Transcript Building Next-Generation SOAs with Service Component

The All-Singing, All-Dancing
Composite Application
Doug Tidwell, IBM
[email protected]
© Copyright 2008 IBM Corporation.
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Status
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© Copyright 2008 IBM Corporation.
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The big picture
• Our composite application processes a purchase
order.
• We’ll take a very quick look at four technologies that
are the future of SOA:
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All of the services involved are accessed with SCA.
The data sources are accessed with SDO.
The interface is based on XForms.
The process definition is based on BPEL.
© Copyright 2008 IBM Corporation.
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Our scenario
• The customer submits an order.
• We check the total of the order. Any order of more
than $750 (£38, €57) must be approved by a
manager. Anything less automatically goes to the
next step in the process.
• If the order is approved, we check the customer’s
account status.
• If the order is approved and the customer’s credit is
OK, we send the customer a notice that their order is
on the way.
© Copyright 2008 IBM Corporation.
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Key standard #1: SCA
• We need a single, coherent, manageable way to
build composite applications.
• I’m assuming we’re all in agreement here…
© Copyright 2008 IBM Corporation.
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Key standard #2: SDO
• We need a single, coherent, manageable way to
move data from one place to the next.
– In a composite application, data will most likely be XML.
– In a composite application, different components will need
data in different formats.
– Similar yet incompatible data binding frameworks will
outnumber the human population by 3Q 2013.
© Copyright 2008 IBM Corporation.
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Key standard #2a: XForms
• With XML as a universal data interchange format,
HTML forms aren’t an ideal option.
– Not built around a data model
– Controls are hand-linked to items in the data model
– Changes to the data model require manual changes to all
interfaces
• XForms overcomes these limitations:
– The form is built around an XML data model (XML Schema,
most likely)
– Controls are bound directly to the XML (XPath ties control x
to element/attribute y)
– The interface can be regenerated from an updated schema.
© Copyright 2008 IBM Corporation.
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Key standard #3: BPEL
• An application with any degree of sophistication will
likely require workflow and human interaction.
– We’ll use BPEL to define the workflow. Many steps in the
workflow will be services.
– A BPEL process is itself a WSDL-addressable service (or an
SCA service)
– Human tasks typically involve reviewing some sort of
business object (XML document)…XForms fits nicely here.
© Copyright 2008 IBM Corporation.
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Our application
Order Processing Composite
Component B
(Credit check)
Component A
(BPEL workflow)
Component C
(Shipping)
© Copyright 2008 IBM Corporation.
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Assembly with SCA
• Current implementations let us access a BPEL
process as an SCA component
(<implementation.bpel>).
• Ideally the BPEL process could access SCA
components as steps in the process, although we’re
not there yet.
© Copyright 2008 IBM Corporation.
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Data access with SDO
• There are a number of business objects:
– Purchase order
• Customer number, items+, status
– Customer
• Customer number, name/address, credit rating
• We’ve kept this simple; a real-world scenario would
use many more objects.
• Each business object is defined with XML Schema
and manipulated by SDO.
© Copyright 2008 IBM Corporation.
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Human interfaces with XForms
• We’ll look at different XForms that deal with the
human tasks in the process.
• These can be generated directly from the XML
documents (BPEL variables) defined in the process.
– We’ll define an XHTML frame to hold the controls and style
everything with CSS.
© Copyright 2008 IBM Corporation.
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Demo
© Copyright 2008 IBM Corporation.
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The SCA Roadshow
Coming soon to a continent near you!
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The SCA Roadshow
• OASIS is sponsoring a series of half-day sessions on
SCA.
• These sessions are vendor-neutral explorations of
SCA as a technology.
• See oasis-opencsa.org/sca-roadshow/ to
register.
– We have three events scheduled for China in May; others
are coming throughout the year.
© Copyright 2008 IBM Corporation.
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oasis-opencsa.org/sca-roadshow/
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If you’re interested in
participating / hosting, contact
Doug Tidwell, [email protected].
© Copyright 2008 IBM Corporation.
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