The Open Group SOA Ontology Technical Standard. Clive Hatton

Transcription

1 The Open Group SOA Ontology Technical Standard Clive Hatton

2 The Open Group Releases SOA Ontology Standard To Increase SOA Adoption and Success Rates Ontology Fosters Common Understanding of SOA Concepts to Improve Alignment Between Business and IT SAN FRANCISCO, December 8, The Open Group today announced the availability of the Service Oriented Architecture (SOA) Ontology Technical Standard to develop and foster a common understanding between business and information technology (IT) communities regarding SOA concepts and terminology. Produced by the members of the Open Group s SOA Work Group, the ontology defines the concepts, terms and semantics of SOA in a common language that will allow for more precise and straightforward communications and facilitate SOA adoption without ambiguity. 3

3 Content What is SOA? How does it relate to other standards? Why an Ontology for SOA? Who will use it? Why now? How will it be used? Where does it apply? What is an Ontology? What does it describe? 4

4 SOA Principles Thomas Erl Standardised Service Contracts Service Loose Coupling Service Abstraction Service Re-usability Service Autonomy Service Statelessness Service Discoverability Service Composability Services within the same service inventory are in compliance with the same contract design standards Service contracts impose low consumer coupling requirements and are themselves decoupled from their surrounding environment Service contracts only contain essential information and information about services is limited to what is published in service contracts Services contain and express agnostic logic and can be positioned as reusable enterprise resources Services exercise a high level of control over their underlying runtime execution environment Services minimize resource consumption by deferring the management of state information when necessary Services are supplemented with communicative meta data by which they can be effectively discovered and interpreted Services are effective composition participants, regardless of the size and complexity of the composition 6

5 Key Features of SOA Services Service re-use Service composition Service discovery Messaging Message monitoring Message control Message transformation Message security Events Complex Event Processing Asset wrapping Virtualisation Model-driven implementation 7

6 Why an Ontology for SOA? "A lack of mutually agreed-upon SOA terms, definitions and concepts can create interoperability issues that inhibit end-to-end business activities within an organization - as well as between vendor, customer, and partner organizations. By providing common terminology and concept mapping that business and technical people may employ to discuss problems and opportunities, the ontology bridges different architecture, engineering, business and marketing domains. It also creates a foundation for further work in domain-specific areas by supplying a consistent framework that can be reused and revised as SOA projects evolve." 8

7 Why Now? The ontology is the result of years of implementation work and lessons learned. "It is grounded in extensive real-world experience developing, deploying and communicating about SOA solutions over the past five years. The Ontology reflects the lessons learned about what terms NOT to use to avoid confusion, and how to best distinguish among some common and often overused concepts like service composition, process, service contracts, and policy and their roles in SOA." 9

8 SOA Standards Landscape WHITEPAPER Explain & position standards for SOA reference models; ontologies; maturity models; modelling languages; standards work on SOA governance 10

9 Audiences for SOA standards Business Architects & Analysts Developers / Practitioners Customers / SOA Adoptors Standards Organizations Analysts Architects 11

10 Specifications White Paper OASIS Reference Model The Open Group SOA Reference Architecture OASIS Reference Architecture The Open Group SOA Governance Framework SOA Open Standards OMG SoaML Specification The Open Group Service Integration Maturity Model The Open Group SOA Ontology 12

11 Working Groups 13

12 SOA Standards Positioning 14

13 Technical Products: Influence 15

14 Governance Information Quality of Service Integration Service interaction, Chaining and Compos ition in a runtime SOA environment The Open Group SOA Reference Architecture Consumer Interfaces Business Processes Services Service Components Operational Systems 16 (C) The Open Group 2009

15 Ontologies Ontologies are useful to ensure that information items are defined in a standard and coherent manner, across teams. Ontologies formally describe the elements of and provide a language for both reference models and reference architectures. An explicit formal specification of the terms in the domain and relations among them. In the context of computer and information sciences, an ontology defines a set of representational primitives with which to model a domain of knowledge or discourse. The representational primitives are typically classes (or sets), attributes (or properties), and relationships (or relations among class members). Denoting an artefact that is designed for a purpose, which is to enable the modelling of knowledge about some domain, real or imagined. 17

16 Examples of Ontologies Zachman Framework 18

17 The Open Group SOA Ontology Intended to: Facilitate understanding of terms & concepts Facilitate model-driven implementation Enables: Automation & tools for processing Integration with other concerns Represented by OWL 19

