You are viewing a plain text version of this content. The canonical link for it is here.
Posted to java-dev@axis.apache.org by Glen Daniels <gl...@thoughtcraft.com> on 2007/06/22 18:52:01 UTC
[axis2] Handler interface (cleanup(), flowComplete() and errors)
A few questions about the Handler interface based on recent conversations:
1) cleanup() never gets called. Can we remove it now that we've got
flowComplete()?
2) flowComplete() seems somewhat flawed in that there is currently no
way (AFAICT) to conclusively determine whether it is being called as a
result of a fault/thrown exception or due to the normal termination of
processing. This leaves no easy way for Handler developers to do
rollbacks of any work they've done. It appears we used to have
revoke(), which I think seems like the right thing (it's easier to code
an explicit fault handler API than it is to remember to check for
something that the compiler won't tell you about), but that was
apparently replaced with flowComplete()?
PROPOSAL - add a "failureReason" field (of type Exception) to
MessageContext, and ensure that the engine ALWAYS sets this if we have
to back out the processing chain due to an error. Leave flowComplete()
as is, but now implementors can mc.getFailureReason() and react
appropriately.
3) Why are we forcing every Handler to keep a pointer to it's
HandlerDesc? We only call this in a couple of places (Phase), and IMHO
it clutters up the interface unnecessarily. It seems like Phase should
be keeping HandlerDescs, and those should be pointing to Handlers...
that would more loosely and cleanly decouple the two classes.
Comments/thoughts?
Thanks,
--Glen
---------------------------------------------------------------------
To unsubscribe, e-mail: axis-dev-unsubscribe@ws.apache.org
For additional commands, e-mail: axis-dev-help@ws.apache.org
Re: [axis2] Handler interface (cleanup(), flowComplete() and errors)
Posted by Davanum Srinivas <da...@gmail.com>.
Glen,
+1 to #1 and #2. I think we should leave #3 as-is. If we do just #1
and #2, people who already have classes that implement Handler's will
not have to change anything.
thanks,
dims
On 6/22/07, Glen Daniels <gl...@thoughtcraft.com> wrote:
>
> A few questions about the Handler interface based on recent conversations:
>
> 1) cleanup() never gets called. Can we remove it now that we've got
> flowComplete()?
>
> 2) flowComplete() seems somewhat flawed in that there is currently no
> way (AFAICT) to conclusively determine whether it is being called as a
> result of a fault/thrown exception or due to the normal termination of
> processing. This leaves no easy way for Handler developers to do
> rollbacks of any work they've done. It appears we used to have
> revoke(), which I think seems like the right thing (it's easier to code
> an explicit fault handler API than it is to remember to check for
> something that the compiler won't tell you about), but that was
> apparently replaced with flowComplete()?
>
> PROPOSAL - add a "failureReason" field (of type Exception) to
> MessageContext, and ensure that the engine ALWAYS sets this if we have
> to back out the processing chain due to an error. Leave flowComplete()
> as is, but now implementors can mc.getFailureReason() and react
> appropriately.
>
> 3) Why are we forcing every Handler to keep a pointer to it's
> HandlerDesc? We only call this in a couple of places (Phase), and IMHO
> it clutters up the interface unnecessarily. It seems like Phase should
> be keeping HandlerDescs, and those should be pointing to Handlers...
> that would more loosely and cleanly decouple the two classes.
>
> Comments/thoughts?
>
> Thanks,
> --Glen
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: axis-dev-unsubscribe@ws.apache.org
> For additional commands, e-mail: axis-dev-help@ws.apache.org
>
>
--
Davanum Srinivas :: http://davanum.wordpress.com
---------------------------------------------------------------------
To unsubscribe, e-mail: axis-dev-unsubscribe@ws.apache.org
For additional commands, e-mail: axis-dev-help@ws.apache.org
Re: [axis2] Handler interface (cleanup(), flowComplete() and
errors)
Posted by Bill Nagy <na...@watson.ibm.com>.
Hi Glen,
On Fri, 2007-06-22 at 12:52 -0400, Glen Daniels wrote:
> A few questions about the Handler interface based on recent conversations:
>
> 1) cleanup() never gets called. Can we remove it now that we've got
> flowComplete()?
I had always assumed that cleanup() was the counterpart to init(), and
thus would be called when a handler was "deregistered" thereby providing
the handler with the ability to release resources that it had acquired.
I'm happy to have it removed until someone actually needs that type of
functionality.
> 2) flowComplete() seems somewhat flawed in that there is currently no
> way (AFAICT) to conclusively determine whether it is being called as a
> result of a fault/thrown exception or due to the normal termination of
> processing. This leaves no easy way for Handler developers to do
> rollbacks of any work they've done. It appears we used to have
> revoke(), which I think seems like the right thing (it's easier to code
> an explicit fault handler API than it is to remember to check for
> something that the compiler won't tell you about), but that was
> apparently replaced with flowComplete()?
>
> PROPOSAL - add a "failureReason" field (of type Exception) to
> MessageContext, and ensure that the engine ALWAYS sets this if we have
> to back out the processing chain due to an error. Leave flowComplete()
> as is, but now implementors can mc.getFailureReason() and react
> appropriately.
+1
> 3) Why are we forcing every Handler to keep a pointer to it's
> HandlerDesc? We only call this in a couple of places (Phase), and IMHO
> it clutters up the interface unnecessarily. It seems like Phase should
> be keeping HandlerDescs, and those should be pointing to Handlers...
> that would more loosely and cleanly decouple the two classes.
>
I assume that you mean removing the getHandlerDesc() method (and not
removing the HandlerDescription being passed into the Handler) -- +1 if
we're already modifying the Handler interface to remove the cleanup()
method.
> Comments/thoughts?
If we're only going to do (1) or (3), but not both, then perhaps we
shouldn't do either unless it provides a great enough improvement to the
code quality such that it's worth forcing users to modify their
implementations.
>
> Thanks,
> --Glen
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: axis-dev-unsubscribe@ws.apache.org
> For additional commands, e-mail: axis-dev-help@ws.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: axis-dev-unsubscribe@ws.apache.org
For additional commands, e-mail: axis-dev-help@ws.apache.org