WIXLIB

IntroductionService-oriented Architectures:A ReviewCSE507: SOA and WS, we studied– services,– Web Services standard,– business process alignment to IT service,– service-oriented architecture basics. We will– review CSE507 material– Discuss plans for IE565 We implemented a simple mash-up application in CSE507:– We will extend it and complete it in this course. Focus of IE565:– Service-enabling approaches for a variety of organizationsand applications (see your textbook)– Study associated concepts and technologies (semantic web,ontology development and use, web2.0) B. RamamurthyPage 1IE565 Spring 20081/17/2008About the textbook IE565 Spring 20081/17/2008What did we do in CSE507?It is one in a series of textbook in this area.Though it approaches service-enabling from semantic web pointof view the industries discussed are quite diverse and veryrelevant to what we are working on.–––––– Page 2 Text book: Enterprise SOA: Service-oriented Architecture Best Practices, D.Krafzig, K. Banke and D. Slama,Prentice-Hall Inc., 2007. WS and SOAFinancial: data and information managementGovernment: access to municipal servicesHealthcare: biomedical research and medical records managementEducation: Course management systemsBusiness: data integration and business process collaborationEnterprise management: knowledge management in steel industryTechnologies such as OWL (Web Ontology Language), RQL,RDQL, SOARQL, and SWRLPage 3IE565 Spring 20081/17/2008SOA and WSIE565 Spring 20081/17/2008SOA Principles A Service-Oriented Architecture (SOA) isa design model for linkingcomputational resources, data andapplications to perform services anddeliver results to service consumers. Web Service (WS) standard provides aplatform-independent method formessaging-based interaction ofapplications.Page 5Page 4IE565 Spring 20081/17/2008 Loosely coupled (service provider and serviceconsumer are loosely coupled: why?) Large scale: complex system with high level of heterogeneity and redundancies.Decoupling of functionality and technologyService contract and agreementsDiscoverabilityOn demand composability of services: compositeservices conceptAgility: respond to changes quicklyStatelessnessInherent interoperabilityStandardsReusabilityPage 6IE565 Spring 20081/17/20081

Evolution of the serviceconceptBusiness Computing A service is ameaningful activity thata computer programperforms on request ofanother computerprogram. Technical definition: Aservice a remotelyaccessible, selfcontained applicationmodule.-- From IBMPage 7IE565 Spring 2008Object/ClassComponentService1/17/2008On to more fundamentalconcepts: Synchronyimmediate response of communicating partnersServer process/thread blocks until response is completedFollows request/response patternUsed when servers are available all the timeTypically communicating partners are tightly coupledExamples:Page 9 request from web client to a web browser for “search” or for“information” CORBA procedure invocation Java RMI (remote method invocation) Traditional remote procedure call (RPC)IE565 Spring 2008Resource Planning (ERP) and Supply ChainManagement (SCM) placed complex requirements onthe computing machines and applications. This was followed by huge compute (IT) demands forEnterprise Application Integration (EAI) andEnterprise Data Integration (EDI). An appealing characteristic of SOA is that it alignsthese business entities by directly mapping them toservices, thus enabling an enterprise integration onthe business level, not on the technical level.Page 8IE565 Spring 20081/17/2008Asynchronous communication Synchronous and asynchronous communications Synchronous:–––––– File systems to main frames Emergence of new paradigms such as Enterprise1/17/2008Interface vs Payload Semantics Communicating partners are decoupled Message driven:– sender creates a message and delivers it to a mediator whothen sends it to “a” recipient– Server need not be available all the time– Sender and receiver loosely coupled– Can facilitate high-performance message-based system– Example: Any event-driven system Any messaging system (instant messenger) Publish-subscribe mode communicationsPage 10IE565 Spring 20081/17/2008Interface Semantics Typically interaction between a client and aProcess1server results in the execution of an activity(ot transaction) Request needs to be specified by the )– Interface semantics: Requested activity can beencoded in the operation signature in the server’s“interface” or– Payload semantics: It can be embedded in themessage itselfreturnResult()Semantics of the activity is explicitly stated in the message/method callPage 11IE565 Spring 20081/17/2008Page 12IE565 Spring 20081/17/20082

