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Service Oriented Service Oriented Architecture (SOA)Architecture (SOA)And Web ServicesAnd Web Services

By By Ahmed ChaudharyAhmed Chaudhary

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Presentation overviewPresentation overview

• Introduction to SOAIntroduction to SOA– Through Examples and MetaphorsThrough Examples and Metaphors

• Introduction to Web ServicesIntroduction to Web Services– Brief overview of XML TechnologiesBrief overview of XML Technologies

• Comparison of SOA and services with Comparison of SOA and services with other paradigmsother paradigms

• Benefits and limitations of SOABenefits and limitations of SOA

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A business trip in the not A business trip in the not so distant futureso distant future

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Information Technology used in Information Technology used in this tripthis trip• Keeping track of all the customer contacts in an Keeping track of all the customer contacts in an

online repositoryonline repository• Obtaining Company Contact Information from an Obtaining Company Contact Information from an

External Service External Service • Online Calendar ServicesOnline Calendar Services• Getting Updates on Clients to Be Visited While on Getting Updates on Clients to Be Visited While on

the Roadthe Road• Travel Agency ServiceTravel Agency Service• Car Rental ServiceCar Rental Service• Airlines and HotelAirlines and Hotel• Services as CommoditiesServices as Commodities

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Another ExampleAnother Example

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SOA ExplainedSOA Explained

• A service-oriented architecture is A service-oriented architecture is essentially a collection of services. essentially a collection of services.

• These services communicate with These services communicate with each other each other

• Some mechanism of connecting Some mechanism of connecting services to each other is needed. services to each other is needed. Those connections are Those connections are Web Services.Web Services.

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What is a service ?What is a service ?

• A function that is well-definedA function that is well-defined

• Self-containedSelf-contained

• Does not depend on the context or Does not depend on the context or state of other services. state of other services.

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The Mail-Order BusinessThe Mail-Order Business• A Mail-Order Business is AsynchronousA Mail-Order Business is Asynchronous

– Work Requests Arrive in Bags of MailWork Requests Arrive in Bags of Mail– Product Arrives in ShipmentsProduct Arrives in Shipments

• Each Message (Order) Is a TransactionEach Message (Order) Is a Transaction– Goods Are Prepared and PackedGoods Are Prepared and Packed– Payment Is ProcessedPayment Is Processed– Stuff is ShippedStuff is Shipped

• Standards and Interchangeability RequiredStandards and Interchangeability Required– Both Goods and FormsBoth Goods and Forms

• Mail-Order Is a Service-Mail-Order Is a Service-Oriented Architecture!Oriented Architecture!– Well defined functionsWell defined functions

– Self-containedSelf-contained– IndependentIndependent

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How Services WorkHow Services Work

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Web ServicesWeb Services

• Web services are the mechanism for Web services are the mechanism for connecting services programmatically connecting services programmatically and are based on standards.and are based on standards.

• Other existing connection mechanisms:Other existing connection mechanisms:– CORBACORBA– DCOMDCOM– EDI etc.EDI etc.

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How Web Services WorkHow Web Services Work

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More on Web ServicesMore on Web Services

• Web services can be published, located, and invoked across the Web.

• The standards required to do so are:– Simple Object Access Protocol (SOAP), also known as

service-oriented architecture protocol, an XML-based RPC and messaging protocol

– Web Service Description Language (WSDL), a descriptive interface and protocol binding language

– Universal Description, Discovery, and Integration (UDDI), a registry mechanism that can be used to look up Web service descriptions

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Some points about Web Some points about Web ServicesServices

• Services aren’t tied to user Services aren’t tied to user interfaces. interfaces.

• Services can be implemented in any Services can be implemented in any language, COBOL, Java, etc., but all language, COBOL, Java, etc., but all services must support the same services must support the same invocation/communication protocols invocation/communication protocols (for example XML/SOAP) (for example XML/SOAP)

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Introduction to XML and Introduction to XML and related Technologiesrelated Technologies

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What is XML?What is XML?

• XML stands for EXML stands for EXXtensible tensible MMarkup arkup LLanguage anguage

• XML is a XML is a markup languagemarkup language much much like HTML like HTML

• XML was designed to XML was designed to describe datadescribe data

• XML tags are not predefined. You XML tags are not predefined. You must must define your own tagsdefine your own tags

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An ExampleAn Example

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What is an XML Schema?What is an XML Schema?

• The purpose of an XML Schema is to The purpose of an XML Schema is to define the building blocks of an XML define the building blocks of an XML document document – defines elements that can appear in a defines elements that can appear in a

document document – defines which elements are child elements defines which elements are child elements – defines the order of elements defines the order of elements – defines the number of child elements defines the number of child elements – defines data types for elements and defines data types for elements and

attributes attributes

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What is SOAP?What is SOAP?

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What is WSDL?What is WSDL?

• WSDL stands for Web Services WSDL stands for Web Services Description Language.Description Language.

• WSDL is a document written in XML. WSDL is a document written in XML.

• The document describes a Web The document describes a Web service. It specifies the location of service. It specifies the location of the service and the operations (or the service and the operations (or methods) the service exposes.methods) the service exposes.

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Comparisons of SOA Comparisons of SOA

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SOA vs CORBA & DCOMSOA vs CORBA & DCOM

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SOA vs. Enterprise Integration SOA vs. Enterprise Integration Architecture (EIA)Architecture (EIA)

• EIA is being reactiveEIA is being reactive

• SOA is being proactiveSOA is being proactive

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Services vs. ComponentsServices vs. Components

• A service is a coarse-grained A service is a coarse-grained processing and maps to a business processing and maps to a business functionfunction

• A component typically maps to A component typically maps to business entities and the business business entities and the business rulesrules

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An example component An example component modelmodel

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Revisiting the Business Revisiting the Business TripTrip

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Why do we need SOA?Why do we need SOA?• There's little "green field" anymoreThere's little "green field" anymore

– New stuff needs existing stuffNew stuff needs existing stuff– Existing stuff needs new stuffExisting stuff needs new stuff

• Heterogeneous SystemsHeterogeneous Systems– No single OS-family / HW-platformNo single OS-family / HW-platform

• Deal with "Big Bang" EffectDeal with "Big Bang" Effect– Everything keeps drifting farther away Everything keeps drifting farther away

from everything else from everything else – Access/Manipulate data from anywhereAccess/Manipulate data from anywhere

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SOA BenefitsSOA Benefits

• Leverage existing assets.Leverage existing assets.

• Easier to integrate and manage Easier to integrate and manage complexity.complexity.

• More responsive and faster time-to-More responsive and faster time-to-market.market.

• Reduce cost and increase reuse.Reduce cost and increase reuse.

• Be ready for what lies ahead.Be ready for what lies ahead.

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SOA LimitationsSOA Limitations

•SOA requires an environmental framework

•Pending security issues

•Handling Transactions

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SummarySummary• SOA is an architectural style that SOA is an architectural style that

encourages the creation of loosely coupled encourages the creation of loosely coupled business services Loosely coupled services business services Loosely coupled services that are interoperable and technology-that are interoperable and technology-agnostic enable business flexibility agnostic enable business flexibility

• An SOA solution consists of a composite set An SOA solution consists of a composite set of business services that realize an end-to-of business services that realize an end-to-end business process end business process

• Each service provides an interface-based Each service provides an interface-based service description to support flexible and service description to support flexible and dynamically re-configurable processes dynamically re-configurable processes

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Q & AQ & A