RE: [JBoss-dev] Proposal for jboss-wide interceptor framework

[Bill B. <bi...@jb...>]

The AOP framework really right now is only for POJO interception.  I do have
the beginnings of DynamicProxies though.  The AOP POJO framework can
intercept static and member methods, constructors, and fields.  YOu can
define metadata on a class via xml, as well as interceptor stacks at the
Class level.  You can add interceptors to a specific instance at runtime.  I
have ported 2 interceptors so far to the AOP framework.  TX and Security.
Security compiles but is currently untested.

For a minimum, I'd like everybody to at least use the Invocation object I've
created for the AOP framework.  The payloads in the
server/src/org/jboss/invocation/Invocation object have been abstracted into
its own object (SimpleMetaData).   The Invocation object holds the
interceptor chain and is typeless as well.  What I mean by typeless is that
the Invocation object can be used for any type of invocation.  Method,
field, Constructor, JMS message, whatever.

I'd like to finish the beginnings of the DP framework and apply them to EJB
client-side interceptors but am having a hard time getting more than an hour
at a time to focus on this big change.

For JMX, you can already define AOP interceptors just like you would for any
Java class.  This isn't a complete solution for JMX though since JMX is
instance based and not class based.  The AOP framework has a concept of
pointcuts.  I'd like to add a MBean pointcut.  What will happen is all MBean
classes will be instrumented by the AOP framework.  The AOP manager will
deploy JMX pointcuts/interceptions by adding interceptors per MBean.  The
AOP framework already supports adding interceptors to a specific Object
instance.  Its just a matter of hooking up the configuration mechanism.  I'm
not sure if this is a good enough solution yet.

As far as remoting goes for AOP, I want to first go the DynamicProxy route.
If a user wants to remote a POJO, a DynamicProxy is created and remote
invocations go through this proxy.  EJB currently has client interceptors
grouped as proxy-invoker binding.  I think this is the kind of approach we
could use for AOP at first.

For EJBs, I think it is just a matter of finishing the AOP DP framework and
using it for client interceptors.  This will force EJBs to use the AOP
Invocation object and to access interceptors the same way as AOP, which is a
little different.

JMX remoting is a problem though because the client can dynamically create a
connection to an MBean via JMX connectors.  The problem is, how do you get
the client-side interceptor chain back to the client when the client creates
a connection?  We don't have this problem with JNDI or EJB because the
client must go to a specific port (JNDI) or repository(EJB to JNDI) and we
can provide the client DPs there.

My problem right now with all this stuff is that I cannot seem to focus on
it for more than an hour without getting interrupted to do something else.

Bill

> -----Original Message-----
> From: jbo...@li...
> [mailto:jbo...@li...]On Behalf Of
> Nathan Phelps
> Sent: Sunday, March 02, 2003 4:17 PM
> To: jbo...@li...
> Subject: RE: [JBoss-dev] Proposal for jboss-wide interceptor framework
>
>
>
> I agree.  As I begin the development of JMS/JBoss 4.0, I'm, frankly,
> confused as to which direction to go concerning the interceptor
> framework--which project is THE project?  There is some great work being
> done right now by a variety of people on this problem, but I have no
> idea how it all fits together--if it fits together.  I wish we could
> settle this problem, agree on which direction we are going, and then get
> the code base stabilized so those of us building services that will use
> THE framework can have the confidence that we're working with the right
> one and that it works as advertised.
>
> Thanks,
>
> Nathan
>
> -----Original Message-----
> From: jbo...@li...
> [mailto:jbo...@li...] On Behalf Of
> Scott M Stark
> Sent: Sunday, March 02, 2003 1:37 PM
> To: jbo...@li...
> Subject: Re: [JBoss-dev] Proposal for jboss-wide interceptor framework
>
> Woa, before we have a full fledged interceptor war show up in main what
> is the
> status of the various JMX, AOP, etc interceptors and associated
> frameworks?
> It seems like several people are running around writing this without
> demonstrating
> how it applies to the existing services. A simple example is how do I
> expose the
> existing JNDI naming service via RMI/JRMP and RMI/HTTP with that ability
> to introduce security and persistence?
>
> xxxxxxxxxxxxxxxxxxxxxxxx
> Scott Stark
> Chief Technology Officer
> JBoss Group, LLC
> xxxxxxxxxxxxxxxxxxxxxxxx
>
>
>
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