to
producing an instance of the class? )
I'm pretty sure we could do this too. We have this bit of code, though I haven't
verified if it's currently used or cruft:
public Object createInterceptor(Class<?> interceptorClass) throws
InstantiationException, IllegalAccessException
{
Object instance = interceptorClass.newInstance();
InterceptorInjector interceptorInjector =
interceptorInjectors.get(interceptorClass);
assert interceptorInjector != null : "interceptorInjector not found for "
+ interceptorClass;
interceptorInjector.inject(null, instance);
return instance;
}
Plenty of room in there to both abstract away the instantiation or give some
post-instantiation callback before the instance is returned.
S,
ALR
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