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


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

  1. 1. Service Oriented Architecture (SOA) And Web Services By Ahmed Chaudhary
  2. 2. Presentation overview <ul><li>Introduction to SOA </li></ul><ul><ul><li>Through Examples and Metaphors </li></ul></ul><ul><li>Introduction to Web Services </li></ul><ul><ul><li>Brief overview of XML Technologies </li></ul></ul><ul><li>Comparison of SOA and services with other paradigms </li></ul><ul><li>Benefits and limitations of SOA </li></ul>
  3. 3. A business trip in the not so distant future
  4. 5. Information Technology used in this trip <ul><li>Keeping track of all the customer contacts in an online repository </li></ul><ul><li>Obtaining Company Contact Information from an External Service </li></ul><ul><li>Online Calendar Services </li></ul><ul><li>Getting Updates on Clients to Be Visited While on the Road </li></ul><ul><li>Travel Agency Service </li></ul><ul><li>Car Rental Service </li></ul><ul><li>Airlines and Hotel </li></ul><ul><li>Services as Commodities </li></ul>
  5. 6. Another Example
  6. 7. SOA Explained <ul><li>A service-oriented architecture is essentially a collection of services. </li></ul><ul><li>These services communicate with each other </li></ul><ul><li>Some mechanism of connecting services to each other is needed. Those connections are Web Services. </li></ul>
  7. 8. What is a service ? <ul><li>A function that is well-defined </li></ul><ul><li>Self-contained </li></ul><ul><li>Does not depend on the context or state of other services. </li></ul>
  8. 9. The Mail-Order Business <ul><li>A Mail-Order Business is Asynchronous </li></ul><ul><ul><li>Work Requests Arrive in Bags of Mail </li></ul></ul><ul><ul><li>Product Arrives in Shipments </li></ul></ul><ul><li>Each Message (Order) Is a Transaction </li></ul><ul><ul><li>Goods Are Prepared and Packed </li></ul></ul><ul><ul><li>Payment Is Processed </li></ul></ul><ul><ul><li>Stuff is Shipped </li></ul></ul><ul><li>Standards and Interchangeability Required </li></ul><ul><ul><li>Both Goods and Forms </li></ul></ul><ul><li>Mail-Order Is a Service- Oriented Architecture! </li></ul><ul><ul><li>Well defined functions </li></ul></ul><ul><ul><li>Self-contained </li></ul></ul><ul><ul><li>Independent </li></ul></ul>
  9. 10. How Services Work
  10. 11. Web Services <ul><li>Web services are the mechanism for connecting services programmatically and are based on standards. </li></ul><ul><li>Other existing connection mechanisms: </li></ul><ul><ul><li>CORBA </li></ul></ul><ul><ul><li>DCOM </li></ul></ul><ul><ul><li>EDI etc. </li></ul></ul>
  11. 12. How Web Services Work
  12. 13. More on Web Services <ul><li>Web services can be published, located, and invoked across the Web. </li></ul><ul><li>The standards required to do so are: </li></ul><ul><ul><li>Simple Object Access Protocol (SOAP), also known as service-oriented architecture protocol, an XML-based RPC and messaging protocol </li></ul></ul><ul><ul><li>Web Service Description Language (WSDL), a descriptive interface and protocol binding language </li></ul></ul><ul><ul><li>Universal Description, Discovery, and Integration (UDDI), a registry mechanism that can be used to look up Web service descriptions </li></ul></ul>
  13. 14. Some points about Web Services <ul><li>Services aren’t tied to user interfaces. </li></ul><ul><li>Services can be implemented in any language, COBOL, Java, etc., but all services must support the same invocation/communication protocols (for example XML/SOAP) </li></ul>
  14. 15. Introduction to XML and related Technologies
  15. 16. What is XML? <ul><li>XML stands for E X tensible M arkup L anguage </li></ul><ul><li>XML is a markup language much like HTML </li></ul><ul><li>XML was designed to describe data </li></ul><ul><li>XML tags are not predefined. You must define your own tags </li></ul>
  16. 17. An Example
  17. 18. What is an XML Schema? <ul><li>The purpose of an XML Schema is to define the building blocks of an XML document </li></ul><ul><ul><li>defines elements that can appear in a document </li></ul></ul><ul><ul><li>defines which elements are child elements </li></ul></ul><ul><ul><li>defines the order of elements </li></ul></ul><ul><ul><li>defines the number of child elements </li></ul></ul><ul><ul><li>defines data types for elements and attributes </li></ul></ul>
  18. 19. What is SOAP?
  19. 20. What is WSDL? <ul><li>WSDL stands for Web Services Description Language. </li></ul><ul><li>WSDL is a document written in XML. </li></ul><ul><li>The document describes a Web service. It specifies the location of the service and the operations (or methods) the service exposes. </li></ul>
  20. 21. Comparisons of SOA
  21. 22. SOA vs CORBA & DCOM
  22. 23. SOA vs. Enterprise Integration Architecture (EIA) <ul><li>EIA is being reactive </li></ul><ul><li>SOA is being proactive </li></ul>
  23. 24. Services vs. Components <ul><li>A service is a coarse-grained processing and maps to a business function </li></ul><ul><li>A component typically maps to business entities and the business rules </li></ul>
  24. 25. An example component model
  25. 26. Revisiting the Business Trip
  26. 28. Why do we need SOA? <ul><li>There's little &quot;green field&quot; anymore </li></ul><ul><ul><li>New stuff needs existing stuff </li></ul></ul><ul><ul><li>Existing stuff needs new stuff </li></ul></ul><ul><li>Heterogeneous Systems </li></ul><ul><ul><li>No single OS-family / HW-platform </li></ul></ul><ul><li>Deal with &quot;Big Bang&quot; Effect </li></ul><ul><ul><li>Everything keeps drifting farther away from everything else </li></ul></ul><ul><ul><li>Access/Manipulate data from anywhere </li></ul></ul>
  27. 29. SOA Benefits <ul><li>Leverage existing assets. </li></ul><ul><li>Easier to integrate and manage complexity. </li></ul><ul><li>More responsive and faster time-to-market. </li></ul><ul><li>Reduce cost and increase reuse. </li></ul><ul><li>Be ready for what lies ahead. </li></ul>
  28. 30. SOA Limitations <ul><li>SOA requires an environmental framework </li></ul><ul><li>Pending security issues </li></ul><ul><li>Handling Transactions </li></ul>
  29. 31. Summary <ul><li>SOA is an architectural style that encourages the creation of loosely coupled business services Loosely coupled services that are interoperable and technology-agnostic enable business flexibility </li></ul><ul><li>An SOA solution consists of a composite set of business services that realize an end-to-end business process </li></ul><ul><li>Each service provides an interface-based service description to support flexible and dynamically re-configurable processes </li></ul>
  30. 32. Q & A