Payload SemanticsPayload SemanticsClientEnvelopWithmessageProcess 1QueueServercreateMessage()sendMessage()Process 2onMessage()receiveMessage()Requested transaction/activity is embedded in the messageDetails of the activity not explicit; the semantics are embedded in the messagePage 13IE565 Spring 20081/17/2008Payload semantics is genericTight vs. Loose Couplingdiscovery and binding enabled by UniversalDescription, Discovery and Integration (UDDI) On the business front loose coupling addresses thegrowing need for companies to be flexible and agilewith respect changes in their own processes andthose of their partners How does loose coupling help in improving agility,flexibility and performance?1/17/2008Page 16IE565 Spring 20081/17/2008Service-oriented architecture (1)LevelTight couplingLoose couplingPhysical couplingDirect physical link requiredPhysical ousType systemStrongly typed (interfacesemantics)Weak type system(payload semantics)Interaction patternOO-style navigation of complexobject treesData-centric, self-containedmessagesControl of processlogicCentral control of process logicDistributed logiccomponentsService discoveryand bindingStatically bound servicesDynamically boundservicesPlatformdependenciesStrong OS and programminglanguage dependenciesOS- and programminglanguage dependentIE565 Spring 20081/17/2008loosely coupled system.Tight vs. Loose couplingPage 17IE565 Spring 2008 On the technology front this is driven by dynamicString executeService (message: String){ }IE565 Spring 2008Page 14 An important characteristics of an SOA that is aString transferMoney (amt: decimal,accTo: String){ }Page 15executeMessage() 1/17/2008 From “The new language of business : SOA and Web 2.0” by S. Carter,IBM Press, 2007Service-oriented architecture is a business driven IT architecturalapproach that supports integrating a business as linked, repeatablebusiness tasks or services.It helps– innovation by assuring IT systems can adapt quickly.– increase flexibility of business processes– strengthen underlying IT architecture– reuse their existing IT investments by creating connections amongdisparate applications and information sourcesThe above in turn help address increasing complexity, need forlowering development, integration and maintenance cost and obtainsustainable competitive edge through technology.SOA begins with a service that could be a simple business task such achecking the credit rating of a potential customer.Page 18IE565 Spring 20081/17/20083

Service-oriented Architecture (2)Service-oriented Architecture (3) From “ Service-oriented architecture: concepts,technology and design”. By T. Erl, Prentice-Hall Inc.,2005. Service-oriented architecture is a term thatrepresents a model in which automation logic isdecomposed in to smaller, distinct units of logiccalled services.– Collectively these units comprise a larger piece ofbusiness automation logic. These pieces can bedistributed.– Services are autonomous units; messages areused for communication among these. Principles of SOA: loose coupling, service contract,autonomy, abstraction, reusability, composability,statelessness, discoverabilityFrom “Service-oriented architecture: A planning andimplementation guide for business and technology”, by E.A.Marks, and M. Bell, Wiley & sons, 2006. SOA is a conceptual business architecture where businessfunctionality, or application logic, is made available to SOA usersor consumers, as shared, reusable services on an IT network. Services in an SOA are modules of business or applicationfunctionality with exposed interfaces, and are invoked bymessages. Essential ingredients of an SOA are: services, enablingtechnology, SOA governance and policies, SOA metrics,organizational and behavior model (culture). Page 19IE565 Spring 20081/17/2008Service-oriented architecture (4) From “Service-oriented Architecture (SOA) compass: businessvalue, planning and enterprise roadmap”. N. Bernstein, S. Bose,M. Fiammante, K. Jones and R. Shaw, IBM press, 2006.A service-oriented architecture is a framework for integratingbusiness processes and supporting IT infrastructure as secure,standardized components– services– that can be reused andcombined to address changing business priorities.Loose coupling, reuse, interoperability between systems.SOA is a synonym for solution architectures making use of Webservice technologies such as SOAP, WSDL, and UDDI. Anyproduct and project conforming to the WC3 Web servicesarchitecture (WSA).SOA is a set of business, process, organizational, governanceand technical methods to enable an agile, business-driven ITenvironment for greater competitive advantage.Page 21IE565 Spring 20081/17/2008Service-oriented architecture (6)Page 20IE565 Spring 2008Service-oriented architecture (5) From “Service-oriented architecture for dummies”, by J. Hurwitz, R. Bloor, C. Baroudi, M.Kaufman, Wiley & sons., 2007.Architecture implies thoughtful planning according to set of guidelines or rules. Ex: a house,a mall, Taj Mahal or Noah’s arkSoftware architecture describes the overall design and structure of a computer system.In a service oriented architecture, business services interact with each other in ways similarto how various services of the restaurant interact.Basic architecture of an order processing system and an SOA of a the same. Lets analyzethis further.Architecture 1:Internet ÅÆ Browser ÅÆWeb ServerÅÆOrder ProcessingÅÆDatabase serverÅÆ DatabaseArchitecture 2: SOA?Internet ÅÆ Browser ÅÆWeb ServerÅÆOrder ProcessingÅÆDatabase serverÅÆ DatabaseCredit checking servicePage 22IE565 Spring 2008SOAbest practices” by D. Krafzig, K. Banke, and D.Slama, Prentice-Hall Inc., 2007. A software architecture describes softwarecomponents of a system and assigns the functionalityof the system to these components. greement– It describes the technical structure, constraints, andcharacteristics of the components and the interfacesbetween them.– The architecture is the blueprint for the system andtherefore high-level plan for its construction.– Lets look at example: web architectureIE565 Spring 20081/17/2008Elements of SOA From “Enterprise SOA: Service-oriented architecturePage 231/17/2008ServicerepositoryService busImplementationoperationslegalDataBusiness logicMonitoring1/17/2008Page 24IE565 Spring 20081/17/20084