SOA Case Study

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SOA Case Study
Eben HewittBangaloreNovember 3-4, 2009
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goal

• Help you implement SOA in your environment by
  learning from the challenges and choices we
  faced.

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who i am

• Architect at a multi-billion dollar, 50 year-old
  US retailer
• Speaker on SOA at JavaOne, others
• Interviewed on SOA by InfoQ
• Author of 5 books including Java SOA Cookbook
  (OReilly, 2009)
• Contributor to 97 Things Every Software Architect
  Should Know (OReilly, 2009)
• Other contributors include Gregor Hohpe, Bill de
  hÓra, Neal Ford, editor Richard Monson-Haefel.
• Many certifications in Java, Web Services, TOGAF
• I kitties

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What is SOA?

• SOA is a kind of architecture...
• that uses services as building blocks
• to facilitate enterprise integration
• and component reuse
• through loose coupling.

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Our Approach

• Start with well-defined business initiatives and
  outcomes
• Deliver architecture and pilot services
  concurrently
• Work within Center of Excellence
• Integrate, Communicate, Educate

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Getting Started

• Central Team (CoE)
• Pilot Project
• QuickScreen Credit Card approvals
• SOA Team Does Full Round-Trip
• Produce and Consume/Integrate
• Service, Orchestration, ESB
• Incubate Reference Architecture Services
  concurrently
• Educate Evangelize Concurrently
• Ref Arch Site Blog

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3-Stage Plan
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Selecting a Pilot

• Does it create business value?
• Does it have limited scope?
• Would it make a good service?
• Is it useful but not mission critical?

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Our Choice SOAP

• Wide industry support
• JAX-WS makes it easy
• Strong interface
• EJB only is Java-specific
• Almost-free add-on standards support
• RM, AT, Addressing

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SOAP APIs
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Our Choice ESB Early

• Performs Routing, Transformation, Orchestration,
  Mediation
• Services exposed as WSDL
• Multiple ESBs
• Data Services (common)
• Payment ESB (PCI)
• All interaction is bus-to-bus
• One Logical Bus per business unit
• Can expand into Regional Buses
• Can be a product or patterns

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Layout
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Our Choice Open Source

• Easiest to Start
• No lengthy RFP process
• No business justification
• Standards
• Easy Exit Strategy

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Determine a Start-From Model

• Determine a Service Elicitation Model
• Top Down or Bottom up or Both
• Determine a Service Creation Model
• Java, WSDL, Java and WSDL, Schema

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Determine a Data Model

• XML-Centric
• Business Document entities
• Start-from-Schema
• Only Schema Types from JAXB exchanged in public
  interfaces
• Limited customizations
• Define Canonical Data Model
• Incrementally
• Transform on ESB as necessary

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Schema Validation with JAXB Types

• Class clazz CreditCard.class
• JAXBContext ctx JAXBContext.newInstance(clazz)
• Marshaller m ctx.createMarshaller()
• QName qName new QName("http//ns.soacookbook.com
  /credit", "creditCard", "")
• JAXBElementltCreditCardgt payload new
  JAXBElementltCreditCardgt(
• qName, CreditCard.class, card)
• SchemaFactory sf SchemaFactory.newInstance(XMLCo
  nstants.W3C_XML_SCHEMA_NS_URI)
• Schema schema sf.newSchema(new StreamSource(new
  File(schemaFile)))
• m.setSchema(schema)
• DocumentBuilder db DocumentBuilderFactory.newIn
  stance().newDocumentBuilder()
• Document doc db.newDocument()
• m.marshal(payload , doc) //return doc, add to
  SOAPMessage Body

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Determine a Schema Design Pattern

• Russian Doll
• Schema mirrors an instance
• Single valid global root element, all other
  elements local
• Easiest to read and write
• Limits reuse
• Salami Slice
• Totally decomposed (no nesting of element
  declarations)
• Must define all elements to be global--many
  potential roots
• Confusing
• Venetian Blind
• Single valid global root element, all other
  elements local
• But all of its types are reusable
• Use named complex types, limiting encapsulation
• Garden of Eden

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Garden of Eden Schema Design

• Combines Venetian Blind and Salami Slice
• All elements and types are global many potential
  root elements
• Allows reuse of both elements and types
• Allows multiple files
• Most flexible
• Exposing types limits encapsulation
• Somewhat harder to read

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Garden of Eden Schema Example

• ltxsdschema xmlnsxsd"http//www.w3.org/2001/XMLS
  chema" targetNamespace"http//schemas.sun.com/poi
  nt/gardenofeden" xmlns"http//schemas.sun.com/poi
  nt/gardenofeden" elementFormDefault"qualified"gt
• ltxsdcomplexType name"PointType"gt
• ltxsdattribute name"x" type"xsdinteger"/gt
• ltxsdattribute name"y" type"xsdinteger"/gt
• lt/xsdcomplexTypegt
• ltxsdcomplexType name"LineType"gt
• ltxsdsequencegt
• ltxsdelement ref"PointA"/gt
• ltxsdelement ref"PointB"/gt
• lt/xsdsequencegt
• lt/xsdcomplexTypegt
• ltxsdelement name"PointA" type"PointType"/gt
• ltxsdelement name"PointB" type"PointType"/gt
• ltxsdelement name"Line" type"LineType"/gt
• lt/xsdschemagt

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Determine WSDL Approach

• Started from Java
• Then graduated to start from WSDL
• Style/Use/BindingDocument/Literal Bare
• Document/Literal Wrapped is Better Choice
• Use Abstract WSDL
• Imports schemas and defines operations
• Protocol Bindings policies defined externally
• Minimize Custom Bindings for Interop
• Asynchronous Ops

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Custom Binding for Async Mapping

• ltbindingsxmlnsxsd"http//www.w3.org/2001/XMLSch
  ema"xmlnswsdl"http//schemas.xmlsoap.org/wsdl/"
  xmlns"http//java.sun.com/xml/ns/jaxwswsdlLoca
  tion"SigCapAsync.wsdl"gt
• ltbindings node"wsdldefinitions"gtltenableAsyncMap
  pinggttruelt/enableAsyncMappinggt
• lt/bindingsgt

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Orchestrations

• Introduce Orchestration early to maximize
  decoupling
• No service directly invokes another to maximize
  reuse
• No service is directly invoked by client (use the
  ESB)
• We used BPEL initially, now Software AG Flow
• Use rules as a service
• Content Based Routing

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Our Choice Wait on UDDI

• UBR never happened
• Is anyone really doing this?
• We can and want to dictate
• Lots about the Business Entity in UDDI
• Many vendor tools make this available

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SOA Governance

• Enforces organizational policies and standards on
  two levels
• Strategic
• Align vision with business. What services? What
  processes? How to optimize business processes?
• Education, guidance
• Technical
• How to build, bundle, store, deploy, operate,
  version, monitor (runtime KPIs)
• BAM, runtime policies

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Phase II
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Vendor Products

• Less code
• Migrate our work
• Enterprise Repository
• Strong Governance
• Performance
• Business Process Management
• Design tools
• BAM
• Support

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Advantages of Vendor Tools

• Robust BAM
• Robust tool support
• Dont have to expert in Java or XML to use
• Manages whole life cycle
• Development
• Business Processes
• Governance

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On the Way SOAP REST

• REST
• Talk to the interface you get
• Atom Publishing Protocol
• Ease of use

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On the Way EDA/SOA

• SPEARS talk at Business Technology Summit

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thank you