11 © copyright 2008 ibm corporation. the all-singing, all-dancing composite application doug...

11© Copyright 2008 IBM Corporation.

The All-Singing, All-Dancing The All-Singing, All-Dancing Composite Application Composite Application

Doug Tidwell, IBMdtidwell@us.ibm.com

2© Copyright 2008 IBM Corporation.

StatusStatus

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The big pictureThe 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:– 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.

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Our scenarioOur 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.

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Key standard #1: SCAKey standard #1: SCA

• We need a single, coherent, manageable way to build composite applications.

• I’m assuming we’re all in agreement here…

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Key standard #2: SDOKey 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.

7© Copyright 2008 IBM Corporation.

Key standard #2a: XFormsKey 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.

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Key standard #3: BPELKey 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.

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Component A(BPEL workflow)

Component B(Credit check)

Order Processing Composite

Our applicationOur application

Component C(Shipping)

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Assembly with SCAAssembly 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.

11© Copyright 2008 IBM Corporation.

Data access with SDOData 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.

12© Copyright 2008 IBM Corporation.

Human interfaces with XFormsHuman 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.

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DemoDemo

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The SCA RoadshowThe SCA Roadshow

Coming soon to a continent near you!

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The SCA RoadshowThe 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.

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oasis-opencsa.org/sca-roadshow/oasis-opencsa.org/sca-roadshow/

1717© Copyright 2008 IBM Corporation.

If you’re interested in participating / hosting, contact

Doug Tidwell, dtidwell@us.ibm.com.