[Dcciv-users] Drink orders are not necessarily completed in the order they were placed.

[Rodriquez V. Lew]

I love BPEL as an execution language but too often I see some vendor
making a pitch that business analysts will use a BPEL-centric tool  to
model business processes.
The topic is often expressed as a simple string.
For practical applications, though, both kinds of problems are relevant
factors in the adoption of Service-oriented architectures.
They look at a message, make a simple decision and republish the message.

YYY

Trading Date : 12/12/06
Name : Chef Selections Inc.
Symbol : CFSC
Today : $0.1
4 Day Target : $0.7
Rating : MAX

YYY

For example, if one component stores data in a central database that is
read by another component, we introduced an "out of band" dependency
between the two components.
There is a reason these elements are patterns and not a coding library.
A lot of the themes we came up with relate to integrating with other
applications, but this time we view them from the perspective of an
application. Using such a two-phase-commit approach would certainly kill
Starbucks' business because the number of customers they can serve
within a certain time interval would decrease dramatically. DC
architectures typically link components directly to one another, making
the solutions brittle. More coupling gives us efficiency and simplicity
but can also introduce rigidity and brittleness. I intentionally held
back on giving everybody a copy of my book and say "Hey, use these
patterns!
However, new language syntax is often a big deterrent to commercial
developers.
But this also means that the system has fewer means of detecting our
mistakes. Not all ontologies are easily represented in a hierarchy tree
as the "Topics with Wildcards" approach requires.
I was a little worried that it would be a boring rerun of last year's
panel but it turned out to be pretty interesting even though Rod Johnson
was unusually kind to the Sun employees on the panel.
An extensible schema allows new versions of services to be introduced
without breaking existing services.
Correlation    By taking advantage of an asynchronous approach Starbucks
also has to deal with the same challenges that asynchrony inherently
brings.
At the same time the publish-subscribe property of the channel ensures
that this debug calculator does not affect any of the existing message
flow.
It is one possible implementation of a Splitter in a specific run-time
environment.
Instead, it is much easier to learn from the shortcomings of the last
attempt and to correct them based on incremental evolution. SeeBeyond
got so much crap from the analysts for its Monk language.
In order to allow for future flexibility we developed a set of
self-contained components, called "calculators", that we could connect
to one another via event channels. ConversationsThe coffee shop
interaction is also a good example of a simple, but common Conversation
pattern.
This feature makes it very convenient for calculators to subscribe to
multiple topics at once. asmx Web services, Soap Extension Reflectors,
WS-Addressing, WSDL and friends.
These systems consist of a collection of individual processing elements
that respond to incoming events. So what were some of the current
research topics that were discussed?
New Programming Model        Testing the actual composition of the
individual elements is another important part of validating the system.
oh wait, what happens in Vegas, stays in Vegas!
Satish Thatte from Microsoft, the other mastermind behind BPEL,
presented as well, so it was a great opportunity to get a behind the
scenes look at BPEL.
One advantage of this approach is that the core application does not
have to be modified internally. Also, this approach often makes it
inefficient to monitor the state of a conversation. As a result they use
asynchronous processing. As a result, the Indigo product management team
has asked me to take the posting down. This is only natural. A Turing
machine is stateful, in particular the band holds state and the head is
at a certain position, which is also state.
Once we get this part out of our system, the debate of statelessness
becomes a lot more productive.
Hidden assumptions are often unavoidable but can also introduce a glut
of problems. All panelists agreed to credit Microsoft with a good sense
of pragmatism and making it easy for developers to get started. But I
believe that other forces are at work.
The advantage is that the state of the conversation can be more easily
obtained by inspecting the blackboard.
Hey, Microsoft listens very actively to developers, the ideas are just
owned by MS in the end.
Descriptive messages constrained by an extensible schema delivered
through the interfaces.
It is one possible implementation of a Splitter in a specific run-time
environment. Waiting for a remote component to complete a task before
continuing execution at the source tends to make distributed
architectures unresponsive and brittle. Publish-Subscribe    One
interesting track focused on publish-subscribe messaging. Message Queues
   In order to remove the dependency on the TCP stack for state
management we can use asynchronous message channels to communicate
between parties. My general attitude is that skepticism is healthy but
you never know until you try. However, new language syntax is often a
big deterrent to commercial developers.
I particularly like the examples, e.
Content-based Subscription.
When a processing element receives an event message it perform its
designated function and publishes one or more resulting events.