معماری سرویس گرا (۱)

معماری سرویس گرا (۱)

اسلاید 1: Service-Oriented ArchitectureTerry Woods

اسلاید 2: 2AgendaA little historyWhat is Service-Oriented Architecture?How do you build a Service-Oriented Architecture Solution?What is an Enterprise Service Bus?Summary

اسلاید 3: A Little History

اسلاید 4: 4In the Beginning …Computers were the domain of scientists for scientistsBusiness and Government discovered the value of computingBusiness requirements needed to be captured and programmed

اسلاید 5: 5Some Past Attempts …COBOL – It was designed to be business-problem oriented, machine-independent, and capable of continuous change and development.SQL – The SQL language allows anyone with a computer terminal to access and use relational databases. Originally thought to be an end-user tool.SAD – Structured Analysis and Design (Yourdon/DeMarco)IE – Information engineering (design by pictures) James MartinOOAD – Object-Oriented Analysis and Design

اسلاید 6: 6Revolution …RevolutionCOBOLBasic programming languageC programming languageSQLStructured analyses and designElectronic data exchangeEvolutionWeb ServicesInformation EngineeringCASEC++JavaObject-Oriented Analysis and DesignHTMLCommon Record (XML)EcosystemStandardsSOA

اسلاید 7: What is Service-Oriented Architecture?

اسلاید 8: 8What is Service-Oriented Architecture?Service-Oriented Architecture (SOA) is an architectural style. Applications built using an SOA style deliver functionality as services that can be used or reused when building applications or integrating within the enterprise or trading partners.

اسلاید 9: 9SOAUses open standards to integrate software assets as servicesStandardizes interactions of servicesServices become building blocks that form business flowsServices can be reused by other applications

اسلاید 10: 10What is a Service?A service is a reusable component that can be used as a building block to form larger, more complex business-application functionality.A service may be as simple as “get me some person data,” or as complex as “process a disbursement.”

اسلاید 11: 11What is a Service?A service provides a discrete business function that operates on data. Its job is to ensure that the business functionality is applied consistently, returns predictable results, and operates within the quality of service required.

اسلاید 12: 12What is a Service?How the service is implemented, and how a user of the service accesses it, are limited only by the SOA infrastructure choices of the enterprise.From a theory point of view, it really doesn’t matter how a service is implemented.

اسلاید 13: 13Characteristics of a ServiceSupports open standards for integration: Although proprietary integration mechanisms may be offered by the SOA infrastructure, SOA’s should be based on open standards. Open standards ensure the broadest integration compatibility opportunities.

اسلاید 14: 14Characteristics of a ServiceLoose coupling: The consumer of the service is required to provide only the stated data on the interface definition, and to expect only the specified results on the interface definition. The service is capable of handling all processing (including exception processing).

اسلاید 15: 15Characteristics of a ServiceStateless: The service does not maintain state between invocations. It takes the parameters provided, performs the defined function, and returns the expected result. If a transaction is involved, the transaction is committed and the data is saved to the database.

اسلاید 16: 16Characteristics of a ServiceLocation agnostic: Users of the service do not need to worry about the implementation details for accessing the service. The SOA infrastructure will provide standardized access mechanisms with service-level agreements.

اسلاید 17: 17Legacy Business Process

اسلاید 18: 18Architectural Choke PointMonolithicExtremely complexVery tightly coupledDifficult to find clean integration pointsLack of standards makes it difficult to integrateRigid architecture makes even small changes complex and costly

اسلاید 19: 19SOA Business Process

اسلاید 20: How Do You Build a Service-Oriented Architecture Solution?

اسلاید 21: 21IT Infrastructure is an EcosystemCOBOLC++JavaJ2EENetworksTCP/IPWeb ServiceMid-Tier Servers.NETMessagingHTMLOperating SystemsCICSRoutersDatabasesMainframes

اسلاید 22: 22Managing the EcosystemTechnology ManagementProduct duplicationStandardsProduct/Vendor lock-inSupport skill setsVersion ManagementManaged EvergreeningLimited versions in production

اسلاید 23: 23Legacy Integration

اسلاید 24: 24SOA Integration

اسلاید 25: 25Integration StackIndustry StandardsLanguage StandardsCustom API’sNative Interfaces

اسلاید 26: Enterprise Service Bus

اسلاید 27: 27What is an Enterprise Service Bus (ESB)?An enterprise service bus is an infrastructure used for building compound applicationsThe enterprise service bus is the glue that holds the compound application togetherThe enterprise service bus is an emerging style for integrating enterprise applications in an implementation-independent fashionAn enterprise service bus can be thought of as an abstraction layer on top of an Enterprise Messaging System

اسلاید 28: 28Key Characteristics of an ESBStreamlines developmentSupports multiple binding strategiesPerforms data transformationIntelligent routingReal time monitoringException handlingService security

اسلاید 29: 29What is an ESB?In its simplest form:An ESB delivers a message from one point to another.Don’t EAI’s already do this?

اسلاید 30: 30EAI LimitationsAn EAI can be a tightly coupled solution An EAI can be location-specificAn EAI can be based on proprietary transport technology

اسلاید 31: 31Let’s Walk Through the ESBGet Person DataUse Standard Student Identification Method (SSIM) identifiers to find the personReturn the Person DataThis is a fictional-use case, and is only intended to illustrate how an ESB would provide a service.

اسلاید 32: 32The ESB BoundariesThe ESB (in its simplest form) is responsible for getting a message from point A to point B.

اسلاید 33: 33Get the Message on the BusA binding component “speaks” the service’s protocol, which happens to be SOAP over JMS.

اسلاید 34: 34Perform the Person ReadThe request is now routed to the Get Person Data Service, which will perform the business logic.

اسلاید 35: 35Do the SSIM LookupA call is made to the SSIM service to perform a lookup of the Student Identifier (SID). The SSIM service lives inside the bus.Note: The SSIM binding components are not shown so the diagram can remain simple.

اسلاید 36: 36Return the Person DataThe process is reversed, returning the response to the requester.

اسلاید 37: 37ESB SummaryLoose CouplingLocation TransparencyTransport Neutral

اسلاید 38: 38Defining the MessageWeb Services Description LanguageOpen Standard for describing Interfaces to Services (http://www.w3.org/TR/wsdl)CharacteristicsDescribes data expected to be sent and receivedDescribes what the service can doDescribes how to reach the serviceWSDL description is an XML document

اسلاید 39: 39Message-Exchange PatternsOne-way. The endpoint receives a message. Request-response. The endpoint receives a message, and sends a correlated message. Solicit-response. The endpoint sends a message, and receives a correlated message. Notification. The endpoint sends a message.

اسلاید 40: Building a Compound Application

اسلاید 41: 41The Ingredients

اسلاید 42: 42Business Processes FlowBusiness processes are a set of activities, supported by services, that support a particular business activity. Business processes are business services built using other business services.Business Process Execution Language (BPEL) is a specification for describing business processes in a portable XML format. BPEL is widely supported in both commercial and open source products.BPEL defines how services interact to form complex business process. It provides a unit of work context, fault handling, and compensation (transaction rollback).

اسلاید 43: 43BPEL

اسلاید 44: 44What BPEL does …BPEL binds services together to form larger complex business servicesControl Flow (branch, loop, parallel)Asynchronous correlationTransaction support, Units of WorkCompensation

اسلاید 45: 45Sample ESB Custom Services Transformation Services Orchestration Routing Application Server

اسلاید 46: 46SummaryWhat is Service-Oriented Architecture?How do you build a Service-Oriented Architecture solution?What is an Enterprise Service Bus?

اسلاید 47: 47We appreciate your feedback and comments. We can be reached at:Phone: 202 377 3023Email: Terry.Woods@ed.govContact Informatio