RE: [alf-dev] Comments on the Flash Demo

["Brian Carroll" <BCarroll@xxxxxxxxxx>]

Here are answers to some of Mike's questions:

1. We had originally looked at using publish-subscribe model in general
and WS-Notification in particular, but on further investigation found
both to be inappropriate.  One notion behind the ALF Service Flows is
that of "managing the process".  That is, having a development manager
determine what the appropriate response to an event should be, rather
than leaving it up to processes to determine which events to respond to.
WS-Notification turned out to not be a good fit for certain classes of
tools, for example batch-oriented tools.  There were several issues with
WS-Notification, especially if used on the "front end" of the Event
Manager to subscribe to Events emitted by tools.  The problem was that
with certain classes of tools, such as transient, batch-oriented tools,
it was difficult for the EventManager to discover that the tool was
running and then subscribe to it to be notified of the event.

2. The meta model for ALF Events is described in the ALF Architecture
document.  A link to it can be found on the Architecture portion of the
ALF home page at www.eclipse.org/alf.

3. We had some meetings with the Higgins team.  Their direction on
Identity is promising but the delivery schedule did not match up with
ALF's. In addition, Higgins only addresses an aspect of what is needed
for ALF SSO.  ALF needs to deliver its 1.0 release candidate before the
Higgins release will be available. I have been following developments
with Higgins and reevaluate its applicability as we are planning the
post 1.0 efforts.  We have has a focus on pluggability and extensions in
the SSO design effort, so incorporating component from Higgins, such as
and Identity Server, should be quite doable.

4. I'll leave this for Tim Buss to elaborate on, but, in general, the
BPEL engine is intended to be pluggable, where any BPEL engine that
conforms to the BPEL spec should be usable.  

5. Yes, the project team recognizes the issues with examples that
include commercial software that requires licenses, and has two
approaches.  First, all the contributors have agreed to provide a "web
services" stub that would allow the ALF POC example to be run without
any proprietary software being needed.  When we post the POC as a
downloadable demo to ALF CVS, it will contain those stubs.  Secondly,
the team has already started to incorporate open source tools into the
example. [Tim can elaborate on this work.]

Regards,
Brian

Brian Carroll
Serena Fellow
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-----Original Message-----
From: alf-dev-bounces@xxxxxxxxxxx [mailto:alf-dev-bounces@xxxxxxxxxxx]
On Behalf Of Mike Milinkovich
Sent: Friday, February 24, 2006 10:29 AM
To: alf-dev@xxxxxxxxxxx
Subject: [alf-dev] Comments on the Flash Demo

I watched the ALF Flash demo
(http://www.eclipse.org/alf/ALF%20POC%20Demo.htm). Great stuff! Very
compelling. I really enjoyed it, and have already pointed several people
to it to learn more about the project.


I have a couple of questions and comments.

  1.. For some reason, I had been assuming that the integration engine
was going to be based on a publish/subscribe model. But it doesn't
appear that's the case. Can you point me to the right document I can
read to understand how the action side of service flows are defined?

  2.. I am not sure I understand the meta-model for the data being
passed when events fire. I would assume that this is the "secret sauce"
for tool integration in ALF, but it's not really mentioned in the demo.
Is this because it's still undefined?

  3.. With regards to the single sign-on, have you made a determination
as to whether Higgins will meet your needs?

  4.. Just out of idle curiousity, has the project evaluated the BPEL
engine that in the progress of migrating from TPTP to STP? The GPL
license used by ActiveBPEL could definitely be an issue. (I really mean
"could". I am not sure how the linking works in this case, so don't know
what the GPL license semantics would be like in this scenario. But as a
general statement, we attempt to avoid GPL code in Eclipse projects.)

  5.. A word of caution on samples and examples, just in case. As an
open source community, we need to ship samples and examples that
leverage open source runtimes. So at some point, you're going to have to
think through an example that leverages open source code, rather than
proprietary ones. I apologize if I'm stating the obvious or repeating
what Bjorn has already said, but I don't want to make the mistake of not
being explicit on the topic.


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