18 SOA Ontology Graphical Overview 20

19 SOA Ontology Class Hierarchy 21

20 SOA Ontology Element An element is an opaque entity. The element has a clearly defined boundary. Element In the context of the SOA ontology we consider in detail only functional elements that belong to the SOA domain. System Human Actor Task Service 22

21 SOA Ontology System and Element Uses Element Is used by A system is an organized collection of other things. Specifically things in a system collection are instances of Element, each such instance being used by the system. System 23

22 Car Wash Example System and Element Car Wash Business instance of System Is used by (owner of) Joe (owner) instance of Human Actor Is used by (employee of) Mary (secretary) instance of Human Actor Is used by (employee of) John (prewash guy) instance of Human Actor Is used by (employee of) Jack (washing manager and operator) instance of Human Actor 24

23 Represents Abstraction Represents Element Represented by Broker Represents Seller Three examples (instances of element) Person Represented by Role Blueprint Represents Buildings 25

24 Car Wash Example External and Internal Views External View Car Wash Business Car Wash Business Internal View Administration Represents Administrative System Uses Uses Joe Mary Car Wash Represents Car Wash System Uses Uses John Jack 26

25 Human Actor and Task A human actor is a person or an organization. Human Actor Element Does Is Done By Task A task is an atomic action which accomplishes a defined result. Tasks are done by people or organizations, specifically by instances of Human Actor. 27

26 Car Wash Example Human Actor and Task John Does Wash Windows Jack Does Push Wash Button 28

27 Service Element Is Performed By Performs 29 A service is a logical representation of a repeatable activity that has a specified outcome. It is self-contained and is a black box to its consumers. Service In the context of the SOA ontology we consider only SOA-based services. Other domains, such as Integrated Service Management, can have services that are not SOA-based and hence are outside the intended scope of the SOA ontology.

28 Doing a Task and Performing a Service John (Human Actor) Does Wash Windows (Task) Uses Soap Water (Service) Performs Water Tap (Element) 30

29 Car Wash Example Represents and Performs Gold Wash (Service) Wash Manager Represents Performs Car Wash (Element) (System) Basic Wash (Service) 31

30 Service Contract and Service Interface Human Actor Legal Agreement Aspects Interaction Aspects Involves Party Has Contract With Service Contract Service Is Party To Is Contract For 32

31 Effect Interacting with something performing a service has effects. These comprise the outcome of that interaction, and are how a service (through the element that performs it) delivers value to its consumers. Service Contract Specifies Is Specified By Effect 33

32 Car Wash Example The Washing Services 34

33 Service Interface An important characteristic of services is that they have simple, well-defined interfaces. This makes it easy to interact with them, and enables other elements to use them in a structured manner. A service interface defines the way in which other elements can interact and exchange information with a service. Service Interface Is Interface Of Has Interface Service 35

34 Information Type A service interface can enable another element to give information to or receive information from a service (when it uses that service); specifically the types of information given or received. Service Interface Has Input Has Output Is Input At Is Output At Information Type 36

35 Composition A composition is the result of assembling a collection of things for a particular purpose. Note in particular that we have purposefully distinguished between the act of composing and the resulting composition as a thing, and that it is in the latter sense we are using the concept of composition here. Orchestrates Element System Composition Orchestrated By 37

36 Service Composition and Process A key SOA concept is the notion of service composition, the result of assembling a collection of services in order to perform a new higherlevel service. Composition Another key SOA concept is the notion of process. A process is a composition whose elements are composed into a sequence or flow of activities and interactions with the objective of carrying out certain work. Service Composition Process 38

37 Car Wash Example The Washing Processes 39

38 Policy A policy is a statement of direction that a human actor may intend to follow or may intend that another human actor should follow. Is Set By Human Actor Policy Sets Policy Knowing the policies that apply to something makes it easier and more transparent to interact with that something. Is Subject To Thing Applies To 40

39 Car Wash Example Policy and Contract Gold Wash (Service) Payment Upfront Applies To (Policy) Basic Wash (Service) Is Contract For Basic Wash Contract (Contract) 41

40 Event An event is something that happens, to which an element may choose to respond. Events can be responded to by any element. Similarly, events may be generated (emitted) by any element. Knowing the events generated or responded to by an element makes it easier and more transparent to interact with that element. Note that some events may occur whether generated or responded to by an element or not. Responded To By Event Generated By Responds To Generates Element 42

41 Internet Purchase Example External View Does Purchase TV (Task) Jill Uses Buy TV Online (Human Actor) (Service) Does Pay For TV (Task) Has Is Party To Buy TV Online Contract (Service Contract) Online TV Sales (Organisation Actor) Does Deliver TV (Task) 43

42 Internet Purchase Example Internal View Select What to Buy Component (Element) Performs Select What to Buy Service (Service) Uses Online Sales Component (Element / Service Composition) Pay Component Performs Pay Service (Element) (Service) 44

43 Internet Purchase Example Process View Online TV Sales Process (Process) Uses Jill (Human Actor) Purchase TV (Task) Pay For TV (Task) Deliver TV (Task) Online TV Sales (Organisation Actor) Uses Buy TV Online (Service) 45

44 Conformance OWL Application Must conform to the OWL standard Must include (in the OWL sense) the whole of the ontology Can add other OWL constructs, including class and property definitions Can import other ontologies in addition to the SOA ontology Non-OWL (Meta-model or Software) Must include a defined and consistent transform to a nontrivial subset of the ontology contained in Appendix A of this Technical Standard Can add other constructs, including class and property definitions Can leverage other ontologies in addition to the SOA ontology 46

45 References www2.opengroup.org/ogsys/jsp/publications/publicationdetails.jsp?catalo gno=c104 Catalog number C104 US ISBN Oct 90 pages 47

46 Governance Information Quality of Service Integration Service interaction, Chaining and Compos ition in a runtime SOA environment The Open Group SOA Reference Architecture Consumer Interfaces Business Processes Services Service Components Operational Systems 48 (C) The Open Group 2009

47 Governance Information Quality of Service Integration Service interaction, Chaining and Compos ition in a runtime SOA environment SOA RA Operational Systems Layer Consumer Interfaces Business Processes Services Service Components Contains existing application assets and other programs. I.e. Programs and data of the operational systems of the enterprise. Operational Systems 49 (C) The Open Group 2009

48 Governance Information Quality of Service Integration Service interaction, Chaining and Compos ition in a runtime SOA environment SOA RA Service Components Layer Consumer Interfaces Business Asset Processes wrapping and virtualization features of SOA are supported by building blocks Services in this layer Enables IT flexibility by strengthening decoupling. Decoupling is achieved by hiding volatile implementation details from consumers. Service Components Operational Systems 50 (C) The Open Group 2009

49 Governance Information Quality of Service Integration Service interaction, Chaining and Compos ition in a runtime SOA environment SOA RA Services Layer The building Consumer blocks in this layer include: Services Interfaces Compositions Service Business descriptions, contracts, and policies Processes Services Service Components Operational Systems 51 (C) The Open Group 2009

50 Governance Information Quality of Service Integration Service interaction, Chaining and Compos ition in a runtime SOA environment SOA RA Business Processes Layer Building blocks in this layer include: Business processes Compositions of business processes and services Consumer Information created or used by business processes Interfaces Business Processes Services Service Components Operational Systems 52 (C) The Open Group 2009

51 Governance Information Quality of Service Integration Service interaction, Chaining and Compos ition in a runtime SOA environment SOA RA Consumer Interfaces Layer Consumer Interfaces Business Processes Services Building blocks in this layer include: Service consumers (people, organizations, and programs) Interface programs (channels, portals and format converters) User profiles and interface configurations. Service Components Operational Systems 53 (C) The Open Group 2009

52 Governance Information Quality of Service Integration Service interaction, Chaining and Compos ition in a runtime SOA environment SOA RA Integration Layer Consumer Interfaces Gives the ability to decouple service providers and Business consumers, which adds flexibility Processes to the architecture. Services Service Components Operational Systems Messaging, message transformation, event processing, composition and service discovery features of SOA are supported by this layer. 54 (C) The Open Group 2009

53 Governance Information Quality of Service Integration Service interaction, Chaining and Compos ition in a runtime SOA environment SOA RA Quality of Service Layer Consumer Interfaces Business Processes Message monitoring, message control, and message security features of SOA are supported by building blocks in this layer. Services Service Components Operational Systems 55 (C) The Open Group 2009

54 Governance Information Quality of Service Integration Service interaction, Chaining and Compos ition in a runtime SOA environment SOA RA Information Layer Consumer Interfaces Business Processes The message transformation feature of SOA is supported by building blocks in this layer Services Service Components Includes building blocks such as: Information models Vocabularies Data models Operational Systems 56 (C) The Open Group 2009

55 Governance Information Quality of Service Integration Service interaction, Chaining and Compos ition in a runtime SOA environment SOA RA Governance Layer Consumer Interfaces Business Processes Services Service Components Operational Systems Includes building blocks such as: Governance rules and procedures Services and programs that support the application of the rules and the operation of the procedures 57 (C) The Open Group 